# Healthy Lifestyle in the First 1000 Days and Overweight and Obesity Throughout Childhood

Adrien M Aubert, Marion Lecorguillé, Mireille C Schipper, Alexander Douglass, Cecily C Kelleher, Sandrine Lioret, Barbara Heude, Romy Gaillard,

Catherine M Phillips

► To cite this version:

Adrien M Aubert, Marion Lecorguillé, Mireille C Schipper, Alexander Douglass, Cecily C Kelleher, et al.. Healthy Lifestyle in the First 1000 Days and Overweight and Obesity Throughout Childhood.

Pediatrics, 2025, 155 (2), 10.1542/peds.2024-066406, hal-05042786

HAL Id: hal-05042786

https://hal.science/hal-05042786v1

Submitted on 22 Apr 2025

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**Healthy lifestyle in the first 1000 days and overweight and obesity throughout childhood.**

Adrien M. Aubert¹ (0000-0002-5738-1997), PhD, Marion Lecorguillé² (0000-0002-6915-533X), PhD, Mireille C. Schipper³,⁴ (no ORCiD iD), MSc, Alexander Douglass¹ (0000-0003-0254-1217), PhD, Cecily C. Kelleher¹ (0000-0001-9548-4914), MD, PhD, Sandrine Lioret² (0000-0002-2483-7820), PhD, Barbara Heude² (0000-0002-1565-1629), PhD, Romy Gaillard³,⁴ (0000-0002-7967-4600), MD, PhD, and Catherine M. Phillips¹ (0000-0003-4916-4463), PhD

**Affiliations:**

¹School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland; adrien.aubert@ucd.ie (A.M.A.); alexander.douglass@ucd.ie (A.D.); cecily.kelleher@ucd.ie (C.C.K.); catherine.phillips@ucd.ie (C.M.P.)

²Université Paris Cité and Université Sorbonne Paris Nord, Inserm, INRAE, Centre for Research in Epidemiology and StatisticS (CRESS), F-75004 Paris, France; marion.lecorguille@inserm.fr (M.L.); sandrine.lioret@inserm.fr (S.L.); barbara.heude@inserm.fr (B.H.)

³The Generation R Study Group (Na 29-15), Erasmus University Medical Center, PO BOX 2040, 3000 CA, Rotterdam, The Netherlands; m.c.schipper@erasmusmc.nl (M.C.S.); r.gaillard@erasmusmc.nl (R.G.)

⁴Department of Pediatrics, Erasmus MC, University Medical Center, Rotterdam, the Netherlands.

**Corresponding Author:**

Adrien M. Aubert

School of Public Health, Physiotherapy and Sports Science, University College Dublin, Belfield, Dublin 4, Ireland.

E-mail: adrien.aubert@ucd.ie

**Short title:**

Lifestyle in the first 1000 days and offspring obesity

**Conflict of Interest Disclosures:**

All authors declare no support from any organisation for the submitted work other than those described above; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
**Funding/Support:**

The EndObesity project was founded by the European Union's Horizon 2020 research and innovation programme under the ERA-NET Cofund action (no 727565) through the Joint Programming Initiative “A Healthy Diet for a Healthy Life” (JPI HDHL)-INTIMIC call “Prevention of unhealthy weight gain and obesity during crucial phases throughout the lifespan (PREPHOBES)”. University College Dublin was supported by the Irish Health Research Board (ref JPI ERA NET HDHL INTIMIC 2020-1).

The **EDEN** study was supported by Foundation for medical research (FRM), National Agency for Research (ANR), National Institute for Research in Public health (IRESP: TGIR cohorte santé 2008 program), French Ministry of Health (DGS), French Ministry of Research, INSERM Bone and Joint Diseases National Research (PRO-A), and Human Nutrition National Research Programs, Paris-Sud University, Nestlé, French National Institute for Population Health Surveillance (InVS), French National Institute for Health Education (INPES), the European Union FP7 programs (FP7/2007-2013, HELIX, ESCAPE, ENRIECO, Medall projects), Diabetes National Research Program (through a collaboration with the French Association of Diabetic Patients (AFD)), French Agency for Environmental Health Safety (now ANSES), Mutuelle Générale de l'Éducation Nationale a complementary health insurance (MGEN), French national agency for food security, and French-speaking association for the study of diabetes and metabolism (ALFEDIAM).

The **Elfe** survey is a joint project between the French Institute for Demographic Studies (INED) and the National Institute of Health and Medical Research (INSERM), in partnership with the French blood transfusion service (Etablissement français du sang, EFS), Santé publique France, the National Institute for Statistics and Economic Studies (INSEE), the Direction générale de la santé (DGS, part of the Ministry of Health and Social Affairs), the Direction générale de la prévention des risques (DGPR, Ministry for the Environment), the Direction de la recherche, des études, de l'évaluation et des statistiques (DREES, Ministry of Health and Social Affairs), the Département des études, de la prospective et des statistiques (DEPS, Ministry of Culture), and the Caisse nationale des allocations familiales (CNAF), with the support of the Ministry of Higher Education and Research and the Institut national de la jeunesse et de l'éducation populaire (INJEP). Via the RECONAI platform, it receives a government grant managed by the National Research Agency under the “Investissements d'avenir” programme (ANR-11-EQPX-0038, ANR-19-COHO-0001).

The general design of the **Generation R Study** is made possible by financial support from the Erasmus Medical Center, Rotterdam, Erasmus University Rotterdam, the Netherlands Organization for Health Research and Development (ZonMw), the Netherlands Organisation for Scientific Research (NWO), the Ministry of Health, Welfare and Sport, and the Ministry of Youth and Families. R.G. received funding from the Netherlands Organisation for Health Research and Development (NOW, ZonMw 05430052110007; NOW, ZonMw VIDI 09150172110034).

The **Lifeways cross-generation cohort** was supported by the Irish Health Research Board (reference HRC/2007/13) and is overseen by an inter-disciplinary steering group. The funders have no role in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication.
If applicable, Clinical Trial registry name, registration number, and data sharing statement:

**Clinical Trial registry name and registration number:**

Not applicable.

**Data sharing:**

The datasets analysed during the current study are not publicly available due to health data protection but can be made available upon request pending application to the corresponding author, the signing of the appropriate data sharing agreement, and approval by the different cohort's committee.

**Abbreviations:**

BMI, Body mass index

CI, Confidence interval

COSI, Childhood Obesity Surveillance Initiative

DASH, Dietary Approaches to Stop Hypertension

DOHaD, Developmental Origins of Health and Disease

EDEN, The study on the pre- and early postnatal determinants of child health and development

Elfe, The French national birth cohort

FFQ, Food frequency questionnaire

Generation R, The Generation R Study

HLS, Healthy lifestyle score

IOTF, International Obesity Task Force

ISCED, International Standard Classification of Education

Lifeways, The Lifeways Cross-Generation Cohort Study

OWOB, Overweight and obesity

RR, Risk ratio

SD, Standard deviation

WHO, World Health Organization

WHtR, Waist-to-height ratio

**Article Summary:**

This study investigates associations of different family healthy lifestyle scores during the first 1,000 days with the risk of offspring overweight-obesity throughout childhood.

**What's Known on This Subject:**

The high prevalence of overweight-obesity in early childhood suggests the involvement of early-life exposures, with potentially modifiable early-life risk factors existing at the family level. Most research to date has analysed familial factors individually and focused mainly on the mother.

**What This Study Adds:**

Greater maternal and parental adherence to healthy lifestyle behaviours during pregnancy was associated with a lower risk of offspring overweight-obesity throughout childhood. These results illustrate the importance of promoting healthy lifestyle behaviours at the family-level during pregnancy.
**Contributors Statement Page:**

Aubert designed and conducted the research, performed the data analyses, and wrote the article.

Lecorguillé and Schipper performed the data analyses, and revised the article critically for
important intellectual content.

Douglass, Kelleher, Lioret, Heude and Gaillard contributed to data collection, oversaw data management and quality, and revised the article critically for important intellectual content.

Phillips designed and supervised the research, and wrote the article.

All authors read and approved the final manuscript as submitted and agree to be accountable
for all aspects of the work.
**Abstract**

***Objectives***

Investigate associations of different family healthy lifestyle scores (HLS) during the first 1,000
days with childhood overweight-obesity (OWOB).

***Methods***

Cohort-specific analyses were conducted on participants (n=25,006) from 4 European birth
cohorts (The study on the pre- and early postnatal determinants of child health and development
[EDEN], Elfe, France; Generation R, the Netherlands; and Lifeways, Ireland). Three composite
HLS were calculated: a maternal pregnancy HLS based on pre-pregnancy body mass index
(BMI) and diet quality, physical activity, smoking status and alcohol consumption during
pregnancy; a parental pregnancy HLS additionally considering paternal BMI and smoking
status; and an infancy HLS based on breastfeeding duration, age of solid food introduction and
exposure to passive smoking. Associations with child BMI (primary outcome) and waist-to-
height ratio (WHtR, available in two cohorts) in early (5-5.5 years), mid- (7-8 years) and late
childhood (9-12 years) were assessed using linear (BMI and WHtR z-scores) and robust Poisson
(IOTF categories) regression analyses, adjusted for sociodemographic confounders.

***Results***

Only a small proportion of families had favourable lifestyle factors during pregnancy and early
infancy, with 3.4-10.0%, 1.9-3.7% and 12.2-23.6% scoring maximum for maternal, parental
and infancy HLS, respectively. Associations between higher HLSs and a lower risk of OWOB
when measured by BMI z-scores or IOTF categories were found for maternal HLS and early
(3/4 cohorts with available data), mid- (1/2) and late childhood (2/4); parental HLS and early
(3/4), mid- (2/2) and late childhood (4/4). Associations between infancy HLS and childhood
OWOB were less consistent and did not remain significant after additional adjustment for
parental HLS. Associations with WHtR were solely significant in EDEN at 5.5 years.

***Conclusions***

Greater maternal and parental adherence to healthy lifestyle behaviours during pregnancy was
associated with a lower risk of offspring OWOB throughout childhood; illustrating the
importance of promoting healthy lifestyle behaviours at the family-level during pregnancy.

**Key words:** healthy lifestyle score; DOHaD/POHaD; childhood overweight and obesity; obesity prevention
**Introduction**

Overweight and obesity (OWOB) impact more than 350 million children and adolescents
worldwide,¹,² including almost 40 million children below 5 years of age.³ Paediatric obesity is
linked with a range of metabolic risk factors, and can affect physical health and emotional
well-being in childhood.⁴⁻⁸ For the majority, childhood obesity tracks into adulthood,⁹⁻¹¹ with
multiple well established long-term consequences (e.g., certain types of cancer,
cardiovascular diseases or type 2 diabetes) which are major drivers of healthcare costs.¹²⁻¹⁵
Thus, childhood obesity represents a serious global public health issue. The World Obesity
Federation projects that the greatest increase in obesity prevalence will be among children and
adolescents, rising from 10% to 20% of the world's boys during the period 2020 to 2035, and
rising from 8% to 18% of the world's girls.¹⁶

The high prevalence of OWOB which is evident from early childhood suggests the
involvement of early-life exposures; in line with the Developmental Origins of Health and
Disease (DOHaD) paradigm which postulates that exposures during the periconceptional
period may alter health and development later in childhood and adulthood.¹⁷⁻¹⁹ Addressing
this hypothesis much of the research to date has focused on individual maternal factors,
identifying associations of maternal health related factors (pregnancy diet quality, dietary
inflammatory potential, smoking status, physical activity level and weight status) with
childhood OWOB risk.²⁰⁻²⁵ Few studies have considered the more recently proposed Paternal
Origins of Health and Disease hypothesis, investigating the potential influence of paternal
lifestyle behaviours.²⁶⁻²⁸ Although OWOB is a multifactorial disease with a complex
aetiology,²⁹ up to 50% of childhood OWOB could be attributed to potentially modifiable
early-life risk factors at the family level.³⁰,³¹ Family lifestyle behaviours are often correlated
and multiple unhealthy behaviours may co-occur and contribute synergistically to OWOB
development.³²⁻³⁵ Furthermore, some studies have suggested that offspring early-life dietary
exposures such as breastfeeding or age of solid food introduction are associated with weight gain in infancy and body mass index (BMI) later in life.<sup>36,37</sup>

Pregnancy and the arrival of a baby is a period when changes in lifestyle habits may occur; mothers/parents have increased motivation to improve their health and lifestyle, and thus pregnancy is considered as a “teachable moment” for behaviour change and represents a unique window of opportunity for prevention interventions.<sup>38,39</sup> Improve our knowledge of the early-life modifiable factors that drive childhood OWOB, considered collectively as part of overall lifestyle, rather than individually, is necessary.<sup>40</sup> Addressing this important gap in the knowledge, we analysed >25,000 participant data from four European birth cohorts, to determine maternal, paternal and infancy a priori healthy lifestyle scores (HLS) during the first 1,000 days (from conception to two years of age) and examine their associations with offspring adiposity and weight status in early, mid- and late childhood.

## Methods

### *Study Design and Participants*

This study used data from four European birth cohorts conducted in three European countries (France, the Netherlands, and Ireland) participating in the EndObesity project which aims to prevent childhood OWOB by targeting family-based lifestyle factors in the first 1,000 days (https://www.healthydietforhealthylife.eu/project/endobesity): the study on the pre- and early postnatal determinants of child health and development (EDEN, France), the French national birth cohort (Elfe, France), the Generation R Study (Generation R, the Netherlands), and the Lifeways Cross-Generation Cohort Study (Lifeways, Ireland). Main characteristics of each of the cohorts are presented in **Table 1** and further details published elsewhere.<sup>41–46</sup> Data were collected from cohort-specific self-administered or face-to-face questionnaires at inclusion,
during the post-birth maternity time, and during the different follow-ups. Variables used in
this research have been previously harmonised as part of the H2020 LifeCycle and ERA-Net
HDHL ALPHABET projects.⁴⁷,⁴⁸ Details regarding the data collection of the healthy lifestyle
factors in the different cohorts are presented in **Supplemental Table 1**.

Parental and infancy healthy lifestyle scores

The 5-item maternal HLS was defined based on maternal diet quality (Dietary Approaches to Stop Hypertension [DASH] score within the top 40% (i.e., 25 in all cohorts),⁴⁸ physical activity level (≥450 MET-min of moderate-to-vigorous intensity), smoking status (non-smoker) and alcohol consumption (non-consumer) during pregnancy as well as pre-pregnancy BMI (18.5-24.9 kg/m²).⁴⁹ The 7-item parental HLS additionally included paternal smoking status (non-smoker) and paternal BMI (18.5-24.9 kg/m²) during pregnancy. The 3-item infancy HLS was defined based on breastfeeding duration (any breastfeeding up to 6 months), age of solid food introduction (no food introduction <4 months or first introduction ≥7 months),⁵⁰ and any exposure to passive smoking during the first year of life (not exposed).

Consistent with previous studies we assigned a score of 1 for each of the protective lifestyle
criteria and 0 if the participant did not meet the criterion. The HLS was the sum of these
scores with a range of 0-5, 0-7 and 0-3 for maternal, parental and infancy HLSs, respectively.

Maternal physical activity level during pregnancy was not available in Generation R so the
maternal and parental HLS were composed of 4 and 6 items, respectively. For each HLS a
higher score denoted greater adherence to healthy lifestyle/more protective lifestyle
behaviours.⁵¹,⁵²
## Childhood OWOB

The International Obesity Task Force (IOTF) references and cut-offs were used to determine the primary outcomes (BMI z-scores and define OWOB), taking child sex and age into account.⁵³ BMI categories were dichotomized as underweight and normal weight (grouped together) versus OWOB. In addition, waist-to-height ratio (WHtR) z-scores, generated from waist circumference divided by height (both in cm) and then standardized (internally for each cohort), was used as a complementary measure of abdominal adiposity, relatively independent of sex, age, and race,⁵⁴ in EDEN and Lifeways.

## Covariates

The following covariates were considered as potential confounders and harmonized for subsequent analyses: maternal parity, maternal and paternal age, educational level, employment status, country of birth, and household income.

## Statistical analyses

We first described characteristics of participants included in the sample and the distribution of the different HLS. Associations between the different HLS and child BMI and WHtR were assessed using robust Poisson (for IOTF categories) and linear (for BMI z-scores and WHtR z-scores) regression models: (1) unadjusted; (2) adjusted for parental confounders. For the infancy HLS, we also studied a third model additionally adjusted for parental HLS (total score), which could be considered as a confounder associated with both infancy HLS (lifestyle behaviours, health literacy) and childhood OWOB (other results reported later).⁵⁵⁻⁵⁸ Missing data for covariates were imputed using multiple imputation by chained equations (20
imputed datasets, using "MICE" R package).⁵⁹ Imputation and analyses were conducted
within each cohort separately.

Descriptive analyses were carried out using the statistical software Stata (StataCorp
LLC), SAS (SAS Institute Inc), or R Studio (Posit Software), depending on the cohort,
whereas the imputation and the regression analyses were carried out using R Studio.
Statistical significance was defined as a two-sided p-value <0.05.

## Results

### Participant characteristics

Maternal, paternal and child characteristics are presented in **Table 2**. The mean (±SD) maternal age ranged from 29.5 (±4.9) to 30.8 (±5.1), and paternal age was on average slightly higher. High educational level ranged from 47.3% to 59.5% for mothers and from 44.2% to 52.7% for fathers. With the exception of Generation R where a majority of the mothers were primiparous (58.4%), around 45% of the mothers were primiparous in the three other cohorts.

In Generation R, 71.1% of the women were born in the cohort country, whereas it was the case for 90.0% and 96.1% of mothers in Elfe and EDEN, respectively. During pregnancy, 19.9% to 26.9% of the women smoked, and 39.7% to 56.0% drank alcohol. Although, the proportion of women with normal pre-pregnancy BMI was relatively close between the four cohorts (from 65.3% to 68.9%), it was not the case for paternal BMI: between 50.1% and 55.1% in EDEN, Elfe and Generation R, but only 30.9% in Lifeways with a BMI in normal range.

For child and infancy characteristics, there was almost equal gender representation,
and 28.6% to 56.1% have been exposed to any passive smoking during their first year of life.
The average duration of breastfeeding ranged from 2.6 (±3.1) months in Lifeways to 4.4
(±3.8) months in Generation R, and the mean age of solid food introduction was between 4 and 5 months in the four cohorts. Based on IOTF categories, the proportion of children living with OWOB was 7.6-11.7% in EDEN, 8.0-10.4% in Elfe, 16.2-16.8% in Generation R, and 26.3-27.5% in Lifeways, depending on the age of assessment.

## Distribution of the maternal, parental and infancy HLS

The distribution of the different HLSs by cohort is presented in **Table 3**. Regarding the maternal pregnancy HLS, 3.4% to 5.0% of the mothers had a HLS of 5/5 (10.0% with a HLS of 4/4 in Generation R), determined by a normal pre-pregnancy BMI, a good diet quality, a high physical activity level (except in Generation R) as well as not smoking or drinking alcohol during pregnancy. Only 1.9% to 2.4% of the participants had a parental pregnancy HLS of 7/7 (3.7% with a HLS of 6/6 in Generation R). For the infancy HLS, 12.2% to 23.6% of the participants had a HLS of 3/3, determined by any breastfeeding up to 6 months, solid food introduction between 4 and 6 months, and no exposure to passive smoking during the first year of life.

## HLS associations with offspring OWOB

Results of regression analyses revealed several consistent associations between the different HLSs and childhood BMI z-scores (Figure 1 and Supplemental Table 2). Maternal pregnancy HLS was inversely associated with childhood BMI z-scores in EDEN (at 5.5 years only), in Elfe (at 5, 7 and 9 years) and Generation R (at 5 and 9 years), with adjusted changes in BMI z-scores (95% CI) ranging from -0.04 (-0.08, -0.01) to -0.07 (-0.10, -0.03), for each additional HLS point. Associations were non-significant for the other periods (EDEN at 8 and 12 years) and cohorts (Lifeways both at 5 and 9 years). Parental pregnancy HLS was inversely associated with childhood BMI z-scores in all cohorts and periods, except in
Lifeways at 5 years, with changes ranging from -0.06 (-0.10, -0.02) to -0.15 (-0.29, -0.01).

Infancy HLS was associated with childhood BMI z-scores in EDEN (at 12 years only), Elfe (at 5 and 7 but not at 9 years) and Generation R (at 5 and 9 years). However, these associations between the infancy HLS and childhood BMI z-scores did not remain significant after additional adjustment for parental HLS.

Associations with childhood OWOB defined by IOTF categories gave broadly similar results (Figure 2 and Supplemental Table 3). Offspring were less likely to be in OWOB during childhood when the maternal and parental HLSs during pregnancy were greater.

Associations with infancy HLS were less clear and did not remain significant after additional adjustment for parental HLS.

Regarding WHtR, an indicator of central adiposity available in EDEN and Lifeways, a greater parental HLS was associated with a lower WHtR z-score in EDEN at 5.5 years (-0.05 (-0.10, -0.01)) but not at 8 years or in Lifeways (at both time points) (Supplemental Table 4). A greater maternal HLS was associated with a lower WHtR z-score in EDEN at 5.5 years and Lifeways at 9 years but only before adjustment for parental confounders. Last, a greater infancy HLS was associated with a lower WHtR z-score in EDEN at 5.5 years but it did not remain significant after additional adjustment for parental HLS.

# Discussion

## Summary of findings

Based on data from four European birth cohorts, we aimed to describe novel HLSs in the first 1,000 days and investigated their associations with offspring risk of OWOB throughout childhood. Only a small proportion of families had favourable lifestyle factors during
pregnancy and early infancy. Maternal and parental pregnancy HLS were inversely associated
with early, mid- and late childhood OWOB when measured by BMI z-scores or IOTF
categories. The associations between infancy HLS and childhood OWOB were less consistent
and did not remain significant after additional adjustment for parental HLS. Associations with
WHtR z-scores (available in two cohorts) were solely significant in EDEN and at 5.5 years.

***Comparison with the published literature***

Using IOTF categories, the proportion of children with OWOB ranged from 7.6% (EDEN at
5.5 years) to 27.5% (Lifeways at 5 years). These wide variations might be partially explained
by differences between cohorts regarding the enrolment period (from 2001 to 2011),
exclusion criteria (“Mother born outside Ireland” was an exclusion criterion in Lifeways), or
selection/attrition bias with participants from higher socioeconomic position more likely to be
included/followed (in EDEN for instance);⁴¹ but also real differences as highlighted in the last
European Childhood Obesity Surveillance Initiative (COSI) report: prevalence of OWOB
among children aged 7-9 years ranging from 6% to 43% across European countries, for an
overall prevalence of 29%.⁶⁰

Several maternal lifestyle factors have already been individually associated with
childhood OWOB in the literature; e.g., diet quality, smoking status, physical activity level, or
BMI.²⁰⁻²⁵ Considering multiple lifestyle factors at the same time, a limited number of
previous studies have shown that better maternal adherence to a healthy lifestyle was
associated with a reduced risk of childhood OWOB.⁵²,⁶¹ Although the research on paternal
lifestyle factors is limited,²⁷ paternal BMI is commonly considered and associated with
childhood OWOB and its related comorbidities.²⁴,²⁷,⁶²,⁶³ In line with our results where the
parental pregnancy HLS (additionally considering paternal BMI and smoking status) was
more consistently associated with childhood OWOB than the maternal pregnancy HLS (i.e.,
effect size, number of cohorts with significant associations). Within the EndObesity project and based on the same cohorts, Lecorguillé et al.³⁵ used principal component analysis to derive a posteriori maternal and parental lifestyle patterns and found, for instance, that parental lifestyle patterns characterised by “high parental BMI, smoking, low diet quality or sedentary behaviours” were associated with higher risk of child OWOB. Confirming the consistency of our results whatever the method used (either a priori or a posteriori) to characterise unhealthy lifestyle factors. Last, previous studies have reported an association between breastfeeding duration or age of solid food introduction and weight gain in infancy and BMI later in life.³⁶,³⁷ We also found an association between the infancy HLS and the risk of childhood OWOB in some cohorts but it did not remain significant after adjustment for parental HLS.

## Potential mechanisms

In addition to the potential genetic inheritance regarding parental and offspring BMI,⁶⁴,⁶⁵ the link between parental HLS and offspring OWOB can be considered via three potential mechanisms: the (epi)genetic susceptibility transmitted through reproductive cells, adverse intra-uterine exposures during the foetal development, and the influence of the acquisition of lifestyle habits.¹⁹,⁶⁶,⁶⁷ Supporting these potential mechanisms, Olshan and Faustman⁶⁸ developed the notion of male-mediated developmental toxicity with animal studies demonstrating that paternal environmental exposures may affect offspring health via epigenetic alterations transmitted through sperm.²⁶,⁶⁹,⁷⁰ Multiple suboptimal maternal lifestyle factors before and during pregnancy have already been associated with childhood OWOB.⁷¹,⁷² Finally, family lifestyle behaviours may influence the acquisition of the offspring lifestyle habits. For instance, diet quality and physical activity level among parents and their offspring have been found to be associated;⁵⁶⁻⁵⁸ and these behaviours, linked with weight status, tend to
track from childhood to adulthood.⁷³,⁷⁴ Furthermore, partner's lifestyle behaviours have been found to be reciprocally associated and may influence each other;⁷⁵ thus, healthy changes in lifestyle behaviours around pregnancy would be beneficial for both parents and their offspring.

### Implications for policy, clinical practice and research

The high prevalence of childhood OWOB,¹,² combined with the low probability for young children living with obesity to return to a normal weight in adolescence,¹¹ highlights the urgent need for more effective public health policies and strategies to prevent paediatric OWOB as early as possible.⁴⁰ With this in mind, multiple actors have called for the creation of early lifestyle intervention strategies which consider the whole family and child environment.¹⁴,⁴⁰,⁶⁷,⁷⁶ As a public health concern affecting the entire society, addressing obesity necessitates a comprehensive, population-wide, multi-sectoral approach rooted in socio-ecological models, to tackle obesity is required. Complementing the individual approach, population wide prevention strategies and initiatives also shift the onus from solely individuals to society. Multiple-behaviours interventions seems to have a greater impact than single one as they may act synergistically to create health benefits for both parents and their offspring.³²⁻³⁴ However most pregnancy interventions have focussed on one or two lifestyle related behaviours, and with a focus on the mothers essentially.⁷⁷ In clinical practice also prevention seems to be a key.¹² In line with this, Fleming et al.⁶⁷ called for new guidance on parental preparation beginning even before conception (engaging both parents), while Geserick et al.¹¹ proposed the surveillance of BMI acceleration in early childhood even in the absence of obesity, and particularly among children with predisposing factors (e.g., maternal OWOB, macrosomia at birth). Ultimately, every contact counts and opportunities for prevention and intervention occur across the life-course from pre-conception to school entry
including antenatal and postnatal care, health contacts, childcare services, pre-schools, and
schools and parenting programmes.⁷⁸,⁷⁹

## Strengths and limitations

The main strength of this study is its large sample size from four birth cohorts conducted in three European countries for a total of >25,000 participant data analysed. We created three composite HLS combining multiple lifestyle behaviours using a harmonised approach.

Furthermore, we were able to apply the same indicators for childhood OWOB in all cohorts, including the widely used IOTF norms;⁵³ reducing the potential misclassification of OWOB and making the classification comparable with the published literature by reducing the variability of a possible internal cut-off.⁴⁰ Despite its strengths, the study has limitations. First, the lifestyle factors were self-reported and subject to both recall and social-desirability bias.

Although we were able to harmonize data across studies, this has resulted in the selection of common variables and the loss of some information not available in all cohorts, e.g., paternal diet quality or physical activity level during pregnancy for instance. In addition, some lifestyle factors may differ between cohorts depending on timing and how the questions were worded (e.g., smoking status asked during the 1st trimester only or at each trimester). However, the fact that analyses are conducted separately in each cohort and can be interpreted individually limits the impact of such variability on our results (i.e., association found in different contexts). The transition to parenthood can affect parental lifestyle, not only during pregnancy but also after childbirth.⁸⁰ It is important to note that the maternal and parental HLSs examined in this study relate to the pregnancy period and may have changed in the postpartum period. Regarding the infancy HLS, we examined selected early infancy factors during the first 1,000 days (e.g., breastfeeding duration or age of solid food introduction) but it is important to keep in mind that other modifiable risk factors for childhood OWOB such as
dietary habits, physical activity and sedentary behaviours are established in the early years of
life.<sup>40,66,74,81</sup> Although BMI and WHtR measures are more prone to measurement errors than
other methods (e.g., dual-energy X-ray absorptiometry scan), these anthropometric indicators
both have shown excellent discriminatory power for body fat in children of both sexes, and
are commonly used in clinical practice with low operational costs,<sup>82</sup> thus enhancing feasibility
in all settings and resources.

Conclusions

Greater maternal and parental adherence to healthy lifestyle behaviours during pregnancy was
associated with a lower risk of early, mid- and late childhood OWOB when measured by BMI
z-scores and IOTF categories. The associations between infancy HLS and childhood OWOB
were less consistent and did not remain significant after additional adjustment for parental
HLS. These results illustrate the importance of promoting healthy lifestyle behaviours at the
family-level during pregnancy and potentially the all first 1,000 days to prevent childhood
OWOB and its adverse health consequences. They also call for further research exploring
family and multi-behavioural approaches for prevention of childhood OWOB.
**Supplemental tables:**

**2/ Supplemental Table 1.** Data collection details of harmonised lifestyle factors in the different cohorts.

**3/ Supplemental Table 2.** Associations (unadjusted and adjusted) between the different HLS and childhood OWOB measured using IOTF z-scores in the different cohorts.

**4/ Supplemental Table 3.** Associations (unadjusted and adjusted) between the different HLS and childhood OWOB measured using IOTF categories in the different cohorts.

**5/ Supplemental Table 4.** Associations (unadjusted and adjusted) between the different HLS and childhood abdominal adiposity measured using WHtR z-scores in the cohorts EDEN and Lifeways.

**Supplementary materials:**

**Ethical approval:**

All participating cohorts obtained ethical approval according to national legislations. Written informed consents were obtained from all families. Research to date has been conducted according to the guidelines laid down in the Declaration of Helsinki. Specific cohort approvals are as follows:

**EDEN:** Ethics Research Committee (Comité Consultatif de Protection des Personnes dans la Recherche Biomédicale) of the Bicêtre Hospital and the Data Protection Authority (Commission Nationale Informatique et Liberté). All research was performed in accordance with relevant guidelines and regulations.

**Elfe:** Ethics Committee (Comité de Protection des Personnes), the national committee on information concerning health research (Comité Consultatif sur le Traitement de l'Information en Matière de Recherche dans le domaine de la Santé), and the data protection authority (Commission Nationale de l'Informatique et des Libertés).

**Generation R:** Medical Ethical Committee of the Erasmus Medical Center, Rotterdam.

**Lifeways:** Ethical Committee of the Coombe University Hospital, Dublin, University College Dublin, Irish College of General Practitioners, St Vincent's University Hospital and University College Hospital, Galway, Ireland.

**Acknowledgements:**

**Whole consortium:** The authors acknowledge all investigators working on the EndObesity Project and are grateful to all the families in the participating cohorts. We used variables that were harmonized in the framework of the H2020 LifeCycle project. The LifeCycle project received funding from the European Union's Horizon 2020 research and innovation programme (Grant Agreement No. 733206 LifeCycle)". We also used the dietary scores derived by A.M.A in the ERA-HDHL ALPHABET Project led by C.M.P. which was supported by the European Union's Horizon 2020 research and innovation programme under the ERA-Net Cofund of the JPI-HDHL (http://www.healthydietforhealthylife.eu) action number 696295 (Biomarkers for Nutrition and Health). Co-funding was provided by Science Foundation Ireland, Ireland (Grant Number SFI/16/ERA-HDHL/3360), the ZonMW The Netherlands (no 529051014; 2017)
ALPHABET project (no 696295; 2017) and the French National Agency of Research (reference AnrR16227KK). **EDEN:** The authors thank the EDEN mother-child cohort study group, whose members are I. Annesi-Maesano, J. Y. Bernard, J. Botton, M.A. Charles, P. Dargent-Molina, B. de Lauzon-Guillain, P. Ducimetière, M. de Agostini, B. Foliguet, A. Forhan, X. Fritel, A. Germa, V. Goua, R. Hankard, B. Heude, M. Kaminski, B. Larroque, N. Lelong, J. Lepeule, G. Magnin, L. Marchand, C. Nabet, F. Pierre, R. Slama, M.J. Saurel-Cubizolles, M. Schweitzer, and O. Thiebaugeorges. **Elfe:** We thank the members of the Elfe INED-INSERM-EFS joint unit and, above all, the families involved in the Elfe cohort, without whom this study would not have been possible. **Generation R:** The Generation R Study is conducted by the Erasmus Medical Centre in close collaboration with the School of Law and the Faculty of Social Sciences of the Erasmus University, Rotterdam, the Municipal Health Service, Rotterdam area, and the Stichting Trombosedienst and Artsenlaboratorium Rijnmond (STAR-MDC), Rotterdam. We gratefully acknowledge the contribution of children and their parents, general practitioners, hospitals, midwives, and pharmacies in Rotterdam. **Lifeways:** We would like to thank all members of the Lifeways cohort for their valuable contribution to the study, as well as research nurses and administrative staff at each hospital. The participation of families is much appreciated, as well as the participation of the families' GPs. **M.L.:** M.L. received a midwife research grant for this project from the Mustela Foundation. M.L.'s work has been also jointly supported by the French National College of Midwives and the Cerba Institute. M.L. has been named one of L'Oreal-UNESCO's For Women in Science 2023 French Young Talents.
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**List of tables, figures and supplemental tables (order of appearance in the text):**

**Table 1.** Characteristics of the mother-child birth cohorts participating in the EndObesity project and included in this study.

**Table 2.** Characteristics of participants of the EndObesity project cohort studies with at least one complete HLS.

**Table 3.** Distribution of the different HLS by cohort.

**Figure 1.** Adjusted associations between the different HLS and childhood OWOB measured using IOTF z-scores in the different cohorts.

**Figure 2.** Adjusted associations between the different HLS and childhood OWOB measured using IOTF categories in the different cohorts.

**Supplemental Table 1.** Data collection details of harmonised lifestyle factors in the different cohorts.

**Supplemental Table 2.** Associations (unadjusted and adjusted) between the different HLS and childhood OWOB measured using IOTF z-scores in the different cohorts.

**Supplemental Table 3.** Associations (unadjusted and adjusted) between the different HLS and childhood OWOB measured using IOTF categories in the different cohorts.

**Supplemental Table 4.** Associations (unadjusted and adjusted) between the different HLS and childhood abdominal adiposity measured using WHtR z-scores in the cohorts EDEN and Lifeways.
<table><caption>**Table 1.** Characteristics of the mother-child birth cohorts participating in the EndObesity project and included in this study.</caption><thead><tr><th>Cohort</th><th>Location, Country</th><th>Enrolment period</th><th>Inclusion criteria</th><th>Exclusion criteria<sup>a</sup></th><th>Number of women enrolled at baseline</th><th>Participants with at least one complete HLS<sup>b</sup></th><th>Outcomes available<sup>c</sup></th></tr></thead><tbody><tr><td>EDEN</td><td>Nancy and Poitiers, France</td><td>2003-2006</td><td>Proposed to all pregnant women visiting the prenatal clinic before 24 weeks of gestation</td><td><ul><li>Multiple pregnancy</li><li>Known diabetes before pregnancy</li><li>Mother &lt;18 years old</li><li>French illiteracy</li><li>Plan to move out of the region within 3 years</li></ul></td><td>2002</td><td>1871</td><td>BMI: 5.5, 8 and 12 years<br>WHtR: 5.5 and 8 years</td></tr><tr><td>Elfe</td><td>All country<sup>d</sup>, France</td><td>2011</td><td>Proposed to all women giving birth during 25 selected days into 4 periods</td><td><ul><li>Stillbirth</li><li>Birth &lt;33 weeks of gestation</li><li>Multiple birth &gt;2</li><li>Mother &lt;18 years old</li><li>Mother unable to give informed consent in French, English, Arabic or Turkish (i.e., the most common languages of women giving birth in France)</li><li>Plan to leave metropolitan France within 3 years</li></ul></td><td>18040</td><td>15813</td><td>BMI: 5, 7 and 9 years<br>WHtR: n.a.</td></tr><tr><td>Generation R</td><td>Rotterdam, The Netherlands</td><td>2002-2006</td><td>Proposed to all pregnant women living in Rotterdam with an expected delivery date between April 2002 and January 2006 (enrolment possible until birth)</td><td><ul><li>None</li></ul></td><td>9778</td><td>6390</td><td>BMI: 5, 9 and 12 years<br>WHtR: n.a.</td></tr><tr><td>Lifeways</td><td>Multicentric<sup>e</sup>, Republic of Ireland</td><td>2001-2003</td><td>Proposed to some<sup>f</sup> pregnant women between 14 and 16 weeks of gestation and attending their first antenatal visit (booking visit) at the maternity hospital.</td><td><ul><li>Mother born outside Ireland<sup>g</sup></li></ul></td><td>1124</td><td>724</td><td>BMI: 5 and 9 years<br>WHtR: 5 and 9 years</td></tr></tbody></table>

Abbreviations: HLS, healthy lifestyle score. BMI, body mass index. WHtR, waist-to-height ratio. n.a., not available.

<footnote><sup>a</sup>Multiple pregnancy was an exclusion criterion in EDEN, whereas we randomly retained one twin of each pair in Elfe (n=287) and Lifeways (n=10). In Generation R, twins were excluded from the analyses (n=106) because the percentage of missing data was higher in this group and more difficult to impute due to physiological differences (e.g., gestational weight gain in twin pregnancies versus singletons).</footnote>

<footnote><sup>b</sup>Participants with a complete maternal HLS (information on maternal diet quality, smoking status and alcohol consumption during pregnancy, and pre-pregnancy BMI), parental HLS (information on maternal diet quality, smoking status and alcohol consumption during pregnancy, pre-pregnancy BMI, paternal smoking status during pregnancy, and paternal BMI), or infancy HLS (information on breastfeeding duration, age of solid food introduction, and exposure to passive smoking).</footnote>

<footnote><sup>c</sup>Anthropometric measurements were collected from clinical examinations, the child's health booklet or assessed by parents.</footnote>

<footnote><sup>d</sup>Metropolitan France, Overseas territories of France not included.</footnote>

<footnote><sup>e</sup>Two representative regions (one urban, one rural), and within those regions two major hospitals providing maternity services were selected for sampling and agreed to participate. In the West of Ireland, University College Hospital Galway (UCHG), provides services for both urban and rural populations and in Dublin, on the East coast, the Coombe Women's Hospital is one of the busiest maternity hospitals in Ireland with over 7,000 babies born annually.</footnote>
<footnote n="4">⁴The cohort was never intended to be representative of the general obstetric population in Ireland. Nor was every pregnant woman approached during the calendar year as staffing levels, with one part-time nurse midwife in each hospital site, did not permit full coverage of every antenatal visit.</footnote>

<footnote n="5">⁵It was decided at the outset to exclude mothers born outside Ireland as the study was unlikely to be powered to allow for meaningful sub-group analyses of this kind.⁴⁵</footnote>
<table><caption>Table 2. Characteristics of participants of the EndObesity project cohort studies with at least one complete HLS.</caption><thead><tr><th></th><th colspan="2">EDEN</th><th colspan="2">Elfe</th><th colspan="2">Generation R</th><th colspan="2">Lifeways</th></tr><tr><th></th><th colspan="2">n=1871</th><th colspan="2">n=15813</th><th colspan="2">n=6390</th><th colspan="2">n=724</th></tr></thead><tbody><tr><td colspan="9"><strong>Maternal characteristics</strong></td></tr><tr><td>Age at birth (years), mean ±SD</td><td>29.5</td><td>±4.9</td><td>30.3</td><td>±4.9</td><td>30.8</td><td>±5.1</td><td>30.1</td><td>±5.8</td></tr><tr><td colspan="9">Educational level at birth (highest ongoing or completed), n (%)</td></tr><tr><td>Low (ISCED 0-2)</td><td>129</td><td>(6.9)</td><td>1084</td><td>(6.9)</td><td>515</td><td>(8.3)</td><td>117</td><td>(16.4)</td></tr><tr><td>Intermediate (ISCED 3-4)</td><td>727</td><td>(39.1)</td><td>5324</td><td>(33.7)</td><td>2761</td><td>(44.5)</td><td>215</td><td>(30.2)</td></tr><tr><td>High (ISCED 5-8)</td><td>1002</td><td>(53.9)</td><td>9405</td><td>(59.5)</td><td>2934</td><td>(47.3)</td><td>381</td><td>(53.4)</td></tr><tr><td>(Self)employed at inclusion<sup>a</sup>, n (%)</td><td>1436</td><td>(77.0)</td><td>12794</td><td>(81.1)</td><td>3976</td><td>(76.5)</td><td>508</td><td>(70.8)</td></tr><tr><td colspan="9">Household income at inclusion, n (%)</td></tr><tr><td>1st quartile (lowest)</td><td>309</td><td>(16.6)</td><td>2037</td><td>(14.4)</td><td>852</td><td>(16.2)</td><td>404</td><td>(60.8)</td></tr><tr><td>2nd quartile</td><td>547</td><td>(29.3)</td><td>3071</td><td>(21.7)</td><td>1280</td><td>(24.4)</td><td>260</td><td>(39.2)</td></tr><tr><td>3rd quartile</td><td>495</td><td>(26.5)</td><td>4744</td><td>(33.6)</td><td>3118</td><td>(59.4)</td><td>-</td><td>-</td></tr><tr><td>4th quartile (highest)</td><td>514</td><td>(27.6)</td><td>4272</td><td>(30.3)</td><td>-</td><td>-</td><td>-</td><td>-</td></tr><tr><td>Primiparity at inclusion, n (%)</td><td>836</td><td>(44.8)</td><td>7177</td><td>(45.9)</td><td>3701</td><td>(58.4)</td><td>324</td><td>(45.4)</td></tr><tr><td>Born in the cohort country<sup>b</sup>, n (%)</td><td>1781</td><td>(96.1)</td><td>14214</td><td>(90.0)</td><td>4506</td><td>(71.1)</td><td>n.a.</td><td>n.a.</td></tr><tr><td colspan="9">Pre or early pregnancy BMI (kg/m<sup>2</sup>), n (%)</td></tr><tr><td>Underweight</td><td>157</td><td>(8.6)</td><td>1217</td><td>(7.8)</td><td>238</td><td>(4.1)</td><td>20</td><td>(2.8)</td></tr><tr><td>Normal</td><td>1199</td><td>(65.3)</td><td>10269</td><td>(65.5)</td><td>3993</td><td>(68.7)</td><td>488</td><td>(68.9)</td></tr><tr><td>Overweight</td><td>323</td><td>(17.6)</td><td>2636</td><td>(16.8)</td><td>1079</td><td>(18.6)</td><td>140</td><td>(19.8)</td></tr><tr><td>Obesity</td><td>157</td><td>(8.6)</td><td>1556</td><td>(9.9)</td><td>502</td><td>(8.6)</td><td>60</td><td>(8.5)</td></tr><tr><td>Pregnancy DASH score, mean ±SD</td><td>23.9</td><td>±4.3</td><td>24.0</td><td>±4.4</td><td>24.1</td><td>±4.5</td><td>24.1</td><td>±4.6</td></tr><tr><td>Non-smoker during pregnancy, n (%)</td><td>1364</td><td>(73.1)</td><td>12582</td><td>(80.1)</td><td>4480</td><td>(73.8)</td><td>557</td><td>(77.0)</td></tr><tr><td>No alcohol consumption during pregnancy, n (%)</td><td>927</td><td>(49.5)</td><td>9507</td><td>(60.3)</td><td>2637</td><td>(44.0)</td><td>408</td><td>(57.1)</td></tr><tr><td>Pregnancy physical activity level ≥450 MET-min/week or considered as "active", n (%)<sup>c</sup></td><td>402</td><td>(21.5)</td><td>4235</td><td>(28.5)</td><td>n.a.</td><td>n.a.</td><td>121</td><td>(16.7)</td></tr><tr><td colspan="9"><strong>Paternal characteristics</strong></td></tr><tr><td>Age at birth (years), mean ±SD</td><td>32.0</td><td>±5.8</td><td>33.3</td><td>±6.1</td><td>33.6</td><td>±5.8</td><td>32.6</td><td>±6.1</td></tr></tbody></table>
## Educational level at birth (highest ongoing or completed), n (%)

Low (ISCED 0-2) 179 (9.8) 1023 (8.0) 290 (6.8) 191 (29.5)

Intermediate (ISCED 3-4) 838 (46.0) 5164 (40.3) 1732 (40.5) 166 (25.7)

High (ISCED 5-8) 805 (44.2) 6642 (51.8) 2254 (52.7) 290 (44.8)

**(Self)employed at inclusion<sup>a</sup>, n (%)** 1668 (91.4) 14141 (91.0) 3726 (92.7) 602 (96.2)

**Born in the cohort country<sup>b</sup>, n(%)** 1719 (92.5) 13844 (89.9) 4288 (69.2) n.a. n.a.

## BMI during pregnancy (kg/m²), n (%)

Underweight 18 (1.1) 92 (0.8) 39 (0.8) 3 (1.3)

Normal 916 (53.7) 6499 (55.1) 2431 (50.1) 71 (30.9)

Overweight 623 (36.5) 4278 (36.2) 1977 (40.7) 120 (52.2)

Obesity 149 (8.7) 933 (7.9) 406 (8.4) 36 (15.7)

**Non-smoker during pregnancy, n (%)** 997 (59.6) 7713 (65.2) 3229 (55.6) 183 (73.2)

<table><caption>Child and infancy characteristics</caption><tbody><tr><th scope="row">Male sex, n (%)</th><td>980 (52.4)</td><td>8113 (51.3)</td><td>3229 (50.5)</td><td>338 (46.9)</td></tr><tr><th scope="row">Breastfeeding duration (months), mean ±SD</th><td>3.2 ±3.5</td><td>2.9 ±3.7</td><td>4.4 ±3.8</td><td>2.6 ±3.1</td></tr><tr><th scope="row">Age of solid food introduction (months), mean ±SD</th><td>4.5 ±1.5</td><td>4.1 ±1.2</td><td>4.9 ±0.9</td><td>4.1 ±1.2</td></tr><tr><th scope="row">No exposure to passive smoking during the first year of life, n (%)</th><td>947 (54.9)</td><td>8860 (61.4)</td><td>2600 (71.4)</td><td>170 (43.9)</td></tr></tbody></table>

<table><caption>Outcomes (age, n available<sup>d</sup>)</caption><thead><tr><th></th><th>5.5 years</th><th>(n=1141)</th><th>5 years</th><th>(n=8875)</th><th>5 years</th><th>(n=4716)</th><th>5 years</th><th>(n=432)</th></tr></thead><tbody><tr><th scope="row">Early childhood (5-5.5 years)</th><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><th scope="row">OWOB (IOTF cat.), n (%)</th><td>87 (7.6)</td><td></td><td>708 (8.0)</td><td></td><td>766 (16.2)</td><td></td><td>119 (27.5)</td><td></td></tr><tr><th scope="row">WHtR, mean ±SD</th><td>0.47 ±0.03</td><td></td><td>n.a. n.a.</td><td></td><td>n.a. n.a.</td><td></td><td>0.50 ±0.04</td><td></td></tr><tr><th scope="row">Mid-childhood (7-8 years)</th><td>8 years (n=737)</td><td></td><td>7 years (n=3772)</td><td></td><td>n.a. n.a.</td><td></td><td>n.a. n.a.</td><td></td></tr><tr><th scope="row">OWOB (IOTF cat.), n (%)</th><td>86 (11.7)</td><td></td><td>364 (9.7)</td><td></td><td>n.a. n.a.</td><td></td><td>n.a. n.a.</td><td></td></tr><tr><th scope="row">WHtR, mean ±SD</th><td>0.45 ±0.05</td><td></td><td>n.a. n.a.</td><td></td><td>n.a. n.a.</td><td></td><td>n.a. n.a.</td><td></td></tr><tr><th scope="row">Late-childhood (9-12 years)</th><td>12 years (n=706)</td><td></td><td>9 years (n=3295)</td><td></td><td>9 years (n=4163)</td><td></td><td>9 years (n=247)</td><td></td></tr><tr><th scope="row">OWOB (IOTF cat.), n (%)</th><td>81 (11.5)</td><td></td><td>344 (10.4)</td><td></td><td>701 (16.8)</td><td></td><td>65 (26.3)</td><td></td></tr><tr><th scope="row">WHtR, mean ±SD</th><td>n.a. n.a.</td><td></td><td>n.a. n.a.</td><td></td><td>n.a. n.a.</td><td></td><td>0.45 ±0.07</td><td></td></tr></tbody></table>
Abbreviations: HLS, healthy lifestyle score. SD, standard deviation. ISCED, International Standard Classification of Education. n.a., not available. BMI, body mass index. DASH, Dietary Approaches to Stop Hypertension. MET, metabolic equivalent of task. OWOB, overweight or obesity. IOTF, International Obesity Task Force. Cat., category. WHtR, waist-to-height ratio.

Values are means and standard deviations (rounded to one decimal) for continuous variables and frequencies and percentages (% excluding missing values and rounded to one decimal) for categorical variables.

aNot employed included unemployed, housewife, student, inactive/other.

b"Mother born outside Ireland" was an exclusion criterion; i.e., "it was decided at the outset to exclude mothers born outside Ireland as the study was unlikely to be powered to allow for meaningful sub-group analyses of this kind."⁴⁵ In addition, paternal country of birth was not collected.

c"Active" defined in EDEN as i) ≥450 MET-min/week from other regular sport of moderate-to-vigorous intensity; or ii) walking or cycling or swimming filled as practiced "very often"; or iii) walking or cycling or swimming filled at least twice (≥2/3) as practiced "often" (reason: time spent in "other regular sport" asked in the parental questionnaire after the frequency of walking, cycling or swimming). "Active" defined in Lifeways as i) ≥450 MET-min/week from sport of moderate-to-vigorous intensity; or ii) "engaging in any regular activity such as jogging or cycling long enough to work up a sweat" ≥5 days/week in Lifeways.

dWith at least one outcome measure (BMI or WHtR).
<table><caption>**Table 3.** Distribution of the different HLS by cohort.</caption><thead><tr><th></th><th colspan="2">EDEN<br>n=1871<br>n (%)</th><th colspan="2">Elfe<br>n=15813<br>n (%)</th><th colspan="2">Generation R<br>n=6390<br>n (%)</th><th colspan="2">Lifeways<br>n=724<br>n (%)</th></tr></thead><tbody><tr><td colspan="9"><strong>Maternal pregnancy HLS</strong></td></tr><tr><td>0</td><td>55</td><td>(3.0)</td><td>219</td><td>(1.5)</td><td>161</td><td>(3.1)</td><td>16</td><td>(2.3)</td></tr><tr><td>1</td><td>290</td><td>(16.1)</td><td>1517</td><td>(10.4)</td><td>811</td><td>(15.7)</td><td>82</td><td>(11.7)</td></tr><tr><td>2</td><td>510</td><td>(28.3)</td><td>3944</td><td>(27.0)</td><td>1792</td><td>(34.7)</td><td>202</td><td>(28.9)</td></tr><tr><td>3</td><td>565</td><td>(31.3)</td><td>5153</td><td>(35.3)</td><td>1891</td><td>(36.6)</td><td>255</td><td>(36.5)</td></tr><tr><td>4</td><td>322</td><td>(17.8)</td><td>3022</td><td>(20.7)</td><td>515</td><td>(10.0)</td><td>116</td><td>(16.6)</td></tr><tr><td>5<sup>a</sup></td><td>62</td><td>(3.4)</td><td>723</td><td>(5.0)</td><td>n.a.</td><td>n.a.</td><td>28</td><td>(4.0)</td></tr><tr><td><strong>Total</strong></td><td colspan="2"><strong>n=1804</strong></td><td colspan="2"><strong>n=14578</strong></td><td colspan="2"><strong>n=5170</strong></td><td colspan="2"><strong>n=699</strong></td></tr><tr><td colspan="9"><strong>Parental pregnancy HLS</strong></td></tr><tr><td>0</td><td>14</td><td>(0.9)</td><td>49</td><td>(0.5)</td><td>42</td><td>(1.0)</td><td>1</td><td>(0.5)</td></tr><tr><td>1</td><td>88</td><td>(5.5)</td><td>343</td><td>(3.2)</td><td>245</td><td>(6.0)</td><td>4</td><td>(1.9)</td></tr><tr><td>2</td><td>239</td><td>(14.9)</td><td>1116</td><td>(10.4)</td><td>660</td><td>(16.3)</td><td>23</td><td>(11.0)</td></tr><tr><td>3</td><td>364</td><td>(22.7)</td><td>2266</td><td>(21.0)</td><td>1070</td><td>(26.4)</td><td>48</td><td>(22.9)</td></tr><tr><td>4</td><td>399</td><td>(24.8)</td><td>3008</td><td>(27.9)</td><td>1221</td><td>(30.1)</td><td>65</td><td>(31.0)</td></tr><tr><td>5</td><td>339</td><td>(21.1)</td><td>2533</td><td>(23.5)</td><td>669</td><td>(16.5)</td><td>48</td><td>(22.9)</td></tr><tr><td>6</td><td>133</td><td>(8.3)</td><td>1204</td><td>(11.2)</td><td>152</td><td>(3.7)</td><td>16</td><td>(7.6)</td></tr><tr><td>7<sup>a</sup></td><td>30</td><td>(1.9)</td><td>261</td><td>(2.4)</td><td>n.a.</td><td>n.a.</td><td>5</td><td>(2.4)</td></tr><tr><td><strong>Total</strong></td><td colspan="2"><strong>n=1606</strong></td><td colspan="2"><strong>n=10780</strong></td><td colspan="2"><strong>n=4059</strong></td><td colspan="2"><strong>n=210</strong></td></tr><tr><td colspan="9"><strong>Infancy HLS</strong></td></tr><tr><td>0</td><td>249</td><td>(14.5)</td><td>1205</td><td>(11.3)</td><td>134</td><td>(4.1)</td><td>7</td><td>(4.7)</td></tr><tr><td>1</td><td>581</td><td>(33.7)</td><td>3613</td><td>(33.8)</td><td>738</td><td>(22.3)</td><td>58</td><td>(39.2)</td></tr><tr><td>2</td><td>629</td><td>(36.5)</td><td>4379</td><td>(41.0)</td><td>1658</td><td>(50.1)</td><td>65</td><td>(43.9)</td></tr><tr><td>3</td><td>263</td><td>(15.3)</td><td>1481</td><td>(13.9)</td><td>780</td><td>(23.6)</td><td>18</td><td>(12.2)</td></tr><tr><td><strong>Total</strong></td><td colspan="2"><strong>n=1722</strong></td><td colspan="2"><strong>n=10678</strong></td><td colspan="2"><strong>n=3310</strong></td><td colspan="2"><strong>n=148</strong></td></tr></tbody></table>

Abbreviations: HLS, healthy lifestyle score. n.a., not available.

Values are frequencies and percentages (% excluding missing values and rounded to one decimal).

<footnote><sup>a</sup>Maternal physical activity level during pregnancy was not available in Generation R so the maternal and parental HLS were composed of 4 and 6 items, respectively.</footnote>
<figure><img src="image_2.png" /><figcaption>**Figure 1.** Adjusted associations between the different HLS and childhood OWOB measured using IOTF z-scores in the different cohorts.</figcaption></figure>

Abbreviations: HLS, healthy lifestyle score. OWOB, overweight or obesity. IOTF, International Obesity Task Force. β, Beta. CI, confidence interval.

Values are Beta and their 95% confidence intervals (β [95% CI]) (rounded to 2 decimals) from linear regression models: adjusted for parental confounders (i.e., maternal parity, maternal and paternal age, educational level, employment status, country of birth [except in Lifeways where “Mother born outside Ireland” was an exclusion criterion and paternal country of birth was not collected], and household income), and with the use of multiple imputed dataset. The second model with infancy HLS is additionally adjusted for parental HLS (forest plot at bottom right).

l Confidence interval truncated.
<figure><img src="image_3.png" /><figcaption>**Figure 2.** Adjusted associations between the different HLS and childhood OWOB measured using IOTF categories in the different cohorts.</figcaption></figure>

Abbreviations: HLS, healthy lifestyle score. OWOB, overweight or obesity. IOTF, International Obesity Task Force. RR, relative risk. CI, confidence interval.

Values are Relative Risks and their 95% confidence intervals (RR [95% CI]) (rounded to 2 decimals) from robust Poisson regression models: adjusted for parental confounders (i.e., maternal parity, maternal and paternal age, educational level, employment status, country of birth [except in Lifeways where “Mother born outside Ireland” was an exclusion criterion and paternal country of birth was not collected], and household income) and with the use of multiple imputed dataset. The second model with infancy HLS is additionally adjusted for parental HLS (forest plot at bottom right).

†Confidence interval truncated.

‡Due to the limited number of cases (n=27 children in the category OWOB) for the number of parameters in these adjusted models, confidence intervals are huge and it seemed not right to present the results in the figure. For transparency, we kept this information in the Supplemental Table 4.
<table><caption>Supplemental Table 1. Data collection details of harmonised lifestyle factors in the different cohorts.</caption><thead><tr><th></th><th></th><th>EDEN</th><th>Elfe</th><th>Generation R</th><th>Lifeways</th></tr></thead><tbody><tr><td colspan="6"><strong>Maternal pregnancy HLS</strong></td></tr><tr><td rowspan="3">Maternal pre-pregnancy BMI</td><td>Assessment period</td><td>24-28 WG</td><td>At birth</td><td>At enrollment</td><td>14-16 WG</td></tr><tr><td>Window period</td><td>Pre-pregnancy weight, current height</td><td>Pre-pregnancy weight, current height</td><td>Pre-pregnancy weight, current height</td><td>Pre-pregnancy weight, current height</td></tr><tr><td>Assessment type</td><td>Face-to-face questionnaire &amp; Clinical examination</td><td>Face-to-face questionnaire</td><td>Clinical examination &amp; Self-administered questionnaire</td><td>Clinical examination &amp; Self-administered questionnaire</td></tr><tr><td rowspan="3">Maternal diet quality during pregnancy (DASH score)<sup>REF1</sup></td><td>Assessment period</td><td>At birth</td><td>At birth</td><td>At enrollment</td><td>14-16 WG</td></tr><tr><td>Window period</td><td>3 last months of pregnancy</td><td>3 last months of pregnancy</td><td>Past 3 months</td><td>Since start of pregnancy</td></tr><tr><td>Assessment type</td><td>Self-administered semi-quantitative FFQ (130 items)<sup>a</sup></td><td>Self-administered semi-quantitative FFQ (125 items)<sup>a</sup></td><td>Self-administered semi-quantitative FFQ (283 items)<sup>a</sup></td><td>Self-administered semi-quantitative FFQ (154 items)<sup>a</sup></td></tr><tr><td rowspan="3">Maternal physical activity level during pregnancy</td><td>Assessment period</td><td>24-28 WG</td><td>At birth</td><td>n.a.</td><td>14-16 WG</td></tr><tr><td>Window period</td><td>1<sup>st</sup> trimester of pregnancy</td><td>3 last months of pregnancy</td><td>n.a.</td><td>Current physical activity level</td></tr><tr><td>Assessment type</td><td>Self-administered questionnaire</td><td>Pregnancy Physical Activity Questionnaire<sup>REF2,3</sup></td><td>n.a.</td><td>Self-administered questionnaire</td></tr><tr><td rowspan="3">Maternal alcohol consumption during pregnancy</td><td>Assessment period</td><td>24-28 WG</td><td>At birth</td><td>At enrollment</td><td>14-16 WG</td></tr><tr><td>Window period</td><td>1<sup>st</sup> trimester of pregnancy</td><td>During pregnancy</td><td>Each trimester of pregnancy</td><td>Current alcohol consumption</td></tr><tr><td>Assessment type</td><td>Face-to-face questionnaire</td><td>Face-to-face questionnaire</td><td>Self-administered questionnaire</td><td>Self-administered questionnaire</td></tr><tr><td rowspan="3">Maternal smoking status during pregnancy</td><td>Assessment period</td><td>24-28 WG</td><td>At birth</td><td>Each trimester</td><td>14-16 WG</td></tr><tr><td>Window period</td><td>1<sup>st</sup> trimester of pregnancy &amp; current smoking status</td><td>Smoking status during pregnancy</td><td>Each trimester of pregnancy</td><td>Current smoking status</td></tr><tr><td>Assessment type</td><td>Face-to-face questionnaire</td><td>Face-to-face questionnaire</td><td>Self-administered questionnaire</td><td>Self-administered questionnaire</td></tr><tr><td colspan="6"><strong>Parental pregnancy HLS<sup>b</sup></strong></td></tr><tr><td rowspan="3">Paternal BMI during pregnancy</td><td>Assessment period</td><td>24-28 WG</td><td>At 2 months</td><td>At enrollment</td><td>14-16 WG</td></tr><tr><td>Window period</td><td>Current weight and height</td><td>Current weight and height</td><td>Current weight and height</td><td>Current weight and height</td></tr><tr><td>Assessment type</td><td>Self-administered questionnaire</td><td>Self-administered questionnaire</td><td>Clinical examination &amp; self-administered questionnaires</td><td>Self-administered questionnaire</td></tr><tr><td rowspan="3">Paternal smoking status during pregnancy</td><td>Assessment period</td><td>24-28 WG</td><td>At 2 months</td><td>At enrollment</td><td>14-16 WG</td></tr><tr><td>Window period</td><td>Current smoking status</td><td>Current smoking status</td><td>Smoking status during pregnancy</td><td>Current smoking status</td></tr><tr><td>Assessment type</td><td>Self-administered questionnaire</td><td>Self-administered questionnaire</td><td>Self-administered questionnaire</td><td>Self-administered questionnaire</td></tr><tr><td colspan="6"><strong>Infancy HLS</strong></td></tr><tr><td rowspan="3">Breastfeeding duration</td><td>Assessment period</td><td>At 4, 8, 12 and 24 months</td><td>At 2, 2-6, 6-10, 12 and 24 months</td><td>At 2, 6 and 12 months</td><td>At birth, 1 and 5 years</td></tr><tr><td>Window period</td><td>Current breastfeeding and/or date of cessation</td><td>Current breastfeeding and/or date of cessation</td><td>Current breastfeeding and/or date of cessation</td><td>Ever breastfed and age of cessation</td></tr><tr><td>Assessment type</td><td>Self-administered questionnaires</td><td>Self-administered questionnaires</td><td>Self-administered questionnaires</td><td>Self-administered child study record and questionnaire</td></tr><tr><td rowspan="3">Age of solid food introduction</td><td>Assessment period</td><td>At 4, 8 and 12 months</td><td>At 2, 2-6, 6-10, and 12 months</td><td>At 6 and 12 months</td><td>At 5 years</td></tr><tr><td>Window period</td><td>Current food consumption and age of introduction</td><td>Current food consumption and age of introduction</td><td>Current food consumption and age of introduction</td><td>Age of introduction</td></tr><tr><td>Assessment type</td><td>Self-administered questionnaires</td><td>Self-administered questionnaires</td><td>Self-administered questionnaires</td><td>Self-administered questionnaire</td></tr></tbody></table>
<table><thead><tr><th></th><th>Assessment period</th><th>At 4, 8 and 12 months</th><th>At 2 and 12 months</th><th>At 2 and 6 months</th><th>Pregnancy<sup>c</sup></th></tr></thead><tbody><tr><th rowspan="2" scope="rowgroup">Any exposure to<br>passive smoking<br>during the first year<br>of life<sup>c</sup></th><th scope="row">Window period</th><td>Current parental<br>smoking and<br>exposure</td><td>Current parental<br>smoking and<br>exposure</td><td>Current parental<br>smoking and<br>exposure</td><td>Current parental<br>smoking and<br>exposure</td></tr><tr><th scope="row">Assessment type</th><td>Self-administered<br>questionnaires</td><td>Self-administered<br>questionnaires</td><td>Self-administered<br>questionnaires</td><td>Self-administered<br>questionnaires</td></tr></tbody></table>

Abbreviations: HLS, healthy lifestyle score. BMI, body mass index. WG, weeks of gestation. DASH, Dietary Approaches to Stop Hypertension. FFQ, food frequency questionnaire. n.a., not available.

Window period means the period targeted by the question.

<sup>a</sup>FFQ total of food items without alcohol.

<sup>b</sup>Combine maternal pregnancy HLS and the two paternal pregnancy HLS described below; i.e., paternal BMI around pregnancy, paternal smoking status during pregnancy.

<sup>c</sup>Include mother smoking, biological father smoking, social father smoking, any smokers close to the child, or exposure to smoke in the home from birth up to 1<sup>st</sup> birthday.

<sup>d</sup>The assumption was made that smokers during pregnancy and those with partners who smoked would continue to expose the child at birth and during the first year of life.

1. Aubert AM, Forhan A, de Lauzon-Guillain B, et al. Deriving the Dietary Approaches to Stop Hypertension (DASH) Score in Women from Seven Pregnancy Cohorts from the European ALPHABET Consortium. *Nutrients*. 2019;11(11). doi:10.3390/nu11112706

2. Chasan-Taber L, Schmidt MD, Roberts DE, Hosmer D, Markenson G, Freedson PS. Development and validation of a Pregnancy Physical Activity Questionnaire. *Med Sci Sports Exerc*. 2004;36(10):1750-1760.

3. Chandonnet N, Saey D, Alméras N, Marc I. French Pregnancy Physical Activity Questionnaire compared with an accelerometer cut point to classify physical activity among pregnant obese women. *PloS One*. 2012;7(6):e38818. doi:10.1371/journal.pone.0038818
<table><caption>**Supplemental Table 2.** Associations (unadjusted and adjusted) between the different HLS and childhood OWOB measured using IOTF z-scores in the different cohorts.</caption><thead><tr><th rowspan="2"></th><th colspan="3">EDEN</th><th colspan="3">Elfe</th><th colspan="2">Generation R</th><th colspan="2">Lifeways</th></tr><tr><th>5.5 years<br>β [95% CI]</th><th>8 years<br>β [95% CI]</th><th>12 years<br>β [95% CI]</th><th>5 years<br>β [95% CI]</th><th>7 years<br>β [95% CI]</th><th>9 years<br>β [95% CI]</th><th>5 years<br>β [95% CI]</th><th>9 years<br>β [95% CI]</th><th>5 years<br>β [95% CI]</th><th>9 years<br>β [95% CI]</th></tr></thead><tbody><tr><th colspan="11" style="text-align: left; font-weight: bold;">Maternal pregnancy HLS</th></tr><tr><td>n included in the model</td><td>n=1105</td><td>n=715</td><td>n=685</td><td>n=8124</td><td>n=3480</td><td>n=3061</td><td>n=3748</td><td>n=3307</td><td>n=410</td><td>n=232</td></tr><tr><td>Unadjusted</td><td>-0.04 [-0.09, 0.01]</td><td>-0.06 [-0.13, 0.005]</td><td>-0.07 [-0.14, -0.01]</td><td>-0.04 [-0.06, -0.02]</td><td>-0.07 [-0.10, -0.04]</td><td>-0.06 [-0.10, -0.03]</td><td>-0.07 [-0.10, -0.03]</td><td>-0.08 [-0.12, -0.05]</td><td>-0.04 [-0.12, 0.05]</td><td>-0.11 [-0.24, 0.02]</td></tr><tr><td>Adjusted</td><td>-0.04 [-0.08, -0.01]</td><td>-0.05 [-0.12, 0.01]</td><td>-0.04 [-0.11, 0.03]</td><td>-0.04 [-0.06, -0.02]</td><td>-0.07 [-0.10, -0.03]</td><td>-0.06 [-0.10, -0.03]</td><td>-0.06 [-0.09, -0.03]</td><td>-0.06 [-0.10, -0.03]</td><td>-0.01 [-0.10, 0.08]</td><td>-0.04 [-0.19, 0.10]</td></tr><tr><th colspan="11" style="text-align: left; font-weight: bold;">Parental pregnancy HLS</th></tr><tr><td>n included in the model</td><td>n=1012</td><td>n=659</td><td>n=635</td><td>n=6961</td><td>n=3175</td><td>n=2818</td><td>n=3047</td><td>n=2739</td><td>n=150</td><td>n=112</td></tr><tr><td>Unadjusted</td><td>-0.05 [-0.09, -0.02]</td><td>-0.08 [-0.13, -0.02]</td><td>-0.12 [-0.18, -0.07]</td><td>-0.07 [-0.09, -0.05]</td><td>-0.10 [-0.12, -0.07]</td><td>-0.10 [-0.13, -0.07]</td><td>-0.10 [-0.12, -0.07]</td><td>-0.12 [-0.15, -0.10]</td><td>0.03 [-0.08, 0.14]</td><td>-0.17 [-0.30, -0.04]</td></tr><tr><td>Adjusted</td><td>-0.06 [-0.10, -0.02]</td><td>-0.07 [-0.13, -0.02]</td><td>-0.10 [-0.16, -0.05]</td><td>-0.07 [-0.09, -0.05]</td><td>-0.10 [-0.12, -0.07]</td><td>-0.10 [-0.13, -0.07]</td><td>-0.09 [-0.11, -0.06]</td><td>-0.10 [-0.13, -0.07]</td><td>0.06 [-0.05, 0.18]</td><td>-0.15 [-0.29, -0.01]</td></tr><tr><th colspan="11" style="text-align: left; font-weight: bold;">Infancy HLS</th></tr><tr><td>n included in the model<sup>a</sup></td><td>n=1124</td><td>n=733</td><td>n=701</td><td>n=7139</td><td>n=3401</td><td>n=2981</td><td>n=2712</td><td>n=2438</td><td>n=131</td><td>n=96</td></tr><tr><td>Unadjusted</td><td>-0.06 [-0.12, -0.004*]</td><td>-0.09 [-0.17, -0.02]</td><td>-0.16 [-0.25, -0.08]</td><td>-0.05 [-0.08, -0.02]</td><td>-0.09 [-0.13, -0.05]</td><td>-0.04 [-0.09, -0.001*]</td><td>-0.10 [-0.14, -0.05]</td><td>-0.13 [-0.18, -0.08]</td><td>-0.17 [-0.38, 0.05]</td><td>-0.22 [-0.49, 0.05]</td></tr><tr><td>Adjusted</td><td>-0.06 [-0.12, 0.01]</td><td>-0.07 [-0.15, 0.01]</td><td>-0.11 [-0.20, -0.02]</td><td>-0.05 [-0.08, -0.02]</td><td>-0.09 [-0.13, -0.05]</td><td>-0.04 [-0.09, 0.002]</td><td>-0.06 [-0.10, -0.01]</td><td>-0.06 [-0.11, -0.01]</td><td>-0.08 [-0.31, 0.15]</td><td>-0.03 [-0.30, 0.24]</td></tr><tr><td>Adjusted<sup>b</sup></td><td>-0.01 [-0.08, 0.06]</td><td>-0.02 [-0.11, 0.07]</td><td>-0.06 [-0.15, 0.04]</td><td>-0.02 [-0.06, 0.02]</td><td>-0.04 [-0.08, 0.01]</td><td>0.01 [-0.04, 0.06]</td><td>0.01 [-0.04, 0.06]</td><td>0.01 [-0.04, 0.06]</td><td>-0.11 [-0.36, 0.14]</td><td>0.14 [-0.15, 0.43]</td></tr></tbody></table>

Abbreviations: HLS, healthy lifestyle score. OWOB, overweight or obesity. IOTF, International Obesity Task Force. β, Beta. CI, confidence interval.

Values are Beta and their 95% confidence intervals (β [95% CI]) (rounded to 2 decimals) **(in bold when significantly associated)** from linear regression models: unadjusted, adjusted for parental confounders (i.e., maternal parity, maternal and paternal age, educational level, employment status, country of birth [except in Lifeways where "Mother born outside Ireland" was an exclusion criterion and paternal country of birth was not collected], and household income) and with the use of multiple imputed dataset.

*Significantly associated as the confidence interval does not contain 0.

a n included in the model before adjustment for parental HLS.

b Additionally adjusted for parental HLS.
<table><caption>**Supplemental Table 3.** Associations (unadjusted and adjusted) between the different HLS and childhood OWOB measured using IOTF categories in the different cohorts.</caption><thead><tr><th rowspan="2"></th><th colspan="3">EDEN</th><th colspan="3">Elfe</th><th colspan="2">Generation R</th><th colspan="2">Lifeways</th></tr><tr><th>5.5 years<br>RR [95% CI]</th><th>8 years<br>RR [95% CI]</th><th>12 years<br>RR [95% CI]</th><th>5 years<br>RR [95% CI]</th><th>7 years<br>RR [95% CI]</th><th>9 years<br>RR [95% CI]</th><th>5 years<br>RR [95% CI]</th><th>9 years<br>RR [95% CI]</th><th>5 years<br>RR [95% CI]</th><th>9 years<br>RR [95% CI]</th></tr></thead><tbody><tr><th colspan="11" style="text-align: left; font-weight: bold;">Maternal pregnancy HLS</th></tr><tr><td>n included in<br>the model</td><td>n=1105</td><td>n=715</td><td>n=685</td><td>n=8124</td><td>n=3480</td><td>n=3061</td><td>n=3748</td><td>n=3307</td><td>n=410</td><td>n=232</td></tr><tr><td>Unadjusted</td><td><strong>0.80 [0.66, 0.97]</strong></td><td>0.88 [0.73, 1.07]</td><td>0.87 [0.71, 1.06]</td><td><strong>0.86 [0.80, 0.92]</strong></td><td><strong>0.79 [0.72, 0.87]</strong></td><td><strong>0.82 [0.72, 0.87]</strong></td><td><strong>0.85 [0.79, 0.92]</strong></td><td><strong>0.81 [0.75, 0.88]</strong></td><td>0.97 [0.83, 1.12]</td><td><strong>0.78 [0.64, 0.95]</strong></td></tr><tr><td>Adjusted</td><td>0.85 [0.70, 1.03]</td><td>0.93 [0.77, 1.13]</td><td>0.97 [0.81, 1.16]</td><td><strong>0.88 [0.82, 0.94]</strong></td><td><strong>0.81 [0.73, 0.90]</strong></td><td><strong>0.84 [0.77, 0.93]</strong></td><td><strong>0.87 [0.81, 0.94]</strong></td><td><strong>0.84 [0.78, 0.91]</strong></td><td>0.98 [0.85, 1.14]</td><td>0.85 [0.66, 1.09]</td></tr><tr><th colspan="11" style="text-align: left; font-weight: bold;">Parental pregnancy HLS</th></tr><tr><td>n included in<br>the model</td><td>n=1012</td><td>n=659</td><td>n=635</td><td>n=6961</td><td>n=3175</td><td>n=2818</td><td>n=3047</td><td>n=2739</td><td>n=150</td><td>n=112</td></tr><tr><td>Unadjusted</td><td><strong>0.79 [0.68, 0.92]</strong></td><td><strong>0.82 [0.71, 0.96]</strong></td><td><strong>0.76 [0.65, 0.90]</strong></td><td><strong>0.81 [0.76, 0.85]</strong></td><td><strong>0.77 [0.71, 0.83]</strong></td><td><strong>0.75 [0.69, 0.81]</strong></td><td><strong>0.76 [0.71, 0.81]</strong></td><td><strong>0.75 [0.70, 0.80]</strong></td><td>1.08 [0.89, 1.31]</td><td><strong>0.73 [0.56, 0.96]</strong></td></tr><tr><td>Adjusted</td><td><strong>0.82 [0.70, 0.96]</strong></td><td>0.86 [0.74, 1.01]</td><td><strong>0.84 [0.71, 0.99]</strong></td><td><strong>0.82 [0.77, 0.87]</strong></td><td><strong>0.78 [0.72, 0.85]</strong></td><td><strong>0.77 [0.71, 0.83]</strong></td><td><strong>0.79 [0.74, 0.85]</strong></td><td><strong>0.80 [0.74, 0.85]</strong></td><td>1.11 [0.92, 1.35]</td><td>0.72 [0.51, 1.02]</td></tr><tr><th colspan="11" style="text-align: left; font-weight: bold;">Infancy HLS</th></tr><tr><td>n included in<br>the model<sup>a</sup></td><td>n=1124</td><td>n=733</td><td>n=701</td><td>n=7139</td><td>n=3401</td><td>n=2981</td><td>n=2712</td><td>n=2438</td><td>n=131</td><td>n=96</td></tr><tr><td>Unadjusted</td><td>0.84 [0.67, 1.04]</td><td>0.93 [0.73, 1.17]</td><td><strong>0.77 [0.61, 0.97]</strong></td><td><strong>0.83 [0.76, 0.92]</strong></td><td><strong>0.77 [0.68, 0.87]</strong></td><td><strong>0.80 [0.71, 0.91]</strong></td><td><strong>0.80 [0.71, 0.90]</strong></td><td><strong>0.69 [0.62, 0.77]</strong></td><td><strong>0.66 [0.46, 0.93]</strong></td><td>0.82 [0.54, 1.26]</td></tr><tr><td>Adjusted</td><td>0.93 [0.74, 1.17]</td><td>1.06 [0.83, 1.35]</td><td>0.92 [0.73, 1.16]</td><td><strong>0.85 [0.76, 0.94]</strong></td><td><strong>0.81 [0.71, 0.92]</strong></td><td><strong>0.81 [0.71, 0.93]</strong></td><td>0.93 [0.82, 1.05]</td><td><strong>0.82 [0.73, 0.93]</strong></td><td>0.73 [0.52, 1.04]</td><td>1.11 [0.73, 1.70]</td></tr><tr><td>Adjusted<sup>b</sup></td><td>1.09 [0.85, 1.39]</td><td>1.28 [0.97, 1.69]</td><td>0.97 [0.75, 1.26]</td><td>0.93 [0.82, 1.05]</td><td>0.90 [0.77, 1.05]</td><td>0.92 [0.79, 1.07]</td><td>1.08 [0.95, 1.24]</td><td>0.94 [0.82, 1.07]</td><td>0.72 [0.49, 1.05]</td><td>1.70 [0.95, 3.04]</td></tr></tbody></table>

Abbreviations: HLS, healthy lifestyle score. OWOB, overweight or obesity. IOTF, International Obesity Task Force. RR, relative risk. CI, confidence interval.

Values are Relative Risks and their 95% confidence intervals (RR [95% CI]) (rounded to 2 decimals) **(in bold when significantly associated)** from robust Poisson regression models: unadjusted, adjusted for parental confounders (i.e., maternal parity, maternal and paternal age, educational level, employment status, country of birth [except in Lifeways where "Mother born outside Ireland" was an exclusion criterion and paternal country of birth was not collected], and household income) and with the use of multiple imputed dataset.

<footnote><sup>a</sup>n included in the model before adjustment for parental HLS.</footnote>

<footnote><sup>b</sup>Additionally adjusted for parental HLS.</footnote>
<table><caption>**Supplemental Table 4.** Associations (unadjusted and adjusted) between the different HLS and childhood abdominal adiposity measured using WHtR z-scores in the EDEN and Lifeways cohorts.</caption><thead><tr><th></th><th colspan="3">EDEN</th><th colspan="2">Lifeways</th></tr><tr><th></th><th>5.5 years</th><th>8 years</th><th>12 years</th><th>5 years</th><th>9 years</th></tr><tr><th></th><th>β</th><th>β [95% CI]</th><th>β [95% CI]</th><th>β [95% CI]</th><th>β [95% CI]</th></tr></thead><tbody><tr><th colspan="6">Maternal pregnancy HLS</th></tr><tr><td>n included in the model</td><td>n=1105</td><td>n=597</td><td>n.a.</td><td>n=408</td><td>n=231</td></tr><tr><td>Unadjusted</td><td><strong>-0.06 [-0.12, -0.01]</strong></td><td>-0.05 [-0.12, 0.03]</td><td>n.a.</td><td>-0.03 [-0.13, 0.06]</td><td><strong>-0.16 [-0.29, -0.04]</strong></td></tr><tr><td>Adjusted</td><td>-0.05 [-0.11, 0.004]</td><td>-0.04 [-0.11, 0.04]</td><td>n.a.</td><td>-0.03 [-0.12, 0.07]</td><td>-0.11 [-0.24, 0.02]</td></tr><tr><th colspan="6">Parental pregnancy HLS</th></tr><tr><td>n included in the model</td><td>n=1012</td><td>n=554</td><td>n.a.</td><td>n=148</td><td>n=112</td></tr><tr><td>Unadjusted</td><td><strong>-0.06 [-0.10, -0.01]</strong></td><td>-0.02 [-0.08, 0.03]</td><td>n.a.</td><td>0.00 [-0.11, 0.12]</td><td>-0.11 [-0.24, 0.01]</td></tr><tr><td>Adjusted</td><td><strong>-0.05 [-0.10, -0.01]</strong></td><td>-0.02 [-0.08, 0.05]</td><td>n.a.</td><td>0.03 [-0.09, 0.14]</td><td>-0.10 [-0.24, 0.03]</td></tr><tr><th colspan="6">Infancy HLS</th></tr><tr><td>n included in the model<sup>a</sup></td><td>n=1124</td><td>n=612</td><td>n.a.</td><td>n=131</td><td>n=97</td></tr><tr><td>Unadjusted</td><td><strong>-0.09 [-0.16, -0.03]</strong></td><td>-0.08 [-0.17, 0.01]</td><td>n.a.</td><td>-0.17 [-0.37, 0.03]</td><td>-0.23 [-0.51, 0.04]</td></tr><tr><td>Adjusted</td><td><strong>-0.07 [-0.14, -0.0007*]</strong></td><td>-0.05 [-0.15, 0.04]</td><td>n.a.</td><td>-0.10 [-0.30, 0.11]</td><td>-0.07 [-0.36, 0.21]</td></tr><tr><td>Adjusted<sup>b</sup></td><td>-0.04 [-0.11, 0.04]</td><td>-0.03 [-0.13, 0.07]</td><td>n.a.</td><td>-0.11 [-0.34, 0.11]</td><td>0.13 [-0.18, 0.44]</td></tr></tbody></table>

Abbreviations: HLS, healthy lifestyle score. WHtR, waist-to-height ratio. β, Beta. CI, confidence interval. n.a., not available.

Values are Beta and their 95% confidence intervals (β [95% CI]) (rounded to 2 decimals) **(in bold when significantly associated)** from linear regression models: unadjusted, adjusted for parental confounders (i.e., maternal parity, maternal and paternal age, educational level, employment status, country of birth [except in Lifeways where "Mother born outside Ireland" was an exclusion criterion and paternal country of birth was not collected], and household income) and with the use of multiple imputed dataset.

*Significantly associated as the confidence interval does not contain 0.

<sup>a</sup>n included in the model before adjustment for parental HLS.

<sup>b</sup>Additionally adjusted for parental HLS.