Childhood Obesity Risk Assessment Longitudinal Study

Childhood obesity is a major public health problem worldwide. Europe has a high prevalence of obesity, which is accentuated in Mediterranean countries. Spain has a high prevalence of both overweight (percentage: 21.5 in boys and 22.2 in girls) and obesity (percentage: 10.6 in boys and 11.8 in girls) in children aged 6-9 years.

From childhood, obesity is associated with an increased risk of diseases such as insulin resistance, type 2 diabetes, hypertension, metabolic syndrome, musculoskeletal problems, sleep disorders and mental health problems. Obesity is a complex, multi-causal problem involving individual risk factors such as behavior and genetics. Behavioral factors include diet, physical activity, sedentary lifestyle, sleep, and others. It is therefore important to study each of the individual risk factors for obesity. There are few large sample studies in European/Spanish children and no longitudinal studies estimating the incidence of obesity in preschool children based on exposure to different risk factors, considering not only the effect of food consumption but also dietary habits and patterns.

The aim of the present study is to identify risk factors for childhood obesity through long-term longitudinal follow-up.

This is a longitudinal, multi-centre prospective cohort study of children aged 3-6 years with annual data collection for an average follow-up of 10 years.

The main objective of the present study is to identify risk factors for childhood obesity through long-term longitudinal follow-up. At least 2,214 participants are required.

The specific objectives are as follows:

1. Assess the associations between perinatal risk factors, socioeconomic, cultural and environmental factors and the risk of developing obesity and its comorbidities.
2. Assess the associations between lifestyles (diet, beverage consumption, physical activity, sedentary lifestyle, sleep) and the risk of developing obesity and its comorbidities.
3. Evaluate the association between genetic polymorphisms, metabolomic and metagenomic profiles (determined by omics techniques) and the development of obesity and its comorbidities.

Study design

The selection visit includes:

A) The administration of a face-to-face questionnaire to check eligibility criteria. Only if the participant is eligible the screening visit will proceed to b).

B) Explanation and clarification of any doubts about the study, delivery of the study information sheet to the participant and completion of the informed consent form signed by both parents (essential for inclusion in the study).

C) The family will be provided with a 3-day prospective food record (2 working days and 1 weekend day), the general data collection booklet and the following questionnaires: adherence of the primary tutor to the Mediterranean diet, dietary behavior, psychosocial, active lifestyle, sedentary behavior and sleep patterns. These questionnaires are to be returned at the next visit.

D) Instructions and bottles for collecting biological samples are given.

Inclusion visit includes:

1. Review of the 3-day food record and all questionnaires from the selection visit.
2. Once the inclusion and exclusion criteria have been evaluated, the participant will be included in the study if all the requirements are met. Then, the next step will be taken.
3. Completion of the 14-point Mediterranean diet adherence questionnaire (to be completed by the primary tutor), baseline questionnaire (height, weight, waist, bioimpedance, blood pressure, child's active lifestyle and Mediterranean diet adherence) and the food and drink frequency questionnaire.
4. Performing a speech fluency test and a fitness assessment examination.
5. Collection of blood, urine, and stools samples.
6. If the participant has an odd-numbered ID, an accelerometer is provided to be used for 7 consecutive days. Collected data must be recorded in a diary.

After the inclusion visit, the participant will undergo two types of follow-up visits in which the following evaluations will be made:

Follow-up visits - Years 01, 02, 04, 06, 07, 08 and 09

1. Baseline questionnaire without collecting biological samples
2. Food frequency questionnaire
3. 14-point Mediterranean diet adherence questionnaire

Follow-up visits - Years 03, 05 and 10 Completion of all questionnaires and determinations corresponding to the inclusion visit.

A window of ±3 months of the corresponding follow-up year since the inclusion visit is allowed.

Justification: The results of this study could help to understand and act on the key determinant factors of the epidemic of overweight and obesity in children.

Long-term follow-up of a large cohort is necessary to develop strategies to combat the serious consequences that overweight and obesity cause on the spanish public health system. This is an important objective and a clear public health priority, since it addresses both the main epidemic of our time (childhood overweight/obesity) as the main cause of healthcare expenditure at increasingly younger ages that makes the current healthcare system unviable (chronic diseases).

The project involves a large number of children from early childhood and follows them over time, covering the key ages for the establishment of dietary habits, lifestyles and adipose rebound. The study can allow the transfer and translation to the general population and the integration of epidemiological, clinical and basic aspects in the proposed research.

Eligibility Criteria:
Inclusion Criteria:

* Children aged 3 to 6 years.
* Compliance with the 3-day food consumption record, the free time physical activity questionnaire and attendance at the scheduled inclusion visit together with the delivery of the signed informed consent.

Exclusion Criteria:

* Children from families with difficulties in participating or complying with the study protocol, as well as difficulties with comprehension, language, or unstable domicile.