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Ethics approval and consent to participate | This study was approved by the China Ethics Committee of Registering Clinical Trials (Registration number: ChiECRCT20200200) and registered at Clinicaltrials.gov (NCT04477733). The study protocol followed the CONSORT guidelines. The study protocol was performed according to the relevant guidelines. Written informed consent was obtained from all patients. | PMC10044711 | ||
Consent for publication | Not Applicable. | PMC10044711 | ||
Competing interests | The authors declare no competing interests. | PMC10044711 | ||
References | PMC10044711 | |||
1. Introduction | cardiometabolic disease, weight loss, cardiovascular dysfunction | INSULIN RESISTANCE, CARDIOVASCULAR DISEASE, TYPE 2 DIABETES | Timing of nutrient intake for athletes may affect exercise performance and cardiometabolic factors. Our objective was to examine the effect of time-restricted eating (TRE) on cardiometabolic health. Using a cross-over study design, 15 endurance-trained male runners were randomized to either a normal dietary pattern (ND) first (12 h eating/fasting times) followed by time-restricted eating (TRE) pattern (16 h fast; 8 h eating) or the reverse, with a 4-week washout period between interventions. Body composition, resting energy expenditure, blood pressure and serum insulin, glucose and lipids were measured using standard laboratory methods. Exercise training and dietary intake (calories and macronutrients) were similar across interventions. No significant differences were observed in resting energy expenditure, markers of insulin resistance, serum lipids or blood pressure. Body composition did change significantly (There are various forms of intermittent fasting (IF). This manuscript will focus on time-restricted eating (TRE), a form of IF that is growing in popularity. This regimen involves a decrease in the window of eating each day, essentially extending the overnight fast, which may or may not result in a decrease in caloric intake. This dietary approach can be used by overweight/obese individuals looking to lose body fat and improve their overall health. Likewise, this diet can also be used by normal weight and otherwise healthy persons who want to improve their health independent of weight loss. Studies show that by extending the overnight fast, as done with TRE, one can expect to see a decrease in risk for various metabolic conditions such as cardiovascular disease, type 2 diabetes, and more. One iteration is the “16/8” diet, where individuals fast for 16 h of the day and eat ad libitum for the remaining 8 h [One important consideration unique to endurance-trained athletes is that they are at risk for being in a low energy availability (LEA) state, which can lead to cardiovascular dysfunction as evidenced by disturbances in the blood lipid profile [Peer-reviewed literature is sparse and contains conflicting information about the effects of TRE in athletes. In addition, we know of no study that had used a longitudinal randomized crossover design. Thus, the aim of this study is to examine the effects of four weeks of the 16/8 TRE diet compared to a normal eating window of 12 h fasting and 12 h eating on body composition, resting energy expenditure, and biomarkers of cardiometabolic disease risk using a randomized crossover study design in competitive male endurance runners. | PMC9961388 |
2. Materials and Methods | PMC9961388 | |||
2.1. Experimental Design | In this cross-over intervention, subjects were randomly assigned to start the study with either a traditional 12-h eating window (12/12) (ND) or a time-restricted 8-h eating window (16/8) (TRE). Diets were self-selected, and subjects were instructed to consume isocaloric diets of the similar macronutrient composition based on diet records kept during the first arm of the study. A normal eating window of 12 h fasting and 12 h eating was modeled after the study designed my Moro, et al. to compare results in resistance-trained versus endurance-trained athletes. Details of the study design, subjects and performance testing are provided in Tovar, et al. [ | PMC9961388 | ||
2.2. Subjects | To be included, subjects were required to be born male, have been actively training for the past 3 years, run ≥ 32 km/wk, have competed in a race ≥ 5 km within the last 12 mo, have a maximal oxygen consumption (VO | PMC9961388 | ||
2.3. Familiarization Visit | RECRUITMENT | Following recruitment, subjects visited the USDA, ARS, Western Human Nutrition Research Center (WHNRC) at the University of California at Davis campus to learn the study parameters and receive instruction using in-house equipment. After signing the informed consent, subjects then completed a health history questionnaire prior to collecting height and weight. After receiving medical clearance by a study physician, subjects engaged in a self-selected 10-min warm up on a treadmill (TMX425 medical treadmill, Trackmaster, Newton, KS, USA), and then completed a treadmill graded test to determine VO | PMC9961388 | |
2.4. Test Day Protocol | Four research test days were scheduled with one at the beginning and end of each of the 4-week periods. Subjects arrived following an overnight fast and were asked to only drink water. They had been instructed to refrain from exercise for 24 h, follow a consistent hydration pattern, and consume the same meal the night before each test day. Upon arrival, body mass was measured on a calibrated electronic scale (Tanita BWB-627A Class III electronic scale; Toledo Scale), height was measured with a wall-mounted stadiometer (Ayrton Stadiometer, Model S100; Ayrton Corp., Prior Lake, MN, USA) and resting energy expenditure (REE) was measured using a metabolic cart (TrueOne 2400, ParvoMedics, Sandy, UT, USA). | PMC9961388 | ||
2.5. Resting Energy Expenditure | Subjects rested for 10 min in a supine position in a dark, quiet room. Respiratory gases were then collected for 20 min. Data from the first 5 min were excluded from analysis to account for subject adjustment to the protocol. The Weir equation was used to determine rate of kcal/day (Equation (1)). Because nitrogen excretion is minimal in such a short period of time, the nitrogen correction was ignored [Energy derived from total carbohydrate and lipid oxidation was calculated using the following equations (Equation (2)) assuming protein oxidation was close to zero for this brief time period [ | PMC9961388 | ||
2.6. Blood Pressure | orthostatic tolerance | Immediately after the REE determination and before standing, resting blood pressure (BP) was measured manually with a single-hosed sphygmomanometer and stethoscope by the same investigator for all trials. After supine blood pressure was measured, subjects were asked to stand for 5 min before collecting standing blood pressure to determine orthostatic tolerance [ | PMC9961388 | |
2.7. Body Composition | A whole-body dual-energy X-ray absorptiometry (DXA) (Hologic Discovery QDR Series 94994; Hologic, Inc.) scan was performed for determination of body composition. The DXA scanner was calibrated prior to each use by the same trained and licensed technician. The scan provided values for total fat mass, total lean mass, body fat percentage, peripheral lean mass, peripheral fat mass, an estimate of android and gynoid fat mass distribution, bone density, bone density z-score and bone mineral mass. All DXA scans were analyzed by a single operator to minimize variance in the results. | PMC9961388 | ||
2.8. Blood Analyses | STERILE, BLOOD | Fasting blood samples were collected using sterile, disposable materials by a licensed phlebotomist. Blood was drawn directly into SST vacutainers. SST tubes sat at room temperature for 30 min and were then centrifuged in a refrigerated Centra CL3R (International Equipment Co.) for 10 min at 100× Insulin was measured in duplicate using Meso Scale Delivery (MSD) Multi-plex Assay System and were conducted according to the manufacturer’s instructions. Briefly, 150 uL of Blocker A was added to each well of the MSD plate, which was then sealed, incubated and shook (1000 rpm) for one hour at room temperature. The plate was then washed with phosphate-buffered saline plus 0.05% Tween-20 (PBS-T), and 50 uL of the sample and standard were added to each well. The plate was then sealed, incubated and shook (1000 rpm) for 2 h at room temperature. The plate was washed again with PBS-T and then 25 uL of detection antibody solution was added to each well. The plate was then sealed, incubated and shook (1000 rpm) at room temperature for one hour. The plate was washed for a final time with PBS-T and then 150 uL of Read Buffer T was added to each well. The plate was read on the MSD QuickPlex SQ 120 imager and quantified using an 8-point standard curve. Insulin concentrations were used to calculate HOMA-IR and QUICKI (Equation (3)).
| PMC9961388 | |
2.9. Statistical Analysis | Johnson transformation | All analyses were done using JMP Pro 14 (SAS Institute Inc, Cary, NC, USA). For each variable, the change from pre- to post-intervention was calculated, and the effects of diet intervention, sequence and interaction were analyzed using a mixed linear model. All variables that were not considered normally distributed were normalized using a Johnson transformation. Post hoc analysis was performed with the Tukey’s test. Significance was set at | PMC9961388 | |
3. Results | PMC9961388 | |||
3.2. Resting Energy Expenditure | After 4 weeks, there was no significant difference between the TRE and ND interventions for resting energy expenditure, resting respiratory exchange ratio, resting energy expenditure by body mass and resting energy expenditure by fat-free mass ( | PMC9961388 | ||
3.3. Body Mass and Composition | We have previously reported [ | PMC9961388 | ||
3.4. Bone Mineral Density | DXA results for bone mineral density and bone mineral density z-score can be found in | PMC9961388 | ||
3.5. Insulin Resistance and Sensitivity | Fasting blood glucose and insulin concentrations were not different between interventions and are shown in | PMC9961388 | ||
3.6. Blood Pressure | No significant differences were observed for systolic or diastolic blood pressure in the supine position or after 5 min of standing between diet interventions ( | PMC9961388 | ||
3.7. Circulating Lipids and Lipoproteins | No differences in total cholesterol and triglycerides, as well as VLDL-, LDL-, HDL- or non-HDL-cholesterol (nHDLc), were detected between diet interventions ( | PMC9961388 | ||
4. Discussion | overweight, cardiovascular disease | OBESE, INSULIN RESISTANCE, CARDIOVASCULAR DISEASE | This report extends the original findings from our TRE study in endurance-trained athletes [The present study is one of just a few studies to investigate the effects of the 16/8 time-restricted eating diet in trained athletes. To our knowledge, there is only one other study conducted in endurance-trained athletes. Brady et al. [Moro et al. studied the 16/8 diet in resistance-trained males while maintaining similar caloric and macronutrient intake and in a similar design, Tinsley et al. investigated a 16/8 TRE diet combined with an 8-week resistance training program, but in resistance-trained female athletes [Interestingly, considering that the energy and macronutrient intake and running distance each week were not significantly different between interventions, a significant decrease in RER was not observed, indicating no significant shift to utilize more fat and less carbohydrate and/or glycogen. There was a slight observed decrease in RER with TRE, and it is conceivable that RER would have decreased significantly if the study duration was longer than 4 weeks or if the present study employed more subjects. Future studies should include a longer intervention to determine if dietary duration may affect this result.It should be noted that it does appear that maintaining energy intake is vital when adopting TRE to achieve goals related to loss of fat mass. The 650 kcal deficit reported in the Tinsley et al. study could cause the body to enter a “conservation mode” or “survival mode” where the body perceives starvation and will employ a number of metabolic adaptations, such as decreasing resting metabolic rate and improving metabolic efficiency, in an attempt to preserve energy and body fat [The primary objective of our study was to determine if the TRE diet intervention affected cardiometabolic variables differently than the response to the normal diet intervention. Traditional clinical markers of cardiovascular disease were not affected by TRE in the present study. This is not surprising because they were actively training, and longer bouts of aerobic exercise lead to greater reliance on free fatty acids for energy production [There is growing evidence to support the notion that TRE can be utilized to combat insulin resistance; however, this has primarily only been studied in overweight and obese populations [Several limitations to the present study should be discussed. For example, participants were allowed to choose the time frame for their window of eating. The window of eating was not standardized because a study by Hutchison et al. showed no difference in fasting glucose, insulin, triglycerides, non-esterified fatty acids or gastrointestinal hormones between early TRE (eating window 8 am to 5 pm) and delayed TRE (12 pm to 9 pm). While they did not examine a full lipid panel, this study provides some insight to the notion that the window of meal timing may not matter with TRE diets [ | PMC9961388 |
5. Conclusions | caloric deficit diet | EVENT | These results suggest that endurance athletes adhering to an isocaloric 16/8 TRE dietary pattern for 4 weeks experienced no identifiable adverse changes in the cardiometabolic risk factors. Athletes who are trying to reduce fat mass before an event should consider adopting a TRE dietary pattern as opposed to a caloric deficit diet in order to maintain fat-free mass and resting energy expenditure. | PMC9961388 |
Author Contributions | Conceptualization: C.E.R., A.P.T., N.L.K., M.D.V.L. and G.A.C.; Methodology: A.P.T., C.E.R., N.L.K., M.D.V.L., B.A.D. and G.A.C.; Formal analysis: A.P.T. and C.E.R.; Investigation: A.P.T., C.E.R., N.L.K., B.A.D. and G.A.C.; Writing—initial draft: C.E.R.; Reviewing and editing: A.P.T., C.E.R., N.L.K., M.D.V.L., B.A.D. and G.A.C.; All authors have read and agreed to the published version of the manuscript. | PMC9961388 | ||
Institutional Review Board Statement | MAY | The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Review Board of the University of California Davis, IRB protocol number 1223350 (24 May 2018). Informed consent was obtained from all participants prior to enrolling in the study. | PMC9961388 | |
Informed Consent Statement | Informed consent was obtained from all subjects involved in the study. | PMC9961388 | ||
Data Availability Statement | The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy concerns. | PMC9961388 | ||
Conflicts of Interest | The authors declare no conflict of interest. | PMC9961388 | ||
Objective | Evidence shows that dialogic book-sharing improves language development in young children in low-middle income countries (LMICs), particularly receptive and expressive language. It is unclear whether this intervention also boosts development of other neurocognitive and socio-emotional domains in children. Using a randomized controlled trial (RCT) nested in the Drakenstein Child Health Study (DCHS), a book-sharing intervention was implemented in caregivers of 3.5-year-old preschool children living in low-income South African communities. | PMC10728827 | ||
Methods | 122 Caregivers and their children (mean age 3.5 years) were randomly assigned to an intervention group ( | PMC10728827 | ||
Results | No differences were observed between intervention and control groups on receptive and expressive language, or any of the neurocognitive or socio-emotional measures from baseline (3.5 years) to 4 months post-intervention administration (4 years). | PMC10728827 | ||
Keywords | PMC10728827 | |||
Introduction | EVENTS | Dialogic book-sharing (DBS) is a parenting reading method used to stimulate reciprocal interactions between young children and their caregivers [As book-sharing can draw focus to various themes and explore the meaning of events [The aim of the present study was to examine the neurocognitive and socio-emotional effects of a DBS intervention in a sample of LMIC preschool children over a period of six months (3.5–4 years), compared to a waitlist control group receiving care as usual. The impact of dialogic book-sharing on receptive and expressive language, verbal fluency, executive function, attention, and basic theory of mind development of the intervention group was assessed by comparing standardized test scores between the two groups, pre- and post-intervention. We hypothesized that, at post-intervention, the intervention group would perform better than the control group on receptive and expressive language measures, as well as on measures of neurocognitive and socio-emotional development. We are testing whether any improvement in performance among the intervention group between pre- and post-intervention is greater than any improvement in performance seen among the control group. | PMC10728827 | |
Methods | PMC10728827 | |||
Study design | We conducted a randomized controlled trial (RCT) to evaluate a dialogic book-sharing intervention for parents or caregivers of children aged 3.5 years. This RCT was retrospectively registered with the Pan African Clinical Trials Registry on 03/04/2022 (PACTR202204697674974). This RCT was nested in the Drakenstein Child Health Study (DCHS), an observational cohort study that recruited pregnant women and collected longitudinal data on an array of variables influencing maternal and child health outcomes [ | PMC10728827 | ||
Study setting | trauma | HIV INFECTION | The DCHS recruited participants from two peri-urban relatively stable, low socioeconomic communities (Mbekweni and Paarl East). The former is predominantly an isiXhosa speaking community, and the latter, an Afrikaans speaking community. These communities experience a high prevalence of substance use, exposure to trauma, HIV infection, and poverty [ | PMC10728827 |
Sample selection and size | miscarriage | MISCARRIAGE, RECRUITMENT | Pregnant women were recruited from two primary health care clinics for the main DCHS study. Mothers were enrolled at 20 to 28 weeks' gestation while attending routine antenatal care and were prospectively followed. Women were eligible for the study if they were 18 years or older, between 20 and 28 weeks gestation, planned attendance at one of the two recruitment clinics, and intended to remain in the area. During a three-year period (March 2012 to March 2015), 1225 pregnant women were enrolled into the DCHS antenatally; 88 (7.2%) mothers were lost to follow up antenatally, had a miscarriage or a stillbirth. In total, 1137 women gave birth to 1143 live infants (4 twins and 1 triplet).For the present study, mother-infant dyads recruited by the DCHS were eligible for inclusion if the children were aged 41 to 43 months at the time of baseline assessment. An adult primary caregiver who cohabited with the child was a prerequisite. Twins and/or children with known neurodevelopmental delay or sensory impairment were excluded. A total of 122 eligible caregiver-child dyads were recruited from the relevant age group in the cohort; 61 dyads were randomized into the intervention group and 61 dyads into the waitlist control group, receiving care as usual. | PMC10728827 |
Measures | All measures were administered in the child's home language as all measures were translated into Afrikaans and isiXhosa. | PMC10728827 | ||
Language | Receptive and expressive language was measured using the Peabody Picture Vocabulary Test, fourth edition (PPVT-4) [ | PMC10728827 | ||
Selective attention | visual inattention | The Balloon Hunt Task is a paper-and-pencil task from TEA-Ch2 J (5–7 years) designed to evaluate visual inattention [ | PMC10728827 | |
Executive function | CARD | Working memory was assessed using the Picture Memory task from the Wechsler Preschool and Primary Scale of Intelligence, fourth edition (WPPSI-IV) [The Dimensional Change Card Sort (DCCS) [The adapted Stroop-like day-night task assesses the child's ability to inhibit an automatic response. In the control trials, the child is required to say “dog” when shown the dog card, and “banana” when shown the banana card. In the conflict condition, the child was required to say the opposite of what is shown on a set of cards (children were instructed to say “dog” when presented with the banana card, and vice versa). There were 2 practice trials and 10 test trials for each condition. The cards were presented in the same order across the sample [ | PMC10728827 | |
Social cognition | Theory of Mind was examined using Diverse Desires and Diverse Beliefs tasks from the early and basic modules of the UCT Theory of Mind battery [ | PMC10728827 | ||
Internalizing and externalizing behavior | The Child Behavior Checklist (CBCL for children aged 1.5–5 years) [ | PMC10728827 | ||
Procedures | PMC10728827 | |||
Study procedures | Consecutive children attending the standard 3.5-year psychosocial assessment of the DCHS were recruited by DCHS fieldworkers for the book-sharing intervention. After enrolment, block randomization to an intervention or control group which was completed off-site. Post-randomization confirmation was obtained that the gender of the children was evenly distributed among both groups. Outcome measures were collected at the 3.5-year psychosocial DCHS visit (baseline for the present study), and post-intervention 6 months later (4 years). Following the 3.5-year visit, the intervention group underwent the book-sharing intervention. The DCHS design allows only a few visits per year to reduce participant burden, the post-intervention assessments were scheduled for the 4-year psychosocial visit. During the pre- and post-intervention assessments, where needed, isiXhosa translators were used during assessments. Numerous breaks were given between tasks to ensure that the child did not get too tired, as assessments took approximately one hour to complete. Participants were reimbursed for travel expenses. | PMC10728827 | ||
Randomization and blinding | This parallel intervention used permuted block randomization. Group allocation was determined by the holder of the sequence who was situated off-site. Participants were allocated to the intervention group ( | PMC10728827 | ||
Intervention program | The intervention commenced in April 2018 and ran to completion in December 2019. The book-sharing program is a group-based parenting intervention based on previous programs implemented and investigated in similar settings in South Africa [Weekly themes of intervention sessions with accompanying books.Denotes books with pictures only.Books are available in isiXhosa and Afrikaans and were provided in these languages.Book only available in English.The interventionists, who were first language speakers of the languages the intervention was administered in, were trained in book-sharing methods by The Mikhulu Trust (Intervention adherence was determined using participant feedback. The sessions were conducted on the same day, time, and place every week. The interventionists made telephonic contact with participants once a week to remind them of the next session. At the beginning of each session, participants were asked to provide feedback regarding their home book-sharing experiences. 69% of the intervention participants attended at least 6 out of 8 intervention sessions. | PMC10728827 | ||
Data analysis | REGRESSION | Intervention and control groups were first compared on social, maternal and child factors at baseline to assess efficacy of the randomization method in producing equivalent groups, using means and standard deviations for continuous variables and frequencies with corresponding percentages for categorical variables. Chi-squared tests (and Fisher tests for infrequent cell counts) were used to compare groups on categorical variables, whilst We ran intention-to-treat (ITT) analyses and included all participants who were enrolled in the RCT, even if they dropped out of the program. A series of complete-case linear mixed-effect models (LMM) using restricted maximum likelihood estimation were conducted in For measures that were only conducted at the post-intervention session, including the Balloons Task, a simple linear regression was run to compare performance between intervention and control groups. Conversely, for the DCCS and Diverse Beliefs tasks, given the dichotomous nature of scoring, logistic regression models were run. | PMC10728827 | |
Results | PMC10728827 | |||
Discussion | non-language neurocognitive | Book-sharing was no more effective than normal development in the waiting list control on receptive and expressive language, as well as neurocognitive and socio-emotional measures, at post-intervention. Both groups improved, as expected, with age when comparing test scores 6 months later.Contrary to individual studies reporting improvements across age ranges [A number of limitations to our study deserve emphasis. First, the sample size was relatively small. However, our sample size is similar to those of previously published DBS studies. Future studies should include larger sample sizes to accurately examine the effects of a book-sharing intervention on receptive and expressive language in older preschool children. Second, at times, assessments were conducted with the use of interpreters; ideally the assessor should be fluent in the child's first language. Third, this book-sharing intervention was relatively short to expect noticeable non-language neurocognitive and socio-emotional variables. An intervention longer in duration may be beneficial in samples where reading and book-sharing are a novel concept as it may help with acceptance and uptake of the intervention homework. Finally, as noted above, the post-intervention assessment was conducted 4 months after the conclusion of the intervention. The null findings may be indicative of failed maintenance efforts rather than the intervention itself. | PMC10728827 | |
Conclusions | neurocognitive and socio-emotional differences | In children aged 3.5 years in a LMIC country setting, dialogic book-sharing did not improve language proficiency (receptive and expressive language), or neurocognitive and socio-emotional gains at 4 months post-intervention. Possible reasons for these findings include that there may be a critical period in which to implement book-sharing interventions to produce noticeable neurocognitive and socio-emotional differences. The findings suggest the importance of early intervention and emphasizes the need for further research on adaptation of book-sharing for older participants in a South African context. | PMC10728827 | |
Trial registration | This trial was retrospectively registered on the Pan African Clinical Trial Registry on 03/04/2022; PACTR202204697674974. | PMC10728827 | ||
Ethics approval and consent to participate | Specific approval was obtained for the Book-sharing RCT protocol (543/2017) from the Faculty of Health Sciences, Human Research Ethics Committee, University of Cape Town. Mothers provided informed consent at enrolment and yearly after that. Informed consent was obtained for all participants in their preferred language: English, Afrikaans, or isiXhosa, before the onset of the study. The DCHS was approved by the Faculty of Health Sciences, Human Research Ethics Committee, University of Cape Town (401/2009) and by the Western Cape Provincial Health Research committee. This study was conducted in accordance with the Declaration of Helsinki. | PMC10728827 | ||
Competing interests | The intervention was conceptualized by PC and DJS, with guidance from LM and HJZ. All other authors declare no conflicts of interest. | PMC10728827 | ||
Declaration of interest | DJS and HJZ are funded by the South African Medical Research Council (SAMRC). | PMC10728827 | ||
Funding | The RCT was conducted with no additional funding beyond what the DCHS already received. Support for the DCHS was provided by the | PMC10728827 | ||
References | PMC10728827 | |||
Data availability | The Drakenstein Child Health Study is committed to the principle of data sharing. De-identified data will be made available to requesting researchers as appropriate. Requests for collaborations to undertake data analysis are welcome. More information can be found on our website [ | PMC10728827 | ||
Acknowledgements | We thank the mothers and their children for participating in the study and the study staff, the clinical and administrative staff of the Western Cape Government Health Department at Paarl Hospital and at the clinics for support of the study. The Mikhulu Trust ( | PMC10728827 | ||
Key Points | PMC10690460 | |||
Question | Is skin-to-skin contact (SSC) between parents and their very preterm infants immediately after birth more effective than standard incubator care in enhancing mother-infant interaction at 4 months? | PMC10690460 | ||
Findings | SECONDARY | In this secondary analysis of a randomized clinical trial including video recordings of 71 mother–very preterm infant dyads in interaction during free play, SSC provided by a parent during the first 6 hours after birth significantly enhanced child interactive behaviors and positive affect at 4 months. | PMC10690460 | |
Meaning | SECONDARY | These findings suggest that alongside necessary nursing and medical care, clinical practices should support the mother-infant relationship by promoting immediate SSC with a parent after birth.This secondary analysis of the IPISTOSS randomized clinical trial examines the effect of immediate skin-to-skin contact at birth for very preterm infants on mother-infant interaction quality at 4 months of corrected infant age. | PMC10690460 | |
Importance | Good-quality parent-infant interactions have protective effects on infant socio-emotional and behavioral development. These interactions are especially critical for very preterm infants at risk of vulnerabilities related to immaturity. Skin-to-skin contact (SSC) has been found to improve mother–preterm infant interaction behaviors, but few studies exist regarding its benefits when initiated immediately after birth. | PMC10690460 | ||
Objective | To determine the effect of immediate SSC at birth for very preterm infants on mother-infant interaction quality at 4 months of corrected age. | PMC10690460 | ||
Design, Setting, and Participants | SECONDARY | This secondary analysis used data from the Immediate Parent-Infant Skin-to-Skin Study (IPISTOSS), a randomized clinical trial conducted between April 1, 2018, and June 30, 2021, at 3 neonatal units in Sweden and Norway. Participants included very preterm infants (28-33 gestational weeks of age) and their parents. Four-month follow-up was concluded in December 2021. Data analyses were performed on March 16 and September 18, 2023. | PMC10690460 | |
Intervention | Infants were allocated to standard incubator care or SSC with either parent initiated at birth and continued throughout the first 6 hours after birth. | PMC10690460 | ||
Main Outcomes and Measures | REGRESSION | The primary outcome was mother-infant interaction quality as measured with the Parent–Child Early Relational Assessment (PCERA), based on video recordings of a 5-minute free-play situation with mother-infant dyads at 4 months of corrected age. A multilevel regression analysis was performed. | PMC10690460 | |
Results | This analysis included 71 infants (31 twins [44%]) and 56 mothers. Infants had a mean (SD) gestational age of 31 weeks 3 (1.3) days, and more than half were male (42 [59%]); mothers had a mean (SD) age of 32 (4.9) years. There were 37 infants allocated to standard care and 34 to SSC with either parent after birth. During the first 6 hours after birth, fathers provided more SSC than mothers, with a median (IQR) of 3.25 (2.25-4.5) and 0.75 (0-2.5) hours, respectively. A statistically significant difference in 1 of 5 PCERA subscales (subscale 3: infant positive affect, communicative and social skills) was observed, with higher-quality mother-infant interaction in the SSC group at 4 months (Cohen | PMC10690460 | ||
Conclusions and Relevance | PRETERM BIRTH | In this study of the effect of immediate parent-infant SSC after very preterm birth, SSC was beneficial for the mother-infant relationship. These findings suggest that immediate SSC should be supported in the clinical setting. | PMC10690460 | |
Trial Registration | ClinicalTrials.gov Identifier: | PMC10690460 | ||
Introduction | SECONDARY | Skin-to-skin contact (SSC) is an evidence-based method of care that involves placing the naked infant on the parent’s bare chest. The SSC method is routinely practiced intermittently for preterm infants in the neonatal unit. Because of its multiple benefits, SSC between newborn infants and mothers provided in the immediate period after birth is considered the standard of care.Good-quality early parent-infant interactions have protective effects on infant social-emotional, cognitive, and behavioral developmentSkin-to-skin contact provides an environment that is sensitive to the infant’s needs and gives opportunities for emotionally supportive interactions that stimulate brain growth and development.There seem to be critical time points after birth when SSC is especially important for the developing parent-infant relationship. Yet evidence remains scarce as to whether parent-infant SSC initiated immediately after birth for preterm infants is more beneficial than standard incubator care (with later initiation of SSC), in terms of supporting the mother-infant relationship. Thus, the main objective of this study was to determine the effect of immediate SSC at birth for very preterm infants on mother-infant interaction at 4 months of corrected infant age. An exploratory and secondary objective was to investigate whether the potential relationship between immediate SSC after birth and mother-infant interaction at 4 months would be mediated through accumulated SSC in the early postpartum period (within 72 hours and 8 days after birth). We hypothesized that SSC provided to the very preterm infant within the first hours after birth improves mother-infant interaction quality in infancy. | PMC10690460 | |
Methods | PMC10690460 | |||
Study Design | SECONDARY | This secondary analysis reports on a secondary outcome from the Immediate Parent-Infant Skin-to-Skin Study (IPISTOSS), a randomized clinical trial with 2 parallel, nonblinded groups conducted between April 1, 2018, and June 30, 2021. | PMC10690460 | |
Setting and Population | major malformations | CONGENITAL INFECTION, PRETERM LABOR | The IPISTOSS study was conducted at 2 neonatal units at Karolinska University Hospital in Stockholm, Sweden, and at the neonatal unit at Stavanger University Hospital in Stavanger, Norway. Screening was performed for women admitted to obstetric units with threatening preterm labor. This study included inborn infants (singletons or twins) with a gestational age of 28 weeks 0 days to 32 weeks 6 days, regardless of birth mode. Infants with congenital infection, major malformations, or other conditions deemed contraindicating to participation were excluded. | PMC10690460 |
Intervention and Procedure | cot | The intervention consisted of SSC between either parent and their very preterm infant (or infants) initiated immediately after birth (SSC group) and continued throughout the first 6 hours after birth and was compared with conventional care in an incubator or cot (control group). Electronic randomization was performed by research staff when birth was imminent. Twins were allocated to the same study group. During the intervention period, only the place of care differed; all other monitoring, nursing, and medical care were identical in both groups, as previously described in the IPISTOSS research protocol in | PMC10690460 | |
Intervention | After vaginal birth, SSC was initiated immediately, or as soon as possible, on the mother’s chest, with positioning assisted by the neonatal team. The infant was cared for initially in the birth unit and later transferred to the neonatal unit while maintaining SSC with either parent. After cesarean delivery, SSC was initiated with the father until the mother could be transferred to the neonatal intensive care unit. Twins were either cared for with one parent each or placed together with one of the parents. | PMC10690460 | ||
Conventional Care | cot | Infants allocated to the control group were stabilized in a warmer (Resuscitaire; GE Healthcare) or in an incubator and then transported to the neonatal unit in an incubator. Intermittent SSC was initiated after the first 6 hours. Parents in the control group were allowed to stay at their infant’s bedside and were able to touch the infant in the incubator or cot. | PMC10690460 | |
Follow-Up Visit at 4 Months | Depression, ±2 | A follow-up visit was conducted at 4 months (±2 weeks) of corrected infant age in the clinic or at participant homes (in Sweden, 20 visits [57%] were conducted at participant homes due to hospital restriction policies during the COVID-19 pandemic). The visit was made in the morning at a time when the infant preferably had slept and was newly fed. Baseline data regarding maternal mental health (Edinburgh Postnatal Depression Scale | PMC10690460 | |
Outcome Assessment | PMC10690460 | |||
Duration of SSC | Duration of SSC (in hours per day) was recorded with the Parent-Infant Closeness Diary | PMC10690460 | ||
Mother-Infant Interaction Quality | Mother-infant interaction quality was assessed with the Parent–Child Early Relational Assessment (PCERA) | PMC10690460 | ||
Statistical Analysis | The IPISTOSS sample size was calculated for the main outcome variable of infant cardiorespiratory stability. | PMC10690460 | ||
Results | PMC10690460 | |||
Study Participants | depression, anxiety | This study included 71 infants (31 twins [44%]) and 56 mothers in the PCERA analysis at 4 months. Infants had a mean (SD) gestational age of 31 weeks 3 (1.3) days and a mean (SD) birthweight of 1535 (408) g; 42 (59%) were boys and 29 (41%) were girls. Mothers had a mean (SD) age of 32 (4.9) years; 32 (57%) were primiparous. A total of 37 infants were allocated to standard care and 34 to SSC with either parent after birth. Baseline characteristics of infants and mothers, including depression symptoms, anxiety symptoms, and parenting stress, were distributed equally between groups, except there were more boys and first-time mothers in the SSC group ( | PMC10690460 | |
Mother and Infant Characteristics | Depression, Anxiety | Abbreviation: SSC, skin-to-skin contact.Unless indicated otherwise, values are presented as No. (%) of participants.Measured with the Edinburgh Postnatal Depression Scale (score, 0-30).Measured with the Spielberger State-Trait Anxiety Inventory (score, 20-80).Measured with the Swedish Parenthood Stress Questionnaire (score 0-5, with 5 indicating highest level of stress). | PMC10690460 | |
Initiation and Duration of SSC During the Intervention and First 8 Days After Birth | For infants in the SSC group, SSC was initiated at a median (IQR) time of 15 (0-62) minutes after birth. During the intervention period of 0 to 6 hours, the median (IQR) SSC duration was 5.25 (4.5-5.5) hours, and fathers provided more SSC than mothers during this period (3.25 [2.25-4.5] vs 0.75 [0-2.5] hours, respectively). | PMC10690460 | ||
Duration of SSC During Intervention 0 to 6 Hours After Birth and Accumulated Within First 72 Hours and First 8 Days | Abbreviation: SSC, skin-to-skin contact.In the SSC group, data were missing for 2 mothers, fathers, and infants 7 to 72 hours after birth and for 4 mothers, fathers, and infants 7 hours to 8 days after birth. | PMC10690460 | ||
Mother-Infant Interaction at 4 Months for the SSC and Control Groups, by PCERA Subscale | Abbreviations: PCERA, Parent–Child Early Relational Assessment; SSC, skin-to-skin contact.Unadjusted and adjusted | PMC10690460 | ||
Differences Between the Skin-to-Skin Contact and Control Groups on Parent–Child Early Relational Assessment (PCERA) Subscale 3 (Infant Positive Affect, Communicative and Social Skills) | For each group, the beanplot figure displays the mean (bold horizontal lines), the spread of individual observations (small horizontal lines), and the shape of the distributions. | PMC10690460 | ||
Exploratory Analysis: Accumulated SSC Duration Within 8 Days After Birth and Mother-Infant Interaction at 4 Months | After the intervention, infants’ accumulated time of SSC was higher in the SSC group during the first 72 hours, with a median (IQR) of 17 (10.5-25) vs 10 (5.25-13.5) hours in the control group (Cohen | PMC10690460 | ||
Discussion | immature nervous system, ’ | SECONDARY | This protocol-based secondary analysis of a multicenter randomized clinical trial investigated the effect of immediate SSC with a parent after birth on interaction between very preterm infants and their mother. Our findings support the existence of an early sensitive period for very preterm infants after birth. Infant expressions of positive affect, communication, and social skills were most favorable in the mother-infant dyads allocated to immediate SSC. The dyadic interaction was more optimal in the SSC group after adjustment for observation setting. Maternal contributions to interaction quality did not differ between groups. Although SSC initiated at birth was also associated with longer SSC duration during the first week after birth, no effects of accumulated SSC after the first 6 hours on mother-infant interaction were observed.Sensitive periods have been defined as opportunities that exist in early environments. These opportunities are biobehavioral experiences between parents and infants that trigger specific neuroendocrine systems influencing gene expression, brain development, and parent-infant attachment.In this study, enhanced interaction quality in the SSC group was observed for infant PCERA subscale 3, which describes positive affect and communicative and social skills. Furthermore, after adjustment for observation setting, a between-group difference was observed for dyadic PCERA subscale 5, which describes emotional tone, reciprocity and regulation between mother and infant. Thus, immediate SSC seems to be especially beneficial for interactive behaviors of very preterm infants, and it may also benefit the dyadic aspects of interaction. One possible interpretation is that infants exposed to SSC at birth became more mature social partners, making it easier for their mother to respond to and interact with them. As reported previously, preterm infants have an increased risk of less synchronous interactions due to their immature nervous system and diffuse behavioral cues.Interestingly, in our study, fathers provided the most SSC at birth. This finding reflected the clinical situation, with mothers often unavailable for SSC during the first hours after a cesarean birth, for example. The beneficial effect of SSC on interaction was assessed in the mother-infant dyad 4 months later. Our findings showed that the higher-quality mother-infant interaction in the SSC group was driven by the infants’ enhanced social skills. Thus, an important conclusion of the present data might be that from a developmental perspective, time spent in SSC after birth is valuable and may be provided by either parent. This finding highlights the role of fathers in supporting the development of their very preterm infant immediately from birth when the mother is not available, | PMC10690460 |
Strengths and Limitations | This study had several strengths, including its randomized design, which ensured substantially decreased selection bias. The study was well controlled, since only the place of care differed during the intervention. At the 4-month follow-up, 20 (22%) of the originally randomized infants were lost to the PCERA analysis; however, no differences between analyzed infants and dropouts were found, minimizing the risk for attrition bias in this study. Another strength was the robust observational measurement tool used. The PCERA is well used in studies worldwide and suitable for the preterm population,This study had limitations. The sample size was small, due to the main trial being terminated earlier because of benefit of the intervention. | PMC10690460 | ||
Conclusions | PRETERM BIRTH, SECONDARY | In this secondary analysis of the IPISTOSS randomized clinical trial, SSC practiced between a parent and a very preterm infant in the immediate postpartum period after birth enhanced child interactive behaviors and positive affect at 4 months of corrected infant age. Skin-to-skin contact may also benefit the dyadic aspects of interaction. These findings support the existence of a sensitive period after very preterm birth, during which close contact between parent and infant may induce a long-term positive effect on the parent-infant relationship. To support infant long-term development, clinical practices should consider the place of care to be in immediate direct SSC with a parent after birth, alongside other necessary nursing and medical care. | PMC10690460 | |
Methods | In a randomized, cross-over design, 16 (8 females) individuals underwent two sessions of a-tDCS and two sham tDCS (s-tDCS) sessions targeting the left M1 (all participants were right limb dominant), with testing of either the left (ipsilateral) or right (contralateral) quadriceps. Knee extensor (KE) MVC force was recorded prior to and following the a-tDCS and s-tDCS protocols. Additionally, a repetitive MVC fatiguing protocol (12 MVCs with work-rest ratio of 5:10-s) was completed following each tDCS protocol. | PMC9821721 | ||
Results | There was a significant interaction effect for stimulation condition x leg tested x time [ | PMC9821721 | ||
Conclusion | a-tDCS may be ineffective at increasing maximal force or endurance and instead may be detrimental to quadriceps force production. | PMC9821721 | ||
Data Availability | The datasets generated during and/or analyzed during the current study are publicly available from the Dryad database ( | PMC9821721 | ||
Introduction | fatigue, fatiguability | CORTEX | Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that can induce both excitatory and inhibitory cortical effects depending on the polarity of the stimulation administered [There is conflict in the literature as to whether tDCS can augment muscle strength and endurance performance. There are many studies that have demonstrated that tDCS is effective at increasing maximal muscle force and endurance [However, many others report no significant effects or decreases of muscle force or endurance when stimulating the motor cortex [Meta-analyses of the overall literature tend to suggest small magnitude improvements in muscle strength [Almost all tDCS studies provide stimulation contralateral to the tested muscle. A 2-week strength training program with a-tDCS to the ipsilateral M1 provided prolonged (48 hours) improvements in strength [Examinations of cortical and spinal excitability of the contralateral, non-exercised limb after an acute session of unilateral fatiguing exercise (monitoring of ipsilateral corticospinal influences) have revealed conflicting results with both decreases [A previous study reported that cathodal tDCS effects were greater in magnitude and duration for female participants when compared to males [The main goal of this study was to determine whether unihemispheric a-tDCS of the left M1 is capable of modulating maximal force production or fatiguability of either the contralateral or ipsilateral KE. It was hypothesized that there would be an increase in maximal force production and fatigue resistance in the contralateral and ipsilateral KE in relation to the site of tDCS. Due to the lack of literature on sex dependent effects of a-tDCS effects on motor function, this research question was exploratory. | PMC9821721 |
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