Variation in the Heritability of Child Body Mass Index by Obesogenic Home Environment

Pathways linking BMI trajectories and mental health in an adult population-based cohort: role of emotional eating and body dissatisfaction

BACKGROUND

Overweight and obesity are associated with poor mental health, and the association is bidirectional. Few studies have examined the association between weight change and mental health over time. We aimed to provide further insight into the association between weight gain and mental health, with a focus on emotional eating and body dissatisfaction as mediating factors.

METHODS

Height and weight were self-reported upon registration, and in Spring 2022, 2023, and 2024 in the Specchio cohort (Geneva, Switzerland). BMI trajectories were estimated by (1) mixed-effects models to calculate participants' personal slopes (increase in BMI score per year), and (2) testing the odds of an upward BMI category transition from baseline to last follow-up. The associations of behavioural and psychosocial factors with BMI trajectories (slopes and transitions), and BMI trajectories with mental health outcomes were estimated using regressions adjusted for age, sex, education, and physical health condition. Structural equation modelling was used to test mediating pathways.

RESULTS

Among 7388 participants (59% women, mean age 51 years), factors associated with increasing BMI over 4 years included financial hardship, short sleep duration, less physical activity, more leisure screen time, depressive and anxiety symptoms, and emotional eating (β range [95% CI] = 0.03 [0, 0.05]-0.12 [0.09, 0.15]). Increasing BMI was associated with body dissatisfaction (β = 0.36 [0.33, 0.38]) and poorer quality of life (β = -0.06 [-0.09, -0.03]) at 4-year follow-up after adjustment for anxiety and depressive symptoms at baseline. Emotional eating partly mediated the association between anxiety and depressive symptoms at baseline and increasing BMI, and between financial hardship and increasing BMI. Body dissatisfaction and poorer self-rated health partly mediated the association between increasing BMI and quality of life at follow-up.

CONCLUSIONS

Emotional eating and body dissatisfaction contribute to the association between BMI trajectories and mental health and should be considered in weight management and mental health promotion strategies.

Genetic associations with consumption of palatable foods in the absence of hunger in response to food cues in children

OBJECTIVE

The objective of this study is to evaluate obesity-related genetic factors in relation to excess consumption and assess if food cues modify associations.

METHODS

Children (9-12 years) completed a randomized crossover experiment. During two visits, children ate a preload and then snacks ad libitum while watching television, embedded with food or non-food advertisements to assess eating in the absence of hunger (EAH). Primary exposures were obesity-associated genotypes, FTO rs9939609 and MC4R rs571312, and a paediatric-specific polygenic risk score (PRS). Outcomes included consumption of all snacks (total EAH) and gummy candy only (gummy candy EAH). Linear mixed-effects models tested whether genetic exposures related to EAH outcomes. We tested for effect modification by food cues using multiplicative interaction terms.

RESULTS

Among 177 children, each FTO risk allele was associated with a 30% increase in gummy candy EAH (p = 0.025) in adjusted models. Food cue exposure exacerbated associations between the FTO variant with gummy candy EAH (p = 0.046). No statistically significant associations were found between MC4R and EAH.

CONCLUSION

The results suggest children with the FTO rs9939609 risk allele may be predisposed to excess consumption of candy and that this association may be exacerbated by food cues.

Identification of positive childhood experiences with the potential to mitigate childhood unhealthy weight status in children within the context of adverse childhood experiences: a prospective cohort study

BACKGROUND

Despite potential protective and mitigating effects of positive childhood experiences (PCEs) on poor health outcomes, limited research has identified relevant PCEs and examined their individual and cumulative associations with weight status, or their mitigating effects on the associations between adverse childhood experiences (ACEs) and obesity in children. This study aims to develop an exploratory PCEs Index with the potential to protect against or mitigate the association between ACEs and unhealthy weight status.

METHODS

Data came from the Growing Up in New Zealand study. The analytic sample was restricted to those who provided obesity data at age 8 and one child per mother, resulting in a sample of 4,895 children. Nine individual ACEs and their cumulative scores, a newly developed PCEs index consisting of six individual PCEs and (their) cumulative scores, and an overweight/obesity variable were included in the analyses.

RESULTS

By age eight, experience of at least 3 PCEs was reported by 72.1% of the sample. However, the experience of the highest number of PCEs (5-6) was only reported by 23% of the sample. Four out of six assessed PCEs were associated with decreased likelihood of overweight/obesity. A dose-response effect was observed where experience of three or more PCEs was associated with decreased odds for obesity (AORs decreased from 0.77 for 3 PCEs to 0.54 for 5-6 PCEs). No consistent mitigating effects were found for individual PCEs; however interactions were found between reporting at least four of the six PCEs, experience of cumulative ACEs, and reduced odds for overweight/obesity at age 8.

CONCLUSIONS

A critical number of PCEs may be required to mitigate the detrimental impacts of ACEs on weight status among children. These findings reinforce the need to consider a constellation of strength-focused ecological domains to alleviate the burden of childhood obesity, particularly for children exposed to multiple adversities.

Ultraprocessed Foods at Home and Children's Attentional Bias Toward Those Foods

This study examines the association between exposure to ultraprocessed foods at home and children’s attentional bias for those foods.

Pediatric obesity in the United States: Age-period-cohort analysis

The rates of obesity among American children aged 2-5 years has reached a historic high. It is crucial to identify the putative sources of population-level increases in obesity prevalence among preschool-aged children because early childhood is a critical window for obesity prevention and thus reduction of future incidence. We used the National Health and Nutrition Examination Survey data and hierarchical age-period-cohort analysis to examine lifecycle (i.e., age), historical (i.e., period), and generational (i.e., cohort) distribution of age- and sex-specific body mass index z-scores (zBMI) among 2-5-year-olds in the U.S. from 1999 to 2018. Our current findings indicate that period effects, rather than differences in groups born at a specific time (i.e., cohort effects), account for almost all of the observed changes in zBMI. We need a broad socioeconomic, cultural, and environmental strategy to counteract the current obesogenic environment that influences children of all ages and generations in order to reach large segments of preschoolers and achieve population-wide improvement.

Gut microbiota and childhood malnutrition: Understanding the link and exploring therapeutic interventions

Childhood malnutrition is a metabolic condition that affects the physical and mental well-being of children and leads to resultant disorders in maturity. The development of childhood malnutrition is influenced by a number of physiological and environmental factors including metabolic stress, infections, diet, genetic variables, and gut microbiota. The imbalanced gut microbiota is one of the main environmental risk factors that significantly influence host physiology and childhood malnutrition progression. In this review, we have evaluated the gut microbiota association with undernutrition and overnutrition in children, and then the quantitative and qualitative significance of gut dysbiosis in order to reveal the impact of gut microbiota modification using probiotics, prebiotics, synbiotics, postbiotics, fecal microbiota transplantation, and engineering biology methods as new therapeutic challenges in the management of disturbed energy homeostasis. Understanding the host-microbiota interaction and the remote regulation of other organs and pathways by gut microbiota can improve the effectiveness of new therapeutic approaches and mitigate the negative consequences of childhood malnutrition.

Biobehavioral susceptibility for obesity in childhood: Behavioral, genetic and neuroimaging studies of appetite

Modern food environments are conducive to overeating and weight gain, but not everyone develops obesity. One reason for this may be that individuals differ in appetitive characteristics, or traits, that manifest early in life and go on to influence their behavioral susceptibility to gain and maintain excess weight. Classic studies showing that eating behavior in children can be measured by behavioral paradigms such as tests of caloric compensation and eating in the absence of hunger inspired the development and validation of psychometric instruments to assess appetitive characteristics in children and infants. A large body of evidence now suggests that food approach traits increase obesity risk, while food avoidant traits, such as satiety responsiveness, decrease obesity risk. Twin studies and genetic association studies have demonstrated that appetitive characteristics are heritable, consistent with a biological etiology. However, family environment factors are also influential, with mounting evidence suggesting that genetic and environmental risk factors interact and correlate with consequences for child eating behavior and weight. Further, neuroimaging studies are revealing that individual differences in responses to visual food cues, as well as to small tastes and larger amounts of food, across a number of brain regions involved in reward/motivation, cognitive control and other functions, may contribute to individual variation in appetitive behavior. Growing evidence also suggests that variation on psychometric measures of appetite is associated with regional differences in brain structure, and differential patterns of resting state functional connectivity. Large prospective studies beginning in infancy promise to enrich our understanding of neural and other biological underpinnings of appetite and obesity development in early life, and how the interplay between genetic and environmental factors affects appetitive systems. The biobehavioral susceptibility model of obesity development and maintenance outlined in this narrative review has implications for prevention and treatment of obesity in childhood.

Gene-Environment Interplay in the Development of Overweight

PURPOSE

Overweight in youth is influenced by genes and environment. Gene-environment interaction (G×E) has been demonstrated in twin studies and recent developments in genetics allow for studying G×E using individual genetic predispositions for overweight. We examine genetic influence on trajectories of overweight during adolescence and early adulthood and determine whether genetic predisposition is attenuated by higher socioeconomic status and having physically active parents.

METHODS

Latent class growth models of overweight were fitted using data from the TRacking Adolescents' Individual Lives Survey (n = 2720). A polygenic score for body mass index (BMI) was derived using summary statistics from a genome-wide association study of adult BMI (N = ∼700,000) and tested as predictor of developmental pathways of overweight. Multinomial logistic regression models were used to examine effects of interactions of genetic predisposition with socioeconomic status and parental physical activity (n = 1675).

RESULTS

A three-class model of developmental pathways of overweight fitted the data best ("non-overweight", "adolescent-onset overweight", and "persistent overweight"). The polygenic score for BMI and socioeconomic status distinguished the persistent overweight and adolescent-onset overweight trajectories from the non-overweight trajectory. Only genetic predisposition differentiated the adolescent-onset from the persistent overweight trajectory. There was no evidence for G×E.

DISCUSSION

Higher genetic predisposition increased the risk of developing overweight during adolescence and young adulthood and was associated with an earlier age at onset. We did not find that genetic predisposition was offset by higher socioeconomic status or having physically active parents. Instead, lower socioeconomic status and higher genetic predisposition acted as additive risk factors for developing overweight.

The heritability of weight gain in infancy: A population-based twin study

BACKGROUND

Rapid weight gain during infancy is a strong predictor of childhood obesity and is affected by genetic and environmental factors. Identifying ages with low heritability will allow for targeted interventions that might be able to prevent the adverse effects of childhood obesity.

OBJECTIVES

The objective of the study is to estimate the heritability of weight gain from birth to defined ages during infancy, as well as during 6-month periods from birth to 18 months of age. We address this by leveraging large-scale computerised anthropometric data from the state-run network of well-baby clinics in Israel.

METHODS

We performed a population-based twin study. We extracted weight measurements recorded between birth to 24 months from well-baby clinics for 9388 twin pairs born in Israel between 2011 and 2015. The reported sexes of the twins were used as a proxy for their zygosity status. We estimated the heritability of the weight z-score change from birth to specific ages and during particular periods in infancy. To assess the validity of the results, we repeated the analysis in a sub-cohort of twin pairs with complete weight measurements.

RESULTS

During the first 2 years of life, heritability was lowest for birthweight (h 2 = 0.40 ± 0.11 ). Heritability for weight gain since birth was highest at 4 months (h 2 = 0.87 ± 0.13 ), and then gradually decreased until age 18 months (h 2 = 0.62 ± 0.13 ). Estimating the heritability in 6-month intervals from birth to 18 months, heritability was highest during the 6-12-month interval (h 2 = 0.84 ± 0.14 ), and was substantially lower during the subsequent 12-18-month interval (h 2 = 0.43 ± 0.16 ).

CONCLUSIONS

Heritability of weight gain decreases substantially in the second year of life, suggesting that this period could be an appropriate time for interventions for infants who are at an increased risk of childhood obesity.

A Silver Lining of Neuropathic Pain: Predicting Favorable Functional Outcome in Spinal Cord Injury

Background

Neuropathic pain (NP) is a common and severe problem following spinal cord injury (SCI). However, its relationship with functional outcome remains unclear.

Methods

A retrospective explorative analysis was performed on SCI patients admitted to a tertiary academic medical center between January 2018 and June 2022. The candidate predictor variables, including demographics, clinical characteristics and complications, were analyzed with logistic and linear regression. Spinal Cord Independence Measure (SCIM) scores at discharge and mean relative functional gain (mRFG) of SCIM were as outcome parameters.

Results

A total of 140 SCI patients included for the final analysis. Among them, 44 (31.43%) patients were tetraplegics, and 96 (68.57%) patients were paraplegics; 68 (48.57%) patients developed NP, and 72 (51.43%) patients did not. Logistic and linear regression analyses of SCIM at discharge both showed that NP [OR=3.10, 95% CI (1.29,7.45), P=0.01; unstandardized β=11.47, 95% CI (4.95,17.99), P<0.01; respectively] was significantly independent predictors for a favorable outcome (SCIM at discharge ≥ 50, logistic regression results) and higher SCIM total score at discharge (linear regression results). Besides, NP [unstandardized β=15.67, 95% CI (8.94,22.41), P<0.01] was also independently associated with higher mRFG of SCIM scores. Furthermore, the NP group had significantly higher mRFG, SCIM total scores and subscales (self-care, respiration and sphincter management, and mobility) at discharge compared to the non-NP group. However, there were no significant differences in mRFG, SCIM total score or subscales at discharge among the NP subgroups in terms of locations (at level pain, below level pain, and both) or timing of occurrence (within and after one month after SCI). This study also showed that incomplete injury, lumbar-sacral injury level and non-anemia were significantly independent predictors for a favorable outcome, and higher mRFG of SCIM scores (except for non-anemia).

Conclusion

NP appears independently associated with better functional recovery in SCI patients, suggesting the bright side of this undesirable complication. These findings may help to alleviate the psychological burden of NP patients and ultimately restore their confidence in rehabilitation.

Dimensions of sleep quality are related to objectively measured eating behaviors among children at high familial risk for obesity

OBJECTIVE

The aim of this study was to evaluate whether dimensions of sleep quality were associated with homeostatic and hedonic eating behaviors among children with healthy weight (BMI-for-age < 90%) but varying maternal weight status.

METHODS

A total of 77 children (mean [SD], age: 7.4 [0.6] years; BMI z score: -0.10 [0.7]) with healthy weight and high (n = 32) or low (n = 45) familial obesity risk based on maternal weight status were served an ad libitum meal (homeostatic eating) followed by palatable snacks to assess eating in the absence of hunger (EAH; hedonic eating). Habitual sleep quality was quantified from seven nights of wrist actigraphy. Partial correlations, adjusted for child energy needs, pre-meal hunger, food liking, and socioeconomic status, evaluated associations of sleep with meal intake and EAH. Additionally, sleep-by-obesity risk interactions were assessed.

RESULTS

Greater sleep fragmentation was associated with higher homeostatic meal energy intake, but only among children at high familial obesity risk (p value for interaction = 0.001; β high risk = 48.6, p = 0.001). Sleep fragmentation was not associated with total EAH but was related to higher and lower intake of carbohydrates (r = 0.33, p = 0.003) and fat (r = -0.33, p = 0.003), respectively.

CONCLUSIONS

Adverse associations of poor sleep with energy intake may be amplified among children already predisposed to obesity. Furthermore, that fragmented sleep relates to preferential intake of carbohydrates over fat during EAH may suggest alterations in taste preferences with poor sleep.

"Nutripiatto": A tool for nutritional education. A survey to assess dietary habits in preschool children

Childhood obesity is a global public health concern linked to metabolic and psychological comorbidities. There is growing evidence that children's lifestyle habits are shifting towards obesity, with dire consequences for their future well-being and healthcare costs. In this interventional study, we enrolled 115 children aged between 4-5 years (53% females and 47% males) and carried out nutrition education interventions to improve their dietary habits. We introduced "Nutripiatto", a visual plate icon and easy guide, which was used by the children during the study. We investigated the children's dietary habits using a Food Frequency Questionnaire at the beginning and end of the study, after one month of using "Nutripiatto". The results showed that the children significantly increased the portion sizes and frequency of vegetable consumption (P<0.001) and reduced the consumption of several junk foods such as French fries and crisps (P<0.001), reaching the recommended dietary allowances and frequency of consumption. Daily consumption of water also significantly increased, reaching the suggested amount of six glasses per day. Based on these results, "Nutripiatto" can be considered an effective visual guide and helpful tool to achieve small changes and empower families to make healthier food choices. It can also be considered an effective educational tool for nutritionists and healthcare professionals to improve children's dietary behavior.

Parental Feeding Practices and Children's Eating Behaviours: An Overview of Their Complex Relationship

Several studies have found an association between eating behaviours and weight status and obesity risk in childhood. Children's eating behaviours arise from a combination of genetic and environmental factors. Parents appear to play a central role in their development as the main responsible for shaping children's feeding environment and eating experiences. The purpose of this paper is to review the literature on parental influences on eating behaviours across childhood, mainly focusing on parental feeding practices. The associations between parental feeding practices and children's eating behaviours have been extensively studied. However, most of the findings come from cross-sectional studies, so the possibility of reverse causality cannot be ruled out (i.e., children's behaviours influencing parents). Most recently, a few longitudinal studies with a cross-lagged design have shown that the relationship between children's eating behaviours and parental feeding practices seems to be bidirectional, where it is not straightforward whether parental feeding practices are a predictor or a consequence of children's eating behaviours. Children's eating behaviours influence parents to adopt certain feeding practices, but these practices also influence children's behaviours over time. Parental feeding practices may have the potential to shape children's eating behaviours and should be targeted to promote the development of non-obesogenic traits. However, parent-child interactions are complex and therefore both parent and child characteristics and the family dynamics should be considered.

Cardiometabolic Traits in Adult Twins: Heritability and BMI Impact with Age

Background: The prevalence of obesity and cardiometabolic diseases continues to rise globally and obesity is a significant risk factor for cardiometabolic diseases. However, to our knowledge, evidence of the relative roles of genes and the environment underlying obesity and cardiometabolic disease traits and the correlations between them are still lacking, as is how they change with age. Method: Data were obtained from the Chinese National Twin Registry (CNTR). A total of 1421 twin pairs were included. Univariate structural equation models (SEMs) were performed to evaluate the heritability of BMI and cardiometabolic traits, which included blood hemoglobin A1c (HbA1c), fasting blood glucose (FBG), systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). Bivariate SEMs were used to assess the genetic/environmental correlations between them. The study population was divided into three groups for analysis: ≤50, 51−60, and >60 years old to assess the changes in heritability and genetic/environmental correlations with ageing. Results: Univariate SEMs showed a high heritability of BMI (72%) and cardiometabolic traits, which ranged from 30% (HbA1c) to 69% (HDL-C). With age increasing, the heritability of all phenotypes has different degrees of declining trends. Among these, BMI, SBP, and DBP presented significant monotonous declining trends. The bivariate SEMs indicated that BMI correlated with all cardiometabolic traits. The genetic correlations were estimated to range from 0.14 (BMI and LDL-C) to 0.39 (BMI and DBP), while the environmental correlations ranged from 0.13 (BMI and TC/LDL-C) to 0.31 (BMI and TG). The genetic contributions underlying the correlations between BMI and SBP and DBP, TC, TG, and HDL-C showed a progressive decrease as age groups increased. In contrast, environmental correlations displayed a significant increasing trend for HbA1c, SBP, and DBP. Conclusions: The findings suggest that genetic and environmental factors have essential effects on BMI and all cardiometabolic traits. However, as age groups increased, genetic influences presented varying degrees of decrement for BMI and most cardiometabolic traits, suggesting the increasing importance of environments. Genetic factors played a consistently larger role than environmental factors in the phenotypic correlations between BMI and cardiometabolic traits. Nevertheless, the relative magnitudes of genetic and environmental factors may change over time.

Causal association between obesity, circulating glutamine levels, and depression: a Mendelian randomization study

BACKGROUND

Observational studies indicated obesity and glutamatergic dysfunction as potential risk factors of depression, and reported disturbance of glutamine metabolism in obese state. However, it remains unclear whether the inter-relationships between obesity, glutamine and depression are causal.

METHODS

We conducted two-sample bidirectional Mendelian Randomization (MR) analyses to explore the causalities between circulating glutamine levels, specific depressive symptoms, major depressive disorder (MDD) and body mass index (BMI). Univariable MR, multivariable MR (MVMR) and linkage disequilibrium score regression (LDSR) analyses were performed.

RESULTS

Genetic downregulation of glutamine was causally associated with MDD, anhedonia, tiredness, and depressed mood at the false discovery rate (FDR)-controlled significance level (estimate, -0·036∼ -0·013, P = 0·005 to P = 0·050). Elevated BMI was causally linked to lower glutamine level (estimate = -0·103, P = 0·037), as well as more severe depressed mood, tiredness, and anhedonia (estimate, 0·017∼0·050, P < 0·001 to P = 0·040). In MVMR analysis, BMI was causally related to depressed mood dependently of glutamine levels. Reversely, it showed limited evidence supporting causal effects of depression on glutamine levels or BMI, except a causal association of tiredness with elevated BMI (estimate = 0·309, P = 0·003). LDSR estimates were directionally consistent with MR results.

CONCLUSION

The present study reported that higher BMI was causally associated with lower glutamine levels. Both obesity and down-regulation of glutamine were causally linked to depression.

Do gene-environment interactions have implications for the precision prevention of type 2 diabetes?

The past decades have seen a rapid global rise in the incidence of type 2 diabetes. This surge has been driven by diabetogenic environmental changes that may act together with a genetic predisposition to type 2 diabetes. It is possible that there is a synergistic gene-environment interaction, where the effects of the diabetogenic environment depend on the genetic predisposition to type 2 diabetes. Randomised trials have shown that it is possible to delay, or even prevent the development of type 2 diabetes in individuals at elevated risk through behavioural modification, focusing on weight loss, physical activity and diet. There is wide heterogeneity between individuals regarding the effectiveness of these interventions, which could, in part, be due to genetic differences. However, the studies of gene-environment interactions performed thus far suggest that behavioural modifications appear equally effective in reducing the incidence of type 2 diabetes from the stage of impaired glucose tolerance, regardless of the known underlying genetic predisposition. Recent studies suggest that there may be several subtypes of type 2 diabetes, which give new opportunities for gaining insight into gene-environment interactions. At present, the role of gene-environment interactions in the development of type 2 diabetes remains unclear. With many puzzle pieces missing in the general picture of type 2 diabetes development, the available evidence of gene-environment interactions is not ready for translation to individualised type 2 diabetes prevention based on genetic profiling.

Individualized morphometric similarity predicts body mass index and food approach behavior in school-age children

Childhood obesity is associated with alterations in brain structure. Previous studies generally used a single structural index to characterize the relationship between body mass index(BMI) and brain structure, which could not describe the alterations of structural covariance between brain regions. To cover this research gap, this study utilized two independent datasets with brain structure profiles and BMI of 155 school-aged children. Connectome-based predictive modeling(CPM) was used to explore whether children’s BMI is reliably predictable by the novel individualized morphometric similarity network(MSN). We revealed the MSN can predict the BMI in school-age children with good generalizability to unseen dataset. Moreover, these revealed significant brain structure covariant networks can further predict children’s food approach behavior. The positive predictive networks mainly incorporated connections between the frontoparietal network(FPN) and the visual network(VN), between the FPN and the limbic network(LN), between the default mode network(DMN) and the LN. The negative predictive network primarily incorporated connections between the FPN and DMN. These results suggested that the incomplete integration of the high-order brain networks and the decreased dedifferentiation of the high-order networks to the primary reward networks can be considered as a core structural basis of the imbalance between inhibitory control and reward processing in childhood obesity.

Prenatal programming of developmental trajectories for obesity risk and early pubertal timing

The thrifty phenotype and fetal overnutrition hypotheses are two developmental hypotheses that originated from the developmental origins of health and disease (DOHaD) perspective. The DOHaD posits that exposures experienced prenatally and early in life may influence health outcomes through altering form and function of internal organs related to metabolic processes. Obesity risk and early pubertal timing might be influenced by similar mechanisms. The thrifty phenotype hypothesis is primarily characterized by experiencing a deprivation of nutrients during gestation paired with an energy rich postnatal environment. The fetal overnutrition hypothesis says that obesity experienced prenatally will be associated with increased lifetime risk of obesity in the offspring. Both hypotheses were tested by examining developmental pathways from genetic and prenatal risk through early growth trajectories (birth to 7 years) to pubertal timing at age 11 years. Participants included 361 children adopted at birth (57% male; 57% non-Hispanic White, 11% Black, 9% Hispanic; adoptive family income Mdn = $70,000-$100,000, birth family income Mdn = < $15,000). Associations between boys' childhood body mass index (BMI) and pubertal timing were confounded by genetics, prenatal risk, and early growth. The thrifty phenotype hypothesis was partially supported for boys' childhood BMI (at ages 4 to 7 years). Both hypotheses were partially supported for girls' childhood BMI but not pubertal timing. A novel Gene × Prenatal Risk interaction showed that genetic risk predicted girls' childhood BMI most strongly at adequate compared with at excessive levels of gestational weight gain. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Stress and eating responses in adolescent females predisposed to obesity: A pilot and feasibility study

OBJECTIVE

To explore how chronic stress, reactivity to acute stress, and obesogenic eating are linked in adolescent females predisposed to obesity.

METHODS

Participants included 21 adolescent females (m_age = 14.57 years) and their biological mothers with obesity (body mass index [BMI] ≥ 30 kg/m²). The pilot and feasibility study involved adolescent self-report of chronic stress, an acute stress-induction paradigm (Trier Social Stress Task, TSST), salivary cortisol collection to assess stress reactivity, and both subjective (self-report) and objective (snack buffet) measures of obesogenic eating.

RESULTS

Adolescent females reporting high chronic stress were significantly more likely to engage in self-reported emotional and external eating and to have higher food cravings (p's < .05) compared to adolescents with low chronic stress. Effect size estimates suggested a blunting effect of cortisol in the high chronic stress group. Blunted cortisol reactivity significantly predicted higher self-reported food cravings for the high chronic stress group (p = .04). Associations among chronic stress, cortisol, and self-reported and objective obesogenic eating reflected medium to large effect sizes.

CONCLUSIONS

This study built on limited extant research on stress and eating to demonstrate that chronic stress was associated with self-reported obesogenic eating patterns in adolescent females predisposed to obesity. Different patterns of cortisol reactivity and eating emerged depending on chronic stress group (low versus high). Understanding these eating patterns in the context of chronic stress can inform interventions to reduce obesity risks in adolescence.

Is calorie labelling on menus the solution to obesity?

From April 2022, as part of the UK government’s new obesity strategy, it is now compulsory for all larger restaurant and cafes in the UK to include calorie labelling on their menus. Is this legislation, however, likely to be effective in reducing our caloric intake, thereby tackling obesity?

Early-life determinants of excessive weight gain among low-income children: Examining the adherence of theoretical frameworks to empirical data using structural equation modelling

BACKGROUND

Although childhood obesity is increasing in low-income regions, theoretical models cannot be adequately applied due to the lack of prospective studies with under 2-year-old children from impoverished populations.

OBJECTIVE

To analyse direct and indirect effects of environmental, maternal, and individual factors on excess weight gain among low-income children during the first year of life.

METHODS

We analysed data from a prospective birth cohort conducted in Brazil, which followed infants at birth, 3rd, 6th, and 12th month of life (n = 205). The weight-for-age z-score was used to calculate the conditional weight gain (CWG). Direct and indirect effects on CWG were estimated using structural equation modelling.

RESULTS

Children's consumption of ultra-processed food (UPF) ≥1 time/day, breastfeeding duration >90 days, and maternal obesity showed a statistically significant direct effect on children's CWG. We observed a positive indirect pathway linking the maternal intake of UPF ≥4 times/day to the CWG, given its direct effect on the infant's UPF consumption.

CONCLUSIONS

In this low-income population, women who were frequent users of UPF tended to introduce these products more frequently into their children's diets. The early trade-off trend in children's diet between breastfeeding and UPF was the leading cause of excessive weight gain.

Ecological factors and childhood eating behaviours at 5 years of age: findings from the ROLO longitudinal birth cohort study

Background

Individual differences in children eating behaviours have been linked with childhood overweight and obesity. The determinants of childhood eating behaviours are influenced by a complex combination of hereditary and ecological factors. This study examines if key ecological predictors of childhood overweight; maternal socio-economic status (SES), children’s screen time, and childcare arrangements, are associated with eating behaviours in children aged 5-years-old.

Methods

This is secondary, cross-sectional analysis of the ROLO (Randomized COntrol Trial of LOw glycemic diet in pregnancy) study, using data from the 5-year follow-up (n = 306). Weight, height, and body mass index (BMI) were obtained from mothers and children at the 5-year follow-up. Children’s BMI z-scores were calculated. SES was determined using maternal education level and neighborhood deprivation score. Information on children’s screen time and childcare arrangements were collected using lifestyle questionnaires. Children’s eating behaviours were measured using the Children’s Eating Behaviour Questionnaire (CEBQ). Multiple linear regression, adjusted for potential confounders, assessed associations between maternal SES, screen time and children’s eating behaviours. One-way ANOVA, independent sample t-tests and Spearman’s correlation examined childcare exposure and children’s eating behaviour.

Results

Mothers in the lowest SES group had higher BMI and were younger than those in the highest SES group (p =  < 0.001, p = 0.03 respectively). In adjusted analysis, the lowest SES group was associated with a 0.463-point higher mean score for ‘Desire to Drink’ (95% CI = 0.054,0.870, p = 0.027) and higher ‘Slowness to Eat’ (B = 0.388, 95% CI = 0.044,0.733, p = 0.027) when compared with the highest SES group. Screen time (hours) was associated with higher ‘Food Fussiness’ (B = 0.032, 95% CI = 0.014,0.051, p = 0.001). Those who attended childcare had higher scores for ‘Desire to Drink’(p = 0.046). No relationship was observed between longer duration (years) spent in childcare and eating behaviours.

Conclusions

In this cohort, the ecological factors examined had an influence on children’s eating behaviours aged 5-years-old. Our results illustrate the complexity of the relationship between the child’s environment, eating behaviour and children’s body composition. Being aware of the ecological factors that impact the development of eating behaviours, in the pre-school years is vital to promote optimal childhood appetitive traits, thus reducing the risk of issues with excess adiposity long-term.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03423-x.

Associations between the home environment and childhood weight change: a cross-lagged panel analysis

BACKGROUND

The obesogenic quality of the home environment is hypothesised to play an important role in children's weight development but few prospective studies have investigated relationships between the home environment and adiposity across childhood.

OBJECTIVE

To investigate the continuity and stability of the home environment from ages 4 to 12, and bi-directional relationships between the home environment and BMI-SDS from ages 4 to 12.

METHODS

Parents from the Gemini cohort completed the Home Environment Interview (HEI), a comprehensive measure of the obesogenic home environment, when their children were aged 4 and 12 (n = 149 families, n = 298 children). The obesogenic home environment was measured using four composite scores capturing the food, activity, media environments, and the overall home environment. Child weights and heights were used to calculate BMI-SDS. Continuity was assessed with Pearson's correlations between scores at each time point, and stability by changes in mean scores over time. Cross-lagged analyses were performed (HEI composites at age 4 to BMI-SDS at age 12 and the reverse) to measure the magnitude and direction of associations.

RESULTS

The home environment showed moderate-to-high continuity from ages 4 to 12 (r = 0.30-0.64). The overall home environment (r = 0.21, p < 0.01) and media composites (r = 0.23, p < 0.01) were cross-sectionally associated with child BMI-SDS at age 12, but not at age 4. Longitudinally, the home media environment at age 4 predicted increases in child BMI-SDS at age 12 (β; 95% CI = 0.18; 0.08,0.28, p < 0.01). No associations were observed for the reverse path, or the remaining composites (the overall, food and activity) in either direction.

CONCLUSION

This study provides evidence that the obesogenic home environment tracks across childhood and highlights the importance of the early home media environment for child weight development. The findings provide insight into key aspects of the home environment that could be targeted when developing obesity treatment or prevention strategies.

Genetic and environmental contributions to variations on appetitive traits at 10 years of age: a twin study within the Generation XXI birth cohort

PURPOSE

Given the variability in adiposity despite ubiquitous exposure to obesogenic food environments, it has been suggested that individuals respond in divergent ways to the environment they live in. The food environment becomes more 'permissive' as children age; therefore, genetic predisposition for a more avid appetite can be better expressed, influencing dietary quality, energy intake and weight gain. Our aim was to explore the genetic and environmental contribution of variations on appetitive traits in a sample of 10-year-old Portuguese children.

METHODS

Participants were twins enrolled in the Generation XXI birth cohort (n = 86 pairs). Parents reported twin's zygosity and child appetitive traits at 10 years of age through the Children's Eating Behavior Questionnaire. Intra-class correlations (ICCs) for all appetitive traits were calculated for monozygotic and dizygotic twins separately to examine patterns of resemblance, and structural equation modeling was conducted aiming to estimate the genetic (A), shared (C) and non-shared (E) environmental variances.

RESULTS

Moderate to strong heritability were found for child appetitive traits, with higher ICCs among monozygotic twin pairs. For all appetitive traits, with the exception of emotional undereating, genetic and non-shared environmental effects contributed to appetite variability. For emotional undereating, environmental effects seem to be more important than genetic effects (C: 0.81; 95% CI 0.71; 0.88 and E: 0.19; 95% CI 0.12; 0.29).

CONCLUSION

There was a significant genetic contribution, followed by non-shared environmental contribution, towards variation in appetitive traits in school-age children. Variation in emotional undereating was primarily explained by shared and non-shared environmental factors.

LEVEL OF EVIDENCE

Evidence obtained from well-designed cohort or case-control analytic studies.

Can adult polygenic scores improve prediction of body mass index in childhood?

BACKGROUND/OBJECTIVES

Modelling genetic pre-disposition may identify children at risk of obesity. However, most polygenic scores (PGSs) have been derived in adults, and lack validation during childhood. This study compared the utility of existing large-scale adult-derived PGSs to predict common anthropometric traits (body mass index (BMI), waist circumference, and body fat) in children and adults, and examined whether childhood BMI prediction could be improved by combining PGSs and non-genetic factors (maternal and earlier child BMI).

SUBJECTS/METHODS

Participants (n = 1365 children, and n = 2094 adults made up of their parents) were drawn from the Longitudinal Study of Australian Children. Children were weighed and measured every two years from 0-1 to 12-13 years, and adults were measured or self-reported measurements were obtained concurrently (average analysed). Participants were genotyped from blood or oral samples, and PGSs were derived based on published genome-wide association studies. We used linear regression to compare the relative utility of these PGSs to predict their respective traits at different ages.

RESULTS

BMI PGSs explained up to 12% of child BMI z-score variance in 10-13 year olds, compared with up to 15% in adults. PGSs for waist circumference and body fat explained less variance (up to 8%). An interaction between BMI PGSs and puberty (p = 0.001-0.002) suggests the effect of some variants may differ across the life course. Individual BMI measures across childhood predicted 10-60% of the variance in BMI at 12-13 years, and maternal BMI and BMI PGS each added 1-9% above this.

CONCLUSION

Adult-derived PGSs for BMI, particularly those derived by modelling between-variant interactions, may be useful for predicting BMI during adolescence with similar accuracy to that obtained in adulthood. The level of precision presented here to predict BMI during childhood may be relevant to public health, but is likely to be less useful for individual clinical purposes.

Male Infertility in the XXI Century: Are Obesogens to Blame?

The permanent exposure to environmental contaminants promoting weight gain (i.e., obesogens) has raised serious health concerns. Evidence suggests that obesogens are one of the leading causes of the marked decline in male fertility and are key players in shaping future health outcomes, not only for those who are directly exposed to them, but also for upcoming generations. It has been hypothesized that obesogens affect male fertility. By using an interdisciplinary strategy, combining in silico, in vitro, in vivo and epidemiological findings, this review aims to contribute to the biological understanding of the molecular transformations induced by obesogens that are the basis of male infertility. Such understanding is shaped by the use of Adverse Outcomes Pathways, a new approach that may shift the paradigm of reproductive toxicology, contributing to the improvement of the diagnosis and management of the adverse effects of obesogens in male fertility.

A Lifestyle Intervention During Pregnancy and Its Effects on Child Weight 2.5 Years Later

Aim

The aim of this study was to evaluate if overweight and obesity in the offspring is reduced by a low-intensity antenatal primary care intervention with focus on diet and physical activity for pregnant women with obesity, comparing children to mothers receiving the intervention with children to mothers who did not.

Methods

This study is a follow-up of children 2.5 years of age after their mothers’ participation in a non-randomised controlled intervention intending to limit gestational weight gain. All study participants received standard antenatal care. The intervention group received lifestyle support via motivational talks with midwife and support from dietician. Data on child weight were collected by medical records, letter and phone.

Results

There was no significant difference between the groups 2.5 years after intervention (International Obesity Task Force ISO-BMI 25 (child BMI corresponding to adult BMI of 25): 20% vs. 21%; ISO-BMI 30: 4.6% vs. 1.3%). The mother’s BMI at the beginning of pregnancy significantly influenced child BMI at 2.5 years (r = 0.13, p = 0.014, r² = 0.017). For each unit of increase in maternal BMI at enrollment, the probability of child ISO-BMI ≥ 25 increased by 7.5% (p = 0.021) and of ≥ 30, by 12.9% (p = 0.017).

Conclusion

The frequency of overweight and obesity of the children at 2.5 years of age was significantly correlated to the mother’s BMI, but not correlated to the mothers’ participation in the antenatal lifestyle intervention. Thus, it seems important to address obesity and lifestyle issues before and between pregnancies.

Trial registration The study has been registered at ClinicalTrials.gov, Identifier: NCT03147079.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10995-022-03395-5.

Interaction of obesity polygenic score with lifestyle risk factors in an electronic health record biobank

BACKGROUND

Genetic and lifestyle factors have considerable effects on obesity and related diseases, yet their effects in a clinical cohort are unknown. This study in a patient biobank examined associations of a BMI polygenic risk score (PRS), and its interactions with lifestyle risk factors, with clinically measured BMI and clinical phenotypes.

METHODS

The Mass General Brigham (MGB) Biobank is a hospital-based cohort with electronic health record, genetic, and lifestyle data. A PRS for obesity was generated using 97 genetic variants for BMI. An obesity lifestyle risk index using survey responses to obesogenic lifestyle risk factors (alcohol, education, exercise, sleep, smoking, and shift work) was used to dichotomize the cohort into high and low obesogenic index based on the population median. Height and weight were measured at a clinical visit. Multivariable linear cross-sectional associations of the PRS with BMI and interactions with the obesity lifestyle risk index were conducted. In phenome-wide association analyses (PheWAS), similar logistic models were conducted for 675 disease outcomes derived from billing codes.

RESULTS

Thirty-three thousand five hundred eleven patients were analyzed (53.1% female; age 60.0 years; BMI 28.3 kg/m²), of which 17,040 completed the lifestyle survey (57.5% female; age: 60.2; BMI: 28.1 (6.2) kg/m²). Each standard deviation increment in the PRS was associated with 0.83 kg/m² unit increase in BMI (95% confidence interval (CI) =0.76, 0.90). There was an interaction between the obesity PRS and obesity lifestyle risk index on BMI. The difference in BMI between those with a high and low obesogenic index was 3.18 kg/m² in patients in the highest decile of PRS, whereas that difference was only 1.55 kg/m² in patients in the lowest decile of PRS. In PheWAS, the obesity PRS was associated with 40 diseases spanning endocrine/metabolic, circulatory, and 8 other disease groups. No interactions were evident between the PRS and the index on disease outcomes.

CONCLUSIONS

In this hospital-based clinical biobank, obesity risk conferred by common genetic variants was associated with elevated BMI and this risk was attenuated by a healthier patient lifestyle. Continued consideration of the role of lifestyle in the context of genetic predisposition in healthcare settings is necessary to quantify the extent to which modifiable lifestyle risk factors may moderate genetic predisposition and inform clinical action to achieve personalized medicine.

Where and when are portion sizes larger in young children? An analysis of eating occasion size among 1·5-5-year-olds in the UK National Diet and Nutrition Survey (2008-2017)

OBJECTIVE

To identify eating occasion-level and individual-level factors associated with the consumption of larger portions in young children and estimate their relative importance.

DESIGN

Cross-sectional.

SETTING

Data from parent-reported 4-d food diaries in the UK National Diet and Nutrition Survey (2008-2017) were analysed. Multilevel models explored variation in eating occasion size (kJ) within (n 48 419 occasions) and between children (n 1962) for all eating occasions. Eating contexts: location, eating companion, watching TV, and sitting at a table and individual characteristics: age, gender, ethnicity and parental socio-economic status were explored as potential correlates of eating occasion size.

PARTICIPANTS

Children aged 1·5-5 years.

RESULTS

Median eating occasion size was 657 kJ (IQR 356, 1117). Eating occasion size variation was primarily attributed (90 %) to differences between eating occasions. Most (73 %) eating occasions were consumed at home. In adjusted models, eating occasions in eateries were 377 kJ larger than at home. Eating occasions sitting at a table, v. not, were 197 kJ larger. Eating in childcare, with additional family members and friends, and whilst watching TV were other eating contexts associated with slightly larger eating occasion sizes.

CONCLUSIONS

Eating contexts that vary from one eating occasion to another are more important than demographic characteristics that vary between children in explaining variation in consumed portion sizes in young children. Strategies to promote consumption of age-appropriate portion sizes in young children should be developed, especially in the home environment, in eating contexts such as sitting at the table, eating with others and watching TV.

Gene-Environment Interactions in Attention-Deficit/Hyperactivity Disorder Symptom Dimensions: The Role of Unhealthy Food Habits

Background: Dietary habits were investigated as environmental risk factors for Attention-Deficit/Hyperactivity Disorder (ADHD). However, no previous studies explored the effects of dietary factors on modifying the role of genetic factors on ADHD. Methods: Based on a Swedish population-based twin study with 1518 twin pairs aged 20-47 years, we tested whether the importance of genetic and environmental effects on ADHD varied as a function of dietary habits. Self-reported dietary habits and ADHD symptoms were collected. Twin methods were used to test the degree to which high-sugar and unhealthy food intake moderated the genetic and environmental influences on ADHD symptoms. Results: In middle-aged adults, genetic influences on inattention symptoms were statistically significantly higher among individuals with higher levels of high-sugar (45%, 95%CI: 25-54%) and unhealthy food intake (51%, 95%CI: 31-60%), compared with those with lower levels of consumption of high-sugar (36%, 95%CI: 25-47%) and unhealthy foods (30%, 95%CI: 20-41%). Similar patterns were also found for the associations between hyperactivity/impulsivity and high-sugar/unhealthy food intake, even though the moderation effects were not statistically significant. Conclusion The present study suggests that genetic factors play a more prominent role in individual differences of ADHD symptoms in the presence of the high consumption of sugar and unhealthy foods. Future longitudinal studies with multiple assessments of ADHD and dietary habits are needed to replicate our findings.

The Home Environment Interview and associations with energy balance behaviours and body weight in school-aged children - a feasibility, reliability, and validity study

BACKGROUND

The home environment is thought to influence children's weight trajectories. However, few studies utilise composite measures of the home environment to examine associations with energy balance behaviours and weight. The present study aimed to adapt and update a comprehensive measure of the obesogenic home environment previously developed for pre-schoolers, and explore associations with school-aged children's energy balance behaviours and weight.

METHODS

Families from the Gemini cohort (n = 149) completed the Home Environment Interview (HEI) via telephone when their children were 12 years old. The HEI comprises four composite scores: one for each domain (food, activity and media) of the environment, as well as a score for the overall obesogenic home environment. The primary caregiver also reported each child's height and weight (using standard scales and height charts), diet, physical activity and sedentary screen-based behaviours. A test-retest sample (n = 20) of caregivers completed the HEI a second time, 7-14 days after the initial interview, to establish test-retest reliability.

RESULTS

Children (n = 298) living in 'higher-risk' home environments (a 1 unit increase in the HEI obesogenic risk score) were less likely to consume fruits (OR; 95% CI = 0.40; 0.26-0.61, p < 0.001), and vegetables (0.30; 0.18-0.52, p < 0.001), and more likely to consume energy-dense snack foods (1.71; 1.08-2.69, p = 0.022), convenience foods (2.58; 1.64-4.05, p < 0.001), and fast foods (3.09; 1.90-5.04, p < 0.001). Children living in more obesogenic home environments also engaged in more screen-time (β (SE) = 4.55 (0.78), p < 0.001), spent more time playing video games (β (SE) = 1.56 (0.43), p < 0.001), and were less physically active (OR; 95% CI = 0.57; 0.40-0.80, p < 0.01). Additionally, there was a positive association between higher-risk overall home environment composite score and higher BMI-SDS (β (SE) = 0.23 (0.09), p < 0.01). This finding was mirrored for the home media composite (β (SE) = 0.12 (0.03), p < 0.001). The individual home food and activity composite scores were not associated with BMI-SDS.

CONCLUSION

Findings reveal associations between the overall obesogenic home environment and dietary intake, activity levels and screen-based sedentary behaviours, as well as BMI in 12 year olds. These findings suggest that the home environment, and in particular the home media environment, may be an important target for obesity prevention strategies.

A Critical Review of Statistical Methods for Twin Studies Relating Exposure to Early Life Health Conditions

When investigating disease etiology, twin data provide a unique opportunity to control for confounding and disentangling the role of the human genome and exposome. However, using appropriate statistical methods is fundamental for exploiting such potential. We aimed to critically review the statistical approaches used in twin studies relating exposure to early life health conditions. We searched PubMed, Scopus, Web of Science, and Embase (2011–2021). We identified 32 studies and nine classes of methods. Five were conditional approaches (within-pair analyses): additive-common-erratic (ACE) models (11 studies), generalized linear mixed models (GLMMs, five studies), generalized linear models (GLMs) with fixed pair effects (four studies), within-pair difference analyses (three studies), and paired-sample tests (two studies). Four were marginal approaches (unpaired analyses): generalized estimating equations (GEE) models (five studies), GLMs with cluster-robust standard errors (six studies), GLMs (one study), and independent-sample tests (one study). ACE models are suitable for assessing heritability but require adaptations for binary outcomes and repeated measurements. Conditional models can adjust by design for shared confounders, and GLMMs are suitable for repeated measurements. Marginal models may lead to invalid inference. By highlighting the strengths and limitations of commonly applied statistical methods, this review may be helpful for researchers using twin designs.

Two genetic analyses to elucidate causality between body mass index and personality

BACKGROUND/OBJECTIVES

Many personality traits correlate with BMI, but the existence and direction of causal links between them are unclear. If personality influences BMI, knowing this causal direction could inform weight management strategies. Knowing that BMI instead influences personality would contribute to a better understanding of the mechanisms of personality development and the possible psychological effects of weight change. We tested the existence and direction of causal links between BMI and personality.

SUBJECTS/METHODS

We employed two genetically informed methods. In Mendelian randomization, allele scores were calculated to summarize genetic propensity for the personality traits neuroticism, worry, and depressive affect and used to predict BMI in an independent sample (N = 3 541). Similarly, an allele score for BMI was used to predict eating-specific and domain-general phenotypic personality scores (PPSs; aggregate scores of personality traits weighted by BMI). In a direction of causation (DoC) analysis, twin data from five countries (N = 5424) were used to assess the fit of four alternative models: PPSs influencing BMI, BMI influencing PPSs, reciprocal causation, and no causation.

RESULTS

In Mendelian randomization, the allele score for BMI predicted domain-general (β = 0.05; 95% CI: 0.02, 0.08; P = 0.003) and eating-specific PPS (β = 0.06; 95% CI: 0.03, 0.09; P < 0.001). The allele score for worry also predicted BMI (β = -0.05; 95% CI: -0.08, -0.02; P < 0.001), while those for neuroticism and depressive affect did not (P ≥ 0.459). In DoC, BMI similarly predicted domain-general (β = 0.21; 95% CI:, 0.18, 0.24; P < 0.001) and eating-specific personality traits (β = 0.19; 95% CI:, 0.16, 0.22; P < 0.001), suggesting causality from BMI to personality traits. In exploratory analyses, links between BMI and domain-general personality traits appeared reciprocal for higher-weight individuals (BMI > ~25).

CONCLUSIONS

Although both genetic analyses suggested an influence of BMI on personality traits, it is not yet known if weight management interventions could influence personality. Personality traits may influence BMI in turn, but effects in this direction appeared weaker.

Multimodal brain predictors of current weight and weight gain in children enrolled in the ABCD study ®

Multimodal neuroimaging assessments were utilized to identify generalizable brain correlates of current body mass index (BMI) and predictors of pathological weight gain (i.e., beyond normative development) one year later. Multimodal data from children enrolled in the Adolescent Brain Cognitive Development Study® at 9-to-10-years-old, consisted of structural magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), resting state (rs), and three task-based functional (f) MRI scans assessing reward processing, inhibitory control, and working memory. Cross-validated elastic-net regression revealed widespread structural associations with BMI (e.g., cortical thickness, surface area, subcortical volume, and DTI), which explained 35% of the variance in the training set and generalized well to the test set (R2 = 0.27). Widespread rsfMRI inter- and intra-network correlations were related to BMI (R2train = 0.21; R2test = 0.14), as were regional activations on the working memory task (R2train = 0.20; (R2test = 0.16). However, reward and inhibitory control tasks were unrelated to BMI. Further, pathological weight gain was predicted by structural features (Area Under the Curve (AUC)train = 0.83; AUCtest = 0.83, p < 0.001), but not by fMRI nor rsfMRI. These results establish generalizable brain correlates of current weight and future pathological weight gain. These results also suggest that sMRI may have particular value for identifying children at risk for pathological weight gain.

Positive maternal attitudes to following healthy infant feeding guidelines attenuate the associations between infant appetitive traits and both infant milk intake and weight

Appetitive traits influence food intake and weight gain throughout the life-course. Here, we investigated whether maternal attitudes to following healthy infant feeding guidelines could modify this association. Baseline data from 544 mother-infant formula-feeding dyads recruited to the Baby Milk Trial were included in this observational, cross-sectional analysis. Infant appetitive traits (food responsiveness and satiety responsiveness), maternal attitudes to following healthy infant feeding guidelines (self-efficacy, outcome-expectancy, intentions) and infant milk intakes were reported by mothers through questionnaires. Infant weight was measured using standard procedures. Associations between the maternal attitudes score or infant appetitive traits with infant milk intake and infant weight were evaluated in linear regression models adjusted for infant sex and age. To identify effect modification, the interaction term between the maternal attitudes score and infant appetitive trait was added to the model. Infants' mean age and weight were 2.3 months (SD = 0.9) and 5.5 kg (SD = 0.9), respectively. The mean daily infant milk intake reported by mothers was 895 ml/day (SD = 215). Higher maternal attitudes score was associated with lower infant milk intake (Beta = -68.4 ml/day/unit (95% CI: 96.6, -40.2)) and infant weight (Beta = -0.13 SD/unit (-0.25, -0.02)). The maternal attitudes score showed interactions with infant food responsiveness on infant milk intake (p = 0.049), and with infant satiety responsiveness on infant weight (p = 0.01). In both cases, a higher maternal attitudes score attenuated the associations between infant appetitive traits and those outcomes. This analysis provides evidence that positive maternal attitudes to following healthy infant feeding guidelines attenuate the effects of infant appetitive traits on infant milk intake and body weight.

Polygenic risk for obesity and its interaction with lifestyle and sociodemographic factors in European children and adolescents

BACKGROUND

Childhood obesity is a complex multifaceted condition, which is influenced by genetics, environmental factors, and their interaction. However, these interactions have mainly been studied in twin studies and evidence from population-based cohorts is limited. Here, we analyze the interaction of an obesity-related genome-wide polygenic risk score (PRS) with sociodemographic and lifestyle factors for BMI and waist circumference (WC) in European children and adolescents.

METHODS

The analyses are based on 8609 repeated observations from 3098 participants aged 2-16 years from the IDEFICS/I.Family cohort. A genome-wide polygenic risk score (PRS) was calculated using summary statistics from independent genome-wide association studies of BMI. Associations were estimated using generalized linear mixed models adjusted for sex, age, region of residence, parental education, dietary intake, relatedness, and population stratification.

RESULTS

The PRS was associated with BMI (beta estimate [95% confidence interval (95%-CI)] = 0.33 [0.30, 0.37], r2 = 0.11, p value = 7.9 × 10-81) and WC (beta [95%-CI] = 0.36 [0.32, 0.40], r2 = 0.09, p value = 1.8 × 10-71). We observed significant interactions with demographic and lifestyle factors for BMI as well as WC. Children from Southern Europe showed increased genetic liability to obesity (BMI: beta [95%-CI] = 0.40 [0.34, 0.45]) in comparison to children from central Europe (beta [95%-CI] = 0.29 [0.23, 0.34]), p-interaction = 0.0066). Children of parents with a low level of education showed an increased genetic liability to obesity (BMI: beta [95%-CI] = 0.48 [0.38, 0.59]) in comparison to children of parents with a high level of education (beta [95%-CI] = 0.30 [0.26, 0.34]), p-interaction = 0.0012). Furthermore, the genetic liability to obesity was attenuated by a higher intake of fiber (BMI: beta [95%-CI] interaction = -0.02 [-0.04,-0.01]) and shorter screen times (beta [95%-CI] interaction = 0.02 [0.00, 0.03]).

CONCLUSIONS

Our results highlight that a healthy childhood environment might partly offset a genetic predisposition to obesity during childhood and adolescence.

Evidence for shared genetics between physical activity, sedentary behaviour and adiposity-related traits

Observational, cross-sectional and longitudinal studies showed that physical activity and sedentary behaviour are associated with adiposity-related traits, apparently in a bidirectional manner. Physical activity is also suggested to suppress the genetic risk of adiposity. Since phenotypic associations with genetic variants are not subject to reverse causation or confounding, they may be used as tools to shed light on cause and effect in this complex interdependency. We review the evidence for shared genetics of physical activity and adiposity-related traits and for gene-by-physical activity interactions on adiposity-related traits in human studies. We outline limitations, challenges and opportunities in studying and understanding of these relationships. In summary, physical activity and sedentary behaviour are genetically correlated with body mass index and fat percentage but may not be correlated with lean body mass. Mendelian randomisation analyses show that physical activity and sedentary behaviour have bidirectional relationships with adiposity. Several studies suggest that physical activity suppresses genetic risk of adiposity. No studies have yet tested whether adiposity enhances genetic predisposition to sedentariness. The complexity of the comprehensive causal model makes the assessment of the single or combined components challenging. Substantial progress in this field may need long-term intervention studies.

Utilizing genome wide data to highlight the social behavioral pathways to health: The case of obesity and cardiovascular health among older adults

We use genome-wide data from the 1992-2016 Health and Retirement Study (n = 12,090) to characterize obesity among older adults as genetically or socially oriented. To illustrate the significance of this approach for social epidemiological research, we deem those with the lowest genetic risk for obesity to be socially-behaviorally obese and obesity among those with the highest polygenic risk is characterized as genetically oriented. We then examine the association between obesity and four indicators of cardiovascular health (type-2 diabetes, hypertension, heart problems, and stroke) among those with low, average, and high genetic risk. Our results show that the association between obesity and cardiovascular health is significantly higher for those with the lowest genetic risk (e.g., social-behavioral obesity). We also demonstrate important sex differences such that this association is particularly strong for heart problems among men and hypertension and stroke among women. Our results further demonstrate the centrality of the social and behavioral determinants of health by utilizing detailed information across the human genome and add to both social and genetic epidemiology literatures.

The current review of adolescent obesity: the role of genetic factors

Obesity, a complex, multi-factor and heterogeneous condition, is thought to result from the interaction of environmental and genetic factors. Considering the result of adolescence obesity in adulthood, the role of genetic factors comes to the fore. Recently, many genome-wide association studies (GWAS) have been conducted and many loci associated with adiposity have been identified. In adolescents, the strongest association with obesity has been found in single nucleotide polymorphisms (SNP) in the FTO gene. Besides FTO, GWAS showed consistent effects between variants in MC4R, TMEM18, TNNI3K, SEC16B, GNPDA2, POMC and obesity. However, these variants may not have similar effects for all ethnic groups. Although recently genetic factors are considered to contribute to obesity, relatively little is known about the specific loci related to obesity and the mechanisms by which they cause obesity.

An overview of obesity mechanisms in humans: Endocrine regulation of food intake, eating behaviour and common determinants of body weight

Obesity is one of the biggest health challenges of the 21st century, already affecting close to 700 million people worldwide, debilitating and shortening lives and costing billions of pounds in healthcare costs and loss of workability. Body weight homeostasis relies on complex biological mechanisms and the development of obesity occurs on a background of genetic susceptibility and an environment promoting increased caloric intake and reduced physical activity. The pathophysiology of common obesity links neuro-endocrine and metabolic disturbances with behavioural changes, genetics, epigenetics and cultural habits. Also, specific causes of obesity exist, including monogenetic diseases and iatrogenic causes. In this review, we provide an overview of obesity mechanisms in humans with a focus on energy homeostasis, endocrine regulation of food intake and eating behavior, as well as the most common specific causes of obesity.

Childhood Obesity and Device-Measured Sedentary Behavior: An Instrumental Variable Analysis of 3,864 Mother-Offspring Pairs

OBJECTIVE

Intergenerational data on mother-offspring pairs were utilized in an instrumental variable analysis to examine the longitudinal association between BMI and sedentary behavior.

METHODS

The sample included 3,864 mother-offspring pairs from the 1970 British Cohort Study. Height and weight were recorded in mothers (age 31 [5.4] years) and offspring (age 10 years) and repeated in offspring during adulthood. Offspring provided objective data on sedentary behavior (7-day thigh-worn activPAL) in adulthood at age 46 to 47 years.

RESULTS

Maternal BMI, the instrumental variable, was associated with offspring BMI at age 10 (change per kg/m² , β = 0.11; 95% CI: 0.09 to 0.12), satisfying a key assumption of instrumental variable analyses. Offspring (change per kg/m² , β = 0.010; 95% CI: -0.02 to 0.03 h/d) and maternal BMI (β = 0.017; 95% CI: 0.001 to 0.03 h/d) was related to offspring sedentary time, suggestive of a causal impact of BMI on sedentary behavior (two-stage least squares analysis, β = 0.18 [SE 0.08], P = 0.015). For moderate-vigorous physical activity, there were associations with offspring BMI (β = -0.010; 95% CI: -0.017 to -0.004) and maternal BMI (β = -0.007; 95% CI: -0.010 to -0.003), with evidence for causality (two-stage least squares analysis, β = -0.060 [SE 0.02], P = 0.001).

CONCLUSIONS

There is strong evidence for a causal pathway linking childhood obesity to greater sedentary behavior.

No Evidence for Passive Gene-Environment Correlation or the Influence of Genetic Risk for Psychiatric Disorders on Adult Body Composition via the Adoption Design

The relationship between genetic and environmental risk is complex and for many traits, estimates of genetic effects may be inflated by passive gene-environment correlation. This arises because biological offspring inherit both their genotypes and rearing environment from their parents. We tested for passive gene-environment correlation in adult body composition traits using the 'natural experiment' of childhood adoption, which removes passive gene-environment correlation within families. Specifically, we compared 6165 adoptees with propensity score matched non-adoptees in the UK Biobank. We also tested whether passive gene-environment correlation inflates the association between psychiatric genetic risk and body composition. We found no evidence for inflation of heritability or polygenic scores in non-adoptees compared to adoptees for a range of body composition traits. Furthermore, polygenic risk scores for anorexia nervosa, attention-deficit/hyperactivity disorder and schizophrenia did not differ in their influence on body composition traits in adoptees and non-adoptees. These findings suggest that passive gene-environment correlation does not inflate genetic effects for body composition, or the influence of psychiatric disorder genetic risk on body composition. Our design does not look at passive gene-environment correlation in childhood, and does not test for 'pure' environmental effects or the effects of active and evocative gene-environment correlations, where child genetics directly influences home environment. However, these findings suggest that genetic influences identified for body composition in this adult sample are direct, and not confounded by the family environment provided by biological relatives.

Earlier onset of menstruation is related to increased body mass index in adulthood and altered functional correlations between visual, task control and somatosensory brain networks

Later onset of puberty has been associated with lower body mass index (BMI) in adulthood independent of childhood BMI. However, how the relationship between time of onset of puberty and BMI in adulthood is associated with neurocognitive outcomes is largely unstudied. In the present study, women were sampled from the Human Connectome Project 1200 parcellation, timeseries and netmats1 release (PTN) release. Inclusion criteria were: four (15 minutes) resting state fMRI scans, current measured BMI, self-reported age at onset of menstruation (a proxy of age at onset of puberty) and no endocrine complications (eg, polycystic ovarian syndrome). The effect of age at onset of menstruation, measured BMI at scan date and the interaction of age at onset of menstruation by BMI on brain functional correlation was modelled using fslnets (https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/FSLNets) controlling for race and age at scan. Corrected significance was set at a family-wise error probability (pFWE) < 0.05. A final sample of n = 510 (age 29.5 years ± 3.6, BMI at scan 25.9 ± 5.6 and age at onset of menstruation 12.7 ± 1.6 were included. Age at onset of menstruation was negatively associated with BMI at scan (r = - 0.19, P < 0.001). The interaction between age at onset of menstruation and BMI at scan was associated with stronger correlation between a somatosensory and visual network (t = 3.45, pFWE = 0.026) and a visual network and cingulo-opercular task control network (t = 4.74, pFWE = 0.0002). Post-hoc analyses of behavioural/cognitive measures showed no effect of the interaction between BMI and age at onset of menstruation on behavioural/cognitive measures. However, post-hoc analyses of heritability showed adult BMI and the correlation between the visual and somatosensory networks have high heritability. In sum, we report increased correlation between visual, taste-associated and self-control brain regions in women at high BMI with later age at onset of menstruation.

Does eating in the absence of hunger extend to healthy snacks in children?

OBJECTIVES

To assess if eating in the absence of hunger (EAH) extends to healthier snacks and examine the relationship between the home food environment and EAH in children with normal weight (NW) or overweight/obesity (OB) who are at low risk (LR) or high risk (HR) for obesity based on maternal obesity.

METHODS

EAH was assessed after lunch and dinner when children received either low energy dense fruit snacks or high energy dense sweet/savoury snacks. The availability of obesogenic foods in the home was assessed by the Home Food Inventory.

RESULTS

Data showed significant main effects of risk group (P=.0003) and snack type (P < .001). EAH was significantly greater in HR-OB (284±8 kcal) than LR-NW (249±9 kcal) or HR-NW (251±8 kcal) children. Serving fruit rather than sweet/savoury snacks reduced energy intake, on average, by 60% (223 kcal) across risk groups. For each unit increase in the obesogenic home food environment, EAH of sweet/savoury snacks decreased by 1.83 calories.

CONCLUSIONS

Offering low energy dense snacks after a meal can moderate EAH and increase children's intake of healthy foods. Increased access to obesogenic foods in the home may reduce the salience of high energy dense snacks when they become available in other settings.

Development of RisObIn.Com, a Screening Tool for Risk of Childhood Obesity in the Community

The prevalence of childhood overweight has increased considerably in the past three decades and there is evidence that childhood obesity can persist into adulthood. A simple tool to identify relevant risk factors may alert families and prevent overweight and obesity. This study aims to develop a pre-school screening tool to assess the risk of childhood obesity. Child anthropometric measurements and several risk factors for childhood obesity factors were obtained. The effect of the variables on the outcome of obesity (defined as increased anthropometry-estimated adiposity) was assessed by binary logistic regression analyses. The identified variables were submitted for expert panel validation and combined for the tool development. A total of 304 children were included. Eight items were included in the tool. A higher score of the tool indicates a greater risk for obesity in childhood with the cutoff point set at 0. The tool sensitivity for obesity was 95%, specificity was 74.4%, the positive predictive value was 37.3%, and negative predictive value was 98.9%. The Risk of childhood Obesity In the Community (RisObIn.Com) tool is proposed to be a comprehensive tool to identify children at high risk for late childhood obesity at admission to primary school. Further studies are needed to assess the performance of the tool.

[Obesity is rarely curable: individual concepts and therapy programs for children and adolescents]

Obesity in children has an increased risk to persist in adulthood. In most cases, obesity starts to develop in children at school age. Lower social economic status and migration background are severe risk factors for obesity. Additionally, genetic predisposition for the development of obesity plays an especially important role in children and adolescents. However, the individual cause for obesity is heterogeneous and complex. This is the reason why only a systematic analysis of individually existing problems is necessary for a differentiated and realistic planning of the treatment. Long-lasting therapy concepts need to be based on current available evidence.The treatment of childhood obesity should rely on multiprofessional lifestyle programs. An exception might be rare monogenic or syndromic forms of obesity, because defects within the central regulatory pathways of body weight regulation could be present. In general, a key component of the treatment strategy should include an improvement of nutrition, physical exercise and self-esteem combined with a reduction of stress. Moreover, the inclusion of parents into the treatment strategy has shown to be beneficial and necessary. Long-term follow-up studies on the development of associated comorbidities are rare. Unfortunately, patient groups at risk are currently not necessarily reached with available treatment programs.A multiprofessional analysis of individual problems and differentiated treatment planning with a participative approach (acknowledging the cultural background and involving members of the family) should lead to long-lasting improvement of the therapeutic outcome. The individual main treatment aim should also include - apart from the reduction of body weight - the improvement of associated comorbidities and quality of life, especially by avoiding any stigmatization. A health-promoting environment is desirable for this salutogenetic approach.

Genetic background and diet affect brown adipose gene coexpression networks associated with metabolic phenotypes

Adipose is a dynamic endocrine organ that is critical for regulating metabolism and is highly responsive to nutritional environment. Brown adipose tissue is an exciting potential therapeutic target; however, there are no systematic studies of gene-by-environment interactions affecting function of this organ. We leveraged a weighted gene coexpression network analysis to identify transcriptional networks in brown adipose tissue from LG/J and SM/J inbred mice fed high- or low-fat diets and correlate these networks with metabolic phenotypes. We identified eight primary gene network modules associated with variation in obesity and diabetes-related traits. Four modules were enriched for metabolically relevant processes such as immune and cytokine response, cell division, peroxisome functions, and organic molecule metabolic processes. The relative expression of genes in these modules is highly dependent on both genetic background and dietary environment. Genes in the immune/cytokine response and cell division modules are particularly highly expressed in high fat-fed SM/J mice, which show unique brown adipose-dependent remission of diabetes. The interconnectivity of genes in these modules is also heavily dependent on diet and strain, with most genes showing both higher expression and coexpression under the same context. We highlight several genes of interest, Col28a1, Cyp26b1, Bmp8b, and Ngef, that have distinct expression patterns among strain-by-diet contexts and fall under metabolic quantitative trait loci previously mapped in an F16 generation of an advanced intercross between LG/J and SM/J. Each of these genes have some connection to obesity and diabetes-related traits, but have not been studied in brown adipose tissue. Our results provide important insights into the relationship between brown adipose and systemic metabolism by being the first gene-by-environment study of brown adipose transcriptional networks.

The obesity epidemic - Nature via nurture: A narrative review of high-income countries

Over the last three decades, the prevalence of obesity has increased rapidly in populations around the world. Despite a wealth of research, the relative contributions of the different mechanisms underlying this global epidemic are not fully understood. While there is growing consensus that the rapid rise in obesity prevalence has been driven by changes to the environment, it is evident that biology plays a central role in determining who develops obesity and who remains lean in the current obesogenic environment. This review summarises evidence on the extent to which genes and the environment influence energy intake and energy expenditure, and as a result, contribute to the ongoing global obesity epidemic. The concept of genetic susceptibility to the environment driving human variation in body weight is discussed.

[Heritability of obesity in children aged 30-36 months and an analysis of single nucleotide polymorphisms at four loci in Xi'an, China]

OBJECTIVE

To study the heritability of obesity in children aged 30-36 months in Xi'an, China, as well as the role of four single nucleotide polymorphisms (SNPs) associated with body mass index in the susceptibility to obesity in children.

METHODS

Random sampling was performed to select 1 637 children, aged 30-36 months, from four communities of Xi'an from March 2017 to December 2018. Physical assessment was performed for these children, and a questionnaire survey was conducted for parents. Then the Falconer regression method was used to calculate the heritability of childhood obesity. Venous blood samples were collected from 297 children who underwent biochemical examinations, among whom there were 140 children with obesity/overweight (obesity/overweight group) and 157 with normal body weight (normal body weight group). The MassARRAY RS1000 typing technique was used to detect CDKAL1 gene rs2206734, KLF9 gene rs11142387, PCSK1 gene rs261967, and GP2 gene rs12597579. The distribution of alleles and genotypes was compared between the obesity/overweight and normal body weight groups. An unconditional logistic regression model was used to investigate the benefits of dominant and recessive genetic models.

RESULTS

For the 1 637 children, the heritability of obesity from the parents was 83%±8%, and the heritability from mother was slightly higher than that from father (86%±11% vs 78%±12%). There were significant differences in the distribution of rs2206734 alleles and genotypes and rs261967 genotypes between the obesity/overweight and normal body weight groups (P<0.0125). The children carrying T allele at rs2206734 had a significantly higher risk of obesity than those carrying CC (OR=0.24, P<0.0125), and the children carrying GG at rs261967 had a significantly higher risk of obesity than those carrying A allele (OR=4.11, P<0.0125).

CONCLUSIONS

Genetic factors play an important role in the pathogenesis of obesity in children, and the SNPs of CDKAL1 rs2206734 and PCSK1 rs261967 are associated with the susceptibility to obesity in children aged 30-36 months in Xi'an.