A study of the birth weight-obesity relation using a longitudinal cohort and sibling and twin pairs

Emotional problems mediate the association between attention deficit/hyperactivity disorder and obesity in adolescents

BACKGROUND

Attention deficit/hyperactivity disorder (ADHD) has been identified as a risk factor for obesity in both children and adolescents. However, the mechanisms underlying the relationship between ADHD and obesity are still unclear. This study aimed to test a theoretical model of whether anxiety/depression is an intermediary factor in the ADHD-obesity relationship.

METHODS

Data were derived from the National Health Interview Survey (NHIS), a principal source of information on the health of the civilian noninstitutionalized population of the United States. A total of 35,108 adolescents aged 12-17 years old from 2010-2015 NHIS and 2016-2018 NHIS representing 46,550,729 individuals in the weighted population, had a parent-reported previous ADHD diagnosis, emotional problems, and height and weight data. Mediation analyses were used to explore whether anxiety/depression is an intermediary factor in the relationship between ever having ADHD and obesity. Mediation analyses were performed using multiple logistic regressions.

RESULTS

The findings showed that ADHD was a predictor of obesity. This relationship was partially mediated by depression(2010-2015: β=0.28, 95%CI:0.13-0.43; 2016-2018: β=0.26, 95%CI:0.03-0.49), as well as anxiety (2010-2015: β=0.28, 95%CI:0.18-0.38).

CONCLUSIONS

Our study suggests the hypothetical role of depression and anxiety as underlying mechanisms in the association between ever having ADHD and obesity in adolescents. When treating children with ADHD, clinicians need to be particularly attentive to whether they show emotional problems and use interventions to eliminate anxiety/depression to protect against obesity.

Having siblings promotes a more healthy weight status—Whereas only children are at greater risk for higher BMI in later childhood

Background

Birth order and having at least one sibling are known to be associated with an increased risk for development of overweight. However, there are no studies assessing pre- and postnatal factors for developing overweight within families. Therefore, the present study aimed to analyse the association of the mother’s weight gain during pregnancy, prepregnancy BMI, mother’s age at birth, breastfeeding, age gap between siblings, and physical activity together with sibling-related characteristics on the development of overweight in children and adolescents.

Methods

Data were obtained from the longitudinal LIFE Child cohort. The study sample included n = 1932 children, stratified into first-born (n = 578), second-born (n = 608), third-or-later-born single-born siblings (n = 162), only children (n = 526), and twin children (n = 58). Children with chronic or syndromic diseases, born prematurely or from mothers with gestational diabetes were excluded. Data were adjusted for multiple children per family using mixed models. Pregnancy weight gain, prepregnancy BMI and mother’s age were considered prenatal co-variates. Postnatal factors included the duration of breastfeeding and the children’s physical activity level.

Results

Particularly until the onset of puberty, the BMI-SDS differed between single-born siblings, only children and twins, and increased with birth order. Compared to children with siblings, only children exhibited a strong increase in BMI-SDS starting at age nine. A higher age gap between siblings was associated with a higher BMI-SDS in second- and third-or-later-born children. Single-born siblings had the highest rate and duration of breastfeeding. Physical activity was highest in twins and third-or-later-born children and lowest in only children. In a multivariate model, being an only child showed a highly significant association with BMI-SDS.

Conclusion

The present study demonstrated that siblings had a lower BMI-SDS than only children did. For single-born siblings, the association between birth order and increased BMI-SDS seemed to persist only up to 11 years of age.

Differences and Correlation Analysis of Birth Weight and Overweight/Obesity in Shanghai Twin Cohort

The objective of this study was to analyze differences in birth weight and overweight/obesity in a Shanghai twin cohort. We also wanted to study their association and explore possible risk factors for the discordance of overweight/obesity within twins. This was an internal case-control study designed for twins. The 2012 Shanghai Twin Registration System baseline survey data of a total of 3417 twin pairs were statistically analyzed using SPSS22 software. Results show that the body mass index (BMI) of the Shanghai twin population increased with age. Twins with a high birth weight had a higher BMI and a higher rate of overweight and obesity; 0- to 6-year-old twins, male twins and dizygotic (DZ) twins had higher rates of overweight/obesity than other groups. The greater the discordant birth weight rate of twins, the more obvious the difference in BMI (p < .05). There was a significant difference in overweight/obesity between twins with a relative difference of birth weight ≥15% in DZ twins (p < .05). DZ twins, male twins and 0- to 6-year-old twins were more likely to be discordant in overweight/obese than others. The discordant birth weight within twins was not a risk factor for discordant overweight/obesity. However, attention should be paid to childhood obesity, and appropriate interventions should be made at the appropriate time. Genetics may play an important role in the occurrence and development of overweight/obesity. In conclusion, discordant growth and development in the uterus early in life may not lead to discordant weight development in the future.

Developmental origins of cardiometabolic health outcomes in twins: A systematic review and meta-analysis

BACKGROUND AND AIMS

Studies of twins can reduce confounding and provide additional evidence about the causes of disease, due to within-pair matching for measured and unmeasured factors. Although findings from twin studies are typically applicable to the general population, few studies have taken full advantage of the twin design to explore the developmental origins of cardiometabolic health outcomes. We aimed to systematically review the evidence from twin studies and generate pooled estimates for the effects of early-life risk factors on later-life cardiometabolic health.

METHODS AND RESULTS

An initial search was conducted in March 2018, with 55 studies of twins included in the review. Risk of bias was assessed using the Newcastle-Ottawa Scale, and eligible studies were included in a meta-analysis, where pooled estimates were calculated. Twenty-six studies analysed twins as individuals, and found that higher birthweight was associated with lower SBP (β = -2.02 mmHg, 95%CI: -3.07, -0.97), higher BMI (β = 0.52 kg/m², 95%CI: 0.20, 0.84) and lower total cholesterol (β = -0.07 mmol/L, 95%CI: -0.11, -0.04). However, no associations were reported in studies which adjusted for gestational age. Few of the included studies separated their analyses into within-pair and between-pair associations.

CONCLUSIONS

Early-life risk factors were associated with cardiometabolic health outcomes in twin studies. However, many estimates from studies in this review were likely to have been confounded by gestational age, and few fully exploited the twin design to assess the developmental origins of cardiometabolic health outcomes.

Are genes destiny? Exploring the role of intrauterine environment in moderating genetic influences on body mass

OBJECTIVES

Genes influence every aspect of human behavior, physiology, and health. Obesity, a major global public health concern, is no exception. However, relatively little is known about whether environmental factors moderate the effects of genetic influences on body mass. By incorporating molecular genetics and the fetal origins of obesity hypothesis into a gene-environment interaction framework, this study investigates how the effect of the obesity-associated gene (FTO) interacts with the effect of intrauterine environment to influence body mass during adulthood.

METHODS

This study uses data from the Wisconsin Longitudinal Study, and uses sibling comparisons that allow for quasi-experimental variation in both genetic and environmental factors.

RESULTS

This study found positive, but noisy, within-family estimates of the FTO-body mass index (BMI) association. The association between birth weight and adult BMI was robust to controlling for unobserved family background factors. More importantly, this study revealed that the association between having a risk allele of the FTO gene and BMI (and obesity status) is largely concentrated among individuals who were heavier at birth. This provides evidence of a gene-environment interaction on BMI (and the development of obesity).

CONCLUSIONS

Genes are not destiny and environmental factors may offset the effects of obesity-promoting genes. Public health efforts to counteract genetic effects on body mass may begin as early as in utero. Efforts to prevent higher birth weight may thus help reduce the risk of obesity later in life, by directly addressing the programming effects of the in utero environment and also indirectly moderating obesity-promoting genetic effects.

Variation in the relationship between birth weight and subsequent obesity by household income

There is evidence to suggest that high birth weight increases subsequent BMI. However, little attention has been paid to variations in this impact between population groups. This study investigates the relationship between high birth weight and subsequent obesity, and whether or not this relationship varies by household income. Data was taken from fourteen rounds of the Health Survey for England (between 2000-2014; N = 31,043) for children aged 2-16. We regressed obesity in childhood against birth weight, accounting for interactions between birth weight and household income, using sibling-fixed effects models. High birth weight was associated with increased risk of subsequent obesity. This association was significantly more pronounced in children from low-income families, compared with children from high-income families. A 1 kg increase in birth weight increased the probability of obesity by 7% in the lowest income tertile and 4% in the highest income tertile. This suggests that early socioeconomic deprivation compound the effect of high birth weight on obesity.

Low birth weight may increase body fat mass in adult women with polycystic ovarian syndrome

BACKGROUND

Women engaged with polycystic ovarian syndrome (PCOS), as the commonest endocrine disorder, are known to have a specific type of adiposity. Birth weight is among different contributors reported to be responsible for this diversity.

OBJECTIVE

We aimed to compare the relation between birth weight and body fat mass (BFM)/ body lean mass (BLM) in PCOS and their age and body mass index (BMI) matched normal controls.

MATERIALS AND METHODS

In this case-control study, a total number of 70 reproductive aged women, diagnosed with PCOS and 70 age- BMI matched healthy women without hirsutism and/or ovulatory dysfunction were recruited., control group had no polycystic ovaries in ultrasonographic scans. A detailed history of birth weight was taken and was divided into the following categories: <2,500 (low birth weight, LBW) and 2,500-4,000 (normal birth weight; NBW).

RESULTS

Results showed that LBW prevalence was higher in women with PCOS than in controls (19.3% (27) vs. 15.7% (22)). Also body fat and lean mass (BFM, BLM) have increased in adult women with PCOS who were born underweight compared to their normal (19.8±9.05 vs. 12.9±4.5, p=0.001 and 48.9±6.9 vs. 43.2±5.8, p=0.004 respectively).

CONCLUSION

Fetal birth weight influences on the adulthood obesity, BFM and BLM. This impact is different among women with and without PCOS.

Birth weight and adult cardiovascular risk factors using multiple birth status as an instrumental variable in the 1958 British Birth Cohort

BACKGROUND

Birth weight is classified as a risk factor for cardiovascular disease by the World Health Organization, but appropriate preventive interventions remain unclear because the observations have not been confirmed in experiments and appear to be contextually specific.

METHODS

Using 9452 participants of the 1958 British Birth Cohort at age 42years in 2000 (58% follow-up), we examined the credibility of multiple birth status as an instrumental variable (IV) for birth weight and, if appropriate, use it to obtain less confounded estimates of the associations of birth weight with cardiovascular disease risk factors including self-reported height, body mass index and hypertension than conventional regression in 2014.

RESULTS

Multiple birth (203 twins and 6 triplets) was associated with older maternal age, but not with paternal occupation or maternal smoking. Multiple births had lower birth weight-for-gestational age z-score. Multiple birth status was not directly associated with height, BMI or hypertension. Using IV estimates birth weight-for-gestational age z-score was not clearly associated with height (0.99cm, 95% confidence interval (CI) -0.27, 2.25), body mass index (BMI) (0.42kg/m(2), 95% CI -0.17, 1.01) or hypertension (risk ratio 0.82, 95% CI 0.54, 1.23) adjusted for maternal age, with a first-stage F statistic of 145.3 from IV analysis.

CONCLUSIONS

Multiple birth status is a credible IV for obtaining a less confounded estimate of the association of birth weight with height, BMI and blood pressure. Such analysis suggests that birth weight may be spuriously related to height, BMI and blood pressure, and thus not an effective target for intervention.

Endocrine and other physiologic modulators of perinatal cardiomyocyte endowment

Immature contractile cardiomyocytes proliferate to rapidly increase cell number, establishing cardiomyocyte endowment in the perinatal period. Developmental changes in cellular maturation, size and attrition further contribute to cardiac anatomy. These physiological processes occur concomitant with a changing hormonal environment as the fetus prepares itself for the transition to extrauterine life. There are complex interactions between endocrine, hemodynamic and nutritional regulators of cardiac development. Birth has been long assumed to be the trigger for major differences between the fetal and postnatal cardiomyocyte growth patterns, but investigations in normally growing sheep and rodents suggest this may not be entirely true; in sheep, these differences are initiated before birth, while in rodents they occur after birth. The aim of this review is to draw together our understanding of the temporal regulation of these signals and cardiomyocyte responses relative to birth. Further, we consider how these dynamics are altered in stressed and suboptimal intrauterine environments.

Association between weight at birth and body composition in childhood: A Brazilian cohort study

BACKGROUND AND AIM

Previous studies have shown that the association between birth weight and obesity later in life apparently follows a U-shaped curve. However, due to the continuous increase of mean birth weight in several countries worldwide, it is expected that higher birth weight will play a more important role as a risk factor for further obesity than low birth weight. This study investigated the association between birth weight and body composition of children in order to establish their relationship in an earlier period of life.

STUDY DESIGN AND SUBJECTS

Prospective cohort study carried out from 1997 to 2006 in Jundiai city, Brazil, involving 486 children at birth and from 5 to 8 years of age. The following anthropometric measurements were determined: birth weight, weight, height, waist circumference and triceps skinfold thickness. Fat mass percentage, fat mass and fat-free mass were measured by electrical bioimpedance analysis by the 310 Body Composition Analyzer, Biodynamics(®). Five multiple linear regression models were developed considering waist circumference, triceps skinfold thickness, fat mass percentage, fat mass and fat-free mass as markers of body composition, and outcomes.

RESULTS

Significant positive associations were observed between birth weight and waist circumference (p<0.001), triceps skinfold thickness (p=0.006), fat mass (p=0.007) and fat-free mass (p<0.001). Approximately 10% of the children presented excess body fat assessed by bioimpedance, and 27.6% of them had central adiposity (waist circumference ≥95th percentile).

CONCLUSIONS

Intrauterine growth, assessed by weight at birth, was positively associated with body composition of children aged 5-8 years, indicating that those with the highest birth weight are more at risk for obesity, and probably to chronic diseases in adulthood.

The association of birth weight with cardiovascular risk factors and mental problems among Iranian school-aged children: the CASPIAN-III study

OBJECTIVE

Both high and low birth weights (HBW and LBW) are risk factors for adulthood diseases. The aim of this study was to investigate the association of birth weight with cardiovascular disease (CVD) risk factors and mental problems among Iranian school-aged children.

METHODS

This national multicenter study of school-aged children entitled CASPIAN III was conducted among 5528 students in ranging from ages 10 to 18 y. Biochemical indices and anthropometric measurements were collected. Mental health was assessed by questionnaire. To investigate the association between birth weight categories and CVD risk factors and mental problems, multivariate logistic regression was used.

RESULTS

HBW adolescents were at higher risk for elevated diastolic blood pressure (DBP) (Ptrend < 0.05), low levels of high-density lipoprotein cholesterol (HDL-C) (Ptrend < 0.05), and lower risk for general obesity (Ptrend < 0.05) compared with the LBW category. HBW had no significant association with mental problems (Ptrend > 0.05) compared with LBW adolescents. The results of regression analysis, which considered normal birth weight as the reference group, showed that LBW students had lower risk for overweight and obesity (P < 0.01), as well as higher DBP (P < 0.05) but they were at higher risk for lower levels of HDL-C (P < 0.01). Furthermore, birth-weight categories had a U-shaped relationship with mental problems and sleep disorders (P < 0.05). Risk for confusion was higher among the LBW group (P < 0.05).

CONCLUSION

Findings from this population-based study revealed a positive relation between birth weight categories and CVD risk factors. Compared with students born with normal weight, those born with HBW and LBW were at higher risk for mental problems, sleep disorders, and confusion.

2-Hour postload serum glucose levels and maternal blood pressure as independent predictors of birth weight in "appropriate for gestational age" neonates in healthy nondiabetic pregnancies

INTRODUCTION

Increased neonatal birth weight (NBW), often associated with diabetic pregnancies, is a recognized indicator of childhood obesity and future metabolic risk. Predictors of NBW in healthy non-diabetic pregnancies are not yet established. Here, we investigated the association of maternal parameters of healthy non-diabetic mothers with NBW of their "appropriate-for-gestational age" neonates.

METHODS

The study involved 36 healthy mother/infant pairs. Examined parameters included NBW, maternal age, first and last trimester (BMI), weight gain, fasting serum lipids and glucose, 2-hour postload glucose levels and blood pressure.

RESULTS

Postload-glucose levels were significantly higher in mothers of heavier neonates. ANOVA results indicated that 15% increase in postload-glucose levels corresponded to more than 0.5 Kg increase in NBW in the third tertile. NBW correlated positively with postload glucose levels, and negatively with systolic blood pressure. Regression analysis showed that the main predictors of NBW were postload-glucose levels (B = 0.455, P = 0.003), followed by systolic blood pressure (B = -0.447, P = 0.004), together predicting 31.7% NBW variation.

CONCLUSION

This study highlights that increased maternal postload sugar levels and blood pressure, within the normal range, highly predicts NBW of healthy mothers. These findings may provide focus for early dietary intervention measures to avoid future risks to the mother and baby.

Effect of obesity on linear growth

PURPOSE OF REVIEW

To describe our current understanding of the mechanisms involved in the regulation of linear growth in childhood obesity.

RECENT FINDINGS

The developmental origins hypothesis has focused on low birth weight individuals with subsequent obesity, identifying a cascade of neuroendocrine regulatory factors involved in the progressive increase in body fat and metabolic risk. Yet, tall stature is the common clinical outcome of childhood obesity. Recent data have expanded our understanding of environmental influences on developing systems. Here, we review the elements of neuroendocrine systems contributing to the integration of metabolic controls involved in growth regulation in the obese child with particular emphasis on growth hormone, ghrelin, insulin-like growth factors and insulin.

SUMMARY

Growth patterns of obesity during childhood are well described, documenting increased linear growth in early childhood associated with accelerated pubertal maturation resulting in normal adult height. Despite recent data suggesting that ghrelin and the growth hormone secretagogue receptor, as well as the insulin-like growth factors, their binding proteins and insulin have potential to be mediators of nutrient exposure and linear growth, it remains to be determined how these systems interrelate and determine growth. This is an area of ongoing investigation.

Invited commentary: does the childhood environment influence the association between every x and every y in adulthood?

The conditions under which children are raised have a long-term impact on health throughout the life course. Because childhood conditions can have such a strong influence on adult risk factors for disease, failure to account for their influences could distort observed associations between adult risk factors and subsequent health outcomes. In other words, childhood conditions could confound the association between every X and Y when X is measured in adulthood. Comparisons of health outcomes between exposed and unexposed siblings have the potential to eliminate confounding effects due to vulnerability factors shared between siblings (i.e., 50% of their genes and aspects of the childhood environment that affect siblings equally). In a large, population-based study of siblings in Denmark, Søndergaard et al. (Am J Epidemiol. 2012;176(8):675-683) found that individuals with higher educational qualifications lived longer than did their siblings with lower educational qualifications. Their results provide evidence for the returns to health resulting from investment in expanded educational opportunities. However, even sibling designs are not conclusive regarding causality; they remain subject to the unmeasured confounding influences of factors that vary within families. Nonetheless, sibling-based approaches should be used more often in studies of adult risk factors to address the long-term influences of the childhood environment on health.

Epigenetic changes in fetal hypothalamic energy regulating pathways are associated with maternal undernutrition and twinning

Undernutrition during pregnancy is implicated in the programming of offspring for the development of obesity and diabetes. We hypothesized that maternal programming causes epigenetic changes in fetal hypothalamic pathways regulating metabolism. This study used sheep to examine the effect of moderate maternal undernutrition (60 d before to 30 d after mating) and twinning to investigate changes in the key metabolic regulators proopiomelanocortin (POMC) and the glucocorticoid receptor (GR) in fetal hypothalami. Methylation of the fetal hypothalamic POMC promoter was reduced in underfed singleton, fed twin, and underfed twin groups (60, 73, and 63% decrease, respectively). This was associated with reduced DNA methyltransferase activity and altered histone methylation and acetylation. Methylation of the hypothalamic GR promoter was decreased in both twin groups and in maternally underfed singleton fetuses (52, 65, and 55% decrease, respectively). This correlated with changes in histone methylation and acetylation and increased GR mRNA expression in the maternally underfed singleton group. Alterations in GR were hypothalamic specific, with no changes in hippocampi. Unaltered levels of OCT4 promoter methylation indicated gene-specific effects. In conclusion, twinning and periconceptional undernutrition are associated with epigenetic changes in fetal hypothalamic POMC and GR genes, potentially resulting in altered energy balance regulation in the offspring.

Prepregnancy body mass index and gestational weight gain in relation to child body mass index among siblings

There is increasing evidence that in utero effects of excessive gestational weight gain may result in increased weight in children; however, studies have not controlled for shared genetic or environmental factors between mothers and children. Using 2,758 family groups from the Collaborative Perinatal Project, the authors examined the association of maternal prepregnancy body mass index (BMI) and gestational weight gain on child BMI at age 4 years using both conventional generalized estimating equations and fixed-effects models that account for shared familial factors. With generalized estimating equations, prepregnancy BMI and gestational weight gain had similar associations with the child BMI z score (β = 0.09 units, 95% confidence interval (CI): 0.08, 0.11; and β = 0.07 units, 95% CI: 0.04, 0.11, respectively. However, fixed effects resulted in null associations for both prepregnancy BMI (β = 0.03 units, 95% CI: -0.01, 0.07) and gestational weight gain (β = 0.03 units, 95% CI: -0.02, 0.08) with child BMI z score at age 4 years. The positive association between gestational weight gain and child BMI at age 4 years may be explained by shared family characteristics (e.g., genetic, behavioral, and environmental factors) rather than in utero programming. Future studies should continue to evaluate the relative roles of important familial and environmental factors that may influence BMI and obesity in children.