Familial associations of adiposity: findings from a cross-sectional study of 12,181 parental-offspring trios from Belarus

Nutritional counselling and risk factors for obesity: an observational study in toddlers

BACKGROUND

Nutrition exerts a fundamental role in the prevention of obesity (OB). The aim of this study was to assess the extent to which well recognized risk factors for early OB can be associated to overweight (OW) or OB under a standardized nutritional approach and surveillance in toddlers.

METHODS

The eligible population was represented by 676 toddlers aged 24-36 months, assigned to 18 primary care pediatricians trained on nutritional issues who shared a standardized nutritional approach. Six-hundred-twenty-nine children (333 boys), mean age 27.8 ± 4.2 months were effectively included in this observational study. Parents received nutritional advice with particular emphasis to proteins and sugar composition supported by leaflets and reinforced at each visit. Body mass index was assessed at the age of 24-36 months. The following individual and family risk factors were considered: gestational age, birth weight, eutocic/caesarean delivery, milk feeding history, household smoking or antibiotics exposure, parents' weight, height and educational level. Prevalence of OW/OB was compared to a group of 742 toddlers (373 boys) under usual care.

RESULTS

Under a standardized nutritional counselling, 28.1% toddlers were classified as OW/OB compared to 36.9% toddlers under usual care (p = 0.005). In unadjusted models, parental OW/OB was significantly associated to OW/OB in toddlers (p < 0.01), while high birth weight did not reach statistical significance (p = 0.07). In adjusted models, including all the explanatory variables studied, only paternal OW/OB vs. normal weight was significantly associated to OW/OB in toddlers (OR 2.035, 95% confidence interval 1.206-3.436). No protective effect of exclusive breast feeding during the first 6 months of age was demonstrated.

CONCLUSIONS

Toddlers under a standardized nutrition counselling focused to limit protein and simple sugars, showed lower prevalence of OW/OB compared to usual care. Healthy promotion activities should take into account the influence of paternal BMI on the offspring adiposity.

Parental Height and Weight Influence Offspring Adiposity at 2 Years; Findings from the ROLO Kids Birth Cohort Study

OBJECTIVE

The perinatal period and in utero environment are important for fetal growth, development, and fetal programming. This study aimed to determine the effect of parental anthropometry and the maternal metabolic milieu on offspring adiposity at 2 years of age.

STUDY DESIGN

This longitudinal birth cohort includes analysis of maternal (n = 337) and paternal (n = 219) anthropometry and maternal and fetal metabolic markers (n = 337), including glucose, homeostatic model of assessment (HOMA), C-peptide, and leptin from participants of the ROLO (the Randomized Control Trial of Low) pregnancy study, and their partners, to determine an association with offspring anthropometry at two years of age.

RESULTS

Linear regression, when adjusted for confounders, indicated maternal and paternal anthropometry and was associated with offspring weight and length at 2 years of age. Maternal height was negatively associated with general adiposity in the total cohort of children (p = 0.002) and in female children (p = 0.006) and central adiposity in the total child cohort (p < 0.001). Paternal height was also negatively associated with general adiposity in all children (p = 0.002) and central adiposity in total (p = 0.023) and female children (p = 0.008). Maternal glucose, insulin resistance, and fetal C-peptide positively correlated with anthropometry in total, male, and female children.

CONCLUSION

Parental anthropometry in the perinatal period has a long-lasting effect on offspring anthropometry beyond the neonatal period. Maternal and fetal metabolic factors influence adiposity, and this extends beyond the perinatal period. Parental adiposity may play a significant role in early childhood adiposity and may be a target for interventions to decrease the risk of early childhood obesity.

KEY POINTS

· Parental height and weight were associated with offspring anthropometry and measures of offspring adiposity at 2 years of age.. · Maternal glucose, insulin resistance, and fetal C-peptide correlated with offspring anthropometry.. · Parental anthropometry has long-term effect on offspring adiposity and is seen at 2 years of age..

Effects of Paternal Obesity on Fetal Development and Pregnancy Complications: A Prospective Clinical Cohort Study

Objectives

To evaluate the association between paternal obesity and fetal development and pregnancy complications.

Study Design

This prospective cohort clinical trial analyzed data from 7683 women with singleton pregnancies. All study subjects were sequentially divided into four groups based on paternal BMI. We compared the differences in fetal growth and pregnancy complications between different paternal BMI groups by univariate logistic regression and independent t-test. Finally, the independent predictors of SGA and macrosomia were determined.

Results

The incidences of preeclampsia, cesarean section, SGA, macrosomia, and postpartum hemorrhage in the paternal obesity group were significantly higher than the normal BMI group. With the increase of paternal BMI, fetal ultrasound measurement parameter, neonatal and placental weight showed an increasing trend (trend P < 0.05). However, these differences disappeared in the obese group. The test for interaction showed the effect of paternal obesity on SGA and macrosomia was significantly affected by maternal obesity. We also found paternal obesity was an independent predictor of both SGA and macrosomia. Based on the above results, we plotted the Nomograms for clinical prediction.

Conclusion

Paternal obesity can affect fetal growth parameters and placental development, which has an adverse impact on pregnancy outcomes. Optimizing the paternal BMI will help improve the health of the next generation.

Influence of post-partum BMI change on childhood obesity and energy intake

Introduction

Association between parent’s Body Mass Index (BMI) and their children, has been widely documented. Individual, familiar and structural factors play a role in this relation. We analyzed the association between maternal BMI change during the first year post-partum and their offspring’s growth-trajectories and energy intake in their first five years of life.

Objective

Compare growth-trajectories and children’s caloric intake according to post-partum mother´s BMI classification.

Methods

The anthropometric assessment was taken in 935 mother-child pairs along the study period. Mothers were classified into four groups according to their BMI-trajectories in the post-partum. Children’s weight for height z-scores (WHZ) was compared among groups using random-effects regression models. A longitudinal comparison of children’s caloric intake by the maternal group was carried out.

Results

At 42 months of age, infants from mothers that remained overweight during the first year post-partum had, on average, 0.61 SD higher WHZ than those from mothers who remained in a recommended BMI group (R-BMI) in the same period. At 60 months of age, children´s prevalence of obesity was almost twice in the maternal overweight group vs R-BMI group (14.2% and 7.3% respectively). Chances for a child of having an over caloric intake were 36.5% (95% IC: 6.6%, 74.8%) and significantly higher among children from overweight mothers than those from R-BMI mothers. The difference in children’s WHZ trajectory remained significant after adjusting for caloric intake, suggesting that contextual factors play a role in shaping children’s obesity. A concurrent ethnographic study with the study subjects provides suggestions as to what these factors might be, including changes in the food landscape.

Conclusion

Children from overweight mothers tended to have a more caloric diet yielding a higher propensity to obesity. Contextual factors such as food landscape might contribute to childhood obesity beyond having an overweight mother. Pregnancy and post-partum is a window of opportunity for interventions to decrease the incidence of children’s overweight.

Association of Periconception Paternal Body Mass Index With Persistent Changes in DNA Methylation of Offspring in Childhood

IMPORTANCE

While prenatal nutrition and maternal obesity are recognized as important contributors to epigenetic changes and childhood obesity, the role of paternal obesity in the epigenome of offspring has not been well studied.

OBJECTIVES

To test whether periconception paternal body mass index (BMI) is associated with DNA methylation patterns in newborns, to examine associations between maternal and paternal BMI and the epigenome of offspring, and to examine persistence of epigenetic marks at ages 3 and 7 years.

DESIGN, SETTING, AND PARTICIPANTS

Project Viva is a prebirth cohort study of mothers and children including 2128 live births that enrolled mothers from April 1999 to July 2002 and followed offspring to adolescence. This study analyzed the subset of participants with available data on paternal BMI and DNA methylation in offspring blood in the newborn period, at age 3 years, and at age 7 years. Data were analyzed from July 2017 to October 2019.

EXPOSURES

The primary exposure was paternal periconception BMI; associations were adjusted for maternal prepregnancy BMI and stratified according to maternal BMI above or below 25.

MAIN OUTCOMES AND MEASURES

The primary outcome was genome-wide DNA methylation patterns in offspring blood collected at birth, age 3 years, and age 7 years.

RESULTS

A total of 429 father-mother-infant triads were included. The mean (SD) periconception paternal BMI was 26.4 (4.0) and mean maternal prepregnancy BMI was 24.5 (5.2); 268 fathers had BMI greater than or equal to 25 (mean [SD], 28.5 [3.3]) and 161 had BMI less than 25 (mean [SD], 22.8 [1.8]). Paternal BMI greater than or equal to 25 was associated with increased offspring birth weight compared with paternal BMI less than 25 (mean [SD] z score, 0.38 [0.91] vs 0.11 [0.96]; P = .004). Cord blood DNA methylation at 9 CpG sites was associated with paternal BMI independent of maternal BMI (q < .05). Methylation at cg04763273, between TFAP2C and BMP7, decreased by 5% in cord blood with every 1-unit increase in paternal BMI (P = 3.13 × 10-8); hypomethylation at this site persisted at ages 3 years and 7 years. Paternal BMI was associated with methylation at cg01029450 in the promoter region of the ARFGAP3 gene; methylation at this site was also associated with lower infant birth weight (β = -0.0003; SD = 0.0001; P = .03) and with higher BMI z score at age 3 years.

CONCLUSIONS AND RELEVANCE

In this study, paternal BMI was associated with DNA methylation, birth weight, and childhood BMI z score in offspring.

Body composition: population epidemiology and concordance in Australian children aged 11-12 years and their parents

OBJECTIVES

Overweight and obesity remain at historically high levels, cluster within families and are established risk factors for multiple diseases. We describe the epidemiology and cross-generational concordance of body composition among Australian children aged 11-12 years and their parents.

DESIGN

The population-based cross-sectional Child Health CheckPoint study, nested within the Longitudinal Study of Australian Children (LSAC).

SETTING

Assessment centres in seven major Australian cities and eight regional cities, or home visits; February 2015-March 2016.

PARTICIPANTS

Of all participating CheckPoint families (n=1874), body composition data were available for 1872 children (49% girls) and 1852 parents (mean age 43.7 years; 88% mothers), including 1830 biological parent-child pairs.

MEASURES

Height, weight, body mass index (BMI), waist circumference and waist-to-height ratio for all participants; body fat and fat-free mass by four-limb bioimpedence analysis (BIA) at assessment centres, or body fat percentage by two-limb BIA at home visits. Analysis: parent-child concordance was assessed using (i) Pearson's correlation coefficients, and (ii) partial correlation coefficients adjusted for age, sex and socioeconomic disadvantage. Survey weights and methods accounted for LSAC's complex sample design.

RESULTS

20.7% of children were overweight and 6.2% obese, as were 33.5% and 31.6% of parents. Boys and girls showed similar distributions for all body composition measures but, despite similar BMI and waist-to-height ratio, mothers had higher proportions of total and truncal fat than fathers. Parent-child partial correlations were greatest for height (0.37, 95% CI 0.33 to 0.42). Other anthropometric and fat/lean measures showed strikingly similar partial correlations, ranging from 0.25 (95% CI 0.20 to 0.29) for waist circumference to 0.30 (95% CI 0.25 to 0.34) for fat-free percentage. Whole-sample and sex-specific percentile values are provided for all measures.

CONCLUSIONS

Excess adiposity remains prevalent in Australian children and parents. Moderate cross-generational concordance across all measures of leanness and adiposity is already evident by late childhood.

Negative control exposure studies in the presence of measurement error: implications for attempted effect estimate calibration

Background

Negative control exposure studies are increasingly being used in epidemiological studies to strengthen causal inference regarding an exposure-outcome association when unobserved confounding is thought to be present. Negative control exposure studies contrast the magnitude of association of the negative control, which has no causal effect on the outcome but is associated with the unmeasured confounders in the same way as the exposure, with the magnitude of the association of the exposure with the outcome. A markedly larger effect of the exposure on the outcome than the negative control on the outcome strengthens inference that the exposure has a causal effect on the outcome.

Methods

We investigate the effect of measurement error in the exposure and negative control variables on the results obtained from a negative control exposure study. We do this in models with continuous and binary exposure and negative control variables using analysis of the bias of the estimated coefficients and Monte Carlo simulations.

Results

Our results show that measurement error in either the exposure or negative control variables can bias the estimated results from the negative control exposure study.

Conclusions

Measurement error is common in the variables used in epidemiological studies; these results show that negative control exposure studies cannot be used to precisely determine the size of the effect of the exposure variable, or adequately adjust for unobserved confounding; however, they can be used as part of a body of evidence to aid inference as to whether a causal effect of the exposure on the outcome is present.

A two-year study of parental obesity status and childhood obesity in China

BACKGROUND AND AIMS

We evaluated the association between parental obesity and their children's obesity parameters [e.g., percentage of body fat (PBF)] over time.

METHODS AND RESULTS

The study included 2066 Chinese parents-children trios (n = 1001 girls and 1065 boys, aged 6-14 years). Children's height, weight, waist circumference (WC) and PBF (bioelectrical impedance analysis) were annually assessed from 2014 (baseline) to 2016. Information on parental height and body weight, and children's diet and physical activity was collected in 2014. The association between parental obesity and changes in their children's PBF during follow-up was analyzed using a mixed effects model. We also examined changes in children's BMI and WC in secondary analyses. Baseline mean BMI, WC, and PBF for children were 17.6 ± 3.5 kg/m², 60.5 ± 9.6 cm, and 16.6 ± 6.5%, respectively. We observed that maternal, but not paternal, obesity was associated with a greater increase in children's PBF during the follow-up. An adjusted mean difference in annual increase of PBF was 0.41% [95% confidence interval (CI): 0.01%, 0.84%] for children with obese mothers, compared with those with normal-weight mothers. Both maternal and paternal obesity was associated with a greater increase in their children's BMI and WC (p trend<0.01 for both); however, the associations were stronger in mother-children pairs than those in father-children pairs.

CONCLUSIONS

Maternal obesity was associated with a greater increase in PBF in Chinese school-aged children.

Anthropometric and cardiometabolic risk factors in parents and child obesity in Segamat, Malaysia

Background

There is little evidence regarding risk factors for child obesity in Asian populations, including the role of parental anthropometric and cardiometabolic risk factors. We examined the relation between parental risk factors and child obesity in a Malaysian population.

Methods

We used data from health and demographic surveillance conducted by the South East Asia Community Observatory in Segamat, Malaysia. Analyses included 9207 individuals (4806 children, 2570 mothers and 1831 fathers). Child obesity was defined based on the World Health Organization 2007 reference. We assessed the relation between parental anthropometric (overweight, obesity and central obesity) and cardiometabolic (systolic hypertension, diastolic hypertension and hyperglycaemia) risk factors and child obesity, using mixed effects Poisson regression models with robust standard errors.

Results

We found a high burden of overweight and obesity among children in this population (30% overweight or obese). Children of one or more obese parents had a 2-fold greater risk of being obese compared with children of non-obese parents. Sequential adjustment for parental and child characteristics did not materially affect estimates (fully adjusted relative risk for obesity in both parents: 2.39, 95% confidence interval: 1.82, 3.10, P < 0.001; P for trend < 0.001). These associations were not modified by parental or child sex. We found no consistent evidence for associations between parental cardiometabolic risk factors and child obesity.

Conclusions

Parental obesity was strongly associated with child obesity in this population. Further exploration of the behavioural and environmental drivers of these associations may help inform strategies addressing child obesity in Asia.

Using Mendelian randomization to determine causal effects of maternal pregnancy (intrauterine) exposures on offspring outcomes: Sources of bias and methods for assessing them

Mendelian randomization (MR), the use of genetic variants as instrumental variables (IVs) to test causal effects, is increasingly used in aetiological epidemiology. Few of the methodological developments in MR have considered the specific situation of using genetic IVs to test the causal effect of exposures in pregnant women on postnatal offspring outcomes. In this paper, we describe specific ways in which the IV assumptions might be violated when MR is used to test such intrauterine effects. We highlight the importance of considering the extent to which there is overlap between genetic variants in offspring that influence their outcome with genetic variants used as IVs in their mothers. Where there is overlap, and particularly if it generates a strong association of maternal genetic IVs with offspring outcome via the offspring genotype, the exclusion restriction assumption of IV analyses will be violated. We recommend a set of analyses that ought to be considered when MR is used to address research questions concerned with intrauterine effects on post-natal offspring outcomes, and provide details of how these can be undertaken and interpreted. These additional analyses include the use of genetic data from offspring and fathers, examining associations using maternal non-transmitted alleles, and using simulated data in sensitivity analyses (for which we provide code). We explore the extent to which new methods that have been developed for exploring violation of the exclusion restriction assumption in the two-sample setting (MR-Egger and median based methods) might be used when exploring intrauterine effects in one-sample MR. We provide a list of recommendations that researchers should use when applying MR to test the effects of intrauterine exposures on postnatal offspring outcomes and use an illustrative example with real data to demonstrate how our recommendations can be applied and subsequent results appropriately interpreted.

Using Genetic Variation to Explore the Causal Effect of Maternal Pregnancy Adiposity on Future Offspring Adiposity: A Mendelian Randomisation Study

BACKGROUND

It has been suggested that greater maternal adiposity during pregnancy affects lifelong risk of offspring fatness via intrauterine mechanisms. Our aim was to use Mendelian randomisation (MR) to investigate the causal effect of intrauterine exposure to greater maternal body mass index (BMI) on offspring BMI and fat mass from childhood to early adulthood.

METHODS AND FINDINGS

We used maternal genetic variants as instrumental variables (IVs) to test the causal effect of maternal BMI in pregnancy on offspring fatness (BMI and dual-energy X-ray absorptiometry [DXA] determined fat mass index [FMI]) in a MR approach. This was investigated, with repeat measurements, from ages 7 to 18 in the Avon Longitudinal Study of Parents and Children (ALSPAC; n = 2,521 to 3,720 for different ages). We then sought to replicate findings with results for BMI at age 6 in Generation R (n = 2,337 for replication sample; n = 6,057 for total pooled sample). In confounder-adjusted multivariable regression in ALSPAC, a 1 standard deviation (SD, equivalent of 3.7 kg/m2) increase in maternal BMI was associated with a 0.25 SD (95% CI 0.21-0.29) increase in offspring BMI at age 7, with similar results at later ages and when FMI was used as the outcome. A weighted genetic risk score was generated from 32 genetic variants robustly associated with BMI (minimum F-statistic = 45 in ALSPAC). The MR results using this genetic risk score as an IV in ALSPAC were close to the null at all ages (e.g., 0.04 SD (95% CI -0.21-0.30) at age 7 and 0.03 SD (95% CI -0.26-0.32) at age 18 per SD increase in maternal BMI), which was similar when a 97 variant generic risk score was used in ALSPAC. When findings from age 7 in ALSPAC were meta-analysed with those from age 6 in Generation R, the pooled confounder-adjusted multivariable regression association was 0.22 SD (95% CI 0.19-0.25) per SD increase in maternal BMI and the pooled MR effect (pooling the 97 variant score results from ALSPAC with the 32 variant score results from Generation R) was 0.05 SD (95%CI -0.11-0.21) per SD increase in maternal BMI (p-value for difference between the two results = 0.05). A number of sensitivity analyses exploring violation of the MR results supported our main findings. However, power was limited for some of the sensitivity tests and further studies with relevant data on maternal, offspring, and paternal genotype are required to obtain more precise (and unbiased) causal estimates.

CONCLUSIONS

Our findings provide little evidence to support a strong causal intrauterine effect of incrementally greater maternal BMI resulting in greater offspring adiposity.

Drosophila melanogaster: An emerging model of transgenerational effects of maternal obesity

The prevalence of obesity in the world is endemic with one rapidly growing health concern being maternal obesity. Obesity during pregnancy increases the risk of gestational diabetes, miscarriage, and preeclampsia, while rendering offspring susceptible to developmental anomalies and long-term metabolic complications including type 2 diabetes and cardiovascular disease. Several studies in humans and rodents demonstrate a correlation between the risks of maternal overnutrition and factors such as epigenetics, mitochondrial dysfunction, insulin resistance, ER stress, and immune system disruption. At present, the molecular mechanisms connecting these factors to maternal obesity are unknown. This review focuses on the use of Drosophila melanogaster to study human metabolic diseases, including obesity, and its emerging use to elucidate the mechanisms of maternal overnutrition and the impact on offspring.

Disentangling the associations between parental BMI and offspring body composition using the four-component model

Objectives

This study sets out to investigate the intergenerational associations between the body mass index (BMI) of parents and the body composition of their offspring.

Methods

The cross‐sectional data were analyzed for 511 parent–offspring trios from London and south‐east England. The offspring were aged 5–21 years. Parental BMI was obtained by recall and offspring fat mass and lean mass were obtained using the four‐component model. Multivariable regression analysis, with multiple imputation for missing paternal values was used. Sensitivity analyses for levels of non‐paternity were conducted.

Results

A positive association was seen between parental BMI and offspring BMI, fat mass index (FMI), and lean mass index (LMI). The mother's BMI was positively associated with the BMI, FMI, and LMI z‐scores of both daughters and sons and of a similar magnitude for both sexes. The father's BMI showed similar associations to the mother's BMI, with his son's BMI, FMI, and LMI z‐scores, but no association with his daughter. Sensitivity tests for non‐paternity showed that maternal coefficients remained greater than paternal coefficients throughout but there was no statistical difference at greater levels of non‐paternity.

Conclusions

We found variable associations between parental BMI and offspring body composition. Associations were generally stronger for maternal than paternal BMI, and paternal associations appeared to differ between sons and daughters. In this cohort, the mother's BMI was statistically significantly associated with her child's body composition but the father's BMI was only associated with the body composition of his sons. Am. J. Hum. Biol. 28:524–533, 2016. © 2016 The Authors American Journal of Human Biology Published by Wiley Periodicals, Inc.

The influence of parent's body mass index on peer selection: an experimental approach using virtual reality

Relatively little is known about the influence of psychosocial factors, such as familial role modeling and social network on the development and maintenance of childhood obesity. We investigated peer selection using an immersive virtual reality environment. In a virtual schoolyard, children were confronted with normal weight and overweight avatars either eating or playing. Fifty-seven children aged 7-13 participated. Interpersonal distance to the avatars, child's BMI, self-perception, eating behavior and parental BMI were assessed. Parental BMI was the strongest predictor for the children's minimal distance to the avatars. Specifically, a higher mothers' BMI was associated with greater interpersonal distance and children approached closer to overweight eating avatars. A higher father's BMI was associated with a lower interpersonal distance to the avatars. These children approached normal weight playing and overweight eating avatar peers closest. The importance of parental BMI for the child's social approach/avoidance behavior can be explained through social modeling mechanisms. Differential effects of paternal and maternal BMI might be due to gender specific beauty ideals. Interventions to promote social interaction with peer groups could foster weight stabilization or weight loss in children.

Transmission of energy-saving efficiency from obese parents to their offspring: the Korean National Health and Nutrition Examination Survey 2007-2011

BACKGROUND/OBJECTIVES

Concerns of a growing obesity epidemic have increased since the association between obesity in parents and that in offspring was reported. However, the evidence regarding whether the energy-saving efficiency of obese parents is conveyed to their offspring and the duration of the expression of such transmitted efficiency is limited.

SUBJECTS/METHODS

We included 7647 matching sets of parent-offspring trios from South Korea. Multiple linear regression models were performed to estimate the energy-saving efficiency, as assessed by the associations between energy intake and obesity-related indices (waist-to-height ratio, waist circumference and body mass index z-score), and to compare the energy-saving efficiency of offspring of obese and non-obese parents. All analyses were based on a complex sample design and were stratified by gender and age.

RESULTS

We identified a parental influence on obesity, that is, the more obese the parent, the higher the obesity-related indices of their offspring, in both genders and all age groups. The energy-saving efficiency of child offspring was highest when both parents were obese and lowest when both were non-obese; this difference was significant (P<0.05) with regard to the energy-saving efficiency of all types of intake studied, except fat. However, the energy-saving efficiency of obese and non-obese parents did not differ when their offspring were adolescents and adults.

CONCLUSIONS

The critical window for transmission of energy-saving efficiency is limited to childhood. These findings suggest that children of obese parents should be more emphatically advised to maintain a balanced diet and to engage in regular physical activity.

Is there a greater maternal than paternal influence on offspring adiposity in India?

Previous research has provided conflicting evidence regarding fetal roots of adiposity in India. To compare the strength of association between maternal and paternal body mass indexes (BMIs) corrected for height with offspring BMI in India to examine the potential for intrauterine mechanisms to influence offspring adiposity in India, we analysed a sample of 16,528 mother-father-offspring trios from the 2005 to 2006 Indian National Family Health Survey. Children were aged 0-59 months with parents aged 15-49 years (mothers) and 15-54 years (fathers). Linear and logistic regression models, specified in multiple ways, were used to estimate associations between parental BMI* (BMI redefined by power term x (kg/m(x)) to be independent from height), and child BMI/top decile of child BMI. Higher values of maternal BMI and paternal BMI were associated with higher values of offspring BMI. In comparing the effects of maternal BMI and paternal BMI, however, no consistent differences were found in the strength of these parental influences on offspring BMI. In the fully adjusted linear model, the standardised coefficient was 0.131 (95% CI 0.110 to 0.154) for maternal BMI* and 0.079 (95% CI 0.056 to 0.103) for paternal BMI*; with evidence of heterogeneity between maternal-offspring and paternal-offspring associations (p=0.005). This was not robust in the unstandardised regression (β=0.056, 95% CI 0.044 to 0.067 for maternal BMI and β=0.039, 95% CI 0.025 to 0.053 for paternal BMI, p=0.093). Mixed results indicate that compared with paternal BMI, maternal BMI did not have a consistently stronger influence on offspring BMI in India.

Stable intergenerational associations of childhood overweight during the development of the obesity epidemic

OBJECTIVE

The obesity epidemic may have developed as a response to the obesogenic environment among the genetically predisposed. This investigation examined whether the intergenerational resemblances in childhood overweight changed across the development of the obesity epidemic in groups of children born to parents with and without childhood overweight.

METHODS

The study population was from the Copenhagen School Health Records Register, which includes age- and sex-specific body mass index (BMI; kg/m(2) ) of children. This study used BMI values from 7-year-old children born 1952-1989 and from their parents at ages 7 and 13 years. The available number of parent-child pairs ranged from 17,926 through 42,184. The odds ratios of childhood overweight (BMI z-score >90th percentile) were calculated using logistic regression by parental BMI groups (BMI > or ≤90th percentile) and child birth year intervals.

RESULTS

Stable levels in parent-child overweight associations were observed across child BMI groups born to parents with and without childhood overweight. A slight upward odds ratio trend was observed across time in children born to two overweight parents at age 13, but not at age 7 years.

CONCLUSIONS

Parent-child resemblance in childhood overweight showed small changes during the development of the obesity epidemic, suggesting that the obesogenic environment inducing the epidemic in Denmark influenced children irrespective of their familial predisposition.

Maternal pre-pregnancy BMI and gestational weight gain, offspring DNA methylation and later offspring adiposity: findings from the Avon Longitudinal Study of Parents and Children

Background: Evidence suggests that in utero exposure to undernutrition and overnutrition might affect adiposity in later life. Epigenetic modification is suggested as a plausible mediating mechanism.

Methods: We used multivariable linear regression and a negative control design to examine offspring epigenome-wide DNA methylation in relation to maternal and offspring adiposity in 1018 participants.

Results: Compared with neonatal offspring of normal weight mothers, 28 and 1621 CpG sites were differentially methylated in offspring of obese and underweight mothers, respectively [false discovert rate (FDR)-corrected P-value < 0.05), with no overlap in the sites that maternal obesity and underweight relate to. A positive association, where higher methylation is associated with a body mass index (BMI) outside the normal range, was seen at 78.6% of the sites associated with obesity and 87.9% of the sites associated with underweight. Associations of maternal obesity with offspring methylation were stronger than associations of paternal obesity, supporting an intrauterine mechanism. There were no consistent associations of gestational weight gain with offspring DNA methylation. In general, sites that were hypermethylated in association with maternal obesity or hypomethylated in association with maternal underweight tended to be positively associated with offspring adiposity, and sites hypomethylated in association with maternal obesity or hypermethylated in association with maternal underweight tended to be inversely associated with offspring adiposity.

Conclusions: Our data suggest that both maternal obesity and, to a larger degree, underweight affect the neonatal epigenome via an intrauterine mechanism, but weight gain during pregnancy has little effect. We found some evidence that associations of maternal underweight with lower offspring adiposity and maternal obesity with greater offspring adiposity may be mediated via increased DNA methylation.

Intrafamilial associations of cardiometabolic risk factors--results of the Ulm Birth Cohort Study

BACKGROUND

The identification of genetic, early childhood and lifestyle factors related to cardiometabolic risk factors in childhood is important for the development of preventive strategies against cardiovascular diseases. Intrafamilial associations of cardiometabolic risk factors are rarely studied and the few existing results are inconsistent.

AIMS

To study the relationship of cardiometabolic risk factors in parent-offspring pairs (trios) of the prospective Ulm Birth Cohort Study (UBCS).

METHODS

At the 8-yr follow-up examination of the UBCS weights, heights, waist circumferences (WC), systolic (sysBP) and diastolic blood pressure (diasBP) of n=304 8 yrs old children and their parents were measured. Fasting plasma samples were collected and concentrations of insulin, glucose, retinol-binding-protein 4 (RBP4), adiponectin, leptin, apolipoprotein A and B (ApoA, ApoB) were analyzed.

RESULTS

BMI values and WC were stronger related in father-offspring than in mother-offspring pairs. Adjustment for potential confounders did not change these results. Fasting plasma concentrations of insulin, glucose, RBP4, ApoB, sysBP and diastBP were stronger correlated in mother-offspring than in father-offspring pairs also after adjusting for potential confounders. Offsprings of fathers that have ≥3 cardiometabolic risk factors had 0.74 kg/m2 higher BMI values and 2.34 cm higher WC compared to offsprings of the reference group (both parents having <3 cardiometabolic risk factors). There was a trend for higher fasting plasma insulin concentrations in offsprings where the mother had ≥3 cardiometabolic risk factors compared to offsprings of the reference group.

CONCLUSION

These results might be explained by gender-specific genetic factors as well as by early life programming.

Peri-conception parental obesity, reproductive health, and transgenerational impacts

Maternal over-nutrition during pregnancy is a risk factor for pregnancy complications and is increasingly associated with adverse childhood outcomes such as increased propensity for obesity and metabolic disease. However, there is emerging evidence that parental lifestyle factors prior to and at conception have a powerful impact on the health of the offspring for more than one generation. Maternal and paternal obesity prior to conception alters the molecular composition of both oocytes and sperm, which can partly escape epigenetic reprogramming at fertilization, altering the developmental trajectory of the resultant embryo, ultimately increasing the incidence of obesity and metabolic disorders in offspring. Understanding the molecular underpinning of these changes may help create interventions to reduce the risk of disease in future generations.

Parent-offspring association of metabolic syndrome in the Framingham Heart Study

BACKGROUND

Metabolic syndrome (MetS) is a clustering of five metabolic risk factors including abdominal obesity, elevated blood pressure, hypertriglyceridemia, low high-density lipoprotein cholesterol (HDL-C), and impaired fasting glucose. Few studies have fully reported the strength of clustering of these risk factors in a parent-offspring relationship. This analysis describes the associations between parents and their adult offspring in regard to MetS. It also estimates the association between each risk factor in parents and the presence of MetS in their offspring.

METHODS

We analyzed data for 1193 offspring (565 sons, and 628 daughters) from the Framingham Offspring Study who attended examinations 5, 6, and 7. Information about their parents was collected from examinations 13, 14 and 15 of the Framingham Original Cohort study. We used pedigree file to combine parental and offspring's data. Participants were classified as having the MetS according to the Adult Treatment Panel III criteria. Analyses were conducted separately for mothers and fathers. Logistic regression was used to estimate the associations.

RESULTS

After adjusting for age, education, smoking, alcohol consumption and physical activity level of offspring, no significant association was found between father's and their offspring's MetS. Mother's MetS was significantly and positively associated with their daughter's MetS (adjusted odds ratio or adj OR: 1.63; 95% confidence Interval, CI:1.02-2.61), but not with their sons' MetS. When analyzed by individual components, maternal impaired glucose (adj OR: 2.03; 95% CI: 1.02- 9.31), abdominal obesity (adj OR: 1.56; 95% CI: 0.98- 2.55) and low HDL-C (adj OR: 2.12; 95% CI: 1.36-3.32) were associated daughter's MetS. Maternal low HDL-C and raised total cholesterol showed marginal association with son's MetS. For fathers, only impaired glucose (adj OR: 4.91; 95% CI: 2.07- 11.68) was associated with their daughter's MetS.

CONCLUSIONS

Using the data from Framingham Heart Study, we demonstrate differential association of MetS and its components between parents and offspring. Mother's MetS was strongly related with daughter's MetS, but the association was inconsistent with son's MetS. No association was found between father's MetS and offspring's Mets. These results provide evidence that daughters with mother's MetS are in higher risk than daughters or sons with father's MetS.

Approaches for drawing causal inferences from epidemiological birth cohorts: a review

Large-scale population-based birth cohorts, which recruit women during pregnancy or at birth and follow up their offspring through infancy and into childhood and adolescence, provide the opportunity to monitor and model early life exposures in relation to developmental characteristics and later life outcomes. However, due to confounding and other limitations, identification of causal risk factors has proved challenging and published findings are often not reproducible. A suite of methods has been developed in recent years to minimise problems afflicting observational epidemiology, to strengthen causal inference and to provide greater insights into modifiable intra-uterine and early life risk factors. The aim of this review is to describe these causal inference methods and to suggest how they may be applied in the context of birth cohorts and extended along with the development of birth cohort consortia and expansion of "omic" technologies.

Trends in parent-child correlations of childhood body mass index during the development of the obesity epidemic

Background

The intergenerational resemblance in body mass index may have increased during the development of the obesity epidemic due to changes in environment and/or expression of genetic predisposition.

Objectives

This study investigates trends in intergenerational correlations of childhood body mass index (BMI; kg/m²) during the emergence of the obesity epidemic.

Methods

The study population was derived from the Copenhagen School Health Records Register, which includes height and weight measurements since birth year 1930. Mothers and fathers with BMIs available at ages 7 (n = 25,923 and n = 20,972) or 13 years (n = 26,750 and n = 21,397), respectively, were linked through the civil registration system introduced in 1968 to their children with BMIs available at age 7 years. Age- and sex-specific BMI z-scores were calculated. Correlations were estimated across eight intervals of child birth years (1952–1989) separately by sex. Trends in these correlations were examined. Whereas the mother-child correlations reflected the biological relationship, a likely decline in the assignment of non-biological fathers through the registration system across time must be considered when interpreting the father-child correlations.

Results

The BMI correlations between mothers and sons ranged from 0.29–0.36 and they decreased marginally, albeit significantly across time at ages 7–7 years (−0.002/year, p = 0.006), whereas those at 13–7 years remained stable (<0.0004/year, p = 0.96). Mother-daughter correlations ranged from 0.30–0.34, and they were stable at ages 7–7 years (0.0001/year, p = 0.84) and at 13–7 years (0.0004/year, p = 0.56). In contrast, father-son correlations increased significantly during this period, both at ages 7–7 (0.002/year, p = 0.007) and at ages 13–7 years (0.003/year, p<0.001), whereas the increase in father-daughter correlations were insignificant both at ages 7–7 (0.001/year, p = 0.37) and at ages 13–7 years (0.001/year, p = 0.18).

Conclusion

During the obesity epidemics development, the intergenerational resemblance with mothers remained stable, whereas the father-child BMI resemblance increased, possibly reflecting changes in family relationships, and unlikely to have influenced the epidemic.

Childhood cardiometabolic outcomes of maternal obesity during pregnancy: the Generation R Study

Maternal prepregnancy obesity is associated with impaired cardiometabolic health in offspring. Whether these associations reflect direct intrauterine causal mechanisms remains unclear. In a population-based prospective cohort study among 4871 mothers, fathers, and their children, we examined the associations of both maternal and paternal prepregnancy body mass index (BMI) with childhood body fat distribution and cardiometabolic outcomes and explored whether any association was explained by pregnancy, birth, and childhood factors. We measured childhood BMI, total body and abdominal fat distribution, blood pressure, and blood levels of lipids, insulin, and C-peptide at the age of 6 years. We observed that higher maternal and paternal prepregnancy BMI were associated with higher childhood BMI, total body and abdominal fat mass measures, systolic blood pressure, and insulin levels and lower high-density lipoprotein cholesterol levels (P<0.05). Stronger associations were present for maternal than paternal BMI, with statistical support for heterogeneity between these associations. The associations for childhood fat mass and cardiometabolic outcomes attenuated after adjustment for childhood current BMI. Compared with children from normal-weight mothers, those from obese mothers had increased risks of childhood overweight (odds ratio, 3.84 [95% confidence interval, 3.01-4.90]) and clustering of cardiometabolic risk factors (odds ratio, 3.00 [95% confidence interval, 2.09-4.34]). Smaller effect estimates for these outcomes were observed for paternal obesity. In conclusion, higher maternal and paternal prepregnancy BMI were associated with an adverse cardiometabolic profile in offspring, with stronger associations present for maternal prepregnancy BMI. These findings suggest that maternal prepregnancy BMI may influence the cardiometabolic health of offspring through direct intrauterine mechanisms.

Comparison of father-offspring and mother-offspring associations of cardiovascular risk factors: family linkage within the population-based HUNT Study, Norway

BACKGROUND

Cardiovascular risk factors are transmitted from parents to offspring; however, the relative contributions of fathers and mothers remain unclear. If maternal exposures during pregnancy influence offspring through the intrauterine environment, associations between mothers and offspring are expected to be stronger than between fathers and offspring. In this family linkage study we compared father-offspring and mother-offspring associations of several cardiovascular risk factors.

METHODS

The study population consisted of 36,528 father-mother-offspring trios who participated at one or more surveys of the HUNT Study, Norway in 1984-86, 1995-97 and 2006-08. Parent-offspring associations were assessed using unstandardized and standardized residuals from linear regression analysis, and possible non-paternity was accounted for in sensitivity analyses.

RESULTS

Age- and sex-adjusted parent-offspring associations for anthropometric factors, blood pressure, blood lipids, blood glucose and resting heart rate were largely similar between fathers and mothers. Use of standardized values and analyses adjusted for non-paternity further emphasized this similarity.

CONCLUSIONS

This study found largely similar father-offspring and mother-offspring associations across all cardiovascular risk factors under study, arguing against strong maternal effects transmitted through intrauterine mechanisms.

Suboptimal maternal nutrition affects offspring health in adult life

Suboptimal maternal nutrition during pregnancy is prevalent and compromises fetal development. Physiological and metabolic adaptations made by the fetus to an inadequate, or excess, maternal nutritional environment, may promote immediate survival but are lasting, conferring significantly increased risks of ill health in childhood and adulthood. In addition, such fetal adaptations are particularly detrimental when nutrient supply is no longer constrained in contemporary nutrient rich environments. Given the prevalence of suboptimal maternal nutritional environments during fetal development, effective prevention, early detection and therapeutic interventions to reduce the increased risks on population health must be a health priority. Therefore, the mechanisms of these lasting in utero adaptations are highly relevant to establishing how exposure to a suboptimal nutritional environment impacts on the health of current generations living in an environment challenged by excess nutrition.

A population-based study of overweight and obesity in expectant parents: socio-demographic patterns and within-couple associations

BACKGROUND

Overweight and obesity in pregnancy increase the risk of several adverse pregnancy outcomes. However, both mothers' and fathers' health play an important role for long-term health outcomes in offspring. While aspects of health and lifestyle of pregnant women have been reported, the health of expectant fathers and correlations of health variables within couples have received less attention. This study aimed to explore the prevalence and socio-demographic patterns of overweight and obesity in Swedish expectant parents, and to assess within-couple associations.

METHODS

This population-based, cross-sectional study investigated self-reported data from 4352 pregnant women and 3949 expectant fathers, comprising 3356 identified couples. Data were collected in antenatal care clinics between January 2008 and December 2011. Descriptive, correlation and logistic regression analyses were performed.

RESULTS

The self-reported prevalence of overweight (BMI 25.0-29.99) and obesity (BMI ≥ 30.0) was 29% among women (pre-pregnancy) and 53% among expectant fathers. In a majority of couples (62%), at least one partner was overweight or obese. The odds of being overweight or obese increased relative to partner's overweight or obesity, and women's odds of being obese were more than six times higher if their partners were also obese in comparison with women whose partners were of normal weight (OR 6.2, CI 4.2-9.3). A socio-demographic gradient was found in both genders in relation to education, occupation and area of residence, with higher odds of being obese further down the social ladder. The cumulative influence of these factors showed a substantial increase in the odds of obesity for the least compared to the most privileged (OR 6.5, CI 3.6-11.8).

CONCLUSIONS

The prevalence of overweight and obesity in expectant parents was high, with a clear social gradient, and a minority of couples reported both partners with a healthy weight at the onset of pregnancy. Partner influence on health and health behaviours, and the role both mothers and fathers play in health outcomes of their offspring, underpin the need for a more holistic and gender inclusive approach to the delivery of pregnancy care and postnatal and child health services, with active measures employed to involve fathers.

Effects of an intervention to promote breastfeeding on maternal adiposity and blood pressure at 11.5 y postpartum: results from the Promotion of Breastfeeding Intervention Trial, a cluster-randomized controlled trial

BACKGROUND

Differences between mothers who do and do not succeed in breastfeeding are likely to confound associations of lactation with later maternal adiposity.

OBJECTIVE

We compared adiposity and blood pressure (BP) in women randomly assigned to an intervention to promote prolonged and exclusive breastfeeding or usual care.

DESIGN

We performed a cluster-randomized trial at 31 hospitals in Belarus in 1996-1997.

RESULTS

Of 17,046 women enrolled at delivery, we assessed 11,867 women (69.6%) at 11.5 y postpartum. The prevalence of exclusive breastfeeding ≥3 mo was 44.5% in 6321 women in the intervention group and 7.1% in 5546 women in the control group. At 11.5 y postpartum, mean (±SD) body mass index (BMI; in kg/m(2)) was 26.5 ± 5.5, the percentage of body fat was 33.6% ± 8.3%, and systolic BP was 124.6 ± 14.6 mm Hg. On intention-to-treat analysis (without imputation) with adjustment for clustering by hospital, mean outcomes were lower in intervention compared with control mothers for BMI (mean difference: -0.27; 95% CI: -0.91, 0.37), body fat (-0.49%; 95% CI: -1.25%, 0.27%), and systolic BP (-0.81 mm Hg; 95% CI: -3.33, 1.71 mm Hg), but effect sizes were small, CIs were wide, and results were attenuated further toward the null after adjustment for baseline characteristics. Results were similar in sensitivity analyses [ie, by using conventional observational analyses disregarding treatment assignment, instrumental variable analyses to estimate the causal effect of breastfeeding, and multiple imputation to account for missing outcome measures (n = 17,046)].

CONCLUSION

In women who initiated breastfeeding, an intervention to promote longer breastfeeding duration did not result in an important lowering of adiposity or BP. This trial was registered at clinicaltrials.gov as NCT01561612 and at Current Controlled Trials as ISRCTN37687716.

Pregnancy weight gain and childhood body weight: a within-family comparison

BACKGROUND

Excessive pregnancy weight gain is associated with obesity in the offspring, but this relationship may be confounded by genetic and other shared influences. We aimed to examine the association of pregnancy weight gain with body mass index (BMI) in the offspring, using a within-family design to minimize confounding.

METHODS AND FINDINGS

In this population-based cohort study, we matched records of all live births in Arkansas with state-mandated data on childhood BMI collected in public schools (from August 18, 2003 to June 2, 2011). The cohort included 42,133 women who had more than one singleton pregnancy and their 91,045 offspring. We examined how differences in weight gain that occurred during two or more pregnancies for each woman predicted her children's BMI and odds ratio (OR) of being overweight or obese (BMI≥85th percentile) at a mean age of 11.9 years, using a within-family design. For every additional kg of pregnancy weight gain, childhood BMI increased by 0.0220 (95% CI 0.0134-0.0306, p<0.0001) and the OR of overweight/obesity increased by 1.007 (CI 1.003-1.012, p = 0.0008). Variations in pregnancy weight gain accounted for a 0.43 kg/m(2) difference in childhood BMI. After adjustment for birth weight, the association of pregnancy weight gain with childhood BMI was attenuated but remained statistically significant (0.0143 kg/m(2) per kg of pregnancy weight gain, CI 0.0057-0.0229, p = 0.0007).

CONCLUSIONS

High pregnancy weight gain is associated with increased body weight of the offspring in childhood, and this effect is only partially mediated through higher birth weight. Translation of these findings to public health obesity prevention requires additional study. Please see later in the article for the Editors' Summary.

Maternal and grandmaternal obesity and environmental factors as determinants of daughter's obesity

Obesity may be the consequence of various environmental or genetic factors, which may be highly correlated with each other. We aimed to examine whether grandmaternal and maternal obesity and environmental risk factors are related to obesity in daughters. Daughters (n = 182) recruited from female students, their mothers (n = 147) and their grandmothers (n = 67) were included in this study. Multivariable logistic regression was used to analyze the association between the daughter's obesity and maternal, grandmaternal, and environmental factors. Maternal heights of 161-175cm (OD: 8.48, 95% CI: 3.61-19.93) and 156-160 cm (2.37, 1.14-4.91) showed positive associations with a higher height of daughter, compared to those of 149-155 cm. Mothers receiving a university or a higher education had a significant OR (3.82, 1.27-11.50) for a higher height of daughter compared to those having a low education (elementary school). Mother having the heaviest weight at current time (59-80 kg, 3.78, 1.73-8.28) and the heaviest weight at 20 years of age (51-65 kg, 3.17, 1.53-6.55) had significant associations with a higher height of daughters, compared to those having the lightest weight at the same times. There was no association between the height, weight, and BMI of daughters and the characteristics and education of her grandmothers. In conclusion, although genetic factors appear to influence the daughter's height more than environmental factors, the daughter's weight appears to be more strongly associated with individual factors than the genetic factors.

Stronger influence of maternal than paternal obesity on infant and early childhood body mass index: the Fels Longitudinal Study

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Excessive early childhood adiposity is a prevalent and increasing concern in many parts of the world. Parental obesity is one of the several factors previously associated with infant and early childhood weight, length and adiposity. Parental obesity represents a surrogate marker of the complex interplay among genetic, epigenetic and shared environmental factors, and is potentially modifiable. The relative contributions of maternal and paternal body mass index (BMI) to infant and early childhood growth, as well as the timing of such effects, have not been firmly established.

WHAT THIS STUDY ADDS

Utilizing serial infant measurements and growth curve modelling, this is the largest study to fully characterize and formally compare associations between maternal and paternal BMI and offspring growth across the entire infancy and early childhood period. Maternal obesity is a stronger determinant of offspring BMI than paternal obesity at birth and from 2 to 3 years of age, suggesting that prevention efforts focused particularly on maternal lifestyle and BMI may be important in reducing excess infant BMI. The observation that maternal BMI effects are not constant, but rather present at birth, wane and re-emerge during late infancy, suggests that there is a window of opportunity in early infancy when targeted interventions on children of obese mothers may be most effective.

BACKGROUND/OBJECTIVE

Parental obesity influences infant body size. To fully characterize their relative effects on infant adiposity, associations between maternal and paternal body mass index (BMI) category (normal: ≤25 kg m(-2) , overweight: 25 - <30 kg m(-2) , obese: ≥30 kg m(-2) ) and infant BMI were compared in Fels Longitudinal Study participants.

METHODS

A median of 9 serial weight and length measures from birth to 3.5 years were obtained from 912 European American children born in 1928-2008. Using multivariable mixed effects regression, contributions of maternal vs. paternal BMI status to infant BMI growth curves were evaluated. Cubic spline models also included parental covariates, infant sex, age and birth variables, and interactions with child's age.

RESULTS

Infant BMI curves were significantly different across the three maternal BMI categories (Poverall  < 0.0001), and offspring of obese mothers had greater mean BMI at birth and between 1.5 and 3.5 years than those of over- and normal weight mothers (P ≤ 0.02). Average differences between offspring of obese and normal weight mothers were similar at birth (0.8 kg m(-2) , P = 0.0009) and between 2 and 3.5 years (0.7-0.8 kg m(-2) , P < 0.0001). Infants of obese fathers also had BMI growth curves distinct from those of normal weight fathers (P = 0.02). Infant BMI was more strongly associated with maternal than paternal obesity overall (P < 0.0001); significant differences were observed at birth (1.11 kg m(-2) , P = 0.006) and from 2 to 3 years (0.62 kg m(-2) , P3 years  = 0.02).

CONCLUSION

At birth and in later infancy, maternal BMI has a stronger influence on BMI growth than paternal BMI, suggesting weight control in reproductive age women may be of particular benefit for preventing excess infant BMI.

Maternal adiposity--a determinant of perinatal and offspring outcomes?

Experimental and animal data suggest that maternal obesity during pregnancy adversely affects offspring health in the short-term and the long-term. Whether these effects occur in humans and influence population health is less clear. This Review explores evidence from intervention studies and observational studies that have used designs (such as family-based comparisons and Mendelian randomization) that might help improve understanding of the causal effects of maternal obesity in humans. Collectively, human studies provide evidence that maternal overweight and obesity is causally related to pregnancy complications, increased offspring weight and adiposity at birth, and the difficulties associated with delivery of large-for-gestational-age infants. The underlying mechanisms for these effects probably involve maternal and fetal dysregulation of glucose, insulin, lipid and amino acid metabolism. Some evidence exists that extreme maternal obesity (BMI ≥40 kg/m(2)) is causally related to a long-term increase in offspring adiposity, but further exploration of this relationship is needed. High gestational weight gain may result in a long-term increase in offspring adiposity if women are already overweight or have obesity at the start of pregnancy. To date, little high-quality human evidence exists that any of these effects are mediated by epigenetic mechanisms, but approaches to appropriately test this possibility are being developed.

Testing the fetal overnutrition hypothesis; the relationship of maternal and paternal adiposity to adiposity, insulin resistance and cardiovascular risk factors in Indian children

OBJECTIVE

We aimed to test the fetal overnutrition hypothesis by comparing the associations of maternal and paternal adiposity (sum of skinfolds) with adiposity and cardiovascular risk factors in children.

DESIGN

Children from a prospective birth cohort had anthropometry, fat percentage (bio-impedance), plasma glucose, insulin and lipid concentrations and blood pressure measured at 9.5 years of age. Detailed anthropometric measurements were recorded for mothers (at 3±2 weeks’ gestation) and fathers (5 years following the index pregnancy).

SETTING

Holdsworth Memorial Hospital, Mysore, India.

SUBJECTS

Children (n 504), born to mothers with normal glucose tolerance during pregnancy.

RESULTS

Twenty-eight per cent of mothers and 38% of fathers were overweight/ obese (BMI≥25.0 kg/m²), but only 4% of the children were overweight/obese (WHO age- and sex-specific BMI≥18.2 kg/m²). The children’s adiposity (BMI, sum of skinfolds, fat percentage and waist circumference), fasting insulin concentration and insulin resistance increased with increasing maternal and paternal sum of skinfolds adjusted for the child’s sex, age and socio-economic status. Maternal and paternal effects were similar. The associations with fasting insulin and insulin resistance were attenuated after adjusting for the child’s current adiposity.

CONCLUSIONS

In this population, both maternal and paternal adiposity equally predict adiposity and insulin resistance in the children. This suggests that shared family environment and lifestyle, or genetic/epigenetic factors, influence child adiposity. Our findings do not support the hypothesis that there is an intrauterine overnutrition effect of maternal adiposity in non-diabetic pregnancies, although we cannot rule out such an effect in cases of extreme maternal obesity, which is rare in our population.

Parent-offspring body mass index associations in the Norwegian Mother and Child Cohort Study: a family-based approach to studying the role of the intrauterine environment in childhood adiposity

In the present study, the authors investigated the role of the intrauterine environment in childhood adiposity by comparing the maternal-offspring body mass index (BMI) association with the paternal-offspring BMI association when the offspring were 3 years of age, using parental prepregnancy BMI (measured as weight in kilograms divided by height in meters squared). The parent-offspring trios (n = 29,216) were recruited during pregnancy from 2001 to 2008 into the Norwegian Mother and Child Cohort Study conducted by The Norwegian Institute of Public Health. Data from self-administered questionnaires were used in linear regression analyses. Crude analyses showed similar parental-offspring BMI associations; the mean difference in offspring BMI was 0.15 (95% confidence interval: 0.13, 0.16) per each 1-standard-deviation increase in maternal BMI and 0.15 (95% confidence interval: 0.13, 0.17) per each 1-standard-deviation increase in paternal BMI. After all adjustments, the mean difference in offspring BMI per each 1-standard-deviation increment of maternal BMI was 0.12, and the mean difference in offspring BMI per each 1-standard-deviation increment of paternal BMI was 0.13. There was no strong support for heterogeneity between the associations (P > 0.6). In conclusion, results from the present large population-based study showed similar parental-offspring BMI associations when the offspring were 3 years of age, which indicates that the maternal-offspring association may be explained by shared familial (environmental and genetic) risk factors rather than by the intrauterine environment.