Prenatal and childhood exposure to per-/polyfluoroalkyl substances (PFASs) and its associations with childhood overweight and/or obesity: a systematic review with meta-analyses

BACKGROUND

Per-/polyfluoroalkyl substances (PFASs) are persistent organic pollutants and suspected endocrine disruptors.

OBJECTIVE

The aim of this work was to conduct a systematic review with meta-analysis to summarise the associations between prenatal or childhood exposure to PFASs and childhood overweight/obesity.

METHODS

The search was performed on the bibliographic databases PubMed and Embase with text strings containing terms related to prenatal, breastfeeding, childhood, overweight, obesity, and PFASs. Only papers describing a biomonitoring study in pregnant women or in children up to 18 years that assessed body mass index (BMI), waist circumference (WC), or fat mass in children were included. When the estimates of the association between a PFAS and an outcome were reported from at least 3 studies, a meta-analysis was conducted; moreover, to correctly compare the studies, we developed a method to convert the different effect estimates and made them comparable each other. Meta-analyses were performed also stratifying by sex and age, and sensitivity analyses were also performed.

RESULTS

In total, 484 and 779 articles were retrieved from PubMed and Embase, respectively, resulting in a total of 826 articles after merging duplicates. The papers included in this systematic review were 49: 26 evaluating prenatal exposure to PFASs, 17 childhood exposure, and 6 both. Considering a qualitative evaluation, results were conflicting, with positive, negative, and null associations. 30 papers were included in meta-analyses (19 prenatal, 7 children, and 4 both). Positive associations were evidenced between prenatal PFNA and BMI, between PFOA and BMI in children who were more than 3 years, and between prenatal PFNA and WC. Negative associations were found between prenatal PFOS and BMI in children who were 3 or less years, and between PFHxS and risk of overweight. Relatively more consistent negative associations were evidenced between childhood exposure to three PFASs (PFOA, PFOS, and PFNA) and BMI, in particular PFOS in boys. However, heterogeneity among studies was high.

CONCLUSION

Even though heterogeneous across studies, the pooled evidence suggests possible associations, mostly positive, between prenatal exposure to some PFASs and childhood BMI/WC; and relatively stronger evidence for negative associations between childhood exposure to PFASs and childhood BMI.

Early sex-dependent differences in metabolic profiles of overweight and adiposity in young children: a cross-sectional analysis

BACKGROUND

Childhood obesity is a global health concern and can lead to lifetime cardiometabolic disease. New advances in metabolomics can provide biochemical insights into the early development of obesity, so we aimed to characterize serum metabolites associated with overweight and adiposity in early childhood and to stratify associations by sex.

METHODS

Nontargeted metabolite profiling was conducted in the Canadian CHILD birth cohort (discovery cohort) at age 5 years (n = 900) by multisegment injection-capillary electrophoresis-mass spectrometry. Clinical outcome was defined using novel combined measures of overweight (WHO-standardized body mass index ≥ 85th percentile) and/or adiposity (waist circumference ≥ 90th percentile). Associations between circulating metabolites and child overweight/adiposity (binary and continuous outcomes) were determined by multivariable linear and logistic regression, adjusting for covariates and false discovery rate, and by subsequent sex-stratified analysis. Replication was assessed in an independent replication cohort called FAMILY at age 5 years (n = 456).

RESULTS

In the discovery cohort, each standard deviation (SD) increment of branched-chain and aromatic amino acids, glutamic acid, threonine, and oxoproline was associated with 20-28% increased odds of overweight/adiposity, whereas each SD increment of the glutamine/glutamic acid ratio was associated with 20% decreased odds. All associations were significant in females but not in males in sex-stratified analyses, except for oxoproline that was not significant in either subgroup. Similar outcomes were confirmed in the replication cohort, where associations of aromatic amino acids, leucine, glutamic acid, and the glutamine/glutamic acid ratio with childhood overweight/adiposity were independently replicated.

CONCLUSIONS

Our findings show the utility of combining measures of both overweight and adiposity in young children. Childhood overweight/adiposity at age 5 years has a specific serum metabolic phenotype, with the profile being more prominent in females compared to males.

Reassessing the causal role of obesity in breast cancer susceptibility: a comprehensive multivariable Mendelian randomization investigating the distribution and timing of exposure

BACKGROUND

Previous Mendelian randomization (MR) studies on obesity and risk of breast cancer adopted a small number of instrumental variables and focused mainly on the crude total effect. We aim to investigate the independent causal effect of obesity on breast cancer susceptibility, considering the distribution of fat, covering both early and late life.

METHODS

Using an enlarged set of female-specific genetic variants associated with adult general [body mass index (BMI)] and abdominal obesity [waist-to-hip ratio (WHR) with and without adjustment for BMI, WHR and WHRadjBMI] as well as using sex-combined genetic variants of childhood obesity (childhood BMI), we performed a two-sample univariable MR to re-evaluate the total effect of each obesity-related exposure on overall breast cancer (Ncase = 133 384, Ncontrol = 113 789). We further looked into its oestrogen receptor (ER)-defined subtypes (NER+ = 69 501, NER- = 21 468, Ncontrol = 105 974). Multivariable MR was applied to estimate the independent causal effect of each obesity-related exposure on breast cancer taking into account confounders as well as to investigate the independent effect of adult and childhood obesity considering their inter-correlation.

RESULTS

In univariable MR, the protective effects of both adult BMI [odds ratio (OR) = 0.89, 95% CI = 0.83-0.96, P = 2.06 × 10-3] and childhood BMI (OR = 0.78, 95% CI = 0.70-0.87, P = 4.58 × 10-6) were observed for breast cancer overall. Comparable effects were found in ER+ and ER- subtypes. Similarly, genetically predicted adult WHR was also associated with a decreased risk of breast cancer overall (OR = 0.87, 95% CI = 0.80-0.96, P = 3.77 × 10-3), restricting to ER+ subtype (OR = 0.88, 95% CI = 0.80-0.98, P = 1.84 × 10-2). Conditional on childhood BMI, the effect of adult general obesity on breast cancer overall attenuated to null (BMI: OR = 1.00, 95% CI = 0.90-1.10, P = 0.96), whereas the effect of adult abdominal obesity attenuated to some extent (WHR: OR = 0.90, 95% CI = 0.82-0.98, P = 1.49 × 10-2; WHRadjBMI: OR = 0.92, 95% CI = 0.86-0.99, P = 1.98 × 10-2). On the contrary, an independent protective effect of childhood BMI was observed in breast cancer overall, irrespective of adult measures (adjusted for adult BMI: OR = 0.84, 95% CI = 0.77-0.93, P = 3.93 × 10-4; adjusted for adult WHR: OR = 0.84, 95% CI = 0.76-0.91, P = 6.57 × 10-5; adjusted for adult WHRadjBMI: OR = 0.80, 95% CI = 0.74-0.87, P = 1.24 × 10-7).

CONCLUSION

Although successfully replicating the inverse causal relationship between adult obesity-related exposures and risk of breast cancer, our study demonstrated such effects to be largely (adult BMI) or partly (adult WHR or WHRadjBMI) attributed to childhood obesity. Our findings highlighted an independent role of childhood obesity in affecting the risk of breast cancer as well as the importance of taking into account the complex interplay underlying correlated exposures.

Prenatal exposure to per- and polyfluoroalkyl substances and childhood adiposity at 7 years of age

BACKGROUND

An increasing number of studies have reported that prenatal per- and polyfluoroalkyl substances (PFAS) exposure may increase childhood adiposity. However, limited data is available in China, and the overall effects of PFAS mixture remain unclear.

OBJECTIVE

To examine the association of prenatal exposure to individual PFAS and their mixture with childhood adiposity at 7 years of age.

METHODS

A total of 206 mother-infant pairs were recruited from the Laizhou Wan (Bay) Birth Cohort in China between 2010 and 2013. Ten PFAS were measured in maternal serum. The measurements of fat mass, body fat percentage, body mass index, waist circumference, waist-to-height ratio and overweight/obesity were used to assess adiposity in children aged 7. We fitted logistic regression, linear regression and weighted quantile sum (WQS) regression models to estimate the association of prenatal exposure to individual PFAS and their mixture with childhood adiposity.

RESULTS

We found negative associations of perfluoroheptanoic acid (PFHpA) and perfluorooctane sulfonamide (PFOSA) exposure with adiposity measurements in all children. The result from the WQS model consistently revealed that the PFAS mixture was inversely related to adiposity measurements. Each quartile increase of the PFAS mixture was associated with a 1.14 kg decrease (95% CI: -2.27, -0.02) in fat mass and a 2.32% decrease (95% CI: -4.51, -0.14) in body fat. Moreover, significant sex differences were found. PFAS mixture was negatively associated with five adiposity measurements in boys, but positively associated with all adiposity measurements except body fat percentage in girls. PFOSA, PFHpA and perfluorobutanesulfonate (PFBS) with weights >0.300 were the main contributors to the overall effects observed among all children, boys and girls, respectively.

CONCLUSION

This study suggests potential sex-specific associations of prenatal exposure to individual PFAS and their mixture with childhood adiposity, with the observed relationship being negative for boys but positive for girls.

Family socioeconomic status and childhood adiposity in Europe - A scoping review

Childhood obesity is a considerable public health problem worldwide. In Europe, lower parental socioeconomic status (SES) relates to higher childhood adiposity. This scoping review strives to discover, which SES indicators are the most commonly used and meaningful determinants of childhood adiposity (greater level of continuous adiposity indicator, e.g. body mass index z-score, or overweight or obesity categorized by established definitions). The review focused on studies about European general populations from the 21st century (January 2000-April 2021) considering children and adolescents aged 0-17 years. PubMed and reference lists of articles were searched in February-April 2021. Total of 53 studies with 121 association analyses between different SES indicators and adiposity indicators, were identified and reviewed. Different SES indicators were grouped to 25 indicators and further to six indicator groups. The most used indicator was mother's education (n of association analyses = 24) and the most used indicator group was parental education (n of association analyses = 51). Of all association analyses, 55% were inverse, 36% were non-significant, and 8% were positive. Composite SES (80%), parental education (69%) and parental occupation (64%) indicators showed most frequently inverse associations with obesity measures (i.e. lower parental SES associating with higher adiposity), while parental income (50% inverse; 50% non-significant) and property and affluence (42% inverse; 50% nonsignificant) indicators showed approximately even number of inverse and non-significant associations. Instead, majority of parental employment (60%) indicators, showed non-significant associations and 33% showed positive associations (i.e. higher parental SES associating with higher adiposity). Despite some variation in percentages, majority of the associations were inverse in each age group and with different outcome categorizations. In girls and in boys, non-significant associations predominated. It seems that children with parents of higher SES have lower likelihood of adiposity in Europe. Parents' employment appears to differ from other SES indicators, so that having an employed parent(s) does not associate with lower likelihood of adiposity. Positive associations seem to occur more frequently in poorer countries. Criteria for uniform childhood SES and adiposity measures should be established and used in studies in order to be able to produce comparable results across countries.

The mediating effect of DNA methylation in the association between maternal sleep during pregnancy and offspring adiposity status: a prospective cohort study

Background

Childhood overweight/obesity is a global public health concern. It is important to identify its early-life risk factors. Maternal poor sleep is common in late pregnancy, and previous studies indicated that poor sleep may influence the offspring’s adiposity status. However, very few studies in humans investigated the effect of the different sleep parameters (sleep quantity, quality, and timing) on the offspring’s adiposity indicators, and long-term studies are even more scarce. In addition, the underlying mechanism remains unclear. The present study therefore aimed to examine the association between the three maternal sleep dimensions in the late pregnancy and the offspring adiposity indicators and to explore the potential mediating effect of the cord blood DNA methylation in the above association.

Methods

Included participants in the current study were 2211 healthy pregnant women with singleton gestation from the Shanghai Birth Cohort (SBC) and Shanghai Sleep Birth Cohort (SSBC). Maternal nighttime sleep duration, quality, and midpoint (an indicator of circadian rhythm) were assessed by the same instrument in both cohorts during late pregnancy, and the offspring’s body mass index (BMI) and subcutaneous fat (SF) were measured at 2 years old. Additionally, in 231 SSBC samples, the genome-wide DNA methylation levels were measured using the Illumina Infinium Methylation EPIC BeadChip. The multivariate linear regression was used to determine the associations between the maternal sleep parameters and the offspring adiposity indicators. The epigenome-wide association study was conducted to identify the maternal sleep-related CpG sites. The mediation analysis was performed to evaluate the potential intermediate role of DNA methylation in the association between maternal sleep and offspring adiposity indicators.

Results

The mean maternal nighttime sleep duration and the sleep midpoint for combined cohorts were 9.24 ± 1.13 h and 3.02 ± 0.82, respectively, and 24.5% of pregnant women experienced poor sleep quality in late pregnancy. After adjusting for the covariates, the maternal later sleep midpoint was associated with the increased SF in offspring (Coef. = 0.62, 95% CI 0.37–0.87, p < 0.001) at 2 years old. However, no significant associations of the nighttime sleep duration or sleep quality with the offspring adiposity indicators were found. In the SSBC sample, 45 differential methylated probes (DMPs) were associated with the maternal sleep midpoint, and then, we observed 10 and 3 DMPs that were also associated with the offspring’s SF and BMI at 2 years, of which cg04351668 (MARCH9) and cg12232388 significantly mediated the relationship of sleep midpoint and SF and cg12232388 and cg12225226 mediated the sleep midpoint–BMI association, respectively.

Conclusions

Maternal later sleep timing in late pregnancy was associated with higher childhood adiposity in the offspring. Cord blood DNA methylation may play a mediation role in that relationship.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-022-01284-w.

Organic UV filters mixture exposure and childhood adiposity: A prospective follow-up study in China

BACKGROUND

UV filters are emerging contaminants with endocrine disrupting effects, but little is known about their health effects, especially for children.

OBJECTIVE

To assess the association between multiple organic UV filters exposure and adiposity measures and by gender in peripubertal children.

METHODS

This prospective follow-up study included 327 children aged 7-15 years old. Urinary organic UV filters including benzophenone derivatives (BP-2, BP-3), octyl dimethyl para-aminobenzoic acid (OD-PABA), ethylhexyl methoxycinnamate (EHMC) and its metabolite (4-MCA and 4'-MAP) were quantified. Six adiposity biometrics including height, weight, waist and hip circumferences, and triceps and subscapular skinfold thickness were measured with 1.5-year duration. The Bayesian kernel machine regression method was used to estimate the associations of UV filters mixture with adiposity measurements, and longitudinal analyses were then considered to further evaluate the associations between individual UV filters and trajectories of growth development using linear mixed models or generalized linear mixed models.

RESULTS

Exposure to mixture of UV filters was negatively associated with most adiposity measurements, with a reduction of 1.399 kg/m² (95% CI: -2.246 to -0.551 kg/m²) in BMI, 0.674 (95% CI: -1.045 to -0.304) in BMI z-score, 0.033 BF% (95% CI: -0.053 to -0.013), and 2.301 mm (95% CI: -3.823 to -0.78) in subscapular skinfold thickness at baseline, comparing the 75th percentile to the 25th level of UV filters mixture exposure. Consistent associations were found at follow-up. Both baseline and follow-up results suggested that EHMC was identified as the most important contributor to lower adiposity measurements, which was also confirmed by linear mixed models in longitudinal analyses. No significant effects were found in girls.

CONCLUSION

This study found that childhood organic UV filters exposure was negatively associated with adiposity measures in peripubertal boys, but not girls.

Evaluating the direct effects of childhood adiposity on adult systemic metabolism: a multivariable Mendelian randomization analysis

BACKGROUND

Individuals who are obese in childhood have an elevated risk of disease in adulthood. However, whether childhood adiposity directly impacts intermediate markers of this risk, independently of adult adiposity, is unclear. In this study, we have simultaneously evaluated the effects of childhood and adulthood body size on 123 systemic molecular biomarkers representing multiple metabolic pathways.

METHODS

Two-sample Mendelian randomization (MR) was conducted to estimate the causal effect of childhood body size on a total of 123 nuclear magnetic resonance-based metabolic markers using summary genome-wide association study (GWAS) data from up to 24 925 adults. Multivariable MR was then applied to evaluate the direct effects of childhood body size on these metabolic markers whilst accounting for adult body size. Further MR analyses were undertaken to estimate the potential mediating effects of these circulating metabolites on the risk of coronary artery disease (CAD) in adulthood using a sample of 60 801 cases and 123 504 controls.

RESULTS

Univariable analyses provided evidence that childhood body size has an effect on 42 of the 123 metabolic markers assessed (based on P < 4.07 × 10-4). However, the majority of these effects (35/42) substantially attenuated when accounting for adult body size using multivariable MR. We found little evidence that the biomarkers that were potentially influenced directly by childhood body size (leucine, isoleucine and tyrosine) mediate this effect onto adult disease risk. Very-low-density lipoprotein markers provided the strongest evidence of mediating the long-term effect of adiposity on CAD risk.

CONCLUSIONS

Our findings suggest that childhood adiposity predominantly exerts its detrimental effect on adult systemic metabolism along a pathway that involves adulthood body size.

ADHD and Risk of Childhood Adiposity: a Review of Recent Research

PURPOSE OF REVIEW

Attention deficit/hyperactivity disorder (ADHD) is considered as a risk factor for childhood adiposity and obesity. Studies on ADHD have provided limited data concerning the connections between eating habits, body mass index, and obesity. The purpose of this review was to examine the current literature regarding recent cohort and cross-sectional studies to determine the links between ADHD and childhood adiposity.

RECENT FINDINGS

Studies in this review were classified into dietary features, nutritional status, neuroimaging findings, genetic overlapping, behavioral, cognitive, and neurocognitive aspects that play a role in mediating and moderating the relationship between ADHD and obesity. While ADHD, childhood adiposity, and overweight/obesity co-occur in children and adolescents, this relationship is largely explained by a variety of multidirectional factors.

The associations of childhood adiposity with menopausal symptoms in women aged 45-49 years: An Australian Cohort Study

OBJECTIVES

To examine the associations of childhood adiposity with menopausal symptoms in women aged 45-49 years.

STUDY DESIGN

National population-based cohort study of 334 girls prospectively followed from childhood (aged 11-15) through to midlife (aged 45-49). Childhood overweight and obesity were defined by international age- and sex-specific standards for body mass index (BMI), and abdominal obesity was defined as waist/height ratio≥0.5.

MAIN OUTCOME MEASURES

Vasomotor symptoms (VMS), vaginal dryness, total menopausal symptoms and domain-specific symptoms (somatic, psychological and urogenital) were measured during 2018-19 using the Menopause Rating Scale (MRS) and classified as none, mild, moderate or severe.

RESULTS

The prevalence of mild, moderate and severe VMS was 24.0 %, 9.0 % and 3.9 %, and of vaginal dryness was 12.6 %, 4.8 % and 2.4 %. No significant associations of childhood overweight/obesity or abdominal obesity with VMS or vaginal dryness were found after adjustment for childhood age, follow-up length, smoking, socioeconomic status and diet quality. Childhood overweight/obesity was associated with increased risks of more severe total (RR:1.17, 95 % CI:1.02-1.36), psychological (RR:1.19, 95 % CI:1.04-1.35) and urogenital (RR:1.29, 95 % CI:1.14-1.46) symptoms measured using the MRS. Associations with childhood abdominal obesity were mostly stronger with more severe total (RR:2.19, 95 % CI:1.48-3.23), somatic (RR:1.52, 95 % CI:1.15-2.02), psychological (RR:1.21, 95 % CI:1.04-1.42) and urogenital (RR:2.11, 95 % CI:1.39-3.20) symptoms.

CONCLUSIONS

Childhood adiposity was not associated with increased risks of more severe VMS or vaginal dryness in women aged 45-49 years. Childhood adiposity, especially abdominal obesity, was associated with more severe total, somatic, psychological and urogenital symptoms. However, the association between these symptoms and menopause is not established.

Prenatal exposure to perfluorobutanesulfonic acid and childhood adiposity: A prospective birth cohort study in Shanghai, China

BACKGROUND

Several per- and polyfluoroalkyl substances (PFAS) have been phased out due to their adverse effects, and replaced by the short-chain perfluorobutanesulfonic acid (PFBS). However, the long-term impacts of PFBS on human health are unknown.

OBJECTIVE

We aimed to investigate the association between prenatal exposure to PFAS, especially PFBS and childhood adiposity at 5 years of age.

METHODS

We conducted a prospective birth cohort study involving 1,140 pregnant women from 2012 to 2017 in Shanghai. Fetal umbilical cord blood was collected at birth. A total of 404 children (196 girls) completed the adiposity measurements using a bioelectrical impedance analysis method and cord plasma PFAS measurements using LC-MS/MS. Multivariable linear models after adjustment for potential confounders were used to evaluate the associations between PFAS and childhood adiposity.

RESULTS

The median concentration of PFAS in the cord plasma ranged from 0.05 (PFBS) to 6.74 ng/mL (PFOA). Results of multivariable linear regression found that in girls, PFBS had a significant positive association with waist circumference and waist to height ratio (P-values < 0.05). Girls in the highest tertile of PFBS concentrations had more fat mass, as well as higher body fat percentage, waist circumference, and waist to height ratio compared to those in the lowest tertile. However, girls in the second tertile of PFDoA had lower body fat percentage, waist circumference and fat mass.

CONCLUSIONS

Adiposity at 5 years of age shows a positive association with prenatal exposure to PFBS in girls. These findings need to be further verified in larger prospective studies.

Genetic risk score for adult body mass index associations with childhood and adolescent weight gain in an African population

Background

Ninety-seven independent single nucleotide polymorphisms (SNPs) are robustly associated with adult body mass index (BMI kg/m²) in Caucasian populations. The relevance of such variants in African populations at different stages of the life course (such as childhood) is unclear. We tested whether a genetic risk score composed of the aforementioned SNPs was associated with BMI from infancy to early adulthood. We further tested whether this genetic effect was mediated by conditional weight gain at different growth periods. We used data from the Birth to Twenty Plus Cohort (Bt20+), for 971 urban South African black children from birth to 18 years. DNA was collected at 13 years old and was genotyped using the Metabochip (Illumina) array. The weighted genetic risk score (wGRS) for BMI was constructed based on 71 of the 97 previously reported SNPs.

Results

The cross-sectional association between the wGRS and BMI strengthened with age from 5 to 18 years. The significant associations were observed from 11 to 18 years, and peak effect sizes were observed at 13 and 14 years of age. Results from the linear mixed effects models showed significant interactions between the wGRS and age on longitudinal BMI but no such interactions were observed in sex and the wGRS. A higher wGRS was associated with an increased relative risk of belonging to the early onset obese longitudinal BMI trajectory (relative risk = 1.88; 95%CI 1.28 to 2.76) compared to belonging to a normal longitudinal BMI trajectory. Adolescent conditional relative weight gain had a suggestive mediation effect of 56% on the association between wGRS and obesity risk at 18 years.

Conclusions

The results suggest that genetic susceptibility to higher adult BMI can be tracked from childhood in this African population. This supports the notion that prevention of adult obesity should begin early in life. The genetic risk score combined with other non-genetic risk factors, such as BMI trajectory membership in our case, has the potential to be used to screen for early identification of individuals at increased risk of obesity and other related NCD risk factors in order to reduce the adverse health risk outcomes later.

Electronic supplementary material

The online version of this article (10.1186/s12263-018-0613-7) contains supplementary material, which is available to authorized users.

Cord blood DNA methylation and adiposity measures in early and mid-childhood

Background

Excess adiposity in childhood is associated with numerous adverse health outcomes. As this condition is difficult to treat once present, identification of risk early in life can help inform and implement strategies to prevent the onset of the condition. We performed an epigenome-wide association study to prospectively investigate the relationship between cord blood DNA methylation and adiposity measurements in childhood.

Methods

We measured genome-wide DNA methylation from 478 children in cord blood and measured overall and central adiposity via skinfold caliper measurements in early (range 3.1–3.3 years) and mid-childhood (age range 7.3–8.3 years) and via dual X-ray absorptiometry (DXA) in mid-childhood. Final models were adjusted for maternal age at enrollment, pre-pregnancy body mass index, education, folate intake during pregnancy, smoking during pregnancy, and gestational weight gain, and child sex, race/ethnicity, current age, and cord blood cell composition.

Results

We identified four promoter proximal CpG sites that were associated with adiposity as measured by subscapular (SS) and triceps (TR) ratio (SS:TR) in early childhood, in the genes KPRP, SCL9A10, MYLK2, and PRLHR. We additionally identified one gene body CpG site associated with early childhood SS + TR on PPAPDC1A; this site was nominally associated with SS + TR in mid-childhood. Higher methylation at one promoter proximal CpG site in MMP25 was also associated with SS:TR in mid-childhood. In regional analyses, methylation at an exonal region of GFPT2 was positively associated with SS:TR in early childhood. Finally, we identified regions of two long, non-coding RNAs which were associated with SS:TR (LOC100049716) and fat-free mass index (LOC102723493) in mid-childhood.

Conclusion

This analysis identified novel CpG loci associated with adiposity outcomes. However, our results suggest little consistency across the various adiposity outcomes tested, particularly among the more accurate DXA measurements of body composition. We recommend using caution when interpreting these associations.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-017-0384-9) contains supplementary material, which is available to authorized users.

Body size from birth through adolescence in relation to risk of benign breast disease in young women

PURPOSE

Body size, from birth throughout adulthood, is associated with breast cancer risk, but few studies have investigated early-life body size and benign breast disease (BBD), a well-established breast cancer risk factor. We consider whether prenatal factors and size at birth, 10, 18 year, and intervening growth, are related to BBD risk.

METHODS

The Growing Up Today Study includes 9032 females who completed questionnaires annually from 1996 to 2001, then 2003, 2005, 2007, 2010, and 2013. In 1996, their mothers provided pregnancy-related data. From 2005 to 2013, participants (18 year+) reported whether they had ever been diagnosed with biopsy-confirmed BBD (N = 142 cases).

RESULTS

Girls had greater adiposity (BMI; kg/m2) at 10 year if they were larger at birth, if mother's pre-pregnancy BMI was higher, or if gestational weight gain was greater (all p < .01). Maternal height was (positively) associated (p < .05) with adolescent peak height growth velocity (PHV; in./year). Greater 10 year adiposity was associated with lower PHV and less height growth 10-18 year (both p < .01). Adiposity at 10 year was inversely associated with BBD (OR 0.83/(kg/m2), p < .01) as was increasing adiposity 10-18 year (OR 0.85/(kg/m2), p = .01). In a separate model, 10 year height (OR 1.13/in., p = .02) and height growth 10-18 year (OR 1.19/in.; p < .01) were positively associated. PHV was similarly positively associated (OR 2.58, p = .01, fastest versus slowest growth quartiles). In a multivariable model of BBD risk, gestational weight gain (daughters at highest risk if <20 lb gained), PHV (slowest growing girls at lowest risk), age 10 year height (positive), and BMI (inverse) were the most critical childhood risk factors (each p < .05).

CONCLUSIONS

Body size factors from pregnancy through adolescence were independently associated with BBD risk in young women.

Total HDL cholesterol efflux capacity in healthy children - Associations with adiposity and dietary intakes of mother and child

BACKGROUND AND AIMS

High-density lipoprotein (HDL) cholesterol efflux capacity in adults may be a measure of the atheroprotective property of HDL. Little however, is known about HDL cholesterol efflux capacity in childhood. We aimed to investigate the relationship between HDL cholesterol efflux capacity and childhood anthropometrics in a longitudinal study.

METHODS AND RESULTS

Seventy-five children (mean age = 9.4 ± 0.4 years) were followed from birth until the age of 9 years. HDL cholesterol efflux capacity was determined at age 9 by incubating serum-derived HDL-supernatants with ³H-cholesterol labeled J774 macrophages and percentage efflux determined. Mothers provided dietary information by completing food frequency questionnaires in early pregnancy and then 5 years later on behalf of themselves and their children. Pearson's correlations and multiple regression analyses were conducted to confirm independent associations with HDL efflux. There was a negative correlation between HDL cholesterol efflux capacity and waist circumference at age 5 (r = -0.3, p = 0.01) and age 9 (r = -0.24, p = 0.04) and BMI at age 5 (r = -0.45, p = 0.01) and age 9 (r = -0.19, p = 0.1). Multiple regression analysis showed that BMI at age 5 remained significantly associated with reduced HDL cholesterol efflux capacity (r = -0.45, p < 0.001). HDL-C was negatively correlated with energy-adjusted fat intake (r = -0.24, p = 0.04) and positively correlated with energy-adjusted protein (r = 0.24, p = 0.04) and starch (r = 0.29, p = 0.01) intakes during pregnancy. HDL-C was not significantly correlated with children dietary intake at age 5. There were no significant correlations between maternal or children dietary intake and HDL cholesterol efflux capacity.

CONCLUSIONS

This novel analysis shows that efflux capacity is negatively associated with adiposity in early childhood independent of HDL-C.

MC3R gene polymorphisms are associated with early childhood adiposity gain and infant appetite in an Asian population

BACKGROUND

Polymorphic variants within human melanocortin-3 receptor gene (MC3R) gene have been associated with obesity. However, its influence on infancy and early childhood adiposity has not been reported before.

OBJECTIVES

We assessed associations between genotype at polymorphic sites within MC3R with early childhood adiposity and interaction with early childhood appetitive traits.

METHODS

We studied 1090 singletons in an Asian mother-offspring cohort genotyped for MC3R and in a subgroup (n = 422) who had completed Child Eating Behaviour Questionnaires (CEBQ) at 12 months. Children were followed from birth to 48 months, and up to 10 measurements of body mass index and five measures of triceps and subscapular skin-folds were obtained.

RESULTS

Independent of potential confounders, each additional MC3R minor allele copy was associated with greater body mass index standard deviation score [B{95% confidence interval}: 0.004 units/month {0.001,0.007}; p = 0.007], triceps [0.009 mm/month {0.001,0.02}; p = 0.021] and subscapular skin-fold [0.008 mm/month {0.002,0.01}; p = 0.011] gain velocity in the first 48 months. Each additional MC3R minor allele copy was also associated with increased odds of overweight [odds ratio {95% confidence interval}: 1.48{1.17-1.88}] and obesity [1.58{1.10-2.28}] in the first 48 months. Every additional copy of MC3R minor allele was positively associated with 'slowness-in-eating' appetitive trait [0.24{0.06,0.39}, p = 0.006]; however, the relationship between 'slowness-in-eating' with adiposity gain was not statistically significant.

CONCLUSIONS

Our findings support the role of MC3R genetic variants in adiposity gain during early childhood.

Childhood adiposity trajectories are associated with late adolescent blood pressure: birth to twenty cohort

BACKGROUND

Elevated blood pressure in childhood is a risk factor for adult hypertension which is a global health problem. Excess adiposity in childhood creates a predisposition to develop adult hypertension. Our aim was to explore distinct sex-specific adiposity trajectories from childhood to late adolescence and examined their association with blood pressure.

METHODS

Latent Class Growth Mixture Modeling (LCGMM) on longitudinal data was used to derive sex-specific and distinct body mass index (BMI: kg/m(2)) trajectories. We studied 1824 black children (boys = 877, girls = 947) from the Birth to Twenty (Bt20) cohort from Soweto, South Africa, and obtained BMI measures at ages 5 through 18 years. Participants with at least two age-point BMI measures, were included in the analysis. Analysis of variance (ANOVA), chi-square test, multivariate linear and standard logistic regressions were used to test study characteristics and different associations.

RESULTS

We identified three (3) and four (4) distinct BMI trajectories in boys and girls, respectively. The overall prevalence of elevated blood pressure (BP) was 34.9 % (39.4 % in boys and 30.38 % in girls). Boys and girls in the early onset obesity or overweight BMI trajectories were more likely to have higher BP values in late adolescence. Compared to those in the normal weight BMI trajectory, girls in early onset obesity trajectories had an increased risk of elevated BP with odds ratio (OR) of 2.18 (95 % confidence interval 1.31 to 4.20) and 1.95 (1.01 to 3.77). We also observed the weak association for boys in early onset overweight trajectory, (p-value = 0.18 and odds ratio of 2.39 (0.67 to 8.57)) CONCLUSIONS: Distinct weight trajectories are observed in black South African children from as early as 5 years. Early onset adiposity trajectories are associated with elevated BP in both boys and girls. It is important to consider individual patterns of early-life BMI development, so that intervention strategies can be targeted to at-risk individuals.

Association between polyunsaturated fatty acid concentrations in maternal plasma phospholipids during pregnancy and offspring adiposity at age 7: the MEFAB cohort

Prenatal polyunsaturated fatty acid (PUFA) concentrations may be involved in the prenatal programming of adiposity. In this study we therefore explored the association between maternal PUFA concentrations, measured up to four times during pregnancy, and offspring adiposity at age 7 in 234 mother-child pairs of the Maastricht Essential Fatty Acid Birth cohort. Only dihomo-gamma-linolenic acid (DGLA, an n-6 fatty acid) concentration was associated with adiposity: per standard deviation increase in relative DGLA concentration, BMI increased by 0.44kg/m(2) (CI95: 0.16, 0.72), sum of skinfolds increased by 3.41mm (CI95: 1.88, 4.95), waist circumference increased by 1.09cm (CI95: 0.40, 1.78), and plasma leptin concentration increased by 0.66µg/l (CI95: 0.20, 1.11). In conclusion, maternal DGLA throughout gestation was associated with increased BMI and some additional measures of adiposity at age 7. This suggests that maternal DGLA might play a role in or reflect the prenatal programming of adiposity.