Adjustment For Maternal BMI Research Articles

Associations of urinary biomarkers of phthalates, phenols, parabens, and organophosphate esters with glycemic traits in pregnancy: The Healthy Start Study

BackgroundCertain endocrine-disrupting chemicals (EDCs) are widespread in consumer products and may alter glucose metabolism. However, the impact of EDC exposures on glucose and insulin regulation during pregnancy is incompletely understood, despite potential adverse consequences for maternal and infant health. We estimated associations between 37 urinary biomarkers of EDCs and glucose-insulin traits among pregnant women. MethodsSeventeen phthalate or phthalate substitute metabolites, six environmental phenols, four parabens, and ten organophosphate ester metabolites were quantified in mid-pregnancy urine from 298 participants in the Healthy Start Study. Fasting blood glucose, insulin, and hemoglobin A1c were assessed concurrently, and Homeostasis Model Assessment 2-Insulin Resistance (HOMA2-IR) was calculated. Gestational diabetes diagnoses and screening results were obtained from medical records for a subset of participants. We estimated associations between each EDC and outcome separately using linear and robust Poisson regression models and analyzed EDC mixture effects. ResultsThe EDC mixture was positively associated with glucose, insulin, and HOMA2-IR, although overall associations were attenuated after adjustment for maternal BMI. Two mixture approaches identified di(2-ethylhexyl) phthalate (DEHP) metabolites as top contributors to the mixture's positive associations. In single-pollutant models, DEHP metabolites were positively associated with fasting glucose, fasting insulin, and HOMA2-IR even after adjustment for maternal BMI. For example, each interquartile range increase in log2-transformed mono(2-ethyl-5-oxohexyl) phthalate was associated with 2.4 mg/dL (95% confidence interval (CI): 1.1, 3.6) higher fasting glucose, 11.8% (95%CI: 3.6, 20.5) higher fasting insulin, and 12.3% (95%CI: 4.2, 21.1) higher HOMA2-IR. Few EDCs were associated with hemoglobin A1c or with a combined outcome of impaired glucose tolerance or gestational diabetes. DiscussionExposures to phthalates and particularly DEHP during pregnancy are associated with altered glucose-insulin regulation. Disruptions in maternal glucose metabolism during pregnancy may contribute to adverse pregnancy outcomes including gestational diabetes and fetal macrosomia, and associated long-term consequences for maternal and child health.

Association of Maternal Metabolites and Metabolite Networks with Newborn Outcomes in a Multi-Ancestry Cohort.

The in utero environment is important for newborn size at birth, which is associated with childhood adiposity. We examined associations between maternal metabolite levels and newborn birthweight, sum of skinfolds (SSF), and cord C-peptide in a multinational and multi-ancestry cohort of 2337 mother-newborn dyads. Targeted and untargeted metabolomic assays were performed on fasting and 1 h maternal serum samples collected during an oral glucose tolerance test performed at 24-32 week gestation in women participating in the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study. Anthropometric measurements were obtained on newborns at birth. Following adjustment for maternal BMI and glucose, per-metabolite analyses demonstrated significant associations between maternal metabolite levels and birthweight, SSF, and cord C-peptide. In the fasting state, triglycerides were positively associated and several long-chain acylcarnitines were inversely associated with birthweight and SSF. At 1 h, additional metabolites including branched-chain amino acids, proline, and alanine were positively associated with newborn outcomes. Network analyses demonstrated distinct clusters of inter-connected metabolites significantly associated with newborn phenotypes. In conclusion, numerous maternal metabolites during pregnancy are significantly associated with newborn birthweight, SSF, and cord C-peptide independent of maternal BMI and glucose, suggesting that metabolites in addition to glucose contribute to newborn size at birth and adiposity.

Association of Assisted Reproductive Technology With Offspring Growth and Adiposity From Infancy to Early Adulthood

People conceived using assisted reproductive technology (ART) make up an increasing proportion of the world's population. To investigate the association of ART conception with offspring growth and adiposity from infancy to early adulthood in a large multicohort study. This cohort study used a prespecified coordinated analysis across 26 European, Asia-Pacific, and North American population-based cohort studies that included people born between 1984 and 2018, with mean ages at assessment of growth and adiposity outcomes from 0.6 months to 27.4 years. Data were analyzed between November 2019 and February 2022. Conception by ART (mostly in vitro fertilization, intracytoplasmic sperm injection, and embryo transfer) vs natural conception (NC; without any medically assisted reproduction). The main outcomes were length / height, weight, and body mass index (BMI; calculated as weight in kilograms divided by height in meters squared). Each cohort was analyzed separately with adjustment for maternal BMI, age, smoking, education, parity, and ethnicity and offspring sex and age. Results were combined in random effects meta-analysis for 13 age groups. Up to 158 066 offspring (4329 conceived by ART) were included in each age-group meta-analysis, with between 47.6% to 60.6% females in each cohort. Compared with offspring who were NC, offspring conceived via ART were shorter, lighter, and thinner from infancy to early adolescence, with differences largest at the youngest ages and attenuating with older child age. For example, adjusted mean differences in offspring weight were -0.27 (95% CI, -0.39 to -0.16) SD units at age younger than 3 months, -0.16 (95% CI, -0.22 to -0.09) SD units at age 17 to 23 months, -0.07 (95% CI, -0.10 to -0.04) SD units at age 6 to 9 years, and -0.02 (95% CI, -0.15 to 0.12) SD units at age 14 to 17 years. Smaller offspring size was limited to individuals conceived by fresh but not frozen embryo transfer compared with those who were NC (eg, difference in weight at age 4 to 5 years was -0.14 [95% CI, -0.20 to -0.07] SD units for fresh embryo transfer vs NC and 0.00 [95% CI, -0.15 to 0.15] SD units for frozen embryo transfer vs NC). More marked differences were seen for body fat measurements, and there was imprecise evidence that offspring conceived by ART developed greater adiposity by early adulthood (eg, ART vs NC difference in fat mass index at age older than 17 years: 0.23 [95% CI, -0.04 to 0.50] SD units). These findings suggest that people conceiving or conceived by ART can be reassured that differences in early growth and adiposity are small and no longer evident by late adolescence.

Early exposure to animals and childhood body mass index percentile and percentage fat mass

ABSTRACT Introduction A few studies have identified childhood animal exposure as associated with adiposity, but results are inconsistent and differ in timing. Methods We conducted an observational cohort study of children ages 4–8 in the Environmental Influences on Child Health Outcomes [ECHO] study. The main exposure was having a dog in the home and/or regular contact with farm animals during the first year of life. Outcomes of interest were child BMI percentile (adjusted for gender and age) categorized as normal/underweight (<85th percentile), overweight (85th to <95th), and obese (≥95th), and percent fat mass (continuous). Associations were analyzed using multinomial logistic regression and multivariable linear regression, respectively, with and without multiple imputation. Results First-year animal exposure occurred in 245 of 770 (31.8%) children. Children with early animal exposure had 0.53 (95% CI: 0.28, 0.997) times the odds of being in the obese BMI category compared to those exposed to animals after controlling for covariates: maternal pre-pregnancy BMI, race/ethnicity, reported child activity level, receiving food assistance, age child began daycare (<1 year vs 1+), exclusively breastfed x6 months, and NICU admission (n = 721). Children with early animal exposure had, on average, 1.5% (95% CI: −3.0, −0.1) less fat mass than exposed children after adjustment for maternal BMI, race/ethnicity, activity, food assistance, breastfeeding, and maternal education (n = 548). Multiple imputation did not alter either result. Conclusion These results provide evidence that exposure to dogs or farm animals in the first year of life is associated with lower odds of obesity and lower percent fat mass in childhood.

Abstract P176: Associations of Gestational Lipids and Apolipoproteins With Pregnancy Outcomes: The Hyperglycemia and Adverse Pregnancy Outcome Study

Introduction: Gestational hyperlipidemia has traditionally been considered physiologic and benign, but the significance of inter-individual variation in lipid levels for maternal-fetal health are poorly understood. We examined associations of gestational lipids and apolipoproteins with adverse obstetric and neonatal outcomes. Methods: Data from the Hyperglycemia and Adverse Pregnancy Outcome Study were analyzed, including 1,813 mother-child dyads from 9 field centers in 6 countries: US (25%), Barbados (24%), UK (20%), China (16%), Thailand (8%), and Canada (7%). Fasting lipids and apolipoproteins were directly measured at a mean of 28 (range 23-34) weeks’ gestation. Cord blood was collected at delivery, neonatal anthropometrics were measured within 72 hours, and medical records were abstracted for obstetric outcomes. Logistic regression was utilized to test associations of lipids and apolipoproteins (per +1 SD; log-transformed if skewed) with pregnancy outcomes, adjusted for center, demographics, and maternal covariates such as BMI, blood pressure, and glycemia. Results: See Table for lipid and apolipoprotein levels in pregnant mothers. In fully adjusted models ( Table ), 1 SD higher log-triglycerides (i.e., ~2.7-fold higher triglyceride level) in late pregnancy was significantly associated with higher odds for preeclampsia (OR 1.53 [95% CI, 1.15-2.05]), large for gestational age infant (1.42 [1.21-1.67]), and infant insulin sensitivity &lt;10 th percentile (1.25 [1.03-1.50]), but not with unplanned primary cesarean section or infant sum of skinfolds &gt;90 th percentile. There were no significant associations of maternal HDL-C, LDL-C, or log-ApoB/A1 ratio with any outcome. Conclusion: Triglyceride levels in the latter half of pregnancy were uniquely associated with both maternal risks (preeclampsia) and neonatal risks (large for gestational age and insulin resistance), even after adjustment for maternal BMI, blood pressure, and glycemia.

Cell-Free Fetal DNA in the Early and Late First Trimester

Objective: The aim of this work was to investigate the association between maternal and fetal characteristics and the fetal fraction at 8–14 weeks’ gestation, with emphasis on the change in the fetal fraction upon repeat sampling. Method: One sample for cell-free DNA (cfDNA) testing was collected at the same time as the biochemical markers for combined first trimester screening (visit 1) and another at the nuchal translucency scan (visit 2). Chromosome-selective cfDNA analysis was performed on frozen plasma. Results: Overall, 321 women were included at visit 1, and 307 had a repeat blood sampling. A fetal fraction was obtained in 532 samples (238 samples with repeat fetal fraction). The fetal fraction decreased with maternal BMI (p < 0.001), was lower in Asian women (p = 0.03), and increased with β-hCG levels (p < 0.001) and gestational age (p = 0.04). Before 10 weeks’ gestation, the fetal fraction was lower (p = 0.02), as was the probability of a sufficient fetal fraction (p = 0.03) after adjustment for maternal BMI. Asian women had a higher increase in fetal fraction upon repeat sampling (p < 0.001). Conclusion: Before 10 weeks’ gestation, the fetal fraction is significantly lower but seems to increase more rapidly compared to later gestations. Presently, combined first trimester screening with cfDNA testing should not include samples before 10 weeks’ gestation.

OR07-1 Cord Blood Metabolomics: Association with Newborn Anthropometrics and C-Peptide across Ancestries

Newborn adiposity is associated with a higher risk of childhood obesity and earlier onset of co-morbid metabolic diseases such as type 2 diabetes mellitus. The cord blood metabolome is one early life marker that provides mechanistic insight into fetal fat deposition, insulin sensitivity, and future obesity and metabolic disease risk and integrates in-utero genetic, nutritional and metabolic cues that contribute to newborn phenotype. We hypothesize that a unique cord blood metabolomic signature associated with newborn adiposity or hyperinsulinemia might emerge as a predictive tool to help identify at-risk children early in life, before disease develops. To evaluate this hypothesis, we performed a cross-sectional, observational study of 1600 newborns who participated in the Hyperglycemia and Adverse Pregnancy Outcome Study. Targeted and nontargeted metabolomics assays were performed on cord blood of newborns across four ancestry groups (Afro-Caribbean, Northern European, Thai, and Mexican American). Newborn birth weight and sum of skinfolds were measured by trained personnel and cord blood was additionally assayed for C-peptide. Associations of cord blood metabolites with newborn phenotype were investigated using 1) per-metabolite analyses within and across ancestries and 2) network analyses to identify interconnected metabolites associated with phenotypes. Several metabolites, including branched-chain amino acids, medium- and long-chain acylcarnitines, nonesterified fatty acids, and triglycerides were significantly negatively associated with cord C-peptide but positively associated with birth weight and/or sum of skinfolds. 1,5-Anhydroglucitol was significantly associated with birth weight and sum of skinfolds in nontargeted metabolite analyses. Network analyses revealed groups of interrelated amino acid, acylcarnitine, and fatty acid metabolites associated with all three newborn outcomes. In conclusion, cord blood metabolites are associated with newborn size and cord C-peptide, even after adjustment for maternal BMI and glucose during pregnancy. The paradoxical inverse association of metabolites with cord blood C-peptide suggests that the metabolite-insulin relationship reverses at a critical point in childhood to the well-described positive association seen in adolescents and adults. The well-known associations of branched chain amino acids and medium- and long-chain acylcarnitines with obesity in adolescents and adults appears to begin at birth and might serve as an early-life marker of obesity risk.

Primary and Repeat Cesarean Deliveries: A Population-based Study in the United States, 1979-2010.

Despite the temporal increase in cesarean deliveries, the extent to which maternal age, period, and maternal birth cohorts may have contributed to these trends remains unknown. We performed an analysis of 123 million singleton deliveries in the United States (1979-2010). We estimated rate ratio (RR) with 95% confidence interval (CI) for primary and repeat cesarean deliveries. We examined changes in cesarean rates with weighted Poisson regression models across three time-scales: maternal age, year of delivery, and birth cohort (mother's birth year). The primary cesarean rate increased by 68% (95% confidence interval [CI]: 67%, 69%) between 1979 (11.0%) and 2010 (18.5%). Repeat cesarean deliveries increased by 178% (95% CI: 176, 179) from 5.2% in 1979 to 14.4% in 2010. Cesarean rates increased with advancing age. Compared with 1979, the RR for the period effect in primary and repeat cesarean deliveries increased up to 1990, fell to a nadir at 1993, and began to rise thereafter. A small birth cohort effect was evident, with women born before 1950 at increased risk of primary cesarean; no cohort effect was seen for repeat cesarean deliveries. Adjustment for maternal BMI had a small effect on these findings. Period effects in primary cesarean were explained by a combination of trends in obesity and chronic hypertension, as well as demographic shifts over time. Maternal age and period appear to have important contributions to the temporal increase in the cesarean rates, although the effect of parity on these associations remains undetermined.

Maternal child-feeding practices and dietary inadequacy of 4-year-old children

This study aimed to evaluate the association between maternal perceived responsibility and child-feeding practices and dietary inadequacy of 4-year-old children. We studied 4122 mothers and children enrolled in the population-based birth cohort – Generation XXI (Porto, Portugal). Mothers self-completed the Child Feeding Questionnaire and a scale on covert and overt control, and answered to a food frequency questionnaire in face-to-face interviews. Using dietary guidelines for preschool children, adequacy intervals were defined: fruit and vegetables (F&V) 4–7 times/day; dairy 3–5 times/day; meat and eggs 5–10 times/week; fish 2–4 times/week. Inadequacy was considered as below or above these cut-points. For energy-dense micronutrient-poor foods and beverages (EDF), a tolerable limit was defined (<6 times/week). Associations between maternal perceived responsibility and child-feeding practices (restriction, monitoring, pressure to eat, overt and covert control) and children's diet were examined by logistic regression models. After adjustment for maternal BMI, education, and diet, and children's characteristics (sex, BMI z-scores), restriction, monitoring, overt and covert control were associated with 11–18% lower odds of F&V consumption below the interval defined as adequate. Overt control was also associated with 24% higher odds of their consumption above it. Higher perceived responsibility was associated with higher odds of children consuming F&V and dairy above recommendations. Pressure to eat was positively associated with consumption of dairy above the adequate interval. Except for pressure to eat, maternal practices were associated with 14–27% lower odds of inadequate consumption of EDF. In conclusion, children whose mothers had higher levels of covert control, monitoring, and restriction were less likely to consume F&V below recommendations and EDF above tolerable limits. Higher overt control and pressure to eat were associated, respectively, with higher possibility of children consuming F&V and dairy above recommendations.

Maternal Dietary Quality Affects Breast Milk Composition

BackgroundPreviously, we have shown that breastmilk (BM) of obese (Ob) mothers has a pro‐inflammatory fatty acid (FA) profile. Nutrition provided in infancy has a profound impact on obesity risk in offspring. Maternal diet, through changes in BM composition, could also impact offspring growth. Here we use a literature‐derived population‐based Dietary Inflammatory Index (DII), a predictor of dietary inflammatory potential, to determine whether BM composition is influenced by modifiable maternal dietary factors.ObjectiveTo examine the relationship between maternal DII, BM composition and infant growth.MethodsBM was collected 4‐10 weeks post‐partum from 21 lean (BMI 18‐25kg/m2) and 21 Ob (BMI&gt;30kg/m2) women. These samples were analyzed for micronutrient and macronutrient composition. Food diaries were collected and specific food parameter estimates were used to calculate a DII for each subject. A higher DII score indicates a pro‐inflammatory diet. Infant growth was obtained at the same time point.ResultsOb women had a higher DII (p=0.059). BM from Ob mothers had a higher omega (n)‐6:n‐3 FA ratio (p&lt;0.01) compared to lean mothers. The DII was strongly positively correlated with BM saturated FA (R=0.46, p&lt;0.01), and strongly negatively correlated with BM n‐3 FA (R= ‐0.46, p&lt;0.01). BM n6:n3 was positively correlated with infant z‐score (R=0.43, p&lt;0.05). These relationships remained significant after adjustment for maternal BMI. image imageConclusionsOur study suggests that maternal diet is a major modifiable factor that affects the inflammatory composition of BM.

Gestational diabetes predicts the risk of childhood overweight and abdominal circumference independent of maternal obesity

Gestational diabetes mellitus is believed to be a risk factor for childhood overweight/obesity. We aimed to assess whether this association is either a reflection or independent of confounding by maternal BMI. Data from 7355 mother-child dyads of the German Perinatal Prevention of Obesity cohort with full anthropometric information on mothers and children, gestational diabetes and confounding factors were obtained at school entry health examination. We calculated crude and adjusted logistic regression models for the association of gestational diabetes and childhood overweight/obesity and abdominal adiposity defined by age- and sex-specific percentiles for BMI and waist circumference. Among all children (mean age 5.8 years), 8.1% were overweight, 2.6% were obese and 15.5% had abdominal adiposity. The prevalence of overweight (obesity) was 21% (8.2%) in children of mothers with gestational diabetes and 10.4% (2.4%) in children of healthy mothers. Analyses with adjustment for maternal BMI and other potential confounders yielded an odds ratio of 1.81 (95% CI 1.23-2.65) and 2.80 (95% CI 1.58-4.99) for the impact of gestational diabetes on childhood overweight and obesity, respectively. Similar results were obtained for the risk of childhood abdominal adiposity (odds ratio 1.64, 95% CI 1.16-2.33) by maternal gestational diabetes. The postulated increased risk of overweight and abdominal adiposity in offspring of mothers with gestational diabetes cannot be explained by maternal BMI alone and may be stronger for childhood obesity than for overweight.

Gestational diabetes and cardiovascular risk factors in the offspring: Results from a cross‐sectional study

While the association of gestational diabetes mellitus and abnormal glucose tolerance is beyond doubt, its associations with other cardiovascular disease risk factors in the offspring are less clearly established. Some of these associations, in particular overweight in the offspring, might be confounded by maternal overweight. Data on 12,542 children in the age of 3-17 years with full information about gestational diabetes mellitus and maternal BMI were available from the German nationwide KiGGS study. We calculated linear and logistic regression models for measurements of body composition, blood pressure, HbA(1c) and cholesterol values in the offspring with gestational diabetes mellitus as the explanatory variable, with and without adjustment for maternal BMI. The prevalence of gestational diabetes mellitus in the dataset was 2.2%. Unadjusted regression analyses suggested weak positive effects of gestational diabetes mellitus on body composition measurements [e.g. a mean increase in BMI standard deviation scores (SDS) of 0.17 units (95% confidence interval: 0.03, 0.30)]. After adjustment for maternal BMI, the observed associations almost disappeared [e.g. BMI SDS: 0.07 (-0.06, 0.20)]. With respect to blood pressure and cholesterol, no potential effects of gestational diabetes mellitus were observed in both unadjusted and adjusted models. Gestational diabetes mellitus does not appear to have a relevant effect on cardiovascular disease correlates such as blood pressure or cholesterol levels in children, and the potential effect of gestational diabetes mellitus on body composition seems to be widely explainable by maternal BMI.

C-reactive protein levels, blood pressure and the risks of gestational hypertensive complications

Aim of this study was to investigate the associations of C-reactive protein levels, as marker of low-grade inflammation, with blood pressure development during pregnancy and the risks of gestational hypertensive complications. We also explored the role of maternal BMI in these associations. High-sensitivity C-reactive protein levels were measured in early pregnancy (median 13.2 weeks, 95% range 9.6-17.6) in 5816 mothers participating in a population-based prospective cohort study in the Netherlands. Blood pressure measurements were performed in each trimester. Information about pregnancy-induced hypertension and preeclampsia was retrieved from hospital charts of the women. Longitudinal analyses showed that C-reactive protein levels were not associated with SBP and DBP patterns throughout pregnancy. Trimester-specific multivariate linear regression models showed that as compared to low C-reactive protein levels (<5.0 mg/l), elevated levels (≥20.0 mg/l) were associated with maternal SBP and DBP. Elevated C-reactive protein levels in early pregnancy were associated with the risks of pregnancy-induced hypertension [odds ratio (OR) 2.78, 95% confidence interval (CI) 1.66-4.66]. After adjustment for maternal BMI, all associations attenuated. Our results suggest that first-trimester C-reactive protein levels are associated with SBP and DBP levels throughout pregnancy and with gestational hypertensive complications, but these associations are largely explained by maternal BMI.

Hypertensive disorders during pregnancy

Hypertensive disorders during pregnancy

Gestational Diabetes and Subsequent Growth Patterns of Offspring: The National Collaborative Perinatal Project

Our objective was to test the hypothesis that intrauterine exposure to gestational diabetes [GDM] predicts childhood growth independent of the effect on infant birthweight. We conducted a prospective analysis of 28,358 mother-infant pairs who enrolled in the National Collaborative Perinatal Project between 1959 and 1965. The offspring were followed until age 7. Four hundred and eighty-four mothers (1.7%) had GDM. The mean birthweight was 3.2 kg (range 1.1-5.6 kg). Maternal characteristics (age, education, race, family income, pre-pregnancy body mass index and pregnancy weight gain) and measures of childhood growth (birthweight, weight at ages 4, and 7) differed significantly by GDM status (all P < 0.05). As expected, compared to their non-diabetic counterparts, mothers with GDM gave birth to offspring that had higher weights at birth. The offspring of mothers with GDM were larger at age 7 as indicated by greater weight, BMI and BMI z-score compared to the offspring of mothers without GDM at that age (all P < 0.05). These differences at age 7 persisted even after adjustment for infant birthweight. Furthermore, the offspring of mothers with GDM had a 61% higher odds of being overweight at age 7 compared to the offspring of mothers without GDM after adjustment for maternal BMI, pregnancy weight gain, family income, race and birthweight [OR = 1.61 (95%CI:1.07, 1.28)]. Our results indicate that maternal GDM status is associated with offspring overweight status during childhood. This relationship is only partially mediated by effects on birthweight.

242 Duration of Breastfeeding and Childhood Obesity in Australian Children: A Prospective Cohort Study

Childhood obesity is increasing in prevalence and leads to morbidity and mortality in later life. Breastfeeding has been suggested to be protective, with an estimated population attributable risk from formula feeding of 15–20%1. We examined associations between breastfeeding and body mass index BMI in a prospective cohort of 2087 Australian children entering the study at 16 to 18 weeks of gestation.Methods: Characteristics of 2,979 mothers recruited from Perth antenatal clinics between 1989 and 1992 were recorded during pregnancy and 8 years later. Children's weight and length or height were measured at birth, 1, 3, 5 and 8 years; information about breastfeeding was collected at birth, 1 and 3 years. We used NCHS standards to define overweight or obesity in 1 year-olds and the standards of Cole et al2 at 3, 5 and 8 years. Analysis excluded children born before 37 weeks gestation or with congenital abnormalities. Associations between obesity and breastfeeding duration were examined in linear and logistic regression.Findings: Surveys included 1710, 1184, 1480 and 1430 children at 1, 3, 5 and 8 years, respectively. At 8 years 19.6% of girls and 15.4% of boys were overweight or obese. Maternal obesity and smoking during pregnancy were each associated with significantly shorter breastfeeding duration; tertiary education was significantly related to longer breastfeeding duration. In multivariate regression, maternal BMI, education, smoking and parity were significant simultaneous predictors of breastfeeding duration. Breastfeeding duration was inversely related to children's BMI at 1 year (coefficient −0.031,95% CL −0.042,−0.020;p<001) with adjustment for sex, birthweight, gestational age and ethnicity, and remained significant after adjustment for maternal BMI, smoking status, age, parity and education (−0.028,95%CL −0.040,−0.016;p<0.001). Breastfeeding duration was unrelated to BMI in 3 year-olds but was a significant predictor at 5 and 8 years, although not independent of maternal factors. In logistic regression, risk of overweight or obesity at 1 year was lower with breastfeeding for at least 12 months, relative to never breastfeeding, before (OR=0.48,95% CI 0.31,0.76) or after (OR=0.37,95% CI 0.30,0.77) adjustment for maternal factors; associations were not statistically significant at 3, 5, or 8 years.Conclusion: Beyond infancy, genetic factors and health-related behaviours within families may be more influential determinants of BMI than breastfeeding history.