Background: There is increasing recognition that the in utero environment might influence obesity risk.
Objective and Hypotheses: We explored the hypothesis that smoking and alcohol consumption in pregnancy are associated with offspring body composition using the Southampton Womens Survey mother-offspring birth cohort study.
Method: At 34 weeks gestation, maternal smoking and any alcohol intake in the preceding 12 weeks were determined by interview. At birth and 6 years of age, body composition was assessed by whole body DXA.
Results: 1075 children were assessed at 6 years; 474 of these children also had a DXA at birth. 11% of mothers had smoked, and 77% consumed alcohol. The relationships between maternal smoking and offspring body composition differed between birth and 6 years: at birth, infants of smokers weighed less (β=−0.30SD, P=0.001) and were less adipose (total fat mass (FM) β=−0.43SD, P=0.005; %FM: β=−0.41SD P=0.006). In contrast, at 6 years, children of smokers were heavier (β=0.31SD, P=0.001) and had greater total FM (β=0.36SD, P<0.0001) and %FM (β=0.38SD, P<0.0001). Total lean mass (LM) was also higher, but %LM lower. Although offspring body composition at birth did not differ by maternal alcohol intake, at 6 years, the associations contrasted with those observed with smoking. Thus, offspring of mothers who had consumed alcohol were of similar weight, but had greater LM (β=0.23, P=0.002) and %LM (β=0.15SD, P=0.052) than children of mothers who abstained. Total FM was similar. These associations were robust to mutual adjustment and for multiple maternal and offspring confounders.
Conclusion: Offspring of mothers who smoked in late pregnancy were lighter at birth, but heavier and more adipose at 6 years of age. In contrast, offspring of mothers who consumed alcohol had greater LM at 6 years. The underlying mechanisms are unknown, but could result from a combination of long-lasting epigenetic modifications during the perinatal period, and postnatal environmental factors.
20 - 22 Sep 2014
European Society for Paediatric Endocrinology