Does maternal smoking during pregnancy cause childhood overweight?
The objective of this study was to examine a possible association between maternal smoking in pregnancy and childhood overweight. From a population-based cohort of 5722 women from Trondheim, Bergen (Norway) and Uppsala (Sweden) enrolled in early pregnancy during 1986-92, a random sample of 482 women was selected for participation. They were followed up throughout pregnancy, and their children from birth until 5 years of age. Data on maternal smoking and diet, socio-economic determinants and breast feeding were recorded prospectively. During pregnancy and childhood, anthropometric measures were also recorded. Maternal smoking status was based on reported number of cigarettes smoked in week 17 of pregnancy. Child overweight was defined by body mass index (BMI) and sum of skinfold thickness (SFT) >or= 85th percentile at 5 years of age. Children of mothers who smoked in pregnancy had increased risk of overweight at 5 years of age (RR 2.5, 95% CI 1.5, 4.2 for BMI; and RR 1.8, 95% CI 1.1, 3.
