Maternal, birth, and early-life influences on adult body size in women.

The authors conducted a follow-up study of 261 women born during 1959-1965 (38% White, 40% African-American, and 22% Latina) to investigate whether maternal and infant factors are independently associated with adult body size after accounting for childhood growth. Standard statistical methods (linear regression and logistic regression) were compared with quantile regression methods to assess the independent effect maternal factors (body mass index (BMI; weight (kg)/height (m)(2)), maternal weight gain), birth measures (birth weight, placental weight), and early infancy and childhood growth measures (birth-4 months, 4 months-1 year, and 1-7 years) have on predicting adult body size. While most of these factors were important predictors of BMI at age 20 years, the size and relative importance of the effect differed across models. For example, maternal weight gain was associated with being overweight (BMI > or = 25) at age 20 years (per 10-pound (4.5-kg) change, odds ratio = 1.65, 95% confidence interval: 1.11, 2.44) and was associated with the upper quantiles (>/=75th percentile) of BMI at age 20 years. In contrast, maternal BMI and birth weight were relatively more important for lower quantiles, particularly at age 40 years. Only rapid growth from ages 1 to 7 years was an important predictor of adult BMI at both age 20 and age 40, irrespective of statistical model. However, the persistence of effects of maternal and infant factors on adult BMI, even after rapid childhood growth is accounted for, suggests a greater need to investigate these early-life influences and whether their impact differs for smaller and larger women.