EARLY RISK FACTORS FOR OBESITY IN CHILDHOOD Prof. Andy Ness, Bristol, United Kingdom    - Biography English - 2007-10-07

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ackground and aims: The prevalence of childhood obesity is increasing. Pregnancy, adiposity rebound and puberty may be critical time periods. The aim of this paper is to summarize findings from the Avon Longitudinal Study of Parents and Children (ALSPAC).

Methods: Avon Longitudinal Study of Parents and Children is a prospective study investigating the health and development of children. A total of 14,541 pregnant women living in the former county of Avon with an expected delivery date between 1991 and 1992 were recruited. Detailed information has been collected from pregnancy onwards. Height and weight were measured at ages 7, 9 and 11, body composition was assessed using dual X-ray absortiometry (DXA) at ages 9 and 11 and physical activity was measured using the actigraph accelerometer at age 11.

Results: Birth weight and ponderal index at birth were both positively associated with lean mass but only ponderal index was associated with fat: lean ratio. Maternal smoking during pregnancy was associated with higher fat mass but estimates are similar for partner smoking. Breastfeeding was associated with obesity and fat mass but these estimates attenuated after adjustment. Measures of early weight and weight gain were associated with later childhood obesity. The adjusted odds ratio for obesity between top and the bottom quintiles of minutes of moderate and vigorous physical activity was 0.03 (95% CI 0.01–0.13, p for trend < 0.0001) in boys and 0.36 (95% CI 0.17–0.74, p for trend =0.006) in girls.

Conclusions: Later obesity is predicted by early weight gain. Associations with maternal smoking and breastfeeding may represent confounding. Immediate exposures like physical activity are important.