Predicting adult obesity from measures in earlier life.

BACKGROUND: As most obese adults were not overweight as children, the prediction of adult obesity from childhood body size alone is limited. We constructed a two-way, multifactor risk assessment framework for predicting adult obesity during childhood using the Foresight Obesity System Map and tested it against longitudinal data from the 1958 National Child Development Study.
METHODS: The framework divided study participants according to two categories of risk: 'conditioning factors' (past/fixed events and conditions) and 'intervention factors' (present and modifiable). At the age of 11 years, conditioning factors were 'low/high birth weight' and 'absence of breastfeeding', and intervention factors were 'low childhood activity level' and 'having at least one obese parent'. From a composite score of all four variables, study participants were assigned to one of the four risk groups: low risk, past 'conditioning' risk only, present 'intervention' risk only and high combined risk. ORs and relative risks for the development of future overweight/obesity at ages 23, 33 and 42 years were calculated for each risk group.
RESULTS: Those identified in the highest risk category at the age of 11 were around twice as likely to become overweight (body mass index (BMI)≥25 kg/m(2)) by the age of 23 years, and obese (BMI≥30 kg/m(2)) by ages 33 and 42 years, in comparison to their low-risk peers (total sample, N=11 752). Increased prevalence of future obesity was also observed for high-risk children who were not already overweight at the age of 11 (filtered sample, N=9549).
CONCLUSIONS: This framework identifies a greater proportion of the population that is at risk for future obesity than does childhood weight assessment alone.