Combined early and adult life risk factor associations for mid-life obesity in a prospective birth cohort: assessing potential public health impact.

OBJECTIVE: The combined effect of life-course influences on obesity development and thus their potential public health impact is unclear. We evaluated combined associations and predicted probabilities for early and adult life risk factors with central and general obesity in mid-adulthood. SETTING: 1958 British birth cohort. PARTICIPANTS: 4629 males and 4670 females with data on waist circumference. OUTCOME MEASURES: 45 year obesity measured via waist circumference, waist-hip ratio (WHR) and BMI. RESULTS: At 45 years, approximately a third of the population were centrally obese and a quarter were generally obese. Three factors (parental overweight, maternal smoking during pregnancy and adult inactivity) were consistently associated with central and general obesity. Predicted probabilities for waist obesity increased from those with none to all three risk factors (0.15-0.33 in men; 0.19-0.39 in women (ptrend