Association of body mass index measured in childhood, adolescence, and young adulthood with risk of ischemic heart disease and stroke: findings from 3 historical cohort studies

Background: It is unclear whether early life body mass index (BMI; in kg/[m.sup.2]) is associated with adult cardiovascular disease. Objective: The objective was to assess the association of early life BMI with the risk of ischemic heart disease (IHD) and stroke. Design: The association between early life BMI and risk of adult mortality from IHD and stroke was assessed in 3 historical cohort studies in which height and weight had been assessed by using standard procedures. Participants were traced and linked to national mortality data. Participants in the 3 cohorts were born between 1922 and 1937, 1927 and 1956, and 1928 and 1950 and were aged 2-15, 9-18, and 16-22 y, respectively, at the time of assessment of their height and weight. Results: Participants in all 3 cohorts had mean BMIs similar to those reported for contemporary children and young adults, but fewer of the cohort participants were overweight or obese. BMI was not associated with future risk of IHD or stroke in any cohort. The pooled (all 3 cohorts) adjusted hazard ratio per SD of early life BMI was 1.09 (95% CI: 1.01, 1.19) for IHD and 0.94 (95% CI: 0.82, 1.08) for stroke. The pooled hazard ratio of IHD when participants who were overweight or obese for their age were compared with all other participants was 1.34 (95% CI: 0.95, 1.91), and no association was found between overweight or obesity and stroke risk. The effects of BMI did not vary by cohort or by age. Conclusion: These results do not provide strong evidence that being overweight or obese in childhood is associated with future cardiovascular disease risk. KEY WORDS Body mass index, childhood, cardiovascular disease, life-course epidemiology