Background and objectives: Body mass index (BMI) in adolescence may be of particular importance as a predictor of future risk of coronary heart disease (CHD). Associations measured either in childhood or in middle age have appeared to be weaker or non-existent. We investigated the association between BMI measured in adolescence and CHD, and also stroke, among middle aged Swedish men and controlled for potential confounders not included in previous studies.
Methods: Data on BMI, smoking and blood pressure (diastolic and systolic) was collected from 49,321 Swedish males, born during 1949-1951, at conscription for military service in 1969/70. Census data on socioeconomic indicators in childhood and adulthood was linked to the cohort. The men were followed from 1991 through 2004 in national registers with regard to mortality and hospitalization from CHD and stroke.
Results: A graded increase of CHD was seen in over six levels of BMI (BMI<18.5, hazard ratio (HR)=1.0, BMI=18.5-20.99 (reference category), BMI=21-22.99, HR=1.2; BMI=23-24.99, HR=1.5; BMI=25-29.99, HR=2.5; BMI > or =30, HR=4.3). A graded association between BMI and stroke was also found, although weaker. Adjustments for cardiovascular risk factors (smoking, diastolic and systolic blood pressure, and early cardiovascular mortality in parents) attenuated the relative risks to some extent, whereas adjustments for socioeconomic indicators in childhood and adulthood had minor effects.
Conclusion: The results strongly suggest that BMI in late adolescence is an important predictor of both CHD and stroke among men before age 55 years, independent of smoking, hypertension and early cardiovascular mortality in parents.