Body mass index in early and mid-adulthood, and subsequent mortality: a historical cohort study

BACKGROUND: The aim of this study was to investigate the associations between body mass index (BMI) in early and mid-adulthood, and BMI change between these ages, and mortality. METHODS: Historical cohort study of 629 men, who had height and weight measured at the Student Health Service of the University of Glasgow in 1948 - 1949 ( median age 22 y) and who reported their weight in a postal questionnaire in 1963 - 1966 ( median age 38 y). The participants were followed up until April 2002 ( mean follow-up: 35 y). During this time, 124 men died, 68 of cardiovascular disease (CVD) and 33 of cancer. FINDINGS: Mean BMI increased from 21.4 kg/m(2) ( standard deviation (s.d.): 2.2 kg/m(2)) in early adulthood to 24.2 kg/m(2) (s.d.: 3.0 kg/m(2)) in mid-adulthood. All-cause mortality was associated with being overweight (BMI greater than or equal to 25 kg/m(2)) at age 22 but not at age 38, adjusted hazard ratio (HR): 1.85 (95% confidence interval (CI) 1.09 - 3.13) and 1.05 (95% CI: 0.73 - 1.52), respectively. BMI at age 22 y was more strongly associated with CVD mortality than was BMI at age 38 y, adjusted HR22 y: 2.41 (95% CI: 1.26 - 4.60) and HR38 y: 1.33 (95% CI: 0.82 - 2.16). There was no clear relationship between cancer mortality and BMI at either age: HR22 y: 0.68 (95% CI: 0.16 - 2.91), HR38 y: 0.90 (95% CI: 0.44 - 1.84), although relatively few men died of cancer in the follow-up period. Similar patterns were seen for obesity (BMI greater than or equal to30 kg/m(2)) as for being overweight. Analyses of weight patterns indicated particularly detrimental effects of overweight persisting from early to mid-adulthood. CONCLUSIONS: BMI in early adulthood is positively related to CVD mortality in later life in men. The risk associated with early adulthood adiposity appeared to be greater than that in mid-adulthood. We did not demonstrate an association between weight gain and later mortality. These results reinforce the need to stem the obesity epidemic in children and young adults.