Body mass index and mortality among US male physicians

Purpose To assess the relationship between body mass index and mortality in a population homogeneous in educational attainment and socioeconomic status. Methods We analyzed the association between body mass index (BMI) and both all-cause and cause-specific mortality among 85,078 men aged 40 to 84 years from the Physiciansʹ Health Study enrollment cohort. Results During 5 years of follow-up, we documented 2856 deaths (including 1212 due to cardiovascular diseases and 891 due to cancer). In age-adjusted analyses, we observed a U-shaped relation between BMI and all-cause mortality; among men who never smoked a linear relation was observed with no increase in mortality among leaner men (P for trend, <0.001). Among never smokers, in multivariate analyses adjusted for age, alcohol intake, and physical activity, the relative risks of all-cause mortality increased in a stepwise fashion with increasing BMI. Excluding the first 2 years of follow-up further strengthened the association (multivariate relative risks, from BMI<20 to greater-or-equal, slanted30 kg/m2, were 0.93, 1.00, 1.00, 1.16, 1.45, and 1.71 [P for trend, <0.001]). In all age strata (40–54, 55–69, and 70–84 years), never smokers with BMIs of 30 or greater had approximately a 70% increased risk of death compared with the referent group (BMI 22.5–24.9). Higher levels of BMI were also strongly related to increased risk of cardiovascular mortality, regardless of physical activity level (P for trend, <0.01). Conclusions All-cause and cardiovascular mortality was directly related to BMI among middle-aged and elderly men. Advancing age did not attenuate the increased risk of death associated with obesity. Lean men (BMI<20) did not have excess mortality, regardless of age.