OBJECTIVE: To describe differences in the 22 y mortality risk associated with body mass index (BMI), body fat or fatfree mass, in order to examine if the differential health consequences of fat and fat-free mass may be responsible for elevated mortality rates at both high and low BMI. DESIGN: Prospective cohort study, a 22 y follow-up. SETTING: General community. The study of men born in 1913, Gothenburg. SUBJECTS: 787 men aged 60 y. MAIN OUTCOME MEASURES: Number and time of total deaths from 1973 to 1995. RESULTS: The risk of dying was a linear function of percentage fat and fat-free mass, and increased from a relative risk of 1.00 in men belonging to the lowest ®fth to 1.4 (95% con®dence interval 1.11 ± 1.99) in men in the highest ®fth of percentage fat mass. For BMI the lowest risk was observed for men belonging to the middle ®fth of BMI. When the relative risk was set at 1.00 for subjects belonging to the middle ®fth of BMI the risk associated with the low BMI ®fth was 1.3 (95% con®dence interval 0.94 ± 1.68) and that with the highest ®fth was 1.5 (95% con®dence interval 1.09 ± 1.96). Analyses including both body fat and fat-free mass showed that total mortality was a linear increasing function of high fat and low fat-free mass. CONCLUSION: The apparent U-shaped association between BMI and total mortality may be the result of compound risk functions from body fat and fat-free mass.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.