A prospective study of adiposity and all-cause mortality: The Malmo diet and cancer study

Objective: This study aims to examine the association between various measures of adiposity and all-cause mortality in Swedish middle-aged and older men and women and, additionally, to describe the influences of age and sex on these associations. Research Methods and Procedures: A prospective analysis was performed in a cohort of 10,902 men and 16,814 women ages 45 to 73 years who participated in the Malmo Diet and Cancer Study in Sweden. Baseline examinations took place between 1991 and 1996, and 982 deaths were documented during an average follow-up of 5.7 years. All-cause mortality was related to the following variables measured at baseline: body mass index (BMI), percentage of body fat, lean body mass (LBM), and waist-to-hip ratio (WHR), with adjustment for age and selected covariates. Body composition data were derived from bioelectrical impedance analysis. Results: The association between percentage of body fat and mortality was modified by age, particularly in women. For instance, fatness was associated with excess mortality in the younger women but with reduced mortality in the older women. Weaker associations were seen for BMI than for percentage of body fat in both sexes. Placement in the top quintiles of waist-to-hip ratio, independent of overall body fat, was a stronger predictor of mortality in women than in men. The observed associations could not be explained by bias from early death or antecedent disease. Discussion: The findings reveal sex and age differences for the effects of adiposity and WHR on mortality and indicate the importance of considering direct measures of adiposity, as opposed to BMI, when describing obesity-related mortality risks.