title: Obesity, leanness, and mortality: effect modification by physical activity in men and women.
abstract: The 13-year mortality from BMI, body fat (BF), and fat-free mass (FFM) was examined among active and sedentary adults. In total, 2,819 men and women aged 35-65 years in 1987/1988, participating in the Danish MONICA project, were included, and followed for 13.6 years for total mortality. In men, physical activity modified the health hazard of both a high and a low BMI, and the U-shaped association disappeared among the active (hazard ratio (HR) = 0.86, CI: 0.72-1.02). Among active men, FFM was inversely related to mortality (HR = 0.55, 95% CI: 0.40-0.77) whereas a direct positive trend was seen for BF. Among women, physical activity modified association between BMI and mortality, but the U-shaped association remained among the active. Among women, no significant associations were found between either BF or FFM and total mortality. All effects were independent of waist- and hip-circumferences. In conclusion, among men, physical activity may play an important role for the prevention of early mortality beyond its direct effects, by modifying the health hazard of both a high and a low BMI, and by lowering the risk associated with a high BF or a low FFM. Among women physical activity lowers mortality, but an effect-modifying potential of physical activity on associations between BMI or body composition could not be identified.
authors.affiliation: Research Unit for Dietary Studies, Institute of Preventive Medicine, Copenhagen University Hospital, Copenhagen, Denmark. blh@ipm.regionh.dk
authors.forename: Berit L
authors.initials: BL
authors.lastname: Heitmann
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Hills
authors.forename: Peder
authors.initials: P
authors.lastname: Frederiksen
authors.forename: Leigh C
authors.initials: LC
authors.lastname: Ward
mesh_terms: D000328:Adult; D001823:Body Composition; D049628:Body Size; D017097:Electric Impedance; D015444:Exercise; D005260:Female; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009765:Obesity / Q000401:mortality* / Q000503:physiopathology* / Q000517:prevention & control*; D016016:Proportional Hazards Models; D011795:Surveys and Questionnaires; D015996:Survival Rate; D013851:Thinness / Q000401:mortality* / Q000503:physiopathology*