Objective: To investigate the independent associations and the possible interaction of body mass index (BMI), leisure time physical activity (LTPA) and perceived physical fitness and functional capability with the risk of mortality.
Design: Prospective 16y follow-up study.
Subjects: A regionally representative cohort of 35-63-y-old Finnish men (n= 1,090) and women (n= 1,122).
Measurements: All-cause, cardiovascular disease (CVD) and coronary heart disease (CHD) mortality were derived from the national census data until the end of September 1996 while the initial levels of BMI, LTPA, physical fitness and function were determined from self-administered questionnaires.
Results: After adjustment for age, marital and employment status, perceived health status, smoking and alcohol consumption, the Cox proportional hazards model showed that BMI was not associated with the risk of death among the men or the women. Compared with the most active subjects the men and women with no weekly vigorous activity had relative risks of 1.61 (95% confidence interval, CI, 0.98-2.64) and 4.68 (95% CI, 1.41-15.57), respectively, for CVD mortality, and for the men there was a relative risk of 1.66 (95% CI, 0.92-2.99) for CHD mortality. When compared with the men who perceived their fitness as better than their age-mates, the men with the 'worse' assessment had a relative risk of 3.29 (95% CI, 1.80-6.02) for all-cause mortality and 4.37 (95% CI, 1.80-10.6) for CVD mortality. Men with at least some difficulty in walking a distance of 2 km had a relative risk of 1.62 (95% CI, 1.05-2.50) for all-cause mortality when compared with those who had no functional difficulties. In addition, in the comparison with subjects with no functional difficulties, the men and women who had some difficulty climbing several flights of stairs had relative risks of 1.47 (95% CI, 0.97-2.23) and 2.39 (95% CI, 1.25-4.60) for all-cause mortality, respectively. For CVD mortality the relative risks were 1.85 (95% CI, 1.04-3.30) and 3.38 (1.22-9.41), respectively.
Conclusions: Although BMI did not prove to be an independent risk factor for mortality from CVD, CHD or from all causes combined, perceived physical fitness and functional capability did. An increase in LTPA seems to have a similar beneficial effect on the mortality risk of obese and nonobese men and women, and the effect also seems to be similar for fit and unfit subjects.