Measured cardiorespiratory fitness and self‐reported physical activity: associations with cancer risk and death in a long‐term prospective cohort study
OBJECTIVES Large epidemiological studies of non-smokers have demonstrated an association between overweight during midlife and increased mortality. However, little is known about whether this association may be explained by physical fitness. Thus, we aimed to examine this association in a long-term follow-up, with adjustment for fitness. METHODS We prospectively studied mortality in relation to overweight in 2014 healthy Norwegian men 40-59 years of age at enrollment in 1972-1975, and recorded cardiovascular and non-cardiovascular mortality during 25-27 years follow-up. Physical fitness was measured in a maximal exercise tolerance bicycle test. RESULTS At baseline 717 men had overweight (body mass index 25.0-29.9) and 1221 had normal weight (body mass index<25.0). During follow-up 746 men died, 377 from cardiovascular causes. Among non-smokers with overweight/normal weight, cardiovascular death rates were 19.4%/11.3%, and non-cardiovascular death rates were 13.2%/14.4%. Overweight was related to cardiovascular mortality, even after adjustment for age, physical fitness, blood pressure and cholesterol level (RR: 1.52, p=0.010), but not to non-cardiovascular mortality (RR: 0.84, p=0.32). Among smokers overweight was not associated with cardiovascular or non-cardiovascular mortality. The difference in cardiovascular mortality between non-smokers with overweight and normal weight first appeared after 15 years of follow-up. CONCLUSION Overweight appears to be an independent long-term predictor of cardiovascular mortality in middle-aged healthy non-smoking men, even after adjustment for physical fitness.