Combined Effects Of Cardiorespiratory Fitness, Not Smoking, And Normal Waist Girth On Morbidity And Mortality

Abstract

Physical inactivity, cigarette smoking, and obesity are key modifiable risk factors for coronary heart disease (CHD). Little is known about the relations between these combined risk factors and incident CHD and mortality. PURPOSE: We investigated the combined effects of cardiorespiratory fitness, not smoking, and normal waist girth on incident CHD and mortalities from cardiovascular disease (CVD), cancer, and all causes in men. METHODS: We followed 40,397 men, ages 20-79 yr, who completed a medical evaluation including a maximal treadmill exercise test and self-reported health habits at baseline examination. We defined a low-risk profile as not smoking, moderate- or high-fitness, and normal waist girth (<94 cm), respectively. The combined low-risk group was defined as satisfying all three above factors. There were 1,147 incident CHD (fatal and nonfatal CHD events) and 2,682 deaths (862 CVD, 985 cancers, and 835 others) during an average of 17.8 yr of follow-up (717,404 man-yr). RESULTS: After adjustment for age, examination year, alcohol intake, and family history of CHD, men who were at low-risk for these 3 factors had 70% lower risk of incident CHD (95% CI: 57%, 79%), 84% lower risk of CVD mortality (95% CI: 77%, 89%), 72% lower risk of cancer mortality (95% CI: 58%, 81%), and 75% lower risk of all-cause mortality (95% CI: 69%, 80%), respectively, as compared with men who had none of these low-risk factors (all p for trend <0.001). Associations persisted after additional adjustment for hypertension, diabetes, and high cholesterol (all p for trend <0.001). The CHD events in this population might have been reduced by 20% (95% CI: 11%, 29%) if they had been physically fit, not smoking, and had normal waist girth. Men with all three exposures had 2.2 times the risk of CHD (95% CI: 1.52, 3.09 p<0.001) compared with men with none of theses risk factors. This was equivalent to being 10.4 years older in chronological age. CONCLUSIONS: Moderate and high levels of cardiorespiratory fitness, not smoking, and normal waist girth are associated with a reduced risk of incident CHD and much lower mortality from CVD, cancer, and all causes in men.