Relation of Physical Activity to Cardiovascular Disease Mortality and the Influence of Cardiometabolic Risk Factors

Physical activity can improve several metabolic risk factors associated with cardiovascular disease (CVD) and is associated with a lower risk of CVD mortality. We sought to evaluate the extent to which metabolic risk factors mediate the association between physical activity and CVD mortality and whether physical activity provides protective effects against CVD mortality in healthy adults and those with metabolic risk factors. A sample of 10,261 adults from the Third National Health and Nutrition Examination Survey with public-access mortality data linkage (follow-up 13.4 +/- 3.9 years) was used. Physical activity was assessed by questionnaire and classified into inactive, light, and moderate/vigorous activity categories. Metabolic risk factors (dyslipidemia, type 2 diabetes mellitus, obesity, hypertension, inflammation, and insulin resistance) were categorized using clinical thresholds. After adjusting for basic confounders, engaging in light or moderate/vigorous physical activity was associated with a lower risk of CVD mortality (p <0.05). Adjustment for each risk-factor set only slightly attenuated this relation. When all risk-factor sets were added to the model simultaneously, light (hazard ratio 0.72, 0.62 to 0.84) and moderate/vigorous (hazard ratio 0.72, 0.62 to 0.85) activity remained at lower risk of CVD mortality. In addition, physical activity provided protective effects for CVD mortality in healthy subjects and those with metabolic risk factors in isolation or in clusters. In conclusion, physical activity was associated with a lower risk of CVD mortality independent of traditional and inflammatory risk factors. Taken together these results suggest that physical activity may protect against CVD mortality regardless of the presence of metabolic risk factors. (C) 2011 Elsevier Inc. All rights reserved. (Am J Cardiol 2011;108:1426-1431)