CARDIORESPIRATORY FITNESS AS A PREDICTOR OF ALZHEIMER??S DISEASE MORTALITY

Abstract

Alzheimer's disease is the most common cause of dementia and affects 4 million people in the United States. A few studies have examined nongenetic risk factors for Alzheimer's disease such as diabetes, hypercholesterolemia, and hypertension. We are not aware of any studies that have examined Alzheimer's disease and cardiorespiratory fitness (CRF). PURPOSE To examine the effect of CRF as a predictor of Alzheimer's disease mortality in men and women. METHODS We followed 40,733 men and 13,258 women (aged 20–89 years at baseline) for up to 26 years. All participants completed a preventive health examination at the Cooper Clinic in Dallas, Texas during 1970–1996. CRF, calculated as METs, was measured by a maximal exercise test on a treadmill. Mortality surveillance was conducted principally through the National Death Index. We documented 41 Alzheimer's disease deaths during 665,090 person-years of observation. We used Cox proportional hazards models to evaluate CRF as a predictor of Alzheimer's disease mortality after adjustment for age, examination year, smoking habit, gender, and health status. RESULTS Older age was a significant predictor of increased Alzheimer's disease mortality. Male gender was nonsignificantly associated with greater risk. For each 1-MET increment in CRF, there was a 17% (95% CI, 0.4% to 30%) lower risk of Alzheimer's disease mortality. CONCLUSION CRF was inversely associated with Alzheimer's disease mortality in men and women. Supported in part by NIH grant AG06945.