We propose to assess the effects of vigorous physical activity and cardiorespiratory fitness on the incidence of diabetes, hypertension, hypercholesterolemia, arthritis, and other chronic conditions in relation to age in a large prospective epidemiological cohort of 54,962 vigorously active men and women. Whereas most epidemiological studies treat age simply as a covariate, our analyses focus directly on the age-specific effects of exercise, fitness and body weight on disease rates. The principal investigator's twenty years of biostatistical and research experience in studies of physical activity will be applied to accomplish the following two specific aims:
Aim 1. Test whether increasing doses of vigorous physical activity and greater cardiorespiratory fitness reduce the age-specific incidence rates of diabetes, hypercholesterolemia, hypertension, angina, cardiovascular disease, stroke, arthritis, gall bladder disease, vision (cataracts, glaucoma, macular degeneration), heart rhythm abnormalities, kidney stones, and cancer.
Aim 2. Test whether age affects the reductions in disease risk associate with increasing levels of physical activity and greater cardiorespiratory fitness. Currently, a number of well-designed cohort studies are able to assess the impact of moderately intense physical activity on disease risk. The National Runners'Health Study is the only cohort specifically recruited to assess the effect of vigorous physical activity on disease risk. The study was initiated in 1991 through recruitment at foot race events and through solicitation of running magazine subscribers. The runners were recontacted between 1999 and 2000 to update their data on running, weight, diet, and medication use, and to determine whether they had any medical conditions. We obtained follow-up surveys or determined the vital status for 80% of the cohort, and obtained a National Death Index search for fatal events through 1998. Although 21 papers have been published to date on the cross-sectional relationship baseline running distance to biomarkers of cardiovascular disease risk, and on the relationship of changes in adiposity observed prospectively to exercise, except for body weight, we have not examined whether the benefits of physical activity apply equally to all age groups. We have also assessed whether the health benefits of physical activity or fitness might be better interpreted as attenuating or postponing the age-related increases in disease risk. There is no current funding to support ongoing data analyses for this important study. Assuming three weeks per manuscript, the small grant award should provide funding for six to eight additional manuscripts.
This application requests salary support for the principal investigator to apply his 20 years of biostatistical experience analyze the relationship of vigorous physical activity to the risks of hypertension, diabetes, high cholesterol, and other medical conditions among men and women of different ages. We will also examine the relationship of cardiorespiratory fitness in relationship to these diseases. This application is concerned exclusively with the analyses of pre-existing data collected as part of the National Runners'Health Study. Although 21 papers have been published to date on the results of this study, the majority of the findings remain unpublished. There is no current funding to support these analyses. This small grant award would support the analyses and preparation of six to eight additional manuscripts.
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