RUNNING AND THE DEVELOPMENT OF DISABILITY WITH AGE

Objective: To determine, by longitudinal study, whether regular vigoro us running activity is associated with accelerated, unchanged, or post poned development of disability with increasing age. Study Design: 8-y ear prospective, longitudinal study with yearly assessments. Participa nts: 451 members of a runners' club and 330 community controls who wer e initially 50 to 72 years old (also characterized as ''ever-runners'' [n = 534] and ''never-runners'' [n = 247], respectively). Measurement s: The dependent variable was disability as assessed by the Health Ass essment Questionnaire and separately validated in these participant co horts. Covariates included age, sex, body mass index, comorbid conditi ons, education level, smoking history, alcohol intake, mean blood pres sure, initial disability level, family history of arthritis, and radio logic evidence of osteoarthritis of the knee in a subsample. Results: Initially, the runners were leaner, reported joint symptoms less frequ ently, took fewer medications, had fewer medical problems, and had few er instances of and less severity of disability, suggesting either tha t the average previous 12 years of running had improved health or that self-selection bias was present. After 8 years of longitudinal study, the differences in initial disability levels (0.026 compared with 0.0 79; P < 0.001) had steadily increased to 0.071 for runners compared wi th 0.242 for controls (P < 0.001). The difference was consistent for m en and women. The rate of development of disability was several times lower in the runners' club members than in community controls; this di fference persisted after adjusting for age, sex, body mass, baseline d isability, smoking history, history of arthritis, or other comorbid co nditions (slopes of progression of disability for the years 1984 to 19 92, after adjusting for covariates: men in the runners' club, 0.004 [S E, 0.002]; community controls, 0.012 [SE, 0.002]; women in the runners ' club, 0.009 [SE, 0.005]; community controls, 0.027 [SE, 0.004]; P < 0.002 for both sets of comparisons). In addition to differences in dis ability, there were significant differences in mortality between the r unners' club members (1.49%) and community controls (7.09%) (P < 0.001 ). These differences remained significant after adjusting for age, sex , body mass, comorbid conditions, education level, smoking history, al cohol intake, and mean blood pressure (P < 0.002, conditional risk rat io for community controls compared with the runners, 4.27; 95% CI, 1.7 8 to 10.26). Conclusions: Older persons who engage in vigorous running and other aerobic activities have lower mortality and slower developm ent of disability than do members of the general population. This asso ciation is probably related to increased aerobic activity, strength, f itness, and increased organ reserve rather than to an effect of postpo ned osteoarthritis development.