Practice of Epidemiology Measures of Lower Body Function and Risk of Mortality over 7 Years of Follow-up

The study examined whether a test of walking speed provides similar predictive information on mortality risk as does a summary measure of lower body function. Data were from the Hispanic Established Population for the Epidemiologic Study of the Elderly database and included Mexican Americans aged 65 years or more (1993– 2000). Primary measures included a short physical performance battery, a test of walking speed, and mortality. The average age of the sample was 72.0 years, and 58.3 percent were women. The observed hazard ratio of mortality risk was similar for the full short physical performance battery and walking speed alone, in both unadjusted and adjusted baseline models. A time-dependent walking speedmeasure showed amore than twofold increased risk of mortality for individuals categorized with slower walking speed. The results also showed a linear association between continuous walking speed and mortality with and without adjustment for baseline covariates. This study provides evidence that walking speed alone can provide similar information on mortality risk as does a more comprehensive summary measure of physical performance. Because walking speed is a quick and easy-toadminister test, findings have implications for clinical use, especially among underserved minority groups where cultural and language barriers may exist.