Four-Year Lower Extremity Disability Trajectories Among African American Men and Women

Abstract

Background. We examined 4-year lower extremity disability trajectories. Methods. Nine hundred ninety-eight African American men and women 49–65 years old were evaluated at baseline and at four annual follow-ups. Lower extremity disability was the number of difficulties with nine standard activities of daily living (ADL), instrumental ADLs (IADL), and lower body function items. Mixed-effect models were used. Results. The 9-item lower extremity disability measure had factorial validity and high reliability (α > 0.88). The mean baseline lower extremity disability score was 2.43, and at the subsequent follow-ups it was 2.23, 2.35, 2.60, and 2.70. The mixed-effect model included significant random intercept and aging effects. Fixed factors with the largest effect sizes (all p ≤.001) were physical performance (−0.238 lower extremity disabilities per point on the Short Physical Performance Battery [SPPB]), fear of falling (1.094), poor or fair self-rated health (0.735), self-reported arthritis (0.659), clinically relevant levels of depression symptoms (0.641), body mass index (0.047 per kg/m² unit), aging (0.082 per year), and asthma (0.558). Conclusions. To improve lower extremity disability trajectories among African Americans, interventions should focus on improving SPPB scores. In addition, fear of falling, poor or fair self-rated health, and clinically relevant levels of depression symptoms should be considered potential intervention candidates warranting further evaluation.