Walking and the 2-year risk of functional decline: An observational study of US adults with arthritis.

Recent studies of middle age and older adults with, or at risk for, arthritis demonstrate that engaging in physical activities like walking - even at levels below the current aerobic physical activity guideline of ≥150 min of moderate-intensity activity - can protect against onset of functional limitations. Using a large nationally representative sample of US adults ≥18 years with arthritis, we investigated whether, among those not meeting the aerobic activity guideline, walking ≥10 min/week vs. <10 min/week reduced the risk of six outcomes (fair/poor health and five physical limitations) over 2 years. We conducted a prospective cohort study among adults with arthritis in the 2010 National Health Interview Survey who participated in the 2011-2012 Medical Expenditure Panel Survey (n = 1426). Among adults not meeting the guideline, we examined the effect of walking on risk of developing each of six outcomes using hazard ratios (HRs) estimated from multivariable Cox regression models. Among adults with arthritis not meeting the guideline, compared to walking <10 min/week, walking ≥10 min/week was associated with a statistically significant decreased risk for all five limitations: walking three blocks (HR: 0.3 [95% CI = 0.2-0.6]), climbing 10 stairs (HR: 0.5 [95% CI = 0.3-0.8]), stooping/kneeling (HR: 0.4 [95% CI = 0.2-0.8]), reaching overhead (HR: 0.5[95% CI = 0.5-0.8]), and grasping (HR: 0.4 [95% CI = 0.2-0.7]). The decrease in risk was not significant for fair/poor health. Even limited walking may prevent the onset of physical limitations among adults with arthritis of all ages not meeting the aerobic activity guideline.