Identifying the relationship between physical and social activity and disability among community-dwelling older adults may provide important information for implementing tailored interventions to prevent disability progression. The aim of this study was to determine the effect of the number of social activities on the relationship between walking habits and disability incidence in older adults. We included 2873 older adults (mean age, 73.1 years; SD, ±5.9 years) from the National Center for Geriatrics and Gerontology-Study of Geriatric Syndromes. Baseline measurements, including frequencies of physical and social activities, health conditions, physical function, cognitive function, metabolic parameters, and other potential disability risk factors (for example, the number of years of education); monthly assessment for disability was monitored through long-term care insurance certification for at least 2 years from baseline. During a mean follow-up of 35.1 months (SD, 6.4 months), 133 participants developed disability. The disability incidence was 19.0 and 27.9 per 1000 person-years for participants who walked more (≥3 times per week) and less (≤3 times per week) frequently, respectively. The potential confounding factor-adjusted disability hazard ratio was 0.67 (95% confidence interval, 0.46 to 0.96; p = 0.030). The relationship between habitual walking and the number of social activities was statistically significant (p = 0.004). The reduction of disability risk by walking was greater among participants with fewer social activities. Habitual walking was associated with disability incidence, with a more pronounced effect among older adults who were less likely to engage in social activities.
Keywords: disability; older adults; social activity; walking habits.