Social role to predict functional disability among community-dwelling older adults in Japan

BACKGROUND: Social factors have been associated with the level of functional disability, particularly in frail older adults. However, limited evidence exists regarding comparative social role of older adults in community settings. PURPOSE: The purpose of this study was to identify the risk of functional disability associated with the status of social role in community-dwelling older adults in Japan. METHODS: A propensity score-adjusted prospective cohort design. The study population included all older adults (aged ≥70 years) who participated a geriatric health examination during July 2004 to July 2005. We followed their functional disability by the occurrence of new long-term care needs certification from 2004 to 2010. The Cox proportional hazard regression model was used to evaluate the risk of functional disability during the follow-up period. Participants were selected by propensity scores adjusting the multiple covariates, and were categorized into the matching groups. RESULTS: A total of 1291 participants were identified in the study cohort: 20.3% (262/1291) was newly presence of functional disability, and 10.5% (136/1291) died before applying for long-term care needs certification. After adjusting for propensity scores and other covariates, the Cox proportional hazard model revealed that social role [Hazard ratio 1.6; 95% Confidential interval 1.6, 2.0] was associated with a decrease in the risk of functional disability. CONCLUSIONS: The study suggested that high status of social role was associated with a moderately lower risk of functional disability in older adults. We need an assessment that takes social role into consideration to appropriately identify the risks related to functional disability.