Association between choices of transportation means and instrumental activities of daily living: observational cohort study of community-dwelling older adults

INTRODUCTION: The association between the physical health of older people and the frequency of going out has been reported, and in recent years, local governments have developed transportation support programs for older people. Although previous studies show an association between the frequency of going out and functional health status, little has been reported on the impact of the choice of means of transport on instrumental activities of daily living (IADL). OBJECTIVE: To evaluate the association between choice of transportation means and the risk of decline in IADL among older adults. METHODS: We conducted an observational, population (community-dwelling)-based cohort study using data from the Resident Health Status Survey, and longitudinal panel data at 2-time points in 2016 and 2019. In addition, we combined this panel data and a database on people who were certified as requiring long-term care to identify participants’ IADL. The propensity score matching method was used to classify the respondents into two groups, “active means of transportation” and “passive means of transportation,“ and determine the risk of a decline in means-tested independence after 3 years. RESULTS: Active means were used by 6,280 (76.2%) and passive means were used by 1,865 (22.6%). 999 (12.1%) individuals declined in IADL in 2019. The results of the comparison by balancing the attributes of “active means of transportation” and “passive means of transportation,“ with propensity score matching, showed that “passive means of transportation” were more likely to be “active” than “passive means of transportation,“ and “active” was more likely to be “passive” The risk of IADL decline was significantly higher than that of “active means of transportation” with an RR of 1.93 (95% CI: 1.62–2.30). CONCLUSION: Passive means of transportation in older adults could be a possible risk for decreasing IADL 3 years later. Increasing the number of opportunities and places in the community for older adults to use active means of transportation may be effective in encouraging socially independent living among older adults.