The impact of free subway passes on the social relationships and mental health of urban older people: A segmented regression analysis.

Objective: This study aimed to examine the impact of free subway passes (FSP) on the social relationships and mental health of urban older people.

Study Design: Segmented regression analysis METHODS: We studied data from the 2019 Korea Community Health Surveys, looking at 38,205 participants aged over 45 in metropolitan areas without activity limitations. The intervention group comprised residents of Ulsan, a city without a subway system and thus not eligible for the FSP policy. The control group included residents of five metropolitans and capital city with subway systems where FSP are available. We used controlled segmented regression analysis to explore how FSP influenced satisfaction with public transportation, social connections, social participation, and mental health (measured by Patient Health Questionnaire-9, PHQ-9 as a proxy variable).

Results: Satisfaction of transportation and social participation of people who reside in metropolitan without FSP was likely to decrease more than people in metropolitan with FSP and capital city (model 1: satisfaction of transportation estimate 0.941; 95 % CI 0.909-0.974, social participation estimate 0.983; 95 % CI 0.969-0.998, model 2: satisfaction of transportation estimate 0.935; 95 % CI 0.899-0.973, social participation estimate 0.979; 95 % CI 0.964-0.994). And people who reside in metropolitan without FSP had marginally increasing PHQ-9 score compared to metropolitan with FSP and capital city (model 1: PHQ-9 score estimate 1.009; 95 % CI 0.999-1.018, model 2: PHQ-9 score estimate 1.007; 95 % CI 0.997-1.018).

Conclusion: FSP use might promote social participation and be marginally associated with reduced depressive symptoms among older adults. Further research is needed to explore the effects of FPS and other public transportation subsidies. The findings of this study might serve as important evidence for developing public transportation policies in other communities.