Individual- and community-level neighbor relationships and physical activity among older Japanese adults living in a metropolitan area: a cross-sectional multilevel analysis

Background: Informal neighbor relationships (NRs) are considered a structural aspect of social relationships. Although NRs might affect physical activity (PA), no previous study has simultaneously examined compositional and contextual associations of NRs with PA. In this study, we examined whether individual-and community-level NRs were independently associated with PA. Methods: We analyzed cross-sectional data from 8592 (4340 men and 4252 women) non-disabled residents aged 65-84 years from all 18 districts of Ota City, Tokyo. PA was assessed by using the International Physical Activity Questionnaire-Short Form. In addition, we calculated moderate-to-vigorous PA (MVPA), its components (vigorous PA [VPA], moderate PA [MPA], and walking time [WT]), and sitting time (ST). Individual-level NRs were categorized as "visiting each other," "standing and chatting," "exchange of greetings," or "none." Community-level NRs were defined as the proportions of residents with active NRs (i.e., those in the categories visiting each other and standing and chatting) in the 18 districts. Using multilevel regression analyses, we examined independent associations of individual-and community-level NRs with PA variables and adjusted for important confounders. Results: Individual-level NRs were consistently positively associated with MVPA and its components (VPA, MPA [in men], and WT) in both sexes, and the dose-response relationships were significant (all P < 0.041 for trend). In men, community-level NRs (by 1% estimation) were positively associated with individual MVPA (2.1 metabolic equivalent-hours/week, 95% confidence interval: 0.7-3.4), VPA (8.6 min/week, 2.7-14.4), and WT (11.6 min/week, 2.2-20.9), regardless of the degree of individual-level NRs. Significant cross-level interactions of NRs with MVPA and VPA were observed among men, and the dose-response relationships were significant (both P < 0.037 for trend). Neither individual- nor community-level NRs were associated with ST in either sex. Conclusions: Men and women with inaccessible neighbors engaged in less MVPA, while men living in communities with active NRs engaged in more MVPA, regardless of individual-level NRs. NRs at the individual and community level might help prevent physical inactivity among men.