Effects of intergenerational contact on social capital in community-dwelling adults aged 25–84 years: a non-randomized community-based intervention

Abstract

Background Accumulating social capital in urban areas is essential to improve community health. Previous studies suggested that intergenerational contact may be effective for enhancing social capital. However, no study has examined the effect of intergenerational contact on social capital through a population-based evaluation. This study aimed to investigate the effects of a community-based intervention to increase the frequency of intergenerational contact on social capital among adults aged 25–84 years. Methods This study used a non-randomized controlled trial design to conduct a community-based intervention (from March 2016 to March 2019). The study area was Tama ward, Kawasaki city, Kanagawa, Japan. The area comprises five districts; one district was assigned as the intervention group and the other four districts as the control group. We provided the intervention to residents in the intervention group. The intervention comprised three phases: Phase 1 was the preparation term (organizing the project committee); Phase 2 was the implementation term (trained volunteer staff members, conducted the intergenerational greeting campaign, and held intergenerational contact events); and Phase 3 was the transition term (surrendering the lead role of the project to the city hall field workers). In the control group, field workers provided public health services as usual. We conducted mail surveys in September 2016 and November 2018 to assess the effects of the intervention on social capital during Phase 2. Eligible participants were randomly selected from community-dwelling adults aged 25–84 years according to age (10,620 control group individuals and 4479 intervention group individuals). We evaluated social trust, norm of reciprocity, and social support as outcome variables. Results In total, 2518 participants completed both surveys and were analyzed (control group: 1727; intervention group: 791). We found that social trust (coefficient = 0.065; 95% confidence interval [CI]: 0.006, 0.125) and norm of reciprocity (coefficient = 0.084; 95% CI: 0.020, 0.149) positively changed in the intervention group compared with the control group. Conclusions This community-based intervention may contribute to sustaining and improving social capital among community-dwelling adults. Trial registration: UMIN000046769 (UMIN-CTR); first registered on January 28, 2022 (retrospectively registered).

The Impact of Generativity on Maintaining Higher-Level Functional Capacity of Older Adults: A Longitudinal Study in Japan

“…The Tama Ward is a typical commuter city in the western suburb of the Tokyo metropolitan area, with a total population of 205,275 and an aging rate of 19% as of 2016. As the initial purpose of this longitudinal study was to assess the effects of community-based interventions on increasing social capital and generativity among residents in the two wards, one district in both the Kita and Tama wards was assigned as the intervention area and the remaining districts as control areas [20]. However, the current study aimed to examine the association between generativity and HLFC decline among older adults and not the effects of the intervention programs.…”

“…Outcomes were defined as the maintenance or decline in HLFC between the baseline and follow-up surveys. HLFC was evaluated using the total score of the Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC), a 13-item index designed to measure HLFC above ADL, based on Lawton's model [20]. The response to each item was scored as 0 for "unable to do" and 1 for "able to do" (ranging from 0 to 13), with higher scores representing greater independence.…”