Development and Validation of a Health-Related Social Capital Instrument for Older People.

Background: Health-related social capital refers to the social resources that individuals can obtain in social networks that affect health behaviors and outcomes. Social capital significantly influences health and is linked to health outcomes in older adults. However, there are few social capital scales to capture the resources of health in older people. Objective: This study aims to develop and validate a health-related social capital scale for older people, with initial development and testing conducted in the Chinese sample. Methods: The scale was developed through a multi-stage process. First, a systematic literature review of social capital and aging literature combined with the focus group discussion informed the generation of an initial 33-item pool. Two rounds of consultation with a panel of 14 experts (in health policy and health management, health behavior, sociology, and public health) refined these items for relevance and clarity, comprising four dimensions with 26 items. A validation study was then conducted to finalize the instrument. A web-based cross-sectional study was conducted in Shanxi Province from December 2022 to February 2023. A total of 505 participants were recruited, and 473 valid questionnaires were retained. Participants' mean age was 66.73 (SD=6.81) and around half of the sample was female (52.60%). Classical Test Theory(CTT) including item analysis, Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA), and reliability (Cronbach's α, McDonald's ω and composite reliability (CR)) and validity (convergent, discriminant, external, content) test were used to select items and evaluate the measurement properties of the final instrument. Results: The final health-related social capital scale consists of 12 items across four dimensions: social network, participation, trust, and support. Each dimension demonstrated strong reliability, with Cronbach's α, McDonald's ω, and composite reliability all exceeding 0.7, with social trust dimension demonstrating the highest reliability. EFA revealed that these four factors explained 60.215% of the variance. CFA confirmed the scale's structural validity and model fit. The Average Variance Extracted (AVE) ranged from 0.538 to 0.629, indicating good convergent validity, while Heterotrait-Monotrait ratio of correlations(HTMT) between 0.174 and 0.397 suggested acceptable discriminant validity. Regression analyses supported the scale's external validity. Content validity was strong, with item-level indices (I-CVI) from 0.923 to 1.00 and scale-level indices (S-CVI/UA of 0.800 and S-CVI/Ave of 0.958). Conclusion: This scale is reliable, valid, and can effectively assess older people's social capital related to health. Although developed and initially validated in China, its theoretical dimensions are designed to be cross-culturally relevant. Further studies are recommended to test and adapt the scale in diverse cultural and geographical settings.