Association between social capital and quality of life among urban residents in less developed cities of western China

China has experienced rapid urbanization over the past several decades. Social capital is considered a vital human resource, and quality of life (QoL) is an important measure of human health embedded in a physical, mental, and social context. No studies have reported on the association between social capital and QoL in Chinese urban residents. We performed a cross-sectional study to investigate social capital in urban community residents of West China, and its relationship with QoL.Our study was carried out between June and July of 2015. A total of 1136 households were surveyed. The Chinese-translated version of the Short-Form Health Survey (SF-12) and social capital questionnaire were used to evaluate people's QoL and social capital. Associations between QoL and social capital were evaluated by 3 logistic regression analyses.A total of 1136 adult participants aged 18 years and older completed the questionnaire. Young residents were more likely to have lower second (SC2), third (SC3), and fourth (SC4) dimensions of social capital. Migrants and residents with higher education levels and high incomes showed lower SC1 and SC2 relative to other participants, and employed residents had relatively low SC1. Unmarried residents had lower SC2 and SC3. Without adjustment for potential confounding factors, participants with higher SC2 had higher average scores for mental components (MCS) of QoL [odds ratio (OR) = 1.48, 95% confidence interval (95% CI): 1.09-2.02], and the same was seen for SC3 (OR = 1.70, 95% CI: 1.24-2.34). After adjusting for socioeconomic status (SES) and risk factors, SC2 and SC3 were still significantly associated with MCS. Social capital was not significantly associated with physical components of QoL in any of the 3 logistic regression models.In conclusion, social capital is related to MCS of QoL, and increasing it may be an effective way to promote health.