Social capital and use of assisted reproductive technology in young couples: Ecological study using application information for government subsidies in Japan

BACKGROUND: Assisted reproductive technology (ART) is a globally established treatment; however, large disparities exist in ART use among young couples. We investigated regional-level factors associated with ART use in Japan. METHODS: We calculated the use rate of ART using the number of women aged <35 years who applied for government subsidies in 2017; we divided that figure by the number of women aged 20–35 years in each prefecture. Prefectural-level average household income; social capital indicators including voting rate, volunteer rate, and move-in rate; and Gini coefficients as indicators of income inequality were linked to ART use, adjusting for prefectural size, the mean age of women at first marriage, number of ART facilities, and additional prefectural subsidies. RESULTS: The rate of ART use (per 10,000 women) varied significantly from 22.0 to 58.8 across Japan's 47 prefectures. Multivariate analysis demonstrated that the use rate increased by 0.048 (95% confidence interval [CI], 0.007 to 0.088) for each 10,000-yen increase in average household income and 1.5 (95% CI, 0.65 to 2.3) for each 1% increase in volunteer rate. Conversely, the use rate decreased by 18.4 (95% CI, −28.6 to −8.1) for each 1% increase in the move-in rate. There was no significant association between ART use and income inequality. CONCLUSION: Although we cannot infer causal relationships, the findings suggest that improving financial access and enhancing social capital may increase access to ART. Further research, particularly multilevel analysis using individual data, is required to confirm these findings.