Health and social inequities among cisgender gay and bisexual men in Japan: a nationwide cross-sectional study using a large-scale web-based survey

Gay and bisexual men (GBM) face elevated risks of hypertension, diabetes, and depression, but these conditions are strongly influenced by social discrimination, economic disadvantage, and recreational substance use, complicating their interpretation. This study aimed to compare the social, lifestyle, and health characteristics of GBM with those of heterosexual men in Japan, where epidemiological data remain limited. We analyzed data from the 2022 wave of the Japan COVID-19 and Society Internet Survey (JACSIS), a large-scale, web-based nationwide survey. Participants were classified as heterosexual, gay, or bisexual according to reported sexual attraction. Inverse probability weighting was applied to estimate population-level prevalence. Multivariable logistic regression was performed to examine associations between sexual orientation and lifestyle-related diseases, recreational substance use, and depression. Among 13,271 eligible men, 830 (6.3%) identified as GBM (721 gay, 109 bisexual); the weighted prevalence was 6.6% (95% CI: 5.9–7.4%). GBM were more likely to report burden from night shift work (27.5% [228/830] vs. 15.9% [1,979/12,441], p < 0.001), workplace harassment (27.7% [185/667] vs. 12.2% [1,185/9,676], p < 0.001), fear of job loss (31.8% [212/667] vs. 22.1% [2,142/9,676], p < 0.001), receipt of public assistance (1.2% [10/830] vs. 0.3% [43/12,441], p < 0.001), and experience of recreational substance use (12.9% [107/830] vs. 4.1% [505/12,441], p < 0.001). Among participants under 50 years, GBM tended to have higher prevalence of hypertension (9.6% [49/508] vs. 5.2% [346/6,626]) and diabetes (6.7% [34/508] vs. 2.5% [168/6,626]), but these associations were not significant after adjustment (hypertension: gay aOR 1.20, 95% CI: 0.91–1.59; bisexual aOR 1.70, 95% CI: 0.89–3.25; diabetes: gay aOR 0.95, 95% CI: 0.65–1.39; bisexual aOR 1.46, 95% CI: 0.60–3.53). Depression was more common among GBM (7.2% [60/830] vs. 3.4% [417/12,441], p < 0.001), but not statistically significant among gay men (gay aOR 1.15 [0.76–1.75], bisexual aOR 2.34 [1.08–5.09]). GBM in Japan showed higher self-reported prevalence of depression, hypertension, and diabetes, particularly among men aged under 50, although these differences were attenuated in multivariable analysis. These findings highlight the importance of social and occupational contexts and recreational substance use when considering health disparities among GBM.