Spatiotemporal trends and associated factors of HIV/AIDS, syphilis, and gonorrhea incidence in China: A Bayesian disease mapping study with spatially varying coefficients.

Sexually transmitted diseases (STDs) remain a major public health concern in China. However, existing research on STDs primarily focuses on specific regions or populations, and often overlooks the spatially varying effects of associated factors. Macro-level analyses of sexually transmitted infections across China are relatively limited. This study analyzes the spatiotemporal distribution and associated factors of the three leading STDs, HIV/AIDS, syphilis, and gonorrhea, at the provincial level in mainland China from 2011 to 2020. We utilize a Bayesian disease mapping model to quantify the spatiotemporal trends of STD incidence rates, and examine their spatially varying associations with socioeconomic, sociodemographic, and meteorological factors. The results reveal distinct geographic patterns for each disease. Overall, HIV/AIDS and syphilis had an upward trend over the study period, while gonorrhea remained relatively stable, with a modest mid-period rise. HIV/AIDS was most prevalent in the southwestern provinces, syphilis was concentrated in the northwest, and gonorrhea was most common in the southeastern coastal provinces. The associations between STD incidence and selected factors exhibited substantial spatial heterogeneity and varied by disease. The primary factors associated with regional disparities in STD epidemics in China included GDP per capita, illiteracy proportion, the number of healthcare institutions, and annual average temperature. This study provides a comprehensive analytical framework for understanding the epidemic trends of STDs and their associated factors. The findings offer both scientific insights and practical guidance to policymakers for designing targeted prevention and control strategies in public health practice.