The Association Between Syphilis Incidence and Dating App Use in Japan

Abstract

Background: The cause of the syphilis resurgence in Japan is uncertain. hypothesized that the spread of mobile dating apps use might have contributed to it. Methods: retrieved the number of reported cases of syphilis, human immunodeficiency virus infection, carbapenem-resistant enterococcus infection, registered foreigners, the total person-lodging days for foreigners for 100,000 general population at the prefectural level in 2017. also obtained the use rate of three major dating app in each prefecture. performed association analyses between them. Findings: The median number of the syphilis cases per 100,000 general population was 2.34 (range 0.72 to 12.90). The values of correlation coefficients between the number of syphilis cases and the number of app users were 0.76 (95% CI 0.60 to 0.86) for App 1, 0.74 (95% CI 0.58 to 0.85) for App 2, and 0.64 (95% CI 0.44 to 0.79) for App 3. The value of correlation coefficient between the number of syphilis cases and the number of registered foreigners was 0.50 (95% CI 0.25 to 0.69) and that between the number of syphilis cases and total person-lodging days for foreigners was 0.14 (95% CI -0.15 to 0.41). Interpretation: The number of dating app users was closely associated with the increase in the number of cases with syphilis. Information concerning the use of social media should be included in future studies on transmission and prevention of sexually-transmitted infections. Funding Statement: The authors declare: We have not received any external funds. Declaration of Interests: KY receives personal fees from Nagatanien and Rohto Pharmaceutical, outside the submitted work. EK receives personal fees from Daiichi-Sankyo, outside the submitted work. TT receives personal fees from MNES Inc., outside the submitted work. Other authors have no potential conflicts of interest to disclose. Ethics Approval Statement: The authors declare: Institutional review board approval was not required because we used publicly available and anonymized data only.