Syphilis prevalence and risk factors among young men presenting to the Brazilian Army in 2016: Results from a national survey

The Conscripts Survey has been conducted periodically by the Brazilian Department of Sexually Transmitted Infections (STIs), AIDS, and Viral Hepatitis (DIAHV) in collaboration with the Brazilian Ministry of Defense for over 2 decades. It aims to assess the syphilis prevalence and obtain data on knowledge regarding STIs and their risk factors among conscripts enlisted for the Brazilian Army. This cross-sectional study was conducted among conscripts across Brazil aged 17 to 22 years from August to December 2016. It included a self-reported questionnaire and blood testing for syphilis, HIV, and hepatitis B and C. In total 38,247 conscripts were enrolled; after exclusion due to a lack of information, 37,282 (93.2%) conscripts were included. The estimated syphilis prevalence rates were: 1.63%, 1.09%, and 0.62% for screened, confirmed, and active syphilis, respectively. Among those with active syphilis, 81.1% reported not having syphilis infection in their lifetime. Higher confirmed syphilis prevalence rates were observed in the South region, followed by North and Southeast regions. Independent factors associated with confirmed syphilis infection were: self-reported STIs in one's lifetime (odds ratio [OR] = 7.24; P < .001), same-sex sexual relationships (OR = 3.43; P = .001), and having the 1st sexual intercourse encounter before 15 years of age (OR = 2.62; P = .04). The proportion of conscripts who reported having sex with other men (MSM) was 4.3%, and the estimated syphilis prevalence in this group was 5.23%, 4.61%, and 3.60% for screened, confirmed, and active syphilis, respectively. The sexual behaviors most frequently associated with confirmed syphilis were: sexual relationship with casual partners in the last year (P < .001), same-sex sexual relationships (P < .001), more than 10 partners (P = .006), and having sexual intercourse before 15 years of age (P = .003). Although not significant, only 25.4% of the conscripts who had a confirmed syphilis reported the use of condoms with steady partners, 32.4% with casual partner, and 24.3% with any partner. We found that syphilis is on the rise among the young Brazilian male population. The increase in its prevalence, particularly among MSM, highlights the need for urgent public health interventions, action plans, and implementation of risk reduction strategies aimed at this population.