PG-7 Association between early sexual debut and risk of HIV and bacterial STIs among men who have sex with men in Nigeria
Authors: Mitchell Andrew , Crowell Trevor , Omari Habib , Ndembi Nicaise , Liu Hongjie , Baral Stefan , Charurat Man , Nowak Rebecca 
Published: April 2019

Introduction:
Younger age at first anal intercourse (AFAI) has been identified as an early indicator of sexual risk-taking and behaviors that occur in the early stages of sexual initiation may persist into adulthood. In sub-Saharan Africa, men who have sex with men (MSM) at a young age may establish long-term behaviors that heighten risk for HIV and sexually transmitted infections (STIs). The objective of this cross-sectional study was to characterize AFAI among Nigerian MSM and to evaluate younger AFAI as a risk factor for HIV and STI infections.

Methods:
From March 2013 to March 2018, TRUST/RV368 recruited MSM into HIV care and treatment in Abuja and Lagos, Nigeria, using respondent-driven sampling (RDS). Comprehensive structured instruments and HIV/STI testing were administered at baseline and quarterly. Men with a reported AFAI and HIV/STI diagnostic results were included in the analysis (n = 1396). AFAI was categorized as younger (≤15 years) and older (≥16 years). Demographics and behavioral differences by AFAI were evaluated using Rao-Scott χ2 tests. Crude and adjusted odds ratios (ORs) for prevalent HIV, Neisseria gonorrhea (NG), and Chlamydia trachomatis (CT) by AFAI were calculated using logistic regression. Multivariate models controlled for demographic characteristics that were significantly associated with AFAI.

Results:
Median AFAI was 17 years (interquartile range [IQR] 15–20] and median age of participants was 24 years (IQR 21–27). Four hundred and forty-eight (448; 32.1%) MSM with younger AFAI were younger at enrollment, less educated, self-identified as homosexual or female-gendered, reported more male partners, more receptive partnerships, had a history of condomless anal sex, and engaged in transactional sex within the past year (all P ≤ 0.01). The first sexual partner was primarily male and self-reporting of forced sex was higher among MSM with younger AFAI (all P ≤ 0.01). Poor mental health and limited access to health services were not associated with younger AFAI (all P > 0.05). In the crude analysis, prevalent HIV (OR 1.20; 95% CI: 0.8 to 1.7) did not differ by AFAI. NG (OR 2.13; 95% CI: 1.0 to 4.5) and CT (OR 1.40; 95% CI: 1.0 to 1.9) prevalence was higher among those MSM with younger AFAI. Adjustment for demographic correlates of AFAI diminished associations of prevalent NG (OR 1.76; 95% CI: 0.9 to 3.6) and CT (OR 1.23; 95% CI: 0.9 to 1.6) with younger AFAI. HIV prevalence trended higher for those with younger AFAI (OR 1.31; 95% CI: 1.0 to 1.9) as compared to older in the multivariate analysis.

Conclusions:
Younger AFAI was strongly associated with recent reporting of condomless sex, receptive anal sex, and multiple partnerships. If these findings are attributed to pattern-forming sexual practices adopted in adolescence, younger AFAI may be indicative of a group at high risk for HIV and STIs. Accessible sexual health education for these young men may promote lasting, safer same-sex practices and reduce the prevalence of HIV and STIs.