Risk factors for curable sexually transmitted infections among youth: findings from the STICH population survey in Zimbabwe

Objectives: Youth are at high risk of sexually transmitted infections (STIs) in Africa. We aimed to determine the risk factors for curable STIs in youth in Zimbabwe.

Methods: A population-based survey was conducted among randomly selected 18-24 year-olds in 16 communities across two provinces in Zimbabwe to ascertain outcomes for a cluster randomised trial investigating the impact of community-based STI screening for youth on population prevalence of STIs. Participants underwent an interviewer-administered questionnaire, HIV testing and screening for Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Trichomonas vaginalis (TV). Risk factors for curable STIs were explored through multivariable logistic regression.

Results: Of the 5601 participants, 62.5% (n=3500) were female, and the median age was 20 (IQR 19-22) years. HIV prevalence was 6.3% (351/5556), and 55.4% (1939/3501) reported condomless sex at last intercourse. Only 7.2% (401/5599) reported STI symptoms, but CT/NG/TV prevalence was 19.8% (1107/5601). On multivariable analysis, factors associated with STI diagnosis included being aged 21-24 years (adjusted OR (aOR) 1.37, 95% CI 1.17 to 1.61); female sex (aOR 2.11, 95% CI 1.76 to 2.53); being unemployed/informally employed (compared with in education/formal employment) (aOR 1.35, 95% CI 1.13 to 1.61); increasing number of sexual partners in the preceding 12 months (one partner: aOR 2.23, 95% CI 1.73 to 2.88; two partners: aOR 2.39, 95% CI 1.69 to 3.39); living with HIV (aOR 1.44, 95% CI 1.07 to 1.94); and previous attempted suicide (aOR 1.58, 95% CI 1.08 to 2.32).

Conclusions: The prevalence of STIs among youth in Zimbabwe is high, particularly among those with HIV. In addition to moving away from syndromic STI management and strengthening implementation of existing prevention tools, there is a need for a more holistic focus on broader risk factors such as mental health and employment opportunities, and of integration of HIV and STI programming.

Trial registration number: ISRCTN15013425, NCT03719521.