Background Age at first sex (AFS) is associated with adverse outcomes. We explore associated factors and correlates of 'early' AFS (<16 years).
Methods: In 2009-11, participants (16-29 years) were recruited. Multivariate Cox regression explored correlates of AFS. Logistic regression analysis explored associations between early AFS and risk behaviours.
Results: Of 3563 participants, 79% were sexually active. Median AFS was 17 years. Compared with those aged 25-29 years, younger participants reported younger AFS [16-17 years: adjusted hazard ratio (AHR)=1.87, P<0.01; 18-19 years: AHR=1.47, P<0.01, 20-24 years: AHR=1.19, P<0.01]. Of those sexually active, 29% reported early AFS. Early AFS was associated with being male [adjusted odds ratio (AOR)=1.25, P<0.05], being younger (16-17 years: AOR=11.10, P<0.01; 18-19 years: AOR=3.60, P<0.01; 20-24 years: AOR=1.83, P<0.01; compared with 25-29 years), having no education after high school (AOR=1.52, P<0.01), living alone (AOR=1.84, P<0.01) or with a partner (AOR=1.57, P=0.01), having more than five lifetime sex partners (AOR=3.22, P=0.01), inconsistent condom use in the past 12 months (AOR=1.43, P<0.01), ever using illicit drugs (AOR=1.69, P<0.01) and ever injecting drugs (AOR=3.45, P<0.01).
Conclusions: The results highlight the importance of comprehensive sex education.