Modeling timing of sexual debut among women in Zimbabwe using a Geoadditive Discrete-Time survival approach

Early sexual debut has undesirable health consequences such as an increased risk of contracting sexually transmitted infections (STIs) including HIV, mental health problems, pregnancy-related complications and death including abortion-related deaths. Despite a global decline in adolescent birth rates, Zimbabwe continues to face a high prevalence of underage pregnancies, highlighting significant early sexual debut among Zimbabwean adolescents. This study examined the spatial variation and the demographic and socio-economic determinants of the timing of early sexual debut among Zimbabwean women.

Data for 9,882 Zimbabwean women of reproductive age were drawn from the 2015 Zimbabwe Demographic and Health Survey (ZDHS). We defined early sexual debut as having first sexual intercourse before the 18 years of age. A fully Bayesian geoadditive discrete-time survival model was used. Adjustments for unequal sampling probabilities were done using the provided survey weights.

Our findings show that women with primary education (aOR = 0.62,95% Crl:0.47-0.81), secondary education (aOR = 0.25,95% Crl:0.19-0.33) and higher education (aOR = 0.06,95% Crl:0.04-0.09) had lower odds of early sexual debut than those with no education. In comparison to those with middle household wealth index, women with higher household wealth index (aOR = 0.83, 95% CrI: 0.71-0.98) had lower odds of early sexual initiation. On the other hand, women with lower household wealth index had higher likelihood of early sexual debut (aOR = 1.13, 95% CrI: 1.03-1.26) than those with middle household wealth index. The type of place of residence and birth year cohort did not have a significant association with the odds of early sexual debut. The hotspots of early sexual debut were in Matabeleland North and Matabeleland South provinces.

To mitigate early sexual debut in Zimbabwe, targeted interventions are essential in Matabeleland North and Matabeleland South provinces as well as in the identified high-risk groups.