Introduction The patterns of sexual partnering and structure of sexual networks should shape HIV transmission in human populations. We examined the empirical association between population casual-sex behaviour and HIV prevalence, and the empirical associations between different measures of casual-sex behaviour.

Methods An ecologic study design was applied to the nationally-representative data of the Demographic and Health Surveys in 25 countries in sub-Saharan Africa. Spearman rank correlation was used to assess the association between HIV prevalence and means and variances of the number of casual-sex partners. Spearman rank correlation was also used to assess the associations between the different means, different variances, and means and variances of the number of casual-sex partners.

Results Correlations between HIV prevalence and means and variances of the number of casual-sex partners were positive, but small and statistically insignificant. The majority of correlations across means and variances of the number of casual-sex partners were positive, large, and statistically significant. However, all correlations between the means, as well as variances, and the variance of unmarried females were weak and statistically insignificant. Population casual-sex behaviour was not predictive of HIV prevalence across these African countries. Nevertheless, the strong correlations across means and variances suggest that self-reported sexual data are self-consistent and may convey credible information.

Conclusion Self-reported population sexual behaviour was not found predictive of HIV prevalence, but appears inherently self-consistent and with valid information content. Unmarried female behaviour seems puzzling, but could be playing an influential role in HIV transmission patterns.

Disclosure of interest statement No pharmaceutical grants were received in the development of this study.