Objective The objective of this paper is to examine the association between marital status and the risk of HIV infection in the informal settlements of Nairobi. The findings from this study will inform HIV prevention programs, particularly among poor and marginalised groups in the informal settlements.

Methods Data are derived from a cross-sectional population-based survey nested in an ongoing Demographic Surveillance System (DSS) in two urban informal settlements in Nairobi city, where a total of about 60 000 individuals living 23 000 households are under surveillance. Descriptive statistics and multivariate logistic regression analysis were used to describe the characteristics of the sample, as well as to assess the association between marital status and risk of HIV infection.

Results The HIV prevalence of respondents who were divorced, separated or widowed was 27%, among those who were married was 12%, and among those who were never married was 5%. Married respondents (OR=1.78; p value<0.05) and those who were divorced, separated or widowed (OR=4.06; p value<0.001) were significantly more likely to be infected with HIV compared to respondents who were never married. Circumcision was also a significant predictor of HIV infection. Men who were circumcised (OR=0.36; p value<0.05) were less likely to be HIV positive compared to those who were not circumcised.

Conclusion There is need for HIV prevention interventions to adopt a more targeted approach, particularly with regard to designing and implementing programs geared towards addressing the increased risk of HIV infection among married people and those who were formerly married.