HIV-1 infection as a risk factor for the development of tuberculosis: a case-control study in Tanzania.

ABSTRACT

PIP: This population-based case-control study in Mwanza Region of Tanzania determined the relative and population-attributable risk of HIV-1 infection for developing active tuberculosis (TB). 441 TB patients aged 15-54 years were considered as cases. 4161 controls constituting a representative population sample were drawn in a stratified cluster sample from urban areas, roadside settlements, and rural villages. HIV-1 was identified among 23.0% of cases in rural, 32.1% in roadside, and 54.1% in urban areas. HIV-1 prevalences among controls were 3.4%, 7.2%, and 12.1%, respectively. The relative risk of HIV infection for the development of active tuberculosis is estimated to be 8.3 with little variation by sex or residence. Risk did, however, seem to be more evident in the age group of 25.34 years. The case detection rate of TB among individuals aged 15-54 years was 125/100,000 people per year. Further, the population-attributable risk was found to be 36/100,000 people per year; this implies that 29% of current TB cases may be attributable to HIV-1 infection. The authors conclude that HIV-1 infection is a major contributing factor to the increased case detection rate of TB observed over the past 10 years in Mwanza Region and that the incidence of TB should continue to increase along with that for HIV-1. Efforts should therefore be made to maintain a high cure rate for TB in the interest of preventing an increased risk of TB infection among HIV-1 infected and uninfected people.