Migration and HIV-1 seroprevalence in a rural Ugandan population

To study the association between change of residence and HIV-1 serostatus in a rural Ugandan population.

A longitudinal cohort study.

As part of the annual surveillance of a population cohort of approximately 10,000 individuals in a rural subcounty of southwest Uganda, information has been collected for all adults on change of residence over a 3-year period and its association with HIV-1 serostatus. Sera were collected by a medical team during home visits. Antibody testing was performed at the Uganda Virus Research Institute using two independent enzyme immunoassay systems and Western blot when appropriate.

At the fourth survey-round, age and sex-standardized seroprevalence rates were 7.9% overall; the rate was 5.5% for 2,129 adults who had not changed address since the first survey, 8.2% for 336 who moved within the village, 12.4% for 128 who moved to a neighbouring village, 11.5% for 1,130 who had left the area and 16.3% for 541 who had joined the study area during the previous 3 years (P << 0.001, 4 degrees of freedom). We also observed an inverse relationship between years lived at the present house at the time of the first survey and both seroprevalence and subsequent seroincidence rates. The reported numbers of lifetime sexual partners were higher in those who changed residence.

Change of residence is strongly associated with an increased risk of HIV-1 infection in this rural population and is likely to be the result of more risky sexual behaviour among those who move. These findings have important implications for the design of AIDS control programmes and intervention studies.