Dobra, A., Bärnighausen, T., Vandormael, A., et al. AIDS (January 2017), 31(1):137–145. doi:10.1097/QAD.0000000000001292.
This population-based cohort study examined the causal relationship between patterns of mobility and risk of HIV acquisition in rural KwaZulu-Natal, South Africa. The study used data (2004–2014) from a demographic information system of the Africa Health Research Institute, along with complete geolocated residential histories. The study geolocated 8,006 migration events for 17,743 individuals with two recorded HIV tests (who were HIV-negative at baseline). Findings showed that even relatively short migration activities substantially increased HIV risk for both men and women. The risk of acquiring HIV infection increased by 50 percent for distances of 40 kilometers (men) and 109 kilometers (women). Those who spent larger periods of time outside the study site were at a significantly higher risk of acquiring HIV; risk increased by 50 percent when participants spent 44 percent (men) and 90 percent (women) of their time outside the community. Distances and periods of residence outside the study area served as proxies for HIV risk factors (increased number of sexual partners, increased likelihood of risky sexual behavior, separation from social networks, increased vulnerability, or lower socioeconomic status). The authors said that this was the first study they knew of that employed complete geolocated residential histories to quantify the space–time dimensions of mobility in relationship to HIV acquisition risks, and noted the potential usefulness of this methodological approach.