Space time migration patterns and risk of HIV acquisition in rural South Africa
Objective: To quantify the space time dimensions of human mobility in relationship to the risk of HIV acquisition. Methods: We used data from the population cohort located in a high HIV prevalence, rural population in KwaZulu Natal, South Africa (2000 2014) We geolocated 8006 migration events (representing 1 028 782 km traveled) for 17 743 individuals =15 years of age) who were HIV negative at baseline and followed up these individuals for HIV acquisition (70 395 person years) Based on the complete geolocated residential history of every individual in this cohort, we constructed two detailed time varying migration indices. We then used interval censored Cox proportional hazards models to quantify the relationship between the migration indices and the risk of HIV acquisition. Results: In total, 17.4% of participants migrated at least once outside the rural study community during the period of observation (median migration distance 107.1 km, interquartile range 18.9 387.5) The two migration indices were highly predictive of hazard of HIV acquisition (P 0.01) in both men and women. Holding other factors equal, the risk of acquiring HIV infection increased by 50% for migration distances of 40 km (men) and 109 km (women) HIV acquisition risk also increased by 50% when participants spent 44% (men) and 90% (women) of their respective time outside the rural study community. Conclusion: This in depth analysis of a population cohort in a rural sub Saharan African population has revealed a clear nonlinear relationship between distance migrated and HIV acquisition. Our findings show that even relatively short distance migration events confer substantial additional risk of acquisition.
AIDS