Migration, urbanisation and mortality: 5-year longitudinal analysis of the PERU MIGRANT study

OBJECTIVE: To compare all-cause and cause-specific mortality among 3 distinct groups: within-country, rural-to-urban migrants, and rural and urban dwellers in a longitudinal cohort in Peru. METHODS: The PERU MIGRANT Study, a longitudinal cohort study, used an age-stratified and sex-stratified random sample of urban dwellers in a shanty town community in the capital city of Peru, rural dwellers in the Andes, and migrants from the Andes to the shanty town community. Participants underwent a questionnaire and anthropomorphic measurements at a baseline evaluation in 2007-2008 and at a follow-up visit in 2012-2013. Mortality was determined by death certificate or family interview. RESULTS: Of the 989 participants evaluated at baseline, 928 (94%) were evaluated at follow-up (mean age 48 years; 53% female). The mean follow-up time was 5.1 years, totalling 4732.8 person-years. In a multivariable survival model, and relative to urban dwellers, migrant participants had lower all cause mortality (HR=0.30; 95% CI 0.12-0.78), and both the migrant (HR=0.07; 95% CI 0.01-0.41) and rural (HR=0.06; 95% CI 0.01-0.62) groups had lower cardiovascular mortality. CONCLUSIONS: Cardiovascular mortality of migrants remains similar to that of the rural group, suggesting that rural-to-urban migrants do not appear to catch up with urban mortality in spite of having a more urban cardiovascular risk factor profile.