Differences in cardiovascular risk factors in rural, urban and rural-to-urban migrants in Peru

Objectives: To assess differences in cardiovascular risk profiles among rural-to-urban migrants and non-migrant groups. Methods: Cross-sectional study in Ayacucho and Lima, Peru. Participants were: rural (n=201); rural-to-urban migrants (n=589); and urban (n=199). Cardiovascular risk factors were assessed according to migrant status (migrants vs non-migrants), age at first migration, length of residency in an urban area and lifetime exposure to an urban area. Results: For most risk factors, the migrant group had intermediate levels of risk between those observed for the rural and urban groups. Prevalence for rural, migrant and urban groups was 3%, 20% and 33%, respectively, for obesity, and 0.8%, 3% and 6% for type-2 diabetes. This gradient of risk was not observed uniformly across all risk factors. Blood pressure did not show a clear gradient of difference between groups. The migrant group had similar systolic blood pressure but lower diastolic blood pressure than the rural group. The urban group had higher systolic blood pressure but similar diastolic blood pressure than rural group. Hypertension was more prevalent among the urban (29%) than both the rural and migrant groups (11% and 16%, respectively). For HbA _1c, although the urban group had higher levels, the migrant and rural groups were similar to each other. No differences were observed in triglycerides between the three groups. Within migrants, those who migrated when aged older than 12 years had higher odds of diabetes, impaired fasting glucose and metabolic syndrome compared to people who migrated at younger ages. Adjustment for age, sex and socioeconomic indicators had little impact on the patterns observed. Conclusions: The impact of rural-to-urban migration on cardiovascular risk profile is not uniform across different risk factors, and is further influenced by the age at which migration occurs. A gradient in levels was observed for some risk factors across study groups. This observation indicates that urbanisation is indeed detrimental to cardiovascular health.