Association between internal migration and epidemic dynamics: an analysis of cause-specific mortality in Kenya and South Africa using health and demographic surveillance data

Abstract

BackgroundMany low- and middle-income countries are facing a double burden of disease with persisting high levels of infectious disease, and an increasing prevalence of non-communicable disease (NCD). Within these settings, complex processes and transitions concerning health and population are underway, altering population dynamics and patterns of disease. Understanding the mechanisms through which changing socioeconomic and environmental contexts may influence health is central to developing appropriate public health policy. Migration, which involves a change in environment and health exposure, is one such mechanism.MethodsThis study uses Competing Risk Models to examine the relationship between internal migration and premature mortality from AIDS/TB and NCDs. The analysis employs 9 to 14 years of longitudinal data from four Health and Demographic Surveillance Systems (HDSS) of the INDEPTH Network located in Kenya and South Africa (populations ranging from 71 to 223 thousand). The study tests whether the mortality of migrants converges to that of non-migrants over the period of observation, controlling for age, sex and education level.ResultsIn all four HDSS, AIDS/TB has a strong influence on overall deaths. However, in all sites the probability of premature death (45q15) due to AIDS/TB is declining in recent periods, having exceeded 0.39 in the South African sites and 0.18 in the Kenyan sites in earlier years. In general, the migration effect presents similar patterns in relation to both AIDS/TB and NCD mortality, and shows a migrant mortality disadvantage with no convergence between migrants and non-migrants over the period of observation. Return migrants to the Agincourt HDSS (South Africa) are on average four times more likely to die of AIDS/TB or NCDs than are non-migrants. In the Africa Health Research Institute (South Africa) female return migrants have approximately twice the risk of dying from AIDS/TB from the year 2004 onwards, while there is a divergence to higher AIDS/TB mortality risk amongst female migrants to the Nairobi HDSS from 2010.ConclusionResults suggest that structural socioeconomic issues, rather than epidemic dynamics are likely to be associated with differences in mortality risk by migrant status. Interventions aimed at improving recent migrant’s access to treatment may mitigate risk.Electronic supplementary materialThe online version of this article (10.1186/s12889-018-5851-5) contains supplementary material, which is available to authorized users.

Internal migration and health in South Africa: determinants of healthcare utilisation in a young adult cohort

“…It is not illuminated by the South African national census, which gives a snapshot of where people reside on census night. Many single-person or small households enumerated in urban settings are likely to be members of rural households situated elsewhere, to which they will return in times of leave or ill-health [ 24 , 58 ]. The high prevalence of temporary migration from rural households in northeast South Africa, especially for young adults, illustrated with respect to the Agincourt HDSS population, reflects a typical pattern for rural Southern Africa, yet this population remains less visible and their health challenges insufficiently understood.…”

“…South Africa’s internal migrants have a significantly higher burden of HIV compared with non-migrants and are at higher risk of HIV acquisition [ 22 , 23 ]. A longitudinal study of premature mortality among internal migrants from the African Health Research Institute and the Agincourt Health and Demographic Surveillance Systems (HDSS) revealed that return migrants to these HDSS areas had a four times higher risk of mortality from AIDS/TB and NCD as compared with permanent residents, suggesting a marked mortality disadvantage among migrants [ 24 ]. Whether suffering from a non-communicable or infectious disease (or increasingly both), individuals with chronic conditions require ongoing treatment and regular medical follow-up [ 25 ].…”

Impact of Migration of Labour Force due to Global COVID-19 Pandemic with Reference to India

“…The relationship between migration and health is found to be multidimensional and bidirectional. Health status can drive a decision to migrate, but such relocation may in turn have an influence on health (Ginsburg et al, 2018). Circular migration has further been associated with the spread of health conditions or behaviours between destination and origin areas, affecting the health status of others.…”

A training manual for event history analysis using longitudinal data

“…The well-known Cox model (semi-parametric proportional hazard model is its full name) and the less known Fine and Gray model for non-independent competing risks [11] can easily be implemented using the same micro data that we used to produce rates and probabilities. The MADIMAH team has successfully applied these methods to analyses of determinants and outcomes of demographic processes, to produce results that are comparable across diverse settings [12, 13].…”