Dimensions of internal migration and their relationship to blood pressure in South Africa

Hypertension incidence among middle-aged and older adults: findings from a 5-year prospective study in rural South Africa, 2010-2015

OBJECTIVES

There is a scarcity of longitudinal cohort studies in sub-Saharan Africa to understand the epidemiology of cardiovascular disease as a basis for intervention. We estimated incident hypertension and associated sociodemographic, health and behavioural risk factors in a population aged 40 years and older over a 5-year period.

DESIGN

We assessed the association between incident hypertension and sociodemographic, health and behavioural factors using Poisson regression. We adjusted for non-response in 2015 using inverse probability sampling weights from a logistic regression including sex and age at baseline.

SETTING

Rural South Africa.

PARTICIPANTS

We used a population-based cohort of normotensive adults in 2010 who were aged 40 years and older at retest in 2015.

RESULTS

Of 676 individuals completing baseline and 5-year follow-up, there were 193 incident cases of hypertension. The overall hypertension incidence rate was 8.374/100 person-years. In multivariable analyses, those who became hypertensive were more likely to be older, have a high waist circumference (incidence rate ratio (IRR): 1.557, 95% CI: 1.074 to 2.259) and be employed (IRR: 1.579, 95% CI: 1.071 to 2.329) at baseline. Being HIV positive and not on antiretroviral therapy at baseline was associated with lower risk of incident hypertension.

CONCLUSIONS

Over a 5-year period, 29% of respondents developed hypertension. Given the high burden of hypertension in South Africa, continued longitudinal follow-up is needed to understand the complex interplay of non-communicable and infectious diseases and their underlying and modifiable risk factors to inform public health prevention strategies and programmes.

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

BACKGROUND

In South Africa, human geographic mobility is high as people engage in both permanent and temporary relocation, predominantly from rural to urban areas. Such mobility can compromise healthcare access and utilisation. The objective of this paper is to explore healthcare utilisation and its determinants in a cohort of internal migrants and permanent residents (non-migrants) originating from the Agincourt sub-district in South Africa's rural northeast.

METHODS

A 5-year cohort study of 3800 individuals aged 18 to 40 commenced in 2017. Baseline data have been collected from 1764 Agincourt residents and 1334 temporary, mostly urban-based, migrants, and are analysed using bivariate analyses, logistic and multinomial regression models, and propensity score matching analysis.

RESULTS

Health service utilisation differs sharply by migrant status and sex. Among those with a chronic condition, migrants had 0.33 times the odds of non-migrants to have consulted a health service in the preceding year, and males had 0.32 times the odds of females of having used health services. Of those who utilised services, migration status was further associated with the type of healthcare utilised, with 97% of non-migrant rural residents having accessed government facilities, while large proportions of migrants (31%) utilised private health services or consulted traditional healers (25%) in migrant destinations. The multinomial logistic regression analysis indicated that, in the presence of controls, migrants had 8.12 the relative risk of non-migrants for utilising private healthcare (versus the government-services-only reference category), and 2.40 the relative risk of non-migrants for using a combination of public and private sector facilities. These findings of differential utilisation hold under statistical adjustment for relevant controls and for underlying propensity to migrate.

CONCLUSIONS

Migrants and non-migrants in the study population in South Africa were found to utilise health services differently, both in overall use and in the type of healthcare consulted. The study helps improve upon the limited stock of knowledge on how migrants interface with healthcare systems in low and middle-income country settings. Findings can assist in guiding policies and programmes to be directed more effectively to the populations most in need, and to drive locally adapted approaches to universal health coverage.

Internal migration, urban living, and non-communicable disease risk in South Africa

This paper offers theoretical and substantive contributions to migration-health scholarship by employing rich panel data with biomarkers to estimate the effect of migration and urban living on non-communicable disease risk in South Africa. Internal migration and urbanization continue to be pervasive demographic and socio-economic phenomena that structure daily life in low- and middle- income countries (LMICs). Yet, how these processes affect illness and disease in low-resource settings is still not well understood. Five waves (2008-2017) of South Africa's National Income Dynamics Study data and fixed-effects modeling are used to estimate the relationship between urban residence, migration, and health. Results indicate that the migration-health relationship differs by gender: urban living for men is associated with lower blood pressure. While urban residence appears to convey a health advantage when men reside in urban compared with rural places, there is no evidence of an urban health advantage among women. Migration does, however, negatively affect women's health through higher blood pressure (BP). These findings highlight the need for further interrogation of the ways in which processes and health consequences of migration and urban living are structured by gender in LMICs. Given the importance of urbanization and the prevalence of migration in LMICs, the gendered determinants of blood pressure may be key to understanding rising hypertension incidence in contexts like South Africa.