Browsing by Author "Michael J. White"

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    Dimensions of internal migration and their relationship to blood pressure in South Africa
    (2019-11) Chantel F. Pheiffer; Stephen T. McGarvey; Carren Ginsburg; Mark Collinson; F. Xavier Gómez-Olivé; Stephen Tollman; Michael J. White
    Hypertension prevalence is on the rise in low and middle income countries like South Africa, and migration and concomitant urbanization are often considered to be associated with this rise. However, relatively little is known about the relationship between blood pressure (BP) and internal migration - a highly prevalent population process in LMICs. This study employs data for a group of 194 adult men and women from an original pilot dataset drawn from the Agincourt Health and Demographic Surveillance System in northeast South Africa. Migrants in the sample are identified, tracked, and interviewed. The relationship between BP and migration distance and the number of months an individual spends away from his/her home village is estimated using robust OLS regression, controlling for a series of socioeconomic, health, and behavioral characteristics. This study finds migrants who move further distances and for longer durations to have significantly higher systolic and diastolic BP compared with shorter-term migrants and those who remain nearby or in their home village. These associations remain robust and statistically significant when adjusting for measures of socioeconomic conditions, as well as body mass index (BMI), and the number of meals consumed per day. Migration, both in terms of distance and time away, explains significant variation in BP among migrants in a typical South African context. This finding suggests the need for further studies of nutritional and psychosocial factors associated with geographic mobility that may be important factors for understanding rising hypertension in LMICs.
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    Epidemiology of chronic multimorbidity and temporary migration in a rural South African community in health transition: A cross-sectional population-based analysis
    (2023-04-21) Armstrong Dzomba; Carren Ginsburg; Chodziwadziwa W. Kabudula; Rachel R. Yorlets; Pedzisai Ndagurwa; Sadson Harawa; Mark N. Lurie; Stephen T. McGarvey; Stephen Tollman; Mark A. Collinson; Michael J. White; Francesc X. Gomez-Olive
    Introduction: In sub-Saharan African settings, the increasing non-communicable disease mortality is linked to migration, which disproportionately exposes subpopulations to risk factors for co-occurring HIV and NCDs. Methods: We examined the prevalence, patterns, and factors associated with two or more concurrent diagnoses of chronic diseases (i.e., multimorbidity) among temporary within-country migrants. Employing a cross-sectional design, our study sample comprised 2144 residents and non-residents 18–40 years interviewed and with measured biomarkers in 2018 in Wave 1 of the Migrant Health Follow-up Study (MHFUS), drawn from the Agincourt Health and Demographic Surveillance System (AHDSS) in rural north-eastern South Africa. We used modified Poisson regression models to estimate the association between migration status and prevalent chronic multimorbidity conditional on age, sex, education, and healthcare utilisation. Results: Overall, 301 participants (14%; 95% CI 12.6–15.6), median age 31 years had chronic multimorbidity. Multimorbidity was more prevalent among non-migrants (14.6%; 95% CI 12.8–16.4) compared to migrants (12.8%; 95% CI 10.3–15.7). Nonmigrants also had the greatest burden of dual-overlapping chronic morbidities, such as HIV-obesity 5.7%. Multimorbidity was 2.6 times as prevalent (PR 2.65. 95% CI 2.07– 3.39) among women compared to men. Among migrants, men, and individuals with secondary or tertiary education manifested lower prevalence of two or more conditions. Discussion: In a rural community with colliding epidemics, we found low but significant multimorbidity driven by a trio of conditions: HIV, hypertension, and obesity. Understanding the multimorbidity burden associated with early adulthood exposures, including potential protective factors (i.e., migration coupled with education), is a critical first step towards improving secondary and tertiary prevention for chronic disease among highly mobile marginalised sub-populations.