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

Abstract

ObjectivesThere 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.DesignWe 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.SettingRural South Africa.ParticipantsWe used a population-based cohort of normotensive adults in 2010 who were aged 40 years and older at retest in 2015.ResultsOf 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.ConclusionsOver 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.

The Meaning of Health in Rural South Africa: Gender, the Life Course, and the Socioepidemiological Context

“…Among those aged 70‐plus, women were significantly more likely to be living with a major chronic disease, and specifically hypertension, compared to same‐aged men (see also Houle et al. 2021).…”

“…Agincourt residents lived through a dramatic rise in mortality in the 2000s driven by the AIDS epidemic (Houle et al 2014;Kabudula et al 2017a), which likely informed their relative assessments of good health. Further, the rising burden of noncommunicable diseases in South Africa (Clark et al 2015;Mayosi et al 2009;Houle et al 2021), as well as the ART-enabled transformation of HIV into a chronic disease, have combined to increase the proportion of the population who are living with chronic illness, as well as stretch the time spent chronically ill into both younger and older ages. This is reflected by our findings of both high levels of morbidity, as well as no significant variation by age group, in chronic illness prevalence among those aged 40 and over.…”

“…The only exception was men in their 50s, who were significantly more likely to be living with HIV compared to same-aged women. Among those aged 70-plus, women were significantly more likely to be living with a major chronic disease, and specifically hypertension, compared to same-aged men (see also Houle et al 2021).…”

“…Respondents were considered hypertensive ( = 1) if their systolic blood pressure was greater than or equal to 140 mmHg, their diastolic blood pressure was greater than or equal to 90 mmHg, or they reported using antihypertensive medication in the past two weeks. (See also Clark et al 2015;Houle et al 2021).…”

Developing and Validating Risk Algorithm for Hypertension in South Africa: Results from a Nationally Representative Cohort (2008–2017)

“…Over the past decades, the burden of hypertension has increased substantially with significant geographical disparities where African countries, including South Africa, have been estimated to have the highest prevalence in the region [4][5][6]. In fact, besides HIV/AIDS epidemic, increasing hypertension rates are considered one of the major health challenges that Black South Africans face [7][8][9].…”