Mid-life household food insecurity and subsequent memory function and rate of decline in rural South Africa, 2004-2022.

INTRODUCTION: We aimed to investigate mid-life food insecurity over time in relation to subsequent memory function and rate of decline in Agincourt, rural South Africa. METHODS: Data from the longitudinal Agincourt Health and Socio-Demographic Surveillance System (Agincourt HDSS) were linked to the population-representative Health and Ageing in Africa: A Longitudinal Study of an INDEPTH Community in South Africa" (HAALSI). Food insecurity (yes vs. no) and food insecurity intensity (never/rarely/sometimes vs. often/very often) in the past month were assessed every 3 years from 2004-2013 in Agincourt HDSS. Cumulative exposure to each food insecurity measure was operationalized as 0, 1, and ≥2 time points. Episodic memory was assessed from 2014/15-2021/22 in HAALSI. Mixed-effects linear regression models were fitted to investigate the associations of each food insecurity measure with memory function and rate of decline over time. RESULTS: A total of 3,186 participants (mean age [SD] in 2004: 53 [12.87]; range: 30-96) were included and 1,173 (36%) participants experienced food insecurity in 2004, while this figure decreased to 490 (15%) in 2007, 489 (15%) in 2010, and 150 (5%) in 2013. Experiencing food insecurity at one time point (vs. never) from 2004-2013 was associated with lower baseline memory function (ß=-0.095; 95% CI: -0.159 to -0.032) in 2014/15 but not rate of memory decline. Higher intensity of food insecurity at ≥ two time points (vs. never) was associated with lower baseline memory function (ß =-0.154, 95% CI: -0.338 to 0.028), although the estimate was imprecise. Other frequencies of food insecurity and food insecurity intensity were not associated with memory function or decline in the fully adjusted models. CONCLUSION: In this setting, mid-life food insecurity may be a risk factor for lower later-life memory function, but not decline.

Pregnancy-related mortality up to 1 year postpartum in sub-Saharan Africa: an analysis of verbal autopsy data from six countries.

OBJECTIVE: To compare the causes of death for women who died during pregnancy and within the first 42 days postpartum with those of women who died between >42 days and within 1 year postpartum. DESIGN: Open population cohort (Health and Demographic Surveillance Systems). SETTING: Ten Health and Demographic Surveillance Systems (HDSS) in The Gambia, Kenya, Malawi, Tanzania, Ethiopia and South Africa. POPULATION: 2114 deaths which occurred within 1 year of the end of pregnancy where a verbal autopsy interview was conducted from 2000 to 2019. METHODS: InterVA5 and InSilicoVA verbal autopsy algorithms were used to attribute the most likely underlying cause of death, which were grouped according to adapted International Classification of Diseases-Maternal Mortality categories. Multinomial regression was used to compare differences in causes of deaths within 42 days versus 43-365 days postpartum adjusting for HDSS and time period (2000-2009 and 2010-2019). MAIN OUTCOME MEASURES: Cause of death and the verbal autopsy Circumstances of Mortality Categories (COMCATs). RESULTS: Of 2114 deaths, 1212 deaths occurred within 42 days postpartum and 902 between 43 and 365 days postpartum. Compared with deaths within 42 days, deaths from HIV and TB, other infectious diseases, and non-communicable diseases constituted a significantly larger proportion of late pregnancy-related deaths beyond 42 days postpartum, and health system failures were important in the circumstances of those deaths. The contribution of HIV and TB to deaths beyond 42 days postpartum was greatest in Southern Africa. The causes of pregnancy-related mortality within and beyond 42 days postpartum did not change significantly between 2000-2009 and 2010-2019. CONCLUSIONS: Cause of death data from the extended postpartum period are critical to inform prevention. The dominance of HIV and TB, other infectious and non-communicable diseases to (late) pregnancy-related mortality highlights the need for better integration of non-obstetric care with ante-, intra- and postpartum care in high-burden settings.

Understanding Household Dynamics From the Ground Up: A Longitudinal Study From a Rural South African Setting.

Investigations into household structure in low- and middle-income countries (LMICs) provide important insight into how families manage domestic life in response to resource allocation and caregiving needs during periods of rapid sociopolitical and health-related challenges. Recent evidence on household structure in many LMICs contrasts with long-standing viewpoints of worldwide convergence to a Western nuclearized household model. Here, we adopt a household-centered theoretical and methodological framework to investigate longitudinal patterns and dynamics of household structure in a rural South African setting during a period of high AIDS-related mortality and socioeconomic change. Data come from the Agincourt Health and Socio-Demographic Surveillance System (2003-2015). Using latent transition models, we derived six distinct household types by examining conditional interdependency between household heads' characteristics, members' age composition, and migration status. More than half of households were characterized by their complex and multigenerational profiles, with considerable within-typology variation in household size and dependency structure. Transition analyses showed stability of household types under female headship, while higher proportions of nuclearized household types dissolved over time. Household dissolution was closely linked to prior mortality experiences-particularly, following death of a male head. Our findings highlight the need to better conceptualize and contextualize household changes across populations and over time.

Estimating the Prevalence of over- and Under-Reporting in HIV Testing, Status and Treatment in Rural Northeast South Africa: A Comparison of a Survey and Clinic Records.

We assess the accuracy of self-reported testing, HIV status, and treatment responses compared to clinical records in Ehlanzeni District, South Africa. We linked a 2018 population-based survey of adults 18-49 years old with clinical data at local primary healthcare facilities from 2014 to 2018. We calculated self-reported testing, HIV status, and treatment, and triangulated findings with clinic record data. We adjusted testing estimates for known gaps in HIV test documentation. Of 2089 survey participants, 1657 used a study facility and were eligible for analysis. Half of men and 84% of women reported an HIV test in the past year. One third of reported tests could be confirmed in clinic data within 1 year and an additional 13% within 2 years; these fractions increased to 57% and 22% respectively limiting to participants with a verified clinic file. After accounting for gaps in clinic documentation, we found that prevalence of recent HIV testing was closer to 15% among men and 51% in women. Estimated prevalence of known HIV was 16.2% based on self-report vs. 27.6% with clinic documentation. Relative to clinical records among confirmed clinic users, self report of HIV testing and of current treatment were highly sensitive but non-specific (sensitivity 95.5% and 98.8%, specificity 24.2% and 16.1% respectively), while self report of HIV status was highly specific but not sensitive (sensitivity 53.0%, specificity 99.3%). While clinical records are imperfect, survey-based measures should be interpreted with caution in this rural South African setting.

Twin epidemics: the effects of HIV and systolic blood pressure on mortality risk in rural South Africa, 2010-2019.

BACKGROUND: Sub-Saharan African settings are experiencing dual epidemics of HIV and hypertension. We investigate effects of each condition on mortality and examine whether HIV and hypertension interact in determining mortality. METHODS: Data come from the 2010 Ha Nakekela population-based survey of individuals ages 40 and older (1,802 women; 1,107 men) nested in the Agincourt Health and socio-Demographic Surveillance System in rural South Africa, which provides mortality follow-up from population surveillance until mid-2019. Using discrete-time event history models stratified by sex, we assessed differential mortality risks according to baseline measures of HIV infection, HIV-1 RNA viral load, and systolic blood pressure. RESULTS: During the 8-year follow-up period, mortality was high (477 deaths). Survey weighted estimates are that 37% of men (mortality rate 987.53/100,000, 95% CI: 986.26 to 988.79) and 25% of women (mortality rate 937.28/100,000, 95% CI: 899.7 to 974.88) died. Over a quarter of participants were living with HIV (PLWH) at baseline, over 50% of whom had unsuppressed viral loads. The share of the population with a systolic blood pressure of 140mm Hg or higher increased from 24% at ages 40-59 to 50% at ages 75-plus and was generally higher for those not living with HIV compared to PLWH. Men and women with unsuppressed viral load had elevated mortality risks (men: adjusted odds ratio (aOR) 3.23, 95% CI: 2.21 to 4.71, women: aOR 2.05, 95% CI: 1.27 to 3.30). There was a weak, non-linear relationship between systolic blood pressure and higher mortality risk. We found no significant interaction between systolic blood pressure and HIV status for either men or women (p>0.05). CONCLUSIONS: Our results indicate that HIV and elevated blood pressure are acting as separate, non-interacting epidemics affecting high proportions of the older adult population. PLWH with unsuppressed viral load were at higher mortality risk compared to those uninfected. Systolic blood pressure was a mortality risk factor independent of HIV status. As antiretroviral therapy becomes more widespread, further longitudinal follow-up is needed to understand how the dynamics of increased longevity and multimorbidity among people living with both HIV and high blood pressure, as well as the emergence of COVID-19, may alter these patterns.

Clusters of HIV Risk and Protective Sexual Behaviors in Agincourt, Rural South Africa: Findings from the Ha Nakekela Population-Based Study of Ages 15 and Older.

Understanding how sexual behaviors cluster in distinct population subgroups along the life course is critical for effective targeting and tailoring of HIV prevention messaging and intervention activities. We examined interrelatedness of sexual behaviors and variation between men and women across a wide age range in a rural South African setting with a high HIV burden. Data come from the Ha Nakekela population-based survey of people aged 15-85-plus drawn from the Agincourt Health and Socio-Demographic Surveillance System. We used latent class analysis of six sexual behavior indicators to identify distinct subgroup sexual behavior clusters. We then examined associations between class membership and sociodemographic and other behavioral risk factors and assessed the accuracy of a reduced set of sexual behavior indicators to classify individuals into latent classes. We identified three sexual behavior classes: (1) single with consistent protective behaviors; (2) risky behaviors; and (3) in union with lack of protective behaviors. Patterns of sexual behaviors varied by gender. Class membership was also associated with age, HIV status, nationality, and alcohol use. With only two sexual behavior indicators (union status and multiple sexual partners), individuals were accurately assigned to their most likely predicted class. There were distinct multidimensional sexual behavior clusters in population subgroups that varied by sex, age, and HIV status. In this population, only two brief questions were needed to classify individuals into risk classes. Replication in other situations is needed to confirm these findings.

Prevalence and correlates of frailty in an older rural African population: findings from the HAALSI cohort study.

BACKGROUND: Frailty is a key predictor of death and dependency, yet little is known about frailty in sub-Saharan Africa despite rapid population ageing. We describe the prevalence and correlates of phenotypic frailty using data from the Health and Aging in Africa: Longitudinal Studies of an INDEPTH Community cohort. METHODS: We analysed data from rural South Africans aged 40 and over. We used low grip strength, slow gait speed, low body mass index, and combinations of self-reported exhaustion, decline in health, low physical activity and high self-reported sedentariness to derive nine variants of a phenotypic frailty score. Each frailty category was compared with self-reported health, subjective wellbeing, impairment in activities of daily living and the presence of multimorbidity. Cox regression analyses were used to compare subsequent all-cause mortality for non-frail (score 0), pre-frail (score 1-2) and frail participants (score 3+). RESULTS: Five thousand fifty nine individuals (mean age 61.7 years, 2714 female) were included in the analyses. The nine frailty score variants yielded a range of frailty prevalences (5.4% to 13.2%). For all variants, rates were higher in women than in men, and rose steeply with age. Frailty was associated with worse subjective wellbeing, and worse self-reported health. Both prefrailty and frailty were associated with a higher risk of death during a mean 17 month follow up for all score variants (hazard ratios 1.29 to 2.41 for pre-frail vs non-frail; hazard ratios 2.65 to 8.91 for frail vs non-frail). CONCLUSIONS: Phenotypic frailty could be measured in this older South African population, and was associated with worse health, wellbeing and earlier death.

Progression of the epidemiological transition in a rural South African setting: findings from population surveillance in Agincourt, 1993-2013.

BACKGROUND: Virtually all low- and middle-income countries are undergoing an epidemiological transition whose progression is more varied than experienced in high-income countries. Observed changes in mortality and disease patterns reveal that the transition in most low- and middle-income countries is characterized by reversals, partial changes and the simultaneous occurrence of different types of diseases of varying magnitude. Localized characterization of this shifting burden, frequently lacking, is essential to guide decentralised health and social systems on the effective targeting of limited resources. Based on a rigorous compilation of mortality data over two decades, this paper provides a comprehensive assessment of the epidemiological transition in a rural South African population. METHODS: We estimate overall and cause-specific hazards of death as functions of sex, age and time period from mortality data from the Agincourt Health and socio-Demographic Surveillance System and conduct statistical tests of changes and differentials to assess the progression of the epidemiological transition over the period 1993-2013. RESULTS: From the early 1990s until 2007 the population experienced a reversal in its epidemiological transition, driven mostly by increased HIV/AIDS and TB related mortality. In recent years, the transition is following a positive trajectory as a result of declining HIV/AIDS and TB related mortality. However, in most age groups the cause of death distribution is yet to reach the levels it occupied in the early 1990s. The transition is also characterized by persistent gender differences with more rapid positive progression in females than males. CONCLUSIONS: This typical rural South African population is experiencing a protracted epidemiological transition. The intersection and interaction of HIV/AIDS and antiretroviral treatment, non-communicable disease risk factors and complex social and behavioral changes will impact on continued progress in reducing preventable mortality and improving health across the life course. Integrated healthcare planning and program delivery is required to improve access and adherence for HIV and non-communicable disease treatment. These findings from a local, rural setting over an extended period contribute to the evidence needed to inform further refinement and advancement of epidemiological transition theory.

Cardiometabolic risk in a population of older adults with multiple co-morbidities in rural south africa: the HAALSI (Health and Aging in Africa: longitudinal studies of INDEPTH communities) study.

BACKGROUND: A consequence of the widespread uptake of anti-retroviral therapy (ART) is that the older South African population will experience an increase in life expectancy, increasing their risk for cardiometabolic diseases (CMD), and its risk factors. The long-term interactions between HIV infection, treatment, and CMD remain to be elucidated in the African population. The HAALSI cohort was established to investigate the impact of these interactions on CMD morbidity and mortality among middle-aged and older adults. METHODS: We recruited randomly selected adults aged 40 or older residing in the rural Agincourt sub-district in Mpumalanga Province. In-person interviews were conducted to collect baseline household and socioeconomic data, self-reported health, anthropometric measures, blood pressure, high-sensitivity C-reactive protein (hsCRP), HbA1c, HIV-status, and point-of-care glucose and lipid levels. RESULTS: Five thousand fifty nine persons (46.4% male) were enrolled with a mean age of 61.7 ± 13.06 years. Waist-to-hip ratio was high for men and women (0.92 ± 0.08 vs. 0.89 ± 0.08), with 70% of women and 44% of men being overweight or obese. Blood pressure was similar for men and women with a combined hypertension prevalence of 58.4% and statistically significant increases were observed with increasing age. High total cholesterol prevalence in women was twice that observed for men (8.5 vs. 4.1%). The prevalence of self-reported CMD conditions was higher among women, except for myocardial infarction, and women had a statistically significantly higher prevalence of angina (10.82 vs. 6.97%) using Rose Criteria. The HIV- persons were significantly more likely to have hypertension, diabetes, or be overweight or obese than HIV+ persons. Approximately 56% of the cohort had at least 2 measured or self-reported clinical co-morbidities, with HIV+ persons having a consistently lower prevalence of co-morbidities compared to those without HIV. Absolute 10-year risk cardiovascular risk scores ranged from 7.7-9.7% for women and from 12.5-15.3% for men, depending on the risk score equations used. CONCLUSIONS: This cohort has high CMD risk based on both traditional risk factors and novel markers like hsCRP. Longitudinal follow-up of the cohort will allow us to determine the long-term impact of increased lifespan in a population with both high HIV infection and CMD risk.

A Successful Failure: Missing the MDG4 Target for Under-Five Mortality in South Africa.

Reflecting on under-five mortality, Peter Byass and colleagues consider how some countries may fail to meet millennium development goal targets despite making considerable advances.

The promise of record linkage for assessing the uptake of health services in resource constrained settings: a pilot study from South Africa.

BACKGROUND: Health and Demographic Surveillance Systems (HDSS) have been instrumental in advancing population and health research in low- and middle- income countries where vital registration systems are often weak. However, the utility of HDSS would be enhanced if their databases could be linked with those of local health facilities. We assess the feasibility of record linkage in rural South Africa using data from the Agincourt HDSS and a local health facility. METHODS: Using a gold standard dataset of 623 record pairs matched by means of fingerprints, we evaluate twenty record linkage scenarios (involving different identifiers, string comparison techniques and with and without clerical review) based on the Fellegi-Sunter probabilistic record linkage model. Matching rates and quality are measured by their sensitivity and positive predictive value (PPV). Background characteristics of matched and unmatched cases are compared to assess systematic bias in the resulting record-linked dataset. RESULTS: A hybrid approach of deterministic followed by probabilistic record linkage, and scenarios that use an extended set of identifiers including another household member's first name yield the best results. The best fully automated record linkage scenario has a sensitivity of 83.6% and PPV of 95.1%. The sensitivity and PPV increase to 84.3% and 96.9%, respectively, when clerical review is undertaken on 10% of the record pairs. The likelihood of being linked is significantly lower for females, non-South Africans and the elderly. CONCLUSION: Using records matched by means of fingerprints as the gold standard, we have demonstrated the feasibility of fully automated probabilistic record linkage using identifiers that are routinely collected in health facilities in South Africa. Our study also shows that matching statistics can be improved if other identifiers (e.g., another household member's first name) are added to the set of matching variables, and, to a lesser extent, with clerical review. Matching success is, however, correlated with background characteristics that are indicative of the instability of personal attributes over time (e.g., surname in the case of women) or with misreporting (e.g., age).

Local Network Interaction as a Mechanism for Wealth Inequality.

Given limited institutional resources, low-income populations often rely on social networks to improve their socioeconomic outcomes. However, it remains in question whether small-scale social interactions could affect large-scale economic inequalities in under-resourced contexts. Here, we leverage population-level data from one of the poorest South African settings to construct a large-scale, geographically defined, inter-household social network. Using a multilevel network model, we show that having social ties in close geographic proximity is associated with stable household asset conditions, while geographically distant ties correlate to changes in asset allocation. Notably, we find that localised network interactions are associated with an increase in wealth inequality at the regional level, demonstrating how macro-level inequality may arise from micro-level social processes. Our findings highlight the importance of understanding complex social connections underpinning inter-household resource dynamics, and raise the potential of large-scale social assistance programs to reduce disparities in resource-ownership by accounting for local social constraints.

Mid-life employment trajectories and subsequent memory function and rate of decline in rural South Africa, 2000-22.

AIM: To investigate mid-life employment trajectories in relation to later-life memory function and rate of decline in rural South Africa. METHODS: Data from the Agincourt Health and Socio-Demographic Surveillance System were linked to the 'Health and Ageing in Africa: A Longitudinal Study of an INDEPTH Community in South Africa' (HAALSI) in rural Agincourt, South Africa (N = 3133). Employment was assessed every 4 years over 2000-12 as being employed (0, 1, 2 and ≥3 time points), being employed in a higher-skill occupation (0, 1, 2 and ≥3 time points) and dynamic employment trajectories identified using sequence analysis. Latent memory z-scores were assessed over 2014-22. Mixed-effects linear regression models were fitted to examine the associations of interest. RESULTS: Sustained mid-life employment from 2000-12 (ß = 0.052, 95% CI: -0.028 to 0.132, 1 vs 0 time points; ß = 0.163, 95% CI: 0.077 to 0.250, 2 vs 0 time points; ß = 0.212, 95% CI: 0.128 to 0.296, ≥3 vs 0 time points) and greater time spent in a higher-skill occupation (ß = 0.077, 95% CI: -0.020 to 0.175, 1 vs 0 time points; ß = 0.241, 95% CI: 0.070 to 0.412, 2 vs 0 time points; ß = 0.361, 95% CI: 0.201 to 0.520, ≥3 vs 0 time points) were associated with higher memory scores in 2014/15, but not subsequent rate of memory decline. Moving from a lower-skill to higher-skill occupation was associated with higher memory function, but a faster rate of decline over 2014-22. CONCLUSIONS: Sustained mid-life employment, particularly in higher-skill occupations, may contribute to later-life memory function in this post-Apartheid South African setting.

Association of alcohol use and multimorbidity among adults aged 40 years and above in rural South Africa.

We assessed the prevalence of reported alcohol use and its association with multimorbidity among adults aged 40 years and above in a rural, transitioning South African setting. Findings could potentially inform alcohol interventions integration in the prevention and treatment of chronic conditions. We analysed data from the first wave of The Health and Ageing in Africa-a longitudinal Study in an INDEPTH community (HAALSI) nested within the Agincourt Health and Demographic Surveillance Systems, conducted between November 2014 and November 2015 (n = 5059). We computed descriptive statistics and performed univariate analysis to determine factors independently associated with multimorbidity. Age, Body Mass Index, education, sex, and household wealth status and variables with a p-value < 0.20 in univariate analysis were included in multivariable Modified Poisson regression models. Any factors with a p-value of < 0.05 in the final models were considered statistically significant. The first wave of HAALSI was completed by 5059 participants aged 40 years and above and included 2714 (53.6%) females. The prevalence of reported ever alcohol use was 44.6% (n = 2253) and of these 51.9% (n = 1171) reported alcohol use in the last 30 days. The prevalence of HIV multimorbidity was 59.6% (3014/5059) and for multimorbidity without HIV 52.5% (2657/5059). Alcohol use was associated with HIV multimorbidity among all participants (RR: 1.05, 95% CI: 1.02-1.08), and separately for males (RR: 1.05, 95% CI: 1.00-1.10) and females (RR: 1.06, 95%CI: 1.02-1.11). Similarly, alcohol use was associated with multimorbidity without HIV among all participants (RR: 1.05, 95% CI: 1.02-1.09), and separately for males (RR: 1.06, 95% CI: 1.00-1.12) and females (RR: 1.06, 95% CI: 1.01-1.11). Reported alcohol use was common and associated with HIV multimorbidity and multimorbidity without HIV among older adults in rural northeast South Africa. There is a need to integrate Screening, Brief Interventions, and Referral for alcohol Treatment in the existing prevention and treatment of multimorbidity in South Africa.

The effects of HIV and systolic blood pressure on mortality risk in rural South Africa, 2010-2019: a data note.

OBJECTIVES: South Africa is experiencing both HIV and hypertension epidemics. Data were compiled for a study to identify effects of HIV and high systolic blood pressure on mortality risk among people aged 40-plus in a rural South African area experiencing high prevalence of both conditions. We aim to release the replication data set for this study. DATA DESCRIPTION: The research data comes from the 2010-11 Ha Nakekela (We Care) population-based survey nested in the Agincourt Health and socio-Demographic Surveillance System (AHDSS) located in the northeast region of South Africa. An age-sex-stratified probability sample was drawn from the AHDSS. The public data set includes information on individual socioeconomic characteristics and measures of HIV status and blood pressure for participants aged 40-plus by 2019. The AHDSS, through its annual surveillance, provided mortality data for nine years subsequent to the survey. These data were converted to person-year observations and linked to the individual-level survey data using participants' AHDSS census identifier. The data can be used to replicate Houle et al. (2022) - which used discrete-time event history models stratified by sex to assess differential mortality risks according to Ha Nakekela measures of HIV-infection, HIV-1 RNA viral load, and systolic blood pressure.

Improvements in Hypertension Control in the Rural Longitudinal HAALSI Cohort of South African Adults Aged 40 and Older, From 2014 to 2019.

BACKGROUND: Over half of the South African adults aged 45 years and older have hypertension but its effective management along the treatment cascade (awareness, treatment, and control) remains poorly understood. METHODS: We compared the prevalence of all stages of the hypertension treatment cascade in the rural HAALSI cohort of older adults at baseline and after four years of follow-up using household surveys and blood pressure data. Hypertension was a mean systolic blood pressure >140 mm Hg or diastolic pressure >90 mm Hg, or current use of anti-hypertension medication. Control was a mean blood pressure <140/90 mm Hg. The effects of sex and age on the treatment cascade at follow-up were assessed. Multivariate Poisson regression models were used to estimate prevalence ratios along the treatment cascade at follow-up. RESULTS: Prevalence along the treatment cascade increased from baseline (B) to follow-up (F): awareness (64.4% vs. 83.6%), treatment (49.7% vs. 73.9%), and control (22.8% vs. 41.3%). At both time points, women had higher levels of awareness (B: 70.5% vs. 56.3%; F: 88.1% vs. 76.7%), treatment (B: 55.9% vs. 41.55; F: 79.9% vs. 64.7%), and control (B: 26.5% vs. 17.9%; F: 44.8% vs. 35.7%). Prevalence along the cascade increased linearly with age for everyone. Predictors of awareness included being female, elderly, or visiting a primary health clinic three times in the previous 3 months, and the latter two also predicted hypertension control. CONCLUSIONS: There were significant improvements in awareness, treatment, and control of hypertension from baseline to follow-up and women fared better at all stages, at both time points.

Significant Improvement in Blood Pressure Levels Among Older Adults With Hypertension in Rural South Africa.

BACKGROUND: Sub-Saharan Africa is undergoing an epidemiologic transition from infectious diseases to cardiovascular diseases. From 2014 to 2019, sociodemographic surveillance was performed in a large cohort in rural South Africa. METHODS: Disease prevalence and incidence were calculated using inverse probability weights. Poisson regression was used to identify disease predictors. The percentage of individuals with controlled (<140/90 mm Hg) versus uncontrolled hypertension was compared between 2014 and 2019. RESULTS: Compared with 2014 (n=5059), study participants in 2019 (n=4176) had similar rates of obesity (mean body mass index, 27.5±10.0 versus 27.0±6.5) but higher smoking (9.1% versus 11.5%) and diabetes (11.1% versus 13.9%). There was no significant increase in hypertension prevalence (58.4% versus 59.8%; age adjusted, 64.3% versus 63.3%), and there was a significant reduction in mean systolic blood pressure (138.0 versus 128.5 mm Hg; P<0.001). Among hypertensive individuals who reported medication use in 2014 and 2019 (n=796), the proportion with controlled hypertension on medication increased from 44.5% to 62.3%. Hypertension incidence was 6.2 per 100 person-years, and age was the only independent predictor. Among normotensive individuals in 2014 (n=2257), 15.2% developed hypertension by 2019, with the majority already controlled on medications by 2019. CONCLUSIONS: The hypertension prevalence and incidence are plateauing in this aging cohort. There was a statistically and clinically significant decline in mean blood pressure and a substantial increase in individuals with controlled hypertension on medication. The prevalence of cardiometabolic risk factors did not decrease over time, suggesting that the blood pressure decrease is likely due to increased medication access and adherence, promoted by local health systems.

Estimating population level 24-h sodium excretion using spot urine samples in older adults in rural South Africa.

BACKGROUND: South Africa has introduced regulations to reduce sodium in processed foods. Assessing salt consumption with 24-h urine collection is logistically challenging and expensive. We assess the accuracy of using spot urine samples to estimate 24-h urine sodium (24hrUNa) excretion at the population level in a cohort of older adults in rural South Africa. METHODS: 24hrUNa excretion was measured and compared to that estimated from matched spot urine samples in 399 individuals, aged 40-75 years, from rural Mpumalanga, South Africa. We used the Tanaka, Kawasaki, International Study of Sodium, Potassium, and Blood Pressure (INTERSALT), and Population Mean Volume (PMV) method to predict 24hrUNa at the individual and population level. RESULTS: The population median 24hrUNa excretion from our samples collected in 2017 was 2.6 g (interquartile range: 1.53-4.21) equal to an average daily salt intake of 6.6 g, whereas 65.4% of participants had a salt excretion above the WHO recommended 5 g/day. Estimated population median 24hrUNa derived from the INTERSALT, both with and without potassium, showed a nonsignificant difference of 0.25 g (P = 0.59) and 0.21 g (P = 0.67), respectively. In contrast, the Tanaka, Kawasaki, and PMV formulas were markedly higher than the measured 24hrUNa, with a median difference of 0.51 g (P = 0.004), 0.99 g (P = 0.00), and 1.05 g (P = 0.00) respectively. All formulas however performed poorly when predicting an individual's 24hrUNa. CONCLUSION: In this population, the INTERSALT formulas are a well suited and cost-effective alternative to 24-h urine collection for the evaluation of population median 24hrUNa excretion. This could play an important role for governments and public health agencies in evaluating local salt regulations and identifying at-risk populations.

Telomere Length, Health, and Mortality in a Cohort of Older Black South African Adults.

Telomere length (TL) may be a biomarker of aging processes as well as age-related diseases. However, most studies of TL and aging are conducted in high-income countries. Less is known in low- and middle-income countries (LMICs) such as South Africa, where life expectancy remains lower despite population aging. We conducted a descriptive analysis of TL in a cohort of older adults in rural South Africa. TL was assayed from venous blood draws using quantitative polymerase chain reaction (T/S ratio). We examined the correlation between TL and biomarkers, demographic characteristics, mental/cognitive health measures, and physical performance measures in a subsample of the Wave 1 2014-2015 "Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa" (HAALSI) cohort (n = 510). We used logistic regression to measure the association between TL and mortality through Wave 3 (2021-2022). In bivariate analyses, TL was significantly correlated with age (r = -0.29, p < .0001), self-reported female sex (r = 0.13, p = .002), mortality (r = -0.1297, p = .003), diastolic blood pressure (r = 0.09, p = .037), pulse pressure (r = -0.09, p = .045), and being a grandparent (r = -0.17, p = .0001). TL was significantly associated with age (ß = -0.003; 95% confidence interval [CI] = -0.005, -0.003). TL was significantly associated in unadjusted multivariate analyses with mortality, but the relationship between TL and mortality was attenuated after adjusting for age (odds ratio [OR] = 0.19; 95% CI = 0.03, 1.27) and other covariates (OR = 0.17; 95% CI = 0.02, 1.19). Our study is the first analysis of TL in an older adult South African population. Our results corroborate existing relationships between TL and age, sex, cardiometabolic disease, and mortality found in higher-income countries.

Epidemiology of chronic multimorbidity and temporary migration in a rural South African community in health transition: A cross-sectional population-based analysis.

Introduction: In sub-Saharan African settings, the increasing non-communicable disease mortality is linked to migration, which disproportionately exposes sub-populations 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). Non-migrants 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.