Publications

2024
W Harriman, Nigel, Daniel Ohene-Kwofie, Sun Jae Jung, Sabrina Hermosilla, Gómez-Olivé FX, and Elyse A. Jennings. 4/2024. “In-Person Social Interactions and Anxiety During the COVID-19 Pandemic: Exploring the Role of Household Size and Virtual Social Contact Among Midlife and Older Black South African Adults.” The Journals of Gerontology: Series B, 79, 4. Publisher's VersionAbstract

Objectives
The current study investigates how physical distancing during the coronavirus disease 2019 (COVID-19) pandemic was associated with increased anxiety among a cohort of midlife older Black South African adults and the extent to which household size and virtual social contact modify this association for men and women.

Methods
We analyze data from a phone survey conducted from July 2021 to March 2022 as part of Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa (n = 2,080). We employ logistic regression to estimate the association between changes in in-person social interactions and anxiety symptoms and examine whether the association is modified by household size and changes in virtual social contact. We perform analyses separately for women and men.

Results
Declines in in-person social interactions were associated with increased anxiety for women and men (odds ratios [OR] = 2.52, p < .001). For women only, declines were greater for those living in larger households (OR = 1.11, p = .032). Declines were buffered by increased virtual social contact for both women (OR = 0.55, p = .025) and men (OR = 0.45, p = .019).

Discussion
Although the anxiety symptoms of women and men were similarly affected by declines in in-person social interaction, the modifying influence of household size is unique to women, likely due to gender-specific social roles. For women, living in larger households may mean greater caregiving burden, exacerbating the detrimental association between physical distancing and anxiety. On the other hand, both women and men may have used virtual means to connect with friends and family living outside their homes, buffering against increased anxiety.

Rishika Chakraborty, Lindsay C. Kobayashi, Janet Jock, Coady Wing, Xiwei Chen, Meredith Phillips, Lisa Berkman, Kathleen Kahn, Chodziwadziwa Whiteson Kabudula, and Molly Rosenberg. 3/6/2024. “Child Support Grant expansion and cognitive function among women in rural South Africa: findings from a natural experiment in HAALSI cohort.” medRxiv. Publisher's VersionAbstract
{Cash transfers are a promising but understudied intervention that may protect cognitive function in adults by promoting their cognitive reserve. South Africa has a rapidly ageing population, however, less is known about the nature of association between cash transfers and cognitive function in this setting. We leveraged natural experiments from Child Support Grant (CSG) age-eligibility expansions to investigate the association between duration of CSG eligibility and cognitive function among biological mothers of child beneficiaries in South Africa. We analysed 2014/2015 baseline data from 944 women, aged 40 - 59 years with at least one CSG-eligible child, enrolled in the HAALSI cohort in Agincourt, South Africa. Duration of CSG eligibility for each mother was calculated based on the birth dates of all their children and the CSG age eligibility expansion years. Cognitive function was measured using a cognitive battery administered to the mothers at baseline interview. Linear regression was used to estimate the association between duration of CSG eligibility, dichotomized as low (<=10 years) and high (>10 years) eligibility, and cognitive function z-scores of the mothers. Our study finds that high duration of CSG eligibility, compared to low, was associated with higher cognitive function z-scores in the full sample [β: 0.15 SD; 95% CI: 0.04, 0.26; p-value = 0.01]. In mothers with one to four lifetime children, but not five or more, high duration of CSG eligibility, compared to low, was associated with higher cognitive function z-scores [β: 0.19 SD; 95% CI: 0.05, 0.34
Xuexin Yu, Chodziwadziwa W Kabudula, Ryan G Wagner, Darina T Bassil, Meagan T Farrell, Stephen M Tollman, Kathleen Kahn, Lisa F Berkman, Molly S Rosenberg, and Lindsay C Kobayashi. 2/15/2024. “Mid-life employment trajectories and subsequent memory function and rate of decline in rural South Africa, 2000–22.” International Journal of Epidemiology, 53, 2, Pp. dyae022. Publisher's VersionAbstract
To investigate mid-life employment trajectories in relation to later-life memory function and rate of decline in rural South Africa.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.Sustained mid-life employment from 2000–12 (β = 0.052, 95\% CI: -0.028 to 0.132, 1 vs 0 time points; β = 0.163, 95\% CI: 0.077 to 0.250, 2 vs 0 time points; β = 0.212, 95\% CI: 0.128 to 0.296, ≥3 vs 0 time points) and greater time spent in a higher-skill occupation (β = 0.077, 95\% CI: -0.020 to 0.175, 1 vs 0 time points; β = 0.241, 95\% CI: 0.070 to 0.412, 2 vs 0 time points; β = 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.Sustained mid-life employment, particularly in higher-skill occupations, may contribute to later-life memory function in this post-Apartheid South African setting.
Haeyoon Chang, Janet Jock, Molly S Rosenberg, Tsai-Chin Cho, Thomas A Gaziano, Lynda Lisabeth, and Lindsay C Kobayashi. 2/8/2024. “The Impact of the Older Person’s Grant Expansion on Hypertension Among Older Men in Rural South Africa: Findings from the HAALSI cohort.” Innovation in Aging, Pp. igae010. Publisher's VersionAbstract
Hypertension is a major modifiable contributor to disease burden in sub-Saharan Africa. We exploited an expansion to age eligibility for men in South Africa’s non-contributory public pension to assess the impact of pension eligibility on hypertension in a rural, low-income South African setting.Data were from 1,247 men aged ≥60 in the population-representative Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa (HAALSI) in 2014/15. We identified cohorts of men from zero (controls, aged ≥65 at pension expansion) through five years of additional pension eligibility based on their birth year. Using the modified Framingham Heart Study hypertension risk prediction model, and the Wand et al. model modified for the South African population, we estimated the difference in the probabilities of hypertension for men who benefitted from the pension expansion relative to the control. We conducted a negative control analysis among older women, who were not eligible for pension expansion, to assess the robustness of our findings.Older men with five additional years of pension eligibility had a 6.9 to 8.1 percentage point greater probability of hypertension than expected without the pension expansion eligibility. After accounting for birth cohort effects through a negative control analysis involving older women reduced estimates to a 3.0 to a 5.2 percentage point greater probability of hypertension than expected. We observed a mean 0.2 percentage point increase in the probability of hypertension per additional year of pension eligibility, but this trend was not statistically significant.While the Older Person’s Grant is important for improving the financial circumstances of older adults and their families in South Africa, expanded pension eligibility may have a small, negative short-term effect on hypertension among older men in this rural, South African setting.
Mahlalela NB, Manne-Goehler J, Ohene-Kwofie D, and Kahn Rohr JK FX. KBTG rnighausen mez-Oliv B Adams L, Montana L. 1/29/2024. “The Association Between HIV-Related Stigma and the Uptake of HIV Testing and ART Among Older Adults in Rural South Africa: Findings from the HAALSI Cohort Study.” AIDS Behav.
Nigel W Harriman, Darina T Bassil, Meagan Farrell, Jacques D Du Toit, Gómez-Olivé FX, Stephen M Tollman, and Lisa F Berkman. 1/5/2024. “Associations between cohort derived dementia and COVID-19 serological diagnosis among older Black adults in rural South Africa.” Frontiers in Public Health, 11. Publisher's VersionAbstract

Objectives: This study investigates the association between cohort derived dementia and serologically confirmed SARS-CoV-2 infection, an underexplored phenomena in low-and middle-income countries. Examining this relationship in a rural South African community setting offers insights applicable to broader healthcare contexts.

Methods: Data were collected from Black South Africans in the Mpumalanga province who participated in the Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa. Cohort derived dementia was developed using a predictive model for consensus-based dementia diagnosis. Multinomial logistic regression models estimated the association between predicted dementia probability in 2018 and SARS-CoV-2 infection risk in 2021, controlling for demographics, socioeconomic status, and comorbidities.

Results: Fifty-two percent of the tested participants had serologically confirmed SARS-CoV-2 infections. In the fully adjusted model, cohort derived dementia was significantly associated with over twice the risk of serological diagnosis of COVID-19 (RRR = 2.12, p = 0.045).

Conclusion: Complying with COVID-19 prevention recommendations may be difficult for individuals with impaired cognitive functioning due to their symptoms. Results can inform community-based public health initiatives to reduce COVID-19 transmission among South Africa’s rapidly aging population.

2023
Victor Del J Brutto, Farid Khasiyev, Minghua Liu, Antonio Spagnolo-Allende, Ye Qiao, Jesus Melgarejo D Arias, Vanessa A Guzman, Kay C Igwe, Danurys L. Sanchez, Howard Andrews, Clarissa D Morales, Meagan T Farrell, Darina T Bassil, Sudha Seshadri, Ryan G Wagner, Victor Mngomezulu, Jennifer Manly, Mitchell SV Elkind, Lisa Berkman, Jose R Romero, Gladys E Maestre, Oscar Del H Brutto, Adam M Brickman, Narayanaswamy Venketasubramanian, Christopher Chen, Caroline Robert, Saima Hilal, Tatjana Rundek, Bruce A Wasserman, and Jose Gutierrez. 12/26/2023. “Association of brain arterial diameters with demographic and anatomical factors in a multi-national pooled analysis of cohort studies.” The Neuroradiology Journal, Pp. 19714009231224429. Publisher's VersionAbstract
Background and PurposeBrain arterial diameters are markers of cerebrovascular disease. Demographic and anatomical factors may influence arterial diameters. We hypothesize that age, sex, height, total cranial volume (TCV), and persistent fetal posterior cerebral artery (fPCA) correlate with brain arterial diameters across populations.MethodsParticipants had a time-of-flight MRA from nine international cohorts. Arterial diameters of the cavernous internal carotid arteries (ICA), middle cerebral arteries (MCA), and basilar artery (BA) were measured using LAVA software. Regression models assessed the association between exposures and brain arterial diameters.ResultsWe included 6,518 participants (mean age: 70 ± 9 years; 41% men). Unilateral fPCA was present in 13.2% and bilateral in 3.2%. Larger ICA, MCA, and BA diameters correlated with older age (Weighted average [WA] per 10 years: 0.18 mm, 0.11 mm, and 0.12 mm), male sex (WA: 0.24 mm, 0.13 mm, and 0.21 mm), and TCV (WA: for one TCV standard deviation: 0.24 mm, 0.29 mm, and 0.18 mm). Unilateral and bilateral fPCAs showed a positive correlation with ICA diameters (WA: 0.39 mm and 0.73 mm) and negative correlation with BA diameters (WA: −0.88 mm and −1.73 mm). Regression models including age, sex, TCV, and fPCA explained on average 15%, 13%, and 25% of the ICA, MCA, and BA diameter interindividual variation, respectively. Using height instead of TCV as a surrogate of head size decreased the R-squared by 3% on average.ConclusionBrain arterial diameters correlated with age, sex, TCV, and fPCA. These factors should be considered when defining abnormal diameter cutoffs across populations.
Nancy Verma and Lindsay Kobayashi. 12/21/2023. “Socioeconomic Gradients in Depressive Symptoms Among Older Adults in Rural South Africa.” Innovation in Aging, 7, 1, Pp. 950-951. Publisher's VersionAbstract
Depression is one of the most common mental health disorders throughout the globe with an estimated 300 million people affected worldwide. Socioeconomic status may influence depression risk, due to its status as a critical influencing factor for health-related issues as well as serving as a barrier for healthy aging. The objective of this analysis was to examine the presence of socioeconomic gradients in depressive symptoms among older adults in Agincourt, a low-income rural region of South Africa. We conducted a cross-sectional analysis of baseline interview data from 2014/2015 for 5,059 participants aged ≥40 in the population-representative Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa (HAALSI). Household wealth was assessed as quintiles of an asset-based index, including ownership of assets such as housing materials, electricity, piped water, vehicles, and technological goods. Household per capita consumption on food, healthcare, leisure activities, and other goods was also assessed as quintiles. The presence of depressive symptoms was measured and categorized using the 8-item Center for Epidemiologic Studies Depression (CES-D) scale. We used multivariable adjusted logistic regression to examine the association between household wealth and household consumption quintiles and depression. In this study population, the prevalence of depressive symptoms was 17%. We observed no significant trends between household wealth, household consumption and depression (p=0.11 for both exposures). Depressive symptoms are not socioeconomically graded among older, rural South Africa adults. The high prevalence of depressive symptoms within the region should be considered as a public health concern.
Maja E. Marcus, Nomsa Mahlalela, Ndeye D. Drame, Julia K. Rohr, Sebastian Vollmer, Stephen Tollman, Lisa Berkman, Kathleen Kahn, Francesc Xavier Gómez-Olivé, Jennifer Manne-Goehler, and Till Bärnighausen. 11/15/2023. “Home-based HIV testing strategies for middle-aged and older adults in rural South Africa.” AIDS, 37, 14, Pp. 2213-2221. Publisher's VersionAbstract
Objective:More than one in four adults over 40 years with HIV in South Africa are unaware of their status and not receiving antiretroviral therapy (ART). HIV self-testing may offer a powerful approach to closing this gap for aging adults. Here, we report the results of a randomized comparative effectiveness trial of three different home-based HIV testing strategies for middle-aged and older adults in rural South Africa.Design:Two thousand nine hundred and sixty-three individuals in the ‘Health and Ageing in Africa: a Longitudinal Study of an INDEPTH Community in South Africa (HAALSI)’ cohort study were randomized 1 : 1 : 1 to one of three types of home-based and home-delivered HIV testing modalities: rapid testing with counseling; self-testing, and both rapid testing with counselling and self-testing.Method:In OLS regression analyses, we estimated the treatment effects on HIV testing and HIV testing frequency at about 1 year after delivery. Finally, we assessed the potential adverse effects of these strategies on the secondary outcomes of depressive symptom as assessed by the CESD-20, linkage to care, and risky sexual behavior.Results:
Erika T. Beidelman, Till W. Bärnighausen, Coady Wing, Stephen M. Tollman, Meredith L. Phillips, and Molly Rosenberg. 11/8/2023. “Disease awareness and healthcare utilization in rural South Africa: a comparative analysis of HIV and diabetes in the HAALSI cohort.” BMC Public Health, 1, 2202. Publisher's VersionAbstract

Background
Studies from rural South Africa indicate that people living with HIV (PLHIV) may have better health outcomes than those without, potentially due to the frequent healthcare visits necessitated by infection. Here, we examined the association between HIV status and healthcare utilization, using diabetes as an illustrative comparator of another high-burden, healthcare-intensive disease.

Methods
Our exposure of interest was awareness of positive disease status for both HIV and diabetes. We identified 742 individuals who were HIV-positive and aware of their status and 305 who had diabetes and were aware of their status. HIV-positive status was further grouped by viral suppression. For each disease, we estimated the association with (1) other comorbid, chronic conditions, (2) health facility visits, (3) household-level healthcare expenditure, and (4) per-visit healthcare expenditure. We used log-binomial regression models to estimate prevalence ratios for co-morbid chronic conditions. Linear regression models were used for all other outcomes.

Results
Virally suppressed PLHIV had decreased prevalence of chronic conditions, increased public clinic visits [β = 0.59, 95% CI: 0.5, 0.7], and reduced per-visit private clinic spending [β = -60, 95% CI: -83, -6] compared to those without HIV. No differences were observed in hospitalizations and per-visit spending at hospitals and public clinics between virally suppressed PLHIV and non-PLHIV. Conversely, diabetic individuals had increased prevalence of chronic conditions, increased visits across facility types, increased household-level expenditures (β = 88 R, 95% CI: 29, 154), per-visit hospital spending (β = 54 R, 95% CI: 7, 155), and per-visit public clinic spending (β = 31 R, 95% CI: 2, 74) compared to those without diabetes.

Conclusions
Our results suggest that older adult PLHIV may visit public clinics more often than their HIV-negative counterparts but spend similarly on a per-visit basis. This provides preliminary evidence that the positive health outcomes observed among PLHIV in rural South Africa may be explained by different healthcare engagement patterns. Through our illustrative comparison between PLHIV and diabetics, we show that shifting disease burdens towards chronic and historically underfunded diseases, like diabetes, may be changing the landscape of health expenditure inequities.

Sarah Gao, K Rohr, Julia, Immaculata De Vivo, Michele Ramsay, Nancy Krieger, Chodziwadziwa W Kabudula, T Farrell, Meagan, Darina T Bassil, W Harriman, Nigel, Diana Corona-Perez, Katarina Pesic, and Lisa F Berkman. 6/23/2023. “Telomere length, health, and mortality in a cohort of older Black South African adults.” The Journals of Gerontology: Series A. Publisher's VersionAbstract
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-value<0.0001), self-reported female sex (r=0.13, p-value=0.002), mortality (r=-0.1297, p-value=0.003), diastolic blood pressure (r=0.09, p-value=0.037), pulse pressure (r=-0.09, p-value=0.045), and being a grandparent (r=-0.17, p-value=0.0001). TL was significantly associated with age (β=-0.003; 95% 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 (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.
M.G. Mpinganjira, T Chirwa, Kabudula CW, Gómez-Olivé FX, Tollman S, and Francis JM. 5/14/2023. “Association of alcohol use and multimorbidity among adults aged 40 years and above in rural South Africa.” Scientific Reports, 13, 7807. Publisher's VersionAbstract
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.
Darina T. Bassil, Meagan T. Farrell, Albert Weerman, Muqi Guo, Ryan G. Wagner, Adam M. Brickman, M. Maria Glymour, Kenneth M. Langa, Jennifer J. Manly, Brent Tipping, India Butler, Stephen Tollman, and Lisa F. Berkman. 4/4/2023. “Feasibility of an online consensus approach for the diagnosis of cognitive impairment and dementia in rural South Africa.” Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring, 15, 2, Pp. e12420. Publisher's VersionAbstract

INTRODUCTION We describe the development and feasibility of using an online consensus approach for diagnosing cognitive impairment and dementia in rural South Africa.

METHODS Cognitive assessments, clinical evaluations, and informant interviews from Cognition and Dementia in the Health and Aging in Africa Longitudinal Study (HAALSI Dementia) were reviewed by an expert panel using a web-based platform to assign a diagnosis of cognitively normal, mild cognitive impairment (MCI), or dementia.

RESULTS Six hundred thirty-five participants were assigned a final diagnostic category, with 298 requiring adjudication conference calls. Overall agreement between each rater's independent diagnosis and final diagnosis (via the portal or consensus conference) was 78.3%. A moderate level of agreement between raters’ individual ratings and the final diagnostic outcomes was observed (average κ coefficient = 0.50).

DISCUSSION Findings show initial feasibility in using an online consensus approach for the diagnosis of cognitive impairment and dementia in remote, rural, and low-resource settings.

Janet Jock, Lindsay Kobayashi, Rishika Chakraborty, Xiwei Chen, Coady Wing, Lisa Berkman, David Canning, Chodziwadziwa Whiteson Kabudula, Stephen Tollman, and Molly Rosenberg. 3/28/2023. “Effects of Pension Eligibility Expansion on Men’s Cognitive Function: Findings from Rural South Africa.” Journal of Aging & Social Policy, Pp. 1-20. Publisher's VersionAbstract
ABSTRACTTwo-thirds of people living with Alzheimer’s disease and related dementias (ADRD) live in low- and middle-income countries, and this figure is expected to rise as these populations are rapidly aging. Since evidence demonstrates links between socioeconomic status and slower rates of cognitive decline, protecting older adults’ cognitive function in resource-limited countries that lack the infrastructure to cope with ADRD is crucial to reduce the burden it places on these populations and their health systems. While cash transfers are a promising intervention to promote healthy cognitive aging, factors such as household wealth and level of education often confound the ability to make causal inferences on the impact of cash transfers and cognitive function. This study uses a quasi-experimental design, leveraging an exogenous expansion to the Old Age Pension for men in South Africa, to approximate causal associations with cognitive function. We found evidence that there is a potential benefit of cash transfers at an earlier age for older individuals. As such, transfers such as pensions or other forms of direct basic income transfers may hold promise as potential interventions to promote healthy cognitive aging.
Cassandra C Soo, Jean-Tristan Brandenburg, Almut Nebel, Stephen Tollman, Lisa F Berkman, Michele Ramsay, and Ananyo Choudhary. 3/27/2023. “Genome-wide association study of population-standardised cognitive performance phenotypes in a rural South African community.” Communications Biology, 6, 1. Publisher's VersionAbstract
Cognitive function is an indicator for global physical and mental health, and cognitive impairment has been associated with poorer life outcomes and earlier mortality. A standard cognition test, adapted to a rural-dwelling African community, and the Oxford Cognition Screen-Plus were used to capture cognitive performance as five continuous traits (total cognition score, verbal episodic memory, executive function, language, and visuospatial ability) for 2,246 adults in this population of South Africans. A novel common variant, rs73485231, reached genome-wide significance for association with episodic memory using data for ~14 million markers imputed from the H3Africa genotyping array data. Window-based replication of previously implicated variants and regions of interest support the discovery of African-specific associated variants despite the small population size and low allele frequency. This African genome-wide association study identifies suggestive associations with general cognition and domain-specific cognitive pathways and lays the groundwork for further genomic studies on cognition in Africa.
Shafika Abrahams-Gessel, Xavier F Gómez-Olivé, Stephen Tollman, Alisha N Wade, Jacques D Du Toit, Enrico G Ferro, Chodziwadziwa W Kabudula, and Thomas A Gaziano. 3/1/2023. “Improvements in Hypertension Control in the Rural Longitudinal HAALSI Cohort of South African Adults Aged 40 and Older, From 2014 to 2019.” American Journal of Hypertension. Publisher's VersionAbstract
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.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 ġt;140 mm Hg or diastolic pressure ġt;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.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.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.
Collin F. Payne, LK Liwin, Alisha N Wade, Brian C. Houle, Jacques D. Du Toit, David Flood, and Jennifer Manne-Goehler. 2/11/2023. “Impact of diabetes on longevity and disability-free life expectancy among older South African adults: A prospective longitudinal analysis.” Diabetes Research and Clinical Practice, 197, 110577. Publisher's VersionAbstract
Aims
We seek to understand the coexisting effects of population aging and a rising burden of diabetes on healthy longevity in South Africa.
Methods
We used longitudinal data from the 2015 and 2018 waves of the “Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa” (HAALSI) study to explore life expectancy (LE) and disability-free life expectancy (DFLE) of adults aged 45 and older with and without diabetes in rural South Africa. We estimated LE and DFLE by diabetes status using Markov-based microsimulation.
Results
We find a clear gradient in remaining LE and DFLE based on diabetes status. At age 45, a man without diabetes could expect to live 7.4 [95% CI 3.4 – 11.7] more years than a man with diabetes, and a woman without diabetes could expect to live 3.9 [95% CI: 0.8 – 6.9] more years than a woman with diabetes. Individuals with diabetes lived proportionately more years subject to disability than individuals without diabetes.
Conclusions
We find large and important decrements in disability-free aging for people with diabetes in South Africa. This finding should motivate efforts to strengthen prevention and treatment efforts for diabetes and its complications for older adults in this setting.
Enrico G. Ferro, Shafika Abrahams-Gessel, David Kapaon, Brian Houle, Jacques Du Toit, Ryan G. Wagner, F. Xavier Gómez-Olivé, Alisha N. Wade, Chodziwadziwa W. Kabudula, Stephen Tollman, and Thomas A. Gaziano. 2/8/2023. “Significant Improvement in Blood Pressure Levels Among Older Adults With Hypertension in Rural South Africa.” Hypertension. Publisher's Version
2022
Jacques D. Du Toit, D Kapaon, Nigel J. Crowther, Shafika Abrahams-Gessel, June Fabian, Chodziwadziwa W. Kabudula, Alisha Wade, Stephen Tollman, and Thomas Gaziano. 11/21/2022. “Estimating population level 24-h sodium excretion using spot urine samples in older adults in rural South Africa.” Journal of Hypertension. Publisher's VersionAbstract

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.

Lindsay C. Kobayashi, Chodziwadziwa Whiteson Kabudula, Mohammed U. Kabeto, Xuexin Yu, Stephen M. Tollman, Kathleen Kahn, Lisa F. Berkman, and Molly S. Rosenberg. 10/18/2022. “Long-term household material socioeconomic resources and cognitive health in a population-based cohort of older adults in rural northeast South Africa, 2001–2015.” SSM - Population Health, 20, Pp. 101263. Publisher's VersionAbstract
Material resources owned by households that affect daily living conditions may be salient for cognitive health during aging, especially in low-income settings, but there is scarce evidence on this topic. We investigated relationships between long-term trends in household material resources and cognitive function among older adults in a population-representative study in rural South Africa. Data were from baseline interviews with 4580 adults aged ≥40 in “Health and Ageing in Africa: A Longitudinal Study of an INDEPTH Community in South Africa” (HAALSI) in 2014/2015 linked to retrospective records on their household material resources from the Agincourt Health and Socio-Demographic Surveillance System (HDSS) from 2001 to 2013. Household material resources were assessed biennially in the Agincourt HDSS using a five-point index that captured dwelling materials, water and sanitation, sources of power, livestock, and technological amenities. Cognitive function was assessed in HAALSI and analyzed as a z-standardized latent variable capturing time orientation, episodic memory, and numeracy. We evaluated the relationships between quintiles of each of the mean resource index score, volatility in resource index score, and change in resource index score and subsequent cognitive function, overall and by resource type. Higher mean household resources were positively associated with cognitive function (βadj = 0.237 standard deviation [SD] units for the highest vs. lowest quintile of mean resource index score; 95% CI: 0.163–0.312; p-trend<0.0001), as were larger improvements over time in household resources (βadj = 0.122 SD units for the highest vs. lowest quintile of change in resources; 95% CI: 0.040–0.205; p-trend = 0.001). Results were robust to sensitivity analyses assessing heterogeneity by age and restricting to those with formal education. The findings were largely driven by technological amenities including refrigerators, stoves, telephones, televisions, and vehicles. These amenities may support cognitive function through improving nutrition and providing opportunities for cognitive stimulation through transportation and social contact outside of the home.

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