Faculty of Health Sciences
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Item Pension exposure and health: Evidence from a longitudinal study in South Africa(2023-10) Carlos Riumallo Herl; Chodziwadziwa Kabudula; Kathleen Kahn; Stephen Tollman; David CanningSocial protection schemes have been expanding around the world with the objective of protecting older persons during retirement. While theoretically they have been seen as tools to improve individual wellbeing, there are few studies that evaluate whether social pensions can improve health. In this study, we exploit the change in eligibility criteria for the South African Old Age grant to estimate the association between pension exposure eligibility and health of older persons. For this, we use data from the Health and Aging in Africa: A longitudinal Study of an INDEPTH Community in South Africa (HAALSI) and model pension exposure in terms of its cumulative effect. Our results show that pension exposure is associated with better health as measured by a set of health indices. Disentangling these effects, we find that pension exposure is most likely to improve health through the delayed onset of physical disabilities in the elderly population. Our study highlights the relevance of social protection schemes as a mechanism to protect older persons physical health.Item Genome-wide association study of population-standardised cognitive performance phenotypes in a rural South African community.(2023-03-27) Cassandra C. Soo; Jean-Tristan Brandenburg; Almut Nebel; Stephen Tollman; Lisa Berkman; Michèle Ramsay; Ananyo ChoudhuryCognitive 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. Windowbased 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.Item Trans-ethnic genomic informed risk assessment for Alzeheimer's disease: an International Hundred K+ Cohorts Consortium study.(2023-07-14) Patrick M Sleiman; Hui-Qi Qu; John J Connolly; Frank Mentch; Alexandre Pereira; Paulo A Lotufo; Stephen Tollman; Ananyo Choudhury; Michele Ramsay; Norihiro Kato; Kouichi Ozaki; Risa Mitsumori; Jae-Pil Jeon; Chang Hyung Hong; Sang Joon Son; Hyun Woong Roh; Dong-Gi Lee; Naaheed Mukadam; Isabelle F Foote; Charles R Marshall; Adam Butterworth; Bram P Prins; Joseph T Glessner; Hakon HakonarsonBackground: As a collaboration model between the International HundredK+ Cohorts Consortium (IHCC) and the Davos Alzheimer's Collaborative (DAC), our aim was to develop a trans-ethnic genomic informed risk assessment (GIRA) algorithm for Alzheimer's disease (AD). Methods: The GIRA model was created to include polygenic risk score calculated from the AD genome-wide association study loci, the apolipoprotein E haplotypes, and non-genetic covariates including age, sex, and the first three principal components of population substructure. Results: We validated the performance of the GIRA model in different populations. The proteomic study in the participant sites identified proteins related to female infertility and autoimmune thyroiditis and associated with the risk scores of AD. Conclusions: As the initial effort by the IHCC to leverage existing large-scale datasets in a collaborative setting with DAC, we developed a trans-ethnic GIRA for AD with the potential of identifying individuals at high risk of developing AD for future clinical applications.Item The adolescent HIV executive function and drumming (AHEAD) study, afeasibility trial of a group drumming intervention amongst adolescents with HIV(2023-04-11) Kirsten Rowe; Julia Ruiz Pozuelo; Alecia Nickless; Absolum David Nkosi; Andeline Dos Santos; Kathleen Kahn; Stephen Tollman; Ryan G Wagner; Gaia Scerif; Alan SteinAHEAD feasibility trial assessed the feasibility and acceptability of an 8-session group drummingprogramme aiming to improve executive function, depression and anxiety symptoms, andperceived social support in adolescents living with HIV in a rural low-income South Africansetting. Sixty-eight 12- to 19-year-old adolescents participated. They were individuallyrandomised. The intervention arm (n= 34) received weekly hour-long group drumming sessions.Controls (n= 34) received no intervention. Feasibility and acceptability were assessed usingrates of: enrolment; retention; attendance; logistical problems; adolescent-reportedacceptability. Secondary measures included:five Oxford Cognitive Screen-Executive Function(OCS-EF) tasks; two Rapid Assessment of Cognitive and Emotional Regulation (RACER) tasks; theSelf-Reporting Questionnaire-20 (SRQ-20) measuring depression and anxiety symptoms; theMultidimensional Scale of Perceived Social Support (MSPSS). All feasibility criteria were withingreen progression limits. Enrolment, retention, and acceptability were high. There was a positiveeffect on adolescent depressed mood with signal for a working memory effect. There were nosignificant effects on executive function or socio-emotional scales. Qualitativefindingssuggested socio-emotional benefits including: group belonging; decreased internalised stigma;improved mood; decreased anxiety. Group drumming is a feasible and acceptable interventionamongst adolescents living with HIV in rural South Africa. A full-scale trial is recommended.Item Significant Improvement in Blood Pressure Levels Among Older Adults With Hypertension in Rural South Africa(2023-08-08) 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. Kabudulah; Stephen Tollman; Thomas A. GazianoBackground: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.Item Forgotten but not gone in rural South Africa: Urinary schistosomiasis and implications for chronic kidney disease screening in endemic countries(2023-02-10) Alison Craik; Mwawi Gondwe; Nokthula Mayindi; Shingirai Chipungu; Bongekile Khoza; Xavier Gómez-Olivé; Stephen Tollman; John Frean; Laurie A. Tomlinson; June FabianBackground: Urinary schistosomiasis caused by infection with Schistosoma haematobium (S. haematobium) remains endemic in Africa and is associated with haematuria and albuminuria/proteinuria. Kidney Disease Improving Global Outcomes clinical guidelines recommend evaluating proteinuria/albuminuria and glomerular filtration rate for chronic kidney disease (CKD) diagnosis. The guidelines are informed by population data outside of Africa but have been adopted in many African countries with little validation. Our study aimed to characterise the burden of urinary schistosomiasis in rural South Africa (SA) and evaluate its relationship with markers of kidney dysfunction with implications for CKD screening. Methods: In this population-based cohort study, we recruited 2021 adults aged 20 – 79 years in the Mpumalanga Province, SA. Sociodemographic data were recorded, urinalysis performed, and serum creatinine and urine albumin and creatinine measured. Kidney dysfunction was defined as an estimated glomerular filtration rate (eGFR) <60ml/min/1.73m2 and/or urine albumin-creatinine ratio >3.0mg/mmol. S. haematobium infection was determined by urine microscopy. Multivariable analyses were performed to determine relationships between S. haematobium and markers of kidney dysfunction. Results: Data were available for 1226 of 2021 participants. 717 (58.5%) were female and the median age was 35 years (IQR 27 – 47). Prevalence of kidney dysfunction and S. haematobium was 20.2% and 5.1% respectively. S. haematobium was strongly associated with kidney dysfunction (OR 8.66; 95% CI 4.10 – 18.3) and related to albuminuria alone (OR 8.69; 95% CI 4.11 – 18.8), with no evidence of an association with eGFR <90ml/min/1.73m2 (OR 0.43; 95% CI 0.05 – 3.59). Discussion: The strong association between urinary schistosomiasis and albuminuria requires careful consideration when screening for CKD. Screening for, and treatment of, schistosomiasis should be a routine part of initial work-up for CKD in S. haematobium endemic areas. Urinary schistosomiasis, a neglected tropical disease, remains a public health concern in the Mpumulanga province of SA.Item 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-OliveIntroduction: 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.Item Estimating population level 24-h sodium excretion using spot urine samples in older adults in rural South Africa(2023-02-01) Jacques D. Du Toita; David Kapaonb; Nigel J. Crowtherc; Shafika Abrahams-Gessele; June Fabian; Chodziwadziwa W. Kabudula; Alisha N. Wade; Stephen Tollman; Thomas A. GazianoBackground: 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.Item Obstacles and facilitators to communicating with children about their parents’ mental illness: a qualitative study in a sub‑district of Mpumalanga, South Africa(2023) Lucy Dean; Hadassah Buechner; Bianca Moffett; Meriam Maritze; Louise J. Dalton; Jeffrey R. Hanna; Elizabeth Rapa; Alan Stein; Stephen Tollman; Kathleen KahnBackground Given that common mental disorders are one of the leading causes of disease burden worldwide, it is likely that many children are growing up with a parent or other adult within their family who has anxiety or depression. Parents with a mental illness may not consider it appropriate to discuss their illness with their child, and consequently an absence of communication may lead to stigmatization, shame, misunderstanding their parents’ symptoms, and even blaming themselves. There is a scarcity of research exploring the experiences and perceptions of healthcare professionals about communication with children of parents with mental illness in low-resource and African contexts. Methods A qualitative study using semi-structured interviews with healthcare professionals (n = 15) was conducted within the Bushbuckridge sub-district of Mpumalanga Province, South Africa. Data were analysed using Thematic Analysis. Results Four themes were identified relating to the obstacles around communication with children. These included: (1) finding an appropriate language to describe mental illness, as well as the prevailing cultural explanations of mental illness (2) the stigma associated with mental illness (3) the perceived role of children in society and (4) mental health services and staff skills. Two themes that addressed facilitators of communication about parental mental illness were identified: (1) the potential to increase mental health awareness amongst the broader community through social media, the internet, and general psychoeducation (2) healthcare professionals’ concerns for the wellbeing and future mental health of patients’ children, as well as their hopes for increased mental health awareness amongst future generations. Conclusions This study provides insight into healthcare professionals’ attitudes and perceptions about talking to patients and families within their community about mental illness. The results provide recommendations about possible ways to promote sharing information about a parent’s mental illness with children at an individual and community level. Future research should focus on the collaborative creation of culturally sensitive psychoeducationalItem Forgotten but not gone in rural South Africa: Urinary schistosomiasis and implications for chronic kidney disease screening in endemic countries [version 1; peer review: awaiting peer review](2023-02-10) Alison Craik; Mwawi Gondwe; Nokthula Mayindi; Shingirai Chipungu; Bongekile Khoza; Xavier Gómez-Olivé; Stephen Tollman; John Frean; Laurie A. Tomlinson; June FabianBackground: Urinary schistosomiasis caused by infection with Schistosoma haematobium (S. haematobium) remains endemic in Africa and is associated with haematuria and albuminuria/proteinuria. Kidney Disease Improving Global Outcomes clinical guidelines recommend evaluating proteinuria/albuminuria and glomerular filtration rate for chronic kidney disease (CKD) diagnosis. The guidelines are informed by population data outside of Africa but have been adopted in many African countries with little validation. Our study aimed to characterise the burden of urinary schistosomiasis in rural South Africa (SA) and evaluate its relationship with markers of kidney dysfunction with implications for CKD screening. Methods: In this population-based cohort study, we recruited 2021 adults aged 20 – 79 years in the Mpumalanga Province, SA. Sociodemographic data were recorded, urinalysis performed, and serum creatinine and urine albumin and creatinine measured. Kidney dysfunction was defined as an estimated glomerular filtration rate (eGFR) <60ml/min/1.73m2 and/or urine albumin-creatinine ratio>3.0mg/mmol. S. haematobium infection was determined by urine microscopy. Multivariable analyses were performed to determine relationships between S. haematobium and markers of kidney dysfunction. Results: Data were available for 1226 of 2021 participants. 717 (58.5%) were female and the median age was 35 years (IQR 27 – 47). Prevalence of kidney dysfunction and S. haematobium was 20.2% and 5.1% respectively. S. haematobium was strongly associated with kidney dysfunction (OR 8.66; 95% CI 4.10 – 18.3) and related to albuminuria alone (OR 8.69; 95% CI 4.11 – 18.8), with no evidence of an association with eGFR <90ml/min/1.73m2 (OR 0.43; 95% CI 0.05 – 3.59). Discussion: The strong association between urinary schistosomiasis and albuminuria requires careful consideration when screening for CKD. Screening for, and treatment of, schistosomiasis should be a routine part of initial work-up for CKD in S. haematobium endemic areas. Urinary schistosomiasis, a neglected tropical disease, remains a public health concern in the Mpumulanga province of SA.