Kidney dysfunction: prevalence and associated risk factors in a community-based study from the North West Province of South Africa.

BACKGROUND: Globally, the World Health Organization ranks chronic kidney disease (CKD) as one of the top 10 causes of mortality. In South Africa, where noncommunicable diseases have become leading causes of mortality, the true population prevalence of CKD is unknown and associated risk factors remain understudied. This study aimed to describe the prevalence of kidney dysfunction and associated risk factors in a community from the North West province of South Africa. METHODS: This cross-sectional study included 1999 participants older than 30 years. Kidney dysfunction was defined as (i) estimated glomerular filtration rate (eGFR) < 90 ml/min/1.73m2, or (ii) urine albuminuria-to-creatinine ratio (uACR) ≥ 3.0 mg/mmol, or a combination (i and ii). Risk factors included age, sex, urban/rural locality, body mass index (BMI), blood pressure (BP), lipid profile, haemoglobin A1c (HbA1C), C-reactive protein (CRP), gamma-glutamyl transferase (GGT), tobacco use, and HIV status. RESULTS: Mean age of participants was 48 (42;56) years, and 655/1999 (33%) had eGFR < 90 ml/min/1.73m2 and/or uACR ≥ 3.0 mg/mmol. Compared to those with normal kidney function, participants with eGFR < 90 ml/min/1.73m2 and/or uACR ≥ 3.0 mg/mmol were older, female, had higher measures of adiposity, systolic, diastolic, and mean arterial blood pressure, serum lipids and C-reactive protein (CRP) (all p ≤ 0.024). In multiple regression analyses eGFR was associated with systolic BP (ß = 0.11) and HIV infection (ß = -0.09), and albuminuria was associated with elevated CRP (ß = 0.12) and HIV infection (ß = 0.11) (all p < 0.026). In both groups (individuals with and without kidney dysfunction respectively), eGFR was associated with age (ß = -0.29, ß = -0.49), male sex (ß = 0.35, ß = 0.28), BMI (ß = -0.12, ß = -0.09), low-density/high-density lipoprotein cholesterol ratio (ß = -0.17, ß = -0.09) and CRP (ß = 0.10, ß = 0.09) (all p < 0.005); and uACR was associated with female sex (ß = 0.10, ß = -0.14), urban locality (ß = -0.11, ß = -0.08), BMI (ß = -0.11, ß-0.11), and systolic BP (ß = 0.27, ß = 0.14) (all p < 0.017). CONCLUSION: In this study from the North West province, South Africa, eGFR < 90 ml/min/1.73m2 and/or uACR ≥ 3.0 mg/mmol was prevalent and associated with modifiable risk factors. The findings may inform screening strategies for kidney disease prevention, focusing on women, obesity, blood pressure control, dyslipidaemia, identifying and treating inflammation, and HIV diagnosis and treatment.

The association of von willebrand factor and its cleaving protease (ADAMTS13) with health behaviours in young black and white adults: the African-PREDICT study.

To reduce cardiovascular risks imposed by Von Willebrand factor (vWF) and ADAMTS13 from young ages, knowledge on health behaviours that may affect their concentrations is essential. We therefore determined whether circulating vWF antigen and ADAMTS13 associate with health behaviours. We included 1196 black and white healthy adults aged 20-30 years and used questionnaires for socio-economic, tobacco and alcohol use data. vWF:Ag was measured from citrated samples and ADAMTS13, cotinine and gamma-glutamyl transferase (GGT) from serum. Salt intake was estimated from 24-hour urine and body mass index (BMI) was calculated. Black adults had higher vWF:Ag and lower ADAMTS13 levels compared to whites (all p < 0.001). In multiple regression analyses in the total group, vWF:Ag associated positively with BMI (p = 0.037), while ADAMTS13 associated negatively with BMI (p = 0.016) and cotinine (p = 0.029); and positively with GGT (p = 0.002). When exploring within each ethnic group, vWF:Ag associated positively with estimated salt intake (p = 0.043) only in blacks. In whites, vWF:Ag associated positively with BMI (p = 0.023) while ADAMTS13 associated positively with GGT (p = 0.003) and negatively with cotinine (p = 0.041). Young black adults may have an increased thrombotic risk due to higher vWF and lower ADAMTS13. The ethnic-specific associations observed may have implications for public health initiatives to improve cardiovascular outcomes.