Cognitive function and cardiometabolic disease risk factors in rural South Africa: baseline evidence from the HAALSI study

• Published in: BMC public health Vol. 19; no. 1; pp. 1579 - 11
• Main Authors: Houle, Brian, Gaziano, Thomas, Farrell, Meagan, Gómez-Olivé, F Xavier, Kobayashi, Lindsay C, Crowther, Nigel J, Wade, Alisha N, Montana, Livia, Wagner, Ryan G, Berkman, Lisa, Tollman, Stephen M
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 27.11.2019; BioMed Central; BMC
• Subjects: Acquired immune deficiency syndrome; Africa; Aged; Aging; AIDS; Blood pressure; Body mass index; Cardiometabolic disease; Cardiovascular Diseases - epidemiology; Cardiovascular Diseases - psychology; Cognition; Cognitive ability; Cognitive function; Confidence intervals; Correlation analysis; Cross-sectional studies; Diabetes; Diabetes mellitus; Dyslipidemia; Emtricitabine; Epidemiology; Female; Future predictions; Health; Health risks; HIV; Human immunodeficiency virus; Humans; Hypertension; Life expectancy; Longitudinal Studies; Male; Medical research; Metabolic Diseases - epidemiology; Metabolic Diseases - psychology; Middle Aged; Mortality; Noncommunicable disease; Numeracy; Obesity; Older people; Population; Population studies; Public health; Regression analysis; Retirement; Risk analysis; Risk Factors; Rural areas; Rural Population - statistics & numerical data; Smoking; Sociodemographics; South Africa - epidemiology; Statistical analysis; Studies; Underweight; South Africa; Sub-Saharan Africa; Africa; Cardiometabolic disease; Noncommunicable disease; Cross-sectional studies; Cognitive function; Epidemiology; Africa
• ISSN: 1471-2458; 1471-2458
• DOI: 10.1186/s12889-019-7938-z

Evidence on cognitive function in older South Africans is limited, with few population-based studies. We aimed to estimate baseline associations between cognitive function and cardiometabolic disease risk factors in rural South Africa. We use baseline data from "Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa" (HAALSI), a population-based study of adults aged 40 and above in rural South Africa in 2015. Cognitive function was measured using measures of time orientation, immediate and delayed recall, and numeracy adapted from the Health and Retirement Study cognitive battery (overall total cognitive score range 0-26). We used multiple linear regression to estimate associations between cardiometabolic risk factors (including BMI, hypertension, dyslipidemia, diabetes, history of stroke, alcohol frequency, and smoking status) and the overall cognitive function score, adjusted for potential confounders. In multivariable-adjusted analyses (n = 3018; male = 1520; female = 1498; median age 59 (interquartile range 50-67)), cardiometabolic risk factors associated with lower cognitive function scores included: diabetes (b = - 1.11 [95% confidence interval: - 2.01, - 0.20] for controlled diabetes vs. no diabetes); underweight BMI (b = - 0.87 [CI: - 1.48, - 0.26] vs. normal BMI); and current and past smoking history compared to never smokers. Factors associated with higher cognitive function scores included: obese BMI (b = 0.74 [CI: 0.39, 1.10] vs. normal BMI); and controlled hypertension (b = 0.53 [CI: 0.11, 0.96] vs. normotensive). We provide an important baseline from rural South Africa on the associations between cardiometabolic disease risk factors and cognitive function in an older, rural South African population using standardized clinical measurements and cut-offs and widely used cognitive assessments. Future studies are needed to clarify temporal associations as well as patterns between the onset and duration of cardiometabolic conditions and cognitive function. As the South African population ages, effective management of cardiometabolic risk factors may be key to lasting cognitive health.