Long-term household material socioeconomic resources and cognitive health in a population-based cohort of older adults in rural northeast South Africa, 2001–2015
Date
2022
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Abstract
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