Subjective social position and cognitive function in a longitudinal cohort of older, rural South African adults, 2014–2019
Date
2021-09-23
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Abstract
Background The relationship between subjective social
position (SSP) and cognitive ageing unclear, especially
in low-income settings. We aimed to investigate the
relationship between SSP and cognitive function over
time among older adults in rural South Africa.
Methods Data were from 3771 adults aged ≥40 in the
population-representative ’Health and Ageing in Africa: A
Longitudinal Study of an INDEPTH Community in South
Africa’ from 2014/2015 (baseline) to 2018/2019 (followup). SSP was assessed at baseline with the 10-rung
MacArthur Network social position ladder. Outcomes
were composite orientation and episodic memory scores
at baseline and follow-up (range: 0–24). Mortality- and
attrition-weighted linear regression estimated the
associations between baseline SSP with cognitive scores
at each of the baseline and follow-up. Models were
adjusted for age, age2
, sex, country of birth, father’s
occupation, education, employment, household assets,
literacy, marital status and health-related covariates.
Results SSP responses ranged from 0 (bottom ladder
rung/lowest social position) to 10 (top ladder rung/
highest social position), with a mean of 6.6 (SD: 2.3).
SSP was positively associated with baseline cognitive
score (adjusted β=0.198 points per ladder rung increase;
95%CI 0.145 to 0.253) and follow-up cognitive score
(adjusted β=0.078 points per ladder rung increase;
95%CI 0.021 to 0.136).
Conclusion Independent of objective socioeconomic
position measures, SSP is associated with orientation
and episodic memory scores over two time points
approximately 3 years apart among older rural South
Africans. Future research is needed to establish the
causality of the observed relationships, whether
they persist over longer follow-up periods and their
consistency in other populations.