Childhood deprivation and later-life cognitive function in a population-based study of older rural South Africans

Abstract

Rationale Little research has evaluated the life course drivers of cognitive aging in South Africa. Objectives We investigated the relationships of self-rated childhood health and father’s occupation during childhood with later-life cognitive function score and whether educational attainment mediated these relationships among older South Africans living in a former region of Apartheid-era racial segregation. Methods Data were from baseline assessments of “Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community” (HAALSI), a population-based study of 5059 men and women aged ≥40 years in 2015 in rural Agincourt sub-district, South Africa. Childhood health, father’s occupation during childhood, and years of education were self-reported in study interviews. Cognitive measures assessed time orientation, numeracy, and word recall, which were included in a z-standardized latent cognitive function score variable. Linear regression models adjusted for age, sex, and country of birth were used to estimate the total and direct effects of each childhood risk factor, and the indirect effects mediated by years of education. Results Poor childhood health predicted lower cognitive scores (total effect = −0.28; 95% CI = −0.35, −0.21, versus good); this effect was not mediated by educational attainment. Having a father in a professional job during childhood, while rare (3% of sample), predicted better cognitive scores (total effect = 0.25; 95% CI = 0.10, 0.40, versus unskilled manual labor, 29% of sample). Half of this effect was mediated by educational attainment. Education was linearly associated with later-life cognitive function score (0.09; 95% CI = 0.09, 0.10 per year achieved). Conclusion In this post-Apartheid, rural South African context, older adults with poor self-reported childhood health or whose father worked in unskilled manual labor had relatively poor cognitive outcomes. Educational attainment strongly predicted cognitive outcomes, and appeared to be, in part, a mechanism of social stratification in later-life cognitive health in this context.

Associations of childhood socioeconomic status with mid‐life and late‐life cognition in Chinese middle‐aged and older population based on a 5‐year period cohort study

“…A growing number of studies regarding late-life cognition have concentrated on the effects of early-life and late-life factors, such as childhood deprivation and adversity, adult socioeconomic status (SES), and lifestyles. [9][10][11][12] Childhood SES is a powerful predictor of health outcomes in later life, always measured by the parental education and occupation or household income. Recently, emerging data have indicated that both higher childhood and adult SES can prevent poor cognitive function in later-life.…”

Using Cross-Cultural Studies to Improve Evidence on Dementia Prevention: Lessons from the Special Issue Sponsored by the International Research Network on Dementia Prevention (IRNDP)

“…The major limitations in these studies is the difficulty of ruling out the confounding influence of individual characteristics such as intelligence or childhood socioeconomic status that may influence both schooling and late-life cognition. Evidence from studies in settings with very different confounders [5], or based on natural experiments that could not plausibly be influenced by individual characteristics [6], strengthens the overall evidence base, even if the new studies have different limitations.…”

The relationships between cognitive function, literacy and HIV status knowledge among older adults in rural South Africa

“…Survey data were collected by trained local fieldworkers using a Computer Assisted Personal Interviews platform in the local xiTsonga language. We assessed three exposures: Cognitive function: a continuous z‐standardized latent variable (mean 0, standard deviation (SD) 1) representing time orientation (ability to state the correct day, month, year and South African president), immediate and delayed recall of 10 words read out loud by the interviewer, and numeracy (ability to count from 1 to 20 and to finish a number skip pattern) . The cognitive function z‐score was derived using confirmatory factor analysis (CFA) with a robust weighted least squares estimator, which used the common covariation between the individual cognitive test items to generate a latent cognitive function z‐score.…”