Socioeconomic inequalities in cognitive function in midlife and early late‐life are partially attributable to modifiable health and lifestyle factors

Abstract

AbstractBackgroundThere are socioeconomic inequalities in dementia risk. Growing evidence highlights the prevention potential of dementia through modifiable health and lifestyle factors. We aimed to investigate whether health and lifestyle factors play a mediating role in the association of socioeconomic inequalities and cognitive function in midlife and early late life in the general population.MethodThe “LIfestyle for BRAin health” (LIBRA) score was computed for 6.203 baseline participants of the LIFE‐Adult study, a population‐based cohort to investigate civilization diseases in the German population. LIBRA is a validated score (range: ‐5.9 to +12.7) that predicts dementia in midlife and early late life, consisting of twelve modifiable health and lifestyle factors (heart disease, kidney disease, diabetes, obesity, hypertension, hypercholesterolemia, alcohol consumption, smoking, physical inactivity, diet, depression, cognitive activity). Socioeconomic status (SES; low/middle/high) was calculated based on education, net equivalence income, and occupational status. We used structural equation modelling to inspect potential mediation of the LIBRA score between SES and measures of cognitive function (Verbal Fluency Test/VFT; Trail Making Test/TMT A and B). Analyses were adjusted for age, sex, marital status, living situation, employment, and social network.ResultParticipants were M = 57.7 (SD = 12.0, range: 40‐79) years old and dementia‐free; 50.7% were female. Individuals with low SES had significantly higher LIBRA scores (indicating higher dementia risk) compared to individuals with middle SES and high SES, who had the lowest LIBRA scores (M = 1.2, SD = 2.3 vs. M = ‐0.4, SD = ‐2.6 vs. M = ‐1.2, SD = 2.5; F(2) = 271.8, p < .001). Likewise, all neuropsychological test scores showed that cognitive function was lowest in individuals with low SES and highest in individuals with high SES. Bootstrapped mediation analysis indicated that 12.4% (VFT) to 22.8% (TMT) of the differences in cognitive function between low SES and high SES were significantly mediated by differences in LIBRA scores.ConclusionDifferences in cognitive function due to socioeconomic inequalities can be partially attributed to differences in modifiable health and lifestyle factors. Thus, promoting health and lifestyle changes in individuals with low SES could contribute to attenuate socioeconomic inequalities in cognitive function, potentially benefiting dementia prevention.