Persistent financial adversity and cognitive ageing: A lifecourse investigation

Background: Little is known about the effect of persistent financial adversity across adulthood on cognitive ageing, and whether these impacts vary based on sex, childhood socioeconomic circumstances (SEC) and genetic risk. Methods: Using data from the 1946 Birth cohort study (N=2,759), with extensive data spanning over 70 years, as well as an embedded neuroimaging study (Insight46, N=356-468), we examined the prospective association between financial adversity (low household income, financial hardships; 26-53 years) and cognitive ageing (cognitive performance at 53 years; decline between 53-69 years, modelled using latent growth curve model; neuroimaging measures of brain health between 69-74 years), and the moderating role of sex, childhood SEC and APOE-ɛ4. Covariates included sex at birth, childhood SEC, childhood cognition (8 years), symptoms of depression and anxiety (13-15 years), and educational attainment (26 years). Findings: Increased exposure to low household income as well as financial hardships was associated with lower processing speed (SE: -0.07 [95% CI: -0.13, -0.02], -0.05 [-0.11, -0.00], respectively) and verbal memory at age 53 (-0.16 [-0.21, -0.11], -0.10 [-0.15, -0.05] respectively). Increased exposure to financial adversity was also associated with slower verbal memory decline from 53 to 69 years, due to already lower baseline scores at 53 years. Persistent financial adversity was associated with greater ventricular volume at 69-71 years, and stronger associations between financial adversity and brain atrophy were found for males, those with lower childhood SEC, and APOE-ɛ4 carriers. APOE-ɛ4 carriers in particular were consistently more vulnerable to the effect of persistent financial adversity on brain atrophy. Interpretation: Persistent exposure to financial adversity influences cognitive performance by midlife and later-life brain atrophy, with impacts being larger for males, disadvantaged childhood SEC and individuals with greater genetic risk. These highlight the potential role of poverty reduction efforts in working-age adults for preventing dementia and promoting cognitive health in an ageing population.