Higher socioeconomic deprivation in areas predicts cognitive decline in New Zealanders without cognitive impairment

Previous studies identified individual-level socioeconomic factors as key determinants of cognitive health. This study investigated the effect of area-based socioeconomic deprivation on cognitive outcomes in midlife to early late-life New Zealanders without cognitive impairment at baseline. Data stemmed from a subsample of the New Zealand Health, Work and Retirement Study, a cohort study on ageing, who completed face-to-face interviews and were reassessed two years later. Cognitive functioning was measured using Addenbrooke's Cognitive Examination-Revised, adapted for culturally acceptable use in Aotearoa New Zealand. Area-based socioeconomic deprivation was assessed using the New Zealand Deprivation Index (NZDep2006). Linear mixed-effects models analysed the association between area-based socioeconomic deprivation and cognitive outcomes. The analysis included 783 participants without cognitive impairment at baseline (54.7% female, mean age 62.7 years, 25.0% Māori, the Indigenous people of Aotearoa New Zealand). There was an association between higher area-based socioeconomic deprivation and lower cognitive functioning (B = -0.08, 95%CI: -0.15;-0.01; p = .050) and cognitive decline (B = -0.12, 95%CI: -0.20;-0.04, p = .013) over two years, while controlling for covariates. The findings emphasise the importance of considering neighbourhood characteristics and broader socioeconomic factors in strategies aimed at mitigating cognitive health disparities and reducing the impact of dementia in disadvantaged communities.