Dementia risk varies along the social gradient, which needs to be considered in risk reduction and prevention strategies. Revealing links of social determinants of health (SDOH) and modifiable health and lifestyle factors for dementia holds clues towards maximizing dementia risk reduction opportunities, especially for vulnerable populations. Therefore, the aim was to investigate associations of SDOH and a dementia risk score in Indigenous Māori and Non-Māori (mainly European descent) in midlife and early late-life.

A subsample of the New Zealand Health, Work and Retirement study completed standardized face-to-face cognitive assessments (adapted ‘Kiwi’ Addenbrooke’s Cognitive Examination/ACE-R) in 2010. We computed the Lifestyle for Brain Health (LIBRA) dementia risk score, comprising 8 risk factors (low/moderate alcohol consumption, heart disease, physical inactivity, chronic kidney disease, diabetes, smoking, hypertension, depression). Higher scores indicate higher dementia risk/poorer lifestyle (range= -1;+9.2). First, we assessed associations of LIBRA and cognition. Second, we performed adjusted regression analysis for area-based (socioeconomic deprivation, health care access, neighbourhood safety) and individual SDOH (education, employment status, net income, social loneliness) with LIBRA stratified for Māori and Non-Māori.

In 918 participants (age: M= 62.9 years, SD= 6.7, range= 48-75; females= 52.8%; Māori= 26.2%), a higher LIBRA score (M= 1.8, SD= 1.6, observed range= -1; +7.4) was associated with lower cognitive functioning (b= -0.30, 95%CI= [-0.48;-0.11], p= .002) and cognitive impairment (OR= 1.41, 95%CI= [1.10;1.81], p= .007), adjusted for age, sex, education, ethnicity and area-based socio- economic deprivation. Higher area-based socio-economic deprivation was associated with higher LIBRA in Māori (b= .10, 95%CI= [0.02;0.18], p= .020), but not in Non-Māori (b= 0.01, 95%CI= [- .03;0.05], p= .677). Employment status and lower neighbourhood safety were associated with higher LIBRA in Non-Māori only. Health care access difficulties and social loneliness were associated with higher LIBRA in both populations, while education and net income were not.

SODH are differentially associated with dementia risk in midlife and early late-life New Zealanders. Area-based socioeconomic deprivation was linked to dementia risk in Indigenous Māori, but not in Non-Māori. This points to systematic inequities in dementia risk, which require equity- focused policy-based public health approaches to risk reduction.