Social determinants of health and risk of dementia among older men and women: A 12-year cohort study in Australia

Abstract

INTRODUCTION

Social determinants of health (SDH) are recognized as contributing factors to cognitive disorders, but their collective influence on dementia risk remains unclear.

METHODS

A gender-disaggregated analysis was conducted on 12,896 community-dwelling older Australians (mean ± SD age: 75.2 ± 4.3 years; 54% women) without major cognitive impairment upon enrollment. Latent class analysis identified clusters from 72 SDH (70 individual-level and 2 neighborhood-level), while Cox proportional hazards regression estimated dementia risk over 12 years (median: 8.4) follow-up.

RESULTS

Four clusters were identified: least disadvantaged (Class 1: 31.5% men; 30.6% women), most disadvantaged (Class 2: 20.2% men; 19.4% women), high social support with Class 1 features (Class 3: 22.2% men; 24.1% women), and high social support with Class 2 features (Class 4: 26.1% men; 25.7% women). Compared to Class 1, men (HR: 1.49, 95% CI: 1.12–1.98) and women (HR: 1.56, 95% CI: 1.17–2.07) in Class 2, and women in Class 4 (HR: 1.66, 95% CI: 1.28–2.16) had a higher dementia risk.

DISCUSSION

Socioeconomic disadvantage was associated with incident dementia. Despite stronger social support, women's cognitive capacity appeared to be disproportionately impacted by adverse SDH.

Highlights

• Four distinct multidimensional clusters were identified from a wide range of 72 social determinants of health.
• These clusters were associated with dementia risk differently in men and women.
• In both men and women, the most socioeconomically disadvantaged group had a higher risk of dementia.
• Despite stronger interpersonal social support, women had a greater risk of dementia.
• The addition of known dementia risk factors in cluster analysis did not change the findings, suggesting that social determinants of health independently predict dementia risk.