Individual and area-based socioeconomic differentials in dementia incidence in England: Evidence from a 12-year follow-up of participants in the English Longitudinal Study of Ageing

David Batty
Dorina Cadar
Hugh Davies
Camille Lassale
David Llewellyn
Andrew Steptoe

Published on 20 March 2018

Key Points
Question What is the association between various socioeconomic markers and dementia incidence?

Findings This longitudinal cohort study found that lower wealth in late life, but not education, was associated with increased risk for dementia, suggesting that people with fewer financial resources were at higher risk. No substantive differences were identified in relation to the area of neighborhood deprivation; an age-cohort effect was observed, highlighting that socioeconomic inequalities were more robust among people born in later years.

Meaning The association between socioeconomic status and dementia incidence in a contemporary cohort of older adults may be driven by wealth rather than education.

Abstract

Importance Lower educational attainment is associated with a higher risk of dementia. However, less clear is the extent to which other socioeconomic markers contribute to dementia risk.

Objective To examine the relationship of education, wealth, and area-based deprivation with the incidence of dementia over the last decade in England and investigate differences between people born in different periods.

Design, Setting, and Participants Data from the English Longitudinal Study of Ageing, a prospective cohort study that is representative of the English population, were used to investigate the associations between markers of socioeconomic status (wealth quintiles and the index of multiple deprivation) and dementia incidence. To investigate outcomes associated with age cohorts, 2 independent groups were derived using a median split (born between 1902-1925 and 1926-1943).

Main Outcomes and Measures Dementia as determined by physician diagnosis and the Informant Questionnaire on Cognitive Decline in the Elderly.

Results A total of 6220 individuals aged 65 years and older enrolled in the study (median [interquartile range] age at baseline, 73.2 [68.1-78.3] years; 3410 [54.8%] female). Of these, 463 individuals (7.4%) had new cases of dementia ascertained in the 12 years between 2002-2003 and 2014-2015. In the cohort born between 1926 and 1943, the hazard of developing dementia was 1.68 times higher (hazard ratio [HR] = 1.68 [95% CI, 1.05-2.86]) for those in the lowest wealth quintile compared with those in the highest quintile, independent of education, index of multiple deprivation, and health indicators. Higher hazards were also observed for those in the second-highest quintile of index of multiple deprivation (HR = 1.62 [95% CI, 1.06-2.46]) compared with those in the lowest (least deprived) quintile.

Conclusions and Relevance In an English nationally representative sample, the incidence of dementia appeared to be socioeconomically patterned primarily by the level of wealth. This association was somewhat stronger for participants born in later years.