Socioeconomic factors, particularly wealth, played an important role in determining the risk for dementia among a nationally representative sample of English people aged 65 years and older, according to the results of a study published in JAMA Psychiatry.
Dorina Cadar, PhD, of the Department of Behavioural Science and Health at the University College London and colleagues used data from the English Longitudinal Study of Ageing, a prospective cohort study, to evaluate the relationship between markers of socioeconomic status, including wealth quintiles and the index of multiple deprivation, and the incidence of dementia. Two age cohorts were considered — those born between 1902 and 1925 and those born between 1926 and 1943. The main outcome measure was dementia as determined by physician diagnosis and the Informant Questionnaire on Cognitive Decline in the Elderly.
The study included 6220 individuals aged 65 years and older, with a median age at enrollment of 73.2 years. Of the initial population, dementia developed in 463 within the 12 years between 2002 to 2003 and 2014 to 2015. Among those in the lowest wealth quintile, the hazard for dementia developing was 1.68 times higher than it was for those in the highest quintile (hazard ratio [HR], 1.68). This finding was independent of education level, index of multiple deprivation, and health indicators. The association with wealth was somewhat stronger for those born between 1926 and 1943. The HR was also higher (1.62) for those in the second-highest quintile of index of multiple deprivation compared with those in the lowest quintile (or least deprived).
The study had a number of limitations, including a possible underestimation of dementia diagnoses, nonresponse, and attrition, which are common to longitudinal surveys. The study also included a small sample of cases of dementia, which precluded examining dementia subtypes such as Alzheimer disease vs vascular or mixed dementia. Furthermore, the study population was 97% white, precluding investigation of the effects that race/ethnicity might have on dementia.
The authors suggest that public health strategies for preventing dementia should target socioeconomic gaps to reduce health disparities and protect the disadvantaged.
Cadar D, Lassale C, Davies H, Llewellyn DJ, Batty GD, Steptoe A. Individual and area-based socioeconomic factors associated with dementia incidence in England: evidence from a 12-year follow-up in the English Longitudinal Study of Ageing [published online May 16, 2018]. JAMA Psychiatry.doi:10.1001/jamapsychiatry.2018.1012