A comprehensive prospective cohort study, led by Rui Li, Ruyi Li, Jinchi Xie, Junxiang Chen, Sen Liu, An Pan, and Gang Liu, examined the association between socioeconomic status, lifestyle factors, and the incidence of early-onset dementia (diagnosed before 65 years of age) versus late-onset dementia.
Utilizing data from the UK Biobank, the study analyzed information from 257,345 individuals for early-onset dementia and 294,133 older individuals for late-onset dementia over a mean follow-up period of 11.9-12.5 years. Of these participants, 502 early-onset dementia cases and 5,768 late-onset dementia cases were documented.
The research revealed distinct risk factor profiles between the two forms of dementia. Notably, low socioeconomic status exhibited a substantially higher risk for early-onset dementia compared to late-onset dementia, with an age and sex-adjusted hazard ratio (HR) of 4.40 versus 1.90, respectively. This highlighted a ratio of HRs of 2.32 between the two forms.
Moreover, after adjusting for various risk factors, individuals with low socioeconomic status had a notably increased risk for early-onset dementia (HR 3.38). The study also observed that unhealthy lifestyles mediated only 3.2% of the association between socioeconomic status and early-onset dementia.
Furthermore, those with both low socioeconomic status and unhealthy lifestyles experienced an even higher risk of early-onset dementia (HR 5.40). Interestingly, there was no significant interaction observed between lifestyle and socioeconomic status in relation to dementia risk.
The study emphasizes that early-onset and late-onset dementia might have varying risk factor profiles, and while some risk factors may be similar, their impact on dementia incidence appears to be greater for early-onset cases. Additionally, the research suggests that addressing social determinants of health beyond promoting healthy lifestyles is crucial in reducing socioeconomic inequities related to dementia risk.
Funding for the study was supported by various organizations, including the National Key Research and Development Program of China, the National Natural Science Foundation of China, the Hubei Province Science Fund for Distinguished Young Scholars, and the Fundamental Research Funds for the Central Universities. Conflict of interest disclosures were made for some authors related to research funding.
