Low Socioeconomic Status Correlates with Raised Dementia Risk
It is well known that low socioeconomic status correlates with a raised risk of age-related disease and mortality, though it is challenging to determine which of the possible causes are in fact more or less important. A web of correlations are linked to socioeconomic status: intelligence, access to medical services, education, personality traits, lifestyle choices, and more. Here the focus of the study is on location of residence as a marker of socioeconomic status, and in this context it is interesting to note the studies that have compared the differences in particulate air pollution versus mortality in wealthier versus poorer neighborhoods in US metropolitan areas. Higher particulate air pollution is by now a noted contribution to age-related disease and mortality, though clearly only part of the story when it comes to how wealth, status, and life expectancy are related.
Dementia risk may be elevated in socioeconomically disadvantaged neighborhoods. Reasons for this remain unclear, and this elevation has yet to be shown at a national population level. We tested whether dementia was more prevalent in disadvantaged neighborhoods across the New Zealand population (N = 1.41 million analytic sample) over a 20-year observation. We then tested whether premorbid dementia risk factors and MRI-measured brain-structure antecedents were more prevalent among midlife residents of disadvantaged neighborhoods in a population-representative NZ-birth-cohort (N = 938 analytic sample).
People residing in disadvantaged neighborhoods were at greater risk of dementia (hazard ratio, HR, per-quintile-disadvantage-increase = 1.09) and, decades before clinical endpoints typically emerge, evidenced elevated dementia-risk scores (CAIDE, LIBRA, Lancet, ANU-ADRI, DunedinARB; β 0.31-0.39) and displayed dementia-associated brain structural deficits and cognitive difficulties/decline. Disadvantaged neighborhoods have more residents with dementia, and decades before dementia is diagnosed, residents have more dementia-risk factors and brain-structure antecedents. Whether or not neighborhoods causally influence risk, they may offer scalable opportunities for primary dementia prevention.