A nationwide analysis from the United States has revealed a clear link between lower income and a greater concentration of several modifiable dementia risk factors. The findings, published in Neurology, suggest that longstanding economic disparities continue to shape the health profiles of millions of Americans and may influence future dementia rates across the population.

Study Analyses Two Decades of National Health Data

Researchers led by Dr Eric L. Stulberg of the University of Pennsylvania examined information from the U.S. National Health and Nutrition Examination Surveys (NHANES), covering the years 1999 to 2008, 2011 to 2014, and predominantly 2015 to 2018. The study included adults aged 18 to 44 (early–midlife), 45 to 64 (midlife), and those aged 65 and over (late life), allowing investigators to identify patterns across different stages of adulthood.

Between 2015 and 2018, a total of 13,145 participants had complete data on relevant health risks. According to the research team, individuals with higher income tended to show a lower prevalence of most dementia-related risk factors, with the notable exceptions of obesity, elevated low-density lipoprotein cholesterol (LDL-C) and traumatic brain injury, which did not appear to follow the same socioeconomic gradient.

Low-Income Groups Face Higher Rates of Preventable Conditions

Among those living on incomes below 100% of the U.S. federal poverty level, the most influential late-life risk factor was vision loss, which accounted for an estimated population-level impact of 20.9%. Vision impairment is increasingly recognised as an important contributor to cognitive decline, with research indicating that untreated visual problems may accelerate functional deterioration in older adults.

The study also found that higher income corresponded with fewer midlife risk factors overall, with a prevalence ratio of 0.91. This suggests that financial stability may play a substantial protective role during the period of life when dementia-related biological changes often begin to develop.

Importantly, the researchers reported that populations historically underrepresented in dementia studies—including several racial and ethnic minority groups in the United States—faced elevated rates of midlife diabetes, midlife obesity, physical inactivity and late-life vision loss. These findings reinforce long-standing concerns about health inequities affecting minority communities.

Opportunities for Early Intervention

Dr Stulberg emphasised that the results highlight the need for targeted public health strategies to reduce preventable dementia risks in lower-income and underserved populations. According to his statement, many of the identified risk factors are modifiable, suggesting that early screening and improved access to health services could reduce the future burden of dementia in vulnerable groups.

Experts note that dementia prevention relies heavily on addressing health issues long before symptoms arise. Evidence summarised by international scientific bodies, including the Lancet Commission on Dementia Prevention, indicates that conditions such as hypertension, diabetes, physical inactivity and sensory loss can influence cognitive outcomes later in life. The current study adds new socioeconomic context to these established findings.

A Continuing Challenge of Health Inequality

The research underscores the intersection between socioeconomic disadvantage and chronic disease risk in the United States, showing that income remains a powerful determinant of health opportunities. As dementia prevalence continues to rise globally, health authorities may increasingly look towards socioeconomic-focused prevention strategies to address the widening gap between income groups.