A study published Wednesday found that having a lower income and being a member of a racial minority group were associated with a higher prevalence of dementia risk factors like hearing loss, high blood pressure, depression and physical inactivity. File Photo by Murray Rudd/Pixabay
A large-scale analysis of data from nationwide surveys reveals that lower income and racial minority status are “significantly” associated with more risk factors for dementia disorders, such as Alzheimer’s disease, a study released Wednesday says.
Health data collected from thousands of Americans suggests that both impoverished people and racial subgroups who have been historically underrepresented in clinical research — such as Black and Hispanic Americans — are more prone to having many dementia risk factors than their higher-income and White counterparts, the authors found.
Those risk factors include obesity, high levels of “bad” LDL cholesterol, traumatic brain injury, untreated hearing loss, untreated hypertension, smoking, depression, diabetes and physical inactivity in midlife years, as well as vision loss and social isolation late in life.
The results, published by the American Academy of Neurology in its flagship medical journal, also demonstrate these groups tend to have more dementia risks that are modifiable — even in old age — and thus could greatly benefit from focused prevention efforts, the authors say.
In the study, researchers tapped data collected as part of the National Health and Nutrition Examination Surveys, which have been conducted by Centers for Disease Control and Prevention annually since 1999. Each year, thousands of Americans answer questions about their health, diet, and personal and social economic characteristics in these surveys.
The authors chose 5,000 respondents, who were divided into six income groups ranging from incomes below the federal poverty level to more than five times that level. Then, for each income group, they determined the percentage of people who had each of 13 risk factors and the percentage of dementia cases that could theoretically be prevented or delayed if those risk factors were eliminated.
They found higher incomes were associated with lower prevalence of each dementia risk factor except obesity, high cholesterol and traumatic brain injury, while each step up in income category yielded a 9% lower likelihood that a person would have an additional risk factor in middle age.
Racial disparities in dementia risk factors were especially wide, the study reported.
Even after adjusting for income, risk factors such as diabetes, physical inactivity, obesity and vision loss showed “significant” associations with Black Americans, Mexican Americans and other racial subgroups who are historically underrepresented in clinical studies when compared to White Americans.
“We found significant associations between individuals self-identified in the Hispanic and non-White race-ethnicity categories with the prevalence of many dementia risk factors after accounting for income,” according to a research team led by Dr. Eric Stulberg of the Thomas Jefferson University Sidney Kimmel Medical College in Philadelphia.
The results suggest that low-income and minority patients are among the most likely to benefit from interventions — but also that previous dementia research may not be broadly applicable to them, Stulberg told UPI.
“Dementia is a complicated condition and can result from multiple pathological processes,” he said. “The underlying reason someone may have dementia varies.
“As our research shows, those with lower incomes tend to have more modifiable and preventable causes of dementia. As such, we may not be able to generalize the results from clinical trials with higher-income individuals to all Americans — including those with lower income or other historically represented groups — if the underlying causes of dementia are different.”
Further, he added, “those with lower incomes and those that are historically underrepresented may benefit for efforts aimed at prevention just as much as treatment, especially as there are currently no cures for dementia.”
The study’s conclusions come with several caveats and limitations: It does not establish causality, but rather only reports associations; it provides a snapshot of a population rather than following people over longer periods; and it relies on survey information reported by participants who may not have remembered or reported it accurately.
That said, one of its most striking results illustrates how interventions targeting two particular areas could make an immediate impact on reducing dementia among low-income patients.
The authors say some 21% of dementia cases could potentially be mitigated if vision loss were addressed, along with 20% of cases linked to social isolation — both of which are considered “late-life” dementia risks and among the most easily preventable.
Regarding vision loss, Stulberg said changes in vision “are not noticed by older adults as they age and hence they are not seeking out preventive visual screening appointments, particularly if they have competing demands for their time and resources, which is often the case for those living below the poverty level.
“Similarly, primary care doctors may not prioritize preventive visual health in a patient population that tends to have higher rates of comorbidities as well as complex social needs.
“Though these are just speculative, future research should work to evaluate rates of visual screening in this population, as well as the effect of systems-level interventions aimed at improving treatment rates of suboptimal visual health.”
Several other experts who have researched socioeconomic disparities in the prevalence of dementia — and who were not connected to the new study — told UPI they generally agree with its conclusions.
While previous studies have linked dementia risks, income and race in various ways, the current effort “provides one of the clearest portraits to date of how income and race-ethnicity intersect to shape dementia risk across the U.S.,” said Dr. Jorge Llibre-Guerra, an assistant professor of neurology and Alzheimer’s researcher at Washington University in St. Louis.
He said its findings are “especially relevant in the United States, given the disparities in access to health care.
“To me, this study underscores that social and structural determinants — rather than biology — drive much of the unequal dementia burden in the U.S., and from a prevention perspective, this is a key finding.”
Llibre-Guerra noted the results also validate previous population-based studies performed in low- and middle-income countries by the 10/66 Dementia Research Group, indicating that control of non-communicable diseases and other risk factors is likely to prevent 56% of dementia cases.
“The message is clear: Dementia prevention requires targeting modifiable risk factors in lower-income and underrepresented communities, where the potential gains are greatest,” he said.
Laura Samuel, an associate professor at the Johns Hopkins University School of Nursing, has performed research demonstrating that financial strain contributes to aging-related health disparities such as dementia. She said new study “documents how people who are Black, Hispanic and those with low incomes have disproportionately high levels of multiple dementia risk factors across each stage of life.
“These findings are notable because the risk factors examined in this study are modifiable, meaning that targeting them should help to prevent dementia,” Samuel said.
“These risk factors typically occur because people lack access to the many resources needed to protect their health, like having enough money and time to care for their health, and access to health care, medications and treatments.”
Importantly, the results also show that “we need to address risk factors even very early in life to prevent late-life dementia.”
“For example, the study shows dramatic differences in educational achievement based on income level, race and ethnicity suggesting that more attention should be paid to equitable educational opportunities when we consider public health strategies,” she added.
Charles Marshall, a professor of clinical neurology at Queen Mary University of London and leader of dementia research at its Center for Preventive Neurology, cautioned that while he has some reservations over how the authors statistically adjusted for variances in risk factors among the populations they looked at, he generally welcomed the findings.
He said that’s “because social determinants of health, like race-ethnicity and socio-economic status, have been relatively neglected in the field of dementia research. When talking about risk factors for dementia and things that can be done to reduce dementia risk, we always need to recognize that individual responsibility should not be overemphasized.
“There are important structural and societal factors influencing brain health that need to be addressed by governments and public health bodies to give everyone in society the best possible chance of living to old age with a healthy brain.”
Finally, the Alzheimer’s Association called the study “relevant and timely” as the aging U.S. population becomes more diverse and demographic factors must increasingly be considered to promote elder health.
“As demonstrated by these findings, the known risk factors for dementia do not impact all individuals and all communities in the same way,” said Lycia Neumann, the nonprofit’s senior director of health services research.
“The current study aligns with previous research that finds low income is linked to increased dementia risk. This is partly due to limited access to healthcare, nutritious food, and safe environments, but also to higher prevalence of chronic conditions such as obesity, diabetes and hypertension,” she said in a statement issued to UPI.
Promoting economic stability and equity at the individual and community levels is, in fact, a current focus of the association’s Public Health Center of Excellence on Dementia Risk Reduction, she noted, adding that the goal of recruiting more minorities and low-income participants into clinical studies on Alzheimer’s and dementia disorders is also an important one.
“Gaining a more comprehensive understanding of Alzheimer’s and all other dementia, as well as ways to prevent or delay its onset, requires more than just research advances; it requires the inclusion of increased numbers of participants from diverse racial and ethnic groups in research, including people at different ages and with different health conditions,” Neumann said.
“Improved representation is essential not only in clinical trials, but in ‘real-world studies,’ as these findings can inform better clinical practice and health policies.”
