Stressful life events, poverty and racial inequities contribute to dementia risk in late life, according to new research unveiled at a recent global gathering of Alzheimer’s experts in London. One major stressful early life event may equate to as much as four years of cognitive aging, with African Americans are most at risk, one study said.
This and other studies presented at the 2017 Alzheimer’s Association International Conference (AAIC 2017) in July add to the growing body of evidence of the role that social determinants of health can have on Alzheimer’s disease. Abstracts from AAIC 2017 will be published in a future issue of Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.
This story in The Guardian provides a good review of the meeting’s highlights.
In one study, researchers from the University of Wisconsin School of Medicine and Public Health examined the impact of lifetime stressful experiences on cognition as part of the Wisconsin Registry for Alzheimer’s Prevention (WRAP) Study. They compared 1,320 African American and non-Hispanic white adults to understand how stressful experiences – such as being fired from a job, dealing with the death of a child, growing up with a parent who abused alcohol or drugs, or experiencing combat – affect cognition differently between these two groups.
Stressful outcomes can include educational difficulties, interpersonal conflicts, financial insecurity, legal/justice system issues, severe health events and psychosocial/physical trauma. Participants answered a questionnaire about stressful experiences and completed cognitive tests to measure memory and problem-solving abilities.
Researchers found an association between stressful life events and poorer late-life cognitive function among all study participants. However, African Americans experienced over 60 percent more stressful events than non-Hispanic whites during their lifetimes – and such experiences were linked with poorer memory and thinking skills in older age.
Among African Americans, adverse events across the lifespan predict cognitive function more strongly than established risk factors, including age, education, and the Alzheimer’s risk gene [APOE-e4], according to lead author Meg Zuelsdorff. Ph.D., a postdoctoral fellow at the University of Wisconsin, Madison.
Disparities linked to Alzheimer’s risk
Another University of Wisconsin study looked at levels of socioeconomic disadvantages such as poverty, education, housing, and employment and to determine whether there was a stronger link to developing Alzheimer’s than by chance alone.
Researchers found that people in the most disadvantaged neighborhoods had markedly worse cognitive performance in all aspects measured (working memory, immediate memory, speed and flexibility of cognition, and verbal learning), even after adjusting for age and education. They also had disproportionately higher levels of one Alzheimer’s disease biomarker in their spinal fluid. This Washington Post story features a detailed map of the most and least-disadvantaged areas in the United States.
Disadvantaged neighborhoods often pose barriers to accessing healthy foods, safe exercise options, healthy environments, and other factors that impact health. It is known that living in a disadvantaged neighborhood increases the risk of diabetes, cancer, and early death, and that moving to less-disadvantaged settings improves health. (For more about these issues, check out AHCJ’s social determinants core topic area).
“This study provides evidence to suggest that living in a neighborhood challenged by poverty, low education, unemployment, and/or substandard housing may increase risk of Alzheimer’s disease, and may account for some of the observed differences in Alzheimer’s disease risk among people of different racial backgrounds and income levels,” said lead researcher Amy Kind, MD, PhD., who is an associate professor in the Department of Geriatrics at the University of Wisconsin School of Medicine and Public Health.
Separately, researchers at the University of California, San Francisco, and Kaiser Permanente found that African Americans born in states with the highest levels of infant mortality had a 40 percent greater risk of dementia compared with African Americans not from those states, with an 80 percent increased risk compared with whites not from those states.
Age disparity and Alzheimer’s
We already know that among the younger elderly (65 and older), there are marked differences in rates of dementia by racial/ethnic groups, with increased rates for African Americans and decreased rates for Asian Americans. For all adults 65 and older, African-Americans are about twice as likely to develop Alzheimer’s or other dementias as older whites, according to the Alzheimer’s Association 2017 Alzheimer’s Disease Facts and Figures, with Hispanics about one and one-half times as likely to have Alzheimer’s or other dementias as older whites. It is unclear whether these difference also apply to the oldest-old (90 years and older).
Investigators from University of California, Irvine, and Kaiser Permanente analyzed dementia diagnoses in a group of 2,351 Kaiser health plan members, age 90 or older, with no diagnoses of dementia between 2010 and 2015. Most of the study participants were women; 72 percent were white, 16 percent African American, 4 percent Latino, and 7 percent Asian American.
The oldest-old Asian Americans had the lowest cumulative incidence (21 percent), followed by whites (31 percent), Latinos (35 percent) and African Americans (39 percent). This analysis matched overall patterns of racial/ethnic disparities in dementia seen in younger elderly. When adjusted for age, education, sex, comorbidities and other criteria, the oldest African Americans had a 28 percent higher risk than the oldest whites. Compared to Asian Americans, African Americans had a 30 percent increased risk of dementia.
While these studies used only U.S. data, they add to global evidence surrounding disparities, race, and dementia risk, according to Maria Carrillo, Ph.D., who is chief science officer at the Alzheimer’s Association. The findings support the need for targeted interventions, whether preventive or service-driven, to help address known gaps, especially in a nation as diverse as the United States.
The Alzheimer’s Association projects that more than 5 million Americans are currently living with the disease and more than 15 million people in the U.S. provide unpaid care. Alzheimer’s disease costs the health system an estimated $259 billion annually — including $175 billion in Medicare and Medicaid payments. In 2017, for every $100 the U.S. government spends on Alzheimer’s research, it will spend $12,500 in Medicare and Medicaid costs caring for individuals living with this fatal disease, according to Alzheimer’s Association projections. The organization called for still greater investment to reach the goal of the National Plan to Address Alzheimer’s Disease, preventing and effectively treating Alzheimer’s by 2025.
Journalists may want to check out this story from The Guardian, which looks at how lifestyle changes may reduce the risk of dementia cases in a third of the at-risk population.
What is your state or city doing to serve and care for the millions of people with dementia, including Alzheimer’s disease, and to support the people who care for them?