Brain model photo by Robina Weermeijer on unsplash.com

November is Alzheimer’s Awareness Month, a reminder that mortality data places Alzheimer’s disease as the fifth leading cause of death across the entire San Joaquin Valley, claiming 9,061 lives between 2019 and 2023. Only heart disease, cancer, COVID-19 and accidents ranked ahead of Alzheimer’s, according to the U.S. Centers for Disease Control.

The disease, which medical researchers describe as the most common type of dementia among people age 65 and older, is considered an epidemic in the U.S. And five of the eight San Joaquin Valley counties rank among the 10 California counties with the highest rates of death from Alzheimer’s, data from the National Institute on Minority Health and Health Disparities shows.

Those include No. 1 ranked Tulare County, where the overall Alzheimer’s mortality rate of 61.6 per 100,000 population leads the state’s 58 counties; second-ranked Fresno County, with a rate of 57.5 deaths per 100,000; third-ranked Kern County, with a rate of 56.0 deaths per 100,000; fifth-ranked Madera County, with a rate of 51.9 deaths per 100,000; and eighth-ranked Stanislaus County, with a rate of 46.1 deaths per 100,000.

 

 

But deaths attributed to Alzheimer’s occur at significantly lower rates among the Valley’s Hispanic or Latino population than they do across the population as a whole, and in particular compared to non-Hispanic whites.

Data from the National Institute on Minority Health and Health Disparities reveals that from 2019 through 2023, the mortality rates for Alzheimer’s were an average of 17.5 greater per 100,000 residents for white residents than for Hispanic or Latino residents in the Valley. And there are also significant disparities in death rates between women and men in each of the eight Valley counties.

 

By county, the data shows average annual death rates from Alzheimer’s:

• Fresno County – Non-Hispanic whites, 65.8 per 100,000 population; Latino or Hispanic, 50.4 per 100,000, a difference of 15.2. Women, 61.6 per 100,000; men, 50.8 per 100,000, a difference of 10.8,

• Kern County – Non-Hispanic whites, 67.4 per 100,000; Latino or Hispanic, 40.1 per 100,000, a difference of 27.3. Women, 63.4 per 100,000; men, 44.1 per 100,000, a difference of 19.3.

• Kings County – Non-Hispanic whites, 39.1 per 100,000; Latino or Hispanic, 30.9 per 100,000, a difference of 8.2. Women, 44.0 per 100,000; men, 23.0 per 100,000, a difference of 21.0.

• Madera County – Non-Hispanic whites, 57.4 per 100,000; Latino or Hispanic, 39.3 per 100,000, a difference of 18.1. Women, 63.1 per 100,000; men, 36.9 per 100,000, a difference of 26.2.

• Merced County – Non-Hispanic whites, 40.0 per 100,000; Latino or Hispanic, 20.3 per 100,000, a difference of 19.7. Women, 31.9 per 100,000; men, 30.0 per 100,000, a difference of 1.9.

• San Joaquin County –Non-Hispanic whites, 41.8 per 100,000; Latino or Hispanic, 30.9 per 100,000. Women, 38.5 per 100,000; men, 31.3 per 100,000, a difference of 7.2.

• Stanislaus County – Non-Hispanic whites, 50.1 per 100,000; Latino or Hispanic, 37.2 per 100,000, a difference of 12.9. Women, 52.8 per 100,000; men 35.4 per 100,000, a difference of 17.4.

• Tulare County: Non-Hispanic whites, 73.2 per 100,000; Latino or Hispanic, 49.1 per 100,000, a difference of 24.1. Women, 68.0 per 100,000; men, 51.5 per 100,000, a difference of 16.5.

 

 

 

There’s ample research to offer explanations why women are at greater risk for Alzheimer’s mortality than men. A 2021 article in the journal Cellular and Molecular Life Sciences indicates that almost two-thirds of Alzheimer’s patients are women, and reported that factors for women’s higher risk include differences in brain structure; differences in responses to stress; pregnancy, menopause and sex hormones, and vascular disorders, among others.

The article by researchers Donghui Zhu of Stony Brook University in New York, Axel Montagne of the University of Edinburgh in Scotland and Zhen Zhao of th eUniversity of Southern California’s Keck School of Medicine states that “women live longer than men on average of 4.5 years, and there are more women aged 85 years or older than men in most global subpopulations, while older age is the greatest risk factor” for Alzheimer’s.

“Women usually have a lower income and lower education than men in most cultures, and they are the primary informal caregivers in their families,” Zhu, Montagne and Zhao added. “The caregiving burden is associated with higher rates of unemployment and an increased psychological risk factors in (Alzheimer’s) including depression and sleep disorders”

Women also generally live to older ages than men, putting them at greater risk. “One explanation is that men may die of competing causes of death earlier in life, so that only the most resilient men survive to older age,” researchers from the Mayo Clinic in Minnesota wrote in the January 2014 issue of Clinical Epidemiology.

Less clear are potential reasons for lower mortality rates from Alzheimer’s among people of Latino or Hispanic descent compared to the non-Hispanic white population. One possible explanation is the number of Latino or Hispanic individuals who are bilingual.

In a 2021 article in the journal Frontiers in Psychiatry, researchers with Gannan Medical University in Ganzhou, China, wrote that “bilingualism has been reported to significantly delay the onset of dementia and plays an important role in the management of Alzheimer’s disease.”

“Effectively, bilingualism can be considered as a pharmacological intervention (for Alzheimer’s) with no side effects,” authors Haiqing Liu and Longhuo Wu added.

The February 2022 issue of Alzheimer’s & Dementia, the journal of the Alzheimer’s Association, included a summary of highlights from the association’s 2021 Latinos & Alzheimer’s Symposium. The collection of participating researchers reported that 59% of Latino adults in the U.S. are bilingual in English and Spanish. “As language experience powerfully shapes brain and cognitive function, bilingualism may play an important role in one’s protection or risk to develop dementia later in life,” they reported.

“One idea is that bilingualism may build cognitive reserve, which would allow the brain to better cope in the face of [Alzheimer’s disease and related dementia] changes,” the researchers added.

Those scientists warn, however, that Latinos in the U.S. “are projected to have the steepest increase in Alzheimer’s disease and related dementias (ADRD) in the next 40 years compared to other ethnic groups.” Among the reasons the Latino population is believed to be at increased risk are underrepresentation in Alzheimer’s research and clinical trials, limited access to quality health care, language barriers, lower educational attainment levels, and challenging socioeconomic conditions including poverty.

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Tim Sheehan is a senior reporter and Health Reporting Fellow with the nonprofit Central Valley Journalism Collaborative. The CVJC fellowship is supported by a grant from the Fresno State Institute for Media and Public Trust. Contact Sheehan at tim@cvlocaljournalism.org.