Saturday, Feb. 22, 2020 | 2 a.m.
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The Alzheimer’s disease tsunami is coming our way, and it is being propelled by the demographics of baby boomers — the oldest of them turned 75 in 2019.
Today, there are nearly 6 million Americans with the disease, according to the Alzheimer’s Association, and that number is expected to nearly triple by 2050. The significant increase in the number of people diagnosed with Alzheimer’s will be a looming public health crisis as society deals with people’s diminished quality of life, the potentially extraordinary costs of caregiving and the economic demands made on younger generations.
Latinos are likely to be most affected by this crisis — both as patients and as families and communities who will have to care for those with the disease.
The Centers for Disease Control and Prevention projects that Latinos, the largest ethnic group in the U.S., will experience the biggest increase in Alzheimer’s disease and related dementias.
Latinos comprise nearly 40% of California residents. By 2060, they will represent more than a quarter of the entire U.S. population.
My colleagues and I studied more than 6,300 Latinos across the U.S. and found that nearly 10% of middle-age and older Latinos — those between ages 50 and 86 — met diagnostic criteria for mild cognitive impairment, which is considered a transitional stage between healthy cognitive aging and Alzheimer’s disease.
We know diabetes, high blood pressure and obesity can contribute to Alzheimer’s disease risk in all populations. This risk is exacerbated for Latinos, who have one of the highest prevalences of diabetes and lack health care access and resources to prevent and manage the factors that contribute to Alzheimer’s risk.
And despite facing greater economic and social disadvantages, average Latino life expectancy is more than three years longer than for whites — which makes the prospect of Latinos developing dementia-related disease more likely.
Genetics play an important part in understanding Alzheimer’s disease as well. Yet we still know too little about how it triggers the disease in whites and African-Americans. We know even less for Latinos. Latinos represent only 1% of all genomic data available worldwide. That is less than any other major genetic ancestry group. Compounding the problem is that the existing genetic Alzheimer’s disease picture for Latinos has been blurred and distorted by scientists reporting genetic findings for one Latino group, and then generalizing their results to all Latinos.
In California, Latinos are mostly of Mexican heritage. Indeed, California was part of Mexico. And before then, indigenous people lived and developed civilizations in the Americas for over 20,000 years. Thus, the ancestry of Latinos in California, or Californios, comes from heritages of three continents: Amerindian, European and, to a lesser extent, African.
Many of these Californios, Mexicans and Central Americans are more related to American Indians than to Spaniards and other Europeans. In our research, we are now seeing the presence of these genetic ancestries in this population.
However, we know very little of the brain health and brain aging of Latinos, and of Californios in particular. These gaps in knowledge will make it harder to address the impact of Alzheimer’s disease. Together with increasing rates of cardiometabolic disorders, such as diabetes, a large and socioeconomically disadvantaged and aging Latino population could create a significant challenge for California in the coming years.
Since 2015, my colleagues and I have been conducting a large, multisite study of cognitive aging and disorders in diverse Latino populations throughout the country. Our goal is to bring advanced biomarker, genetic and other new tools to bear on understanding, preventing and ultimately curing Alzheimer’s disease among Californios and Latinos across the country.
We’ve already begun to fill major scientific gaps in our understanding of the genetic risks. For example, we found that prevalence of mild cognitive impairment did not vary between Latino groups as had been previously described in the medical studies. We found that cardiometabolic risk factor, including diabetes, increased the prevalence of this kind of impairment. And we discovered that the APOE4 gene, which increases risk for Alzheimer’s disease, varied widely by Latino group.
We need more investment in medical research that focuses on Latinos and Californios. This applies to not only Alzheimer’s disease, but also to diabetes, cancer, heart disease and more. Indeed, given that Latinos form the largest ethnic/racial minority in the U.S. and a plurality of Californians, more research on this population should be a public health priority.
Equally important, more Latinos need to step up and volunteer to participate in research. While the current generation may not benefit immediately, the work being done will benefit our children and future generations.
Hector González is an associate professor of neurosciences at UC San Diego.
