race & dementia | Researchers at Washington University School of Medicine have new insights into racial disparities in dementia. The team found that genetic ancestry plays no role. Rather, these differences are related to the social determinants of health. The study looked at the population of four Latin American countries to investigate the complex web of risk factors associated with cognitive decline. “Marginalized racial and ethnic groups have higher rates of dementia in many countries, and disentangling the biological from the social contributors has been challenging,” says corresponding author Dr. Jorge Llibre-Guerra, an assistant professor of neurology. “Latin America provides a unique framework to separate the two. It is the region with the largest mixture of genetic ancestries, plus it has profound social inequalities. This study clearly shows that poor cognitive health is part of the legacy of the racial caste system. It’s not family ancestry that is putting people at risk. In a way, the findings are reassuring because social determinants of health are modifiable.”
diet & alzheimer’s
A study from Harvard has found that red meat may increase dementia risk. People who consume two servings of processed red meat a week have a 14% high risk of developing the disease. Findings also indicate that replacing one serving of processed red meat with nuts and legumes can lower the risk by around 20%. Researchers at the T.H. Chan School of Public Health looked at the food-frequency of more than 130,000 participants in the Nurses’ Health Study and Health Professionals Follow-Up Study, which is tracked for up to 43 years. Each additional serving of processed red meat was linked to around 1.6 years of additional cognitive aging for both global cognition and verbal memory.
treatments on the horizon
The Alzheimer’s Association reports that a study in Philadelphia has found a glucagon-like peptide-1 (GLP-1) drug may be able to help slow cognitive decline. The drug is used to help manage diabetes and lower the risk of heart disease, stroke and kidney disease by mimicking a natural hormone released by the stomach after eating. In animal models, it was discovered that it may have neuroprotective effects, reducing early forms of amyloid and normalizing the brain’s processing of glucose. The study found that the drug liraglutide may be capable of reducing cognitive decline by as much as 18% after one year for patients with mild Alzheimer’s. “We are in an era of unprecedented promise, with new treatments in various stages of development that slow or may possibly prevent cognitive decline due to Alzheimer’s disease,” says Maria C. Carrillo, Ph.D., Alzheimer’s Association chief science officer and medical affairs lead. “This research provides hope that more options for changing the course of the disease are on the horizon.”
the accuracy of blood tests
There are currently at least five companies offering blood tests for Alzheimer’s disease. Researchers at Washington University School of Medicine led a data analysis to compare six of the commercially available tests head-to-head. The blood tests are designed to detect signs of Alzheimer’s disease, particularly the presence of amyloid plaques in the brain. The study found that some of the tests are accurate enough to replace invasive spinal taps previously required to make a diagnosis. Most therapies available for Alzheimer’s target amyloid, so doctors need a way to confirm its presence before they can prescribe treatment. Across the six tests, five distinct biomarkers linked to Alzheimer’s were measured using various techniques. One proved exceptionally accurate at identifying signs of the disease: a form of tau known as phosphorylated tau 217 (p-tau217).
the impact of air pollution
Wildfire smoke, motor vehicles and factories all emit a type of air pollution called fine particulate matter (PM2.5). Researchers have been looking at the risk such pollution has in developing dementia. Now, a decade-long study of more than 1.2 million people in California has found that wildfire smoke notably increases the risk, according to the Alzheimer’s Association. Exposure to non-wildfire PM2.5 also raised the risk of dementia diagnosis, but not as much. Researchers observed a 21% increase in the odds of dementia diagnosis for every increase of one microgram per meter in the three-year average of wildfire PM2.5 exposure. Comparatively, a 3% increased risk was found for every three micrograms per meter of non-wildfire PM2.5 exposure.
neuron insights
Research at Washington University School of Medicine in St. Louis has found a way to study neurons without a brain biopsy. The team transformed skin cells from patients with late-onset Alzheimer’s disease into brain cells. The lab-derived neurons accurately reproduced the hallmarks of the disease, such as amyloid plaques, tau protein deposits and neuronal cell death. The cells offered insight into aspects of their genomes that change their activity as we age. The findings suggest new potential courses of treatment. “In these patients, our new model system has identified a role for retrotransposable elements associated with the disease process,” says senior author Andrew Yoo, Ph.D., a professor of developmental biology. “We were pleased to see that we could reduce the damage with a drug treatment that suppresses these elements.”