Dementia Rates Rise in Latin America While Declining in Wealthy Nations

A two-decade study published in JAMA Neurology reveals a concerning trend: while dementia prevalence is slowly declining in the United States and much of Europe, it is increasing significantly in parts of Latin America. Researchers found that the proportion of elderly individuals living with dementia rose from 10.6% to 16.9% across five Latin American locations, a jump from one in ten to nearly one in six. This increase was particularly pronounced in Mexico (from 9.6% to 14.5%), Peru (from 7.6% to 11.7%), and Puerto Rico (from 10.7% to 15.7%), while rates remained stable in Cuba and the Dominican Republic. The study, conducted by researchers from Washington University in St. Louis and Newcastle University, analyzed data from 16,950 individuals aged 65 and older across two waves: 2003-2006 and 2016-2020. A key differentiator of this research was its door-to-door methodology, interviewing participants in their homes rather than relying solely on hospital admissions, thus capturing individuals who rarely seek medical attention and are often excluded from statistics. This approach suggests that dementia has been underestimated in the region, with recent estimates indicating approximately 1.2 million people with dementia in Mexico alone, far exceeding previous model-based calculations. Even after accounting for age and known risk factors like education, diabetes, and obesity, dementia continued to rise in Mexico and Puerto Rico, indicating that unmeasured factors are at play. Experts suggest that the cumulative life exposures, known as the exposome, encompassing factors beyond formal education and healthcare access, such as mental stimulation, effective disease management, and environmental exposures like pesticides, pollutants, and social isolation, may contribute significantly to these rising rates. The study also noted that improved education alone did not prevent the increase, highlighting the importance of the quality of education and continuous cognitive stimulation throughout life. While Brazil was not included in the study, experts believe a similar trend might be occurring due to the country's rapid aging population and significant internal disparities, suggesting a potential unpreparedness for the demographic shift. The World Health Organization and The Lancet emphasize that up to 45% of dementia risk is preventable through lifestyle modifications, including managing modifiable risk factors such as smoking, alcohol consumption, social isolation, sedentary behavior, air pollution, hypertension, and diabetes, alongside a healthy diet, regular exercise, and cognitive engagement.