A new piece in the puzzle of Alzheimer’s disease this World Alzheimer’s Day

An increased risk of Alzheimer’s disease is amongst the latest discovered consequences of COVID-19 infection, contributing to new theories of its cause after 30 years this World Alzheimer’s Day, September 21st. Alzheimer's is the most common form of dementia, most known for its affect on memory and behaviour, and significant burden to not only patients but their caregivers. Strikingly, the Alzheimer Society of Canada estimates the ~597,000 Canadians living with dementia (in 2020) will triple to 1.7 million over the next 3 decades given our aging population.

Historically, Alzheimer’s was thought to be caused by the build-up of beta-amyloid protein in the brain, which ignited years of targeted drug development and research. Still, no new treatment shown to actually improve patients’ cognitive function has entered the Canadian market in 20 years. Then, just this year, the merit of the beta-amyloid theory data was questioned, bringing new theories of the cause of Alzheimer’s disease to light – one being a dysfunctional immune system and resultant inflammation.

Enter COVID-19. A study just published from reviewing 6.2 million U.S. seniors’ (65 and older) medical records showed those who contracted COVID-19 were almost 70% more likely to be diagnosed with Alzheimer's within a year of infection, with women at a higher risk than men. This is not to suggest COVID-19 causes Alzheimer's, but the inflammatory nature of viral infection may exacerbate the dysfunctional immune response already underway in the brain.

Despite the ongoing uncertainty surrounding Alzheimer’s, this #WorldAlzDay highlights the several new ways of thinking about this age-old disease.

-Danyelle