Alzheimer’s Disease (AD) is the most common form of dementia and is currently the 6th leading cause of death in the United States (CDC, 2021). In addition, the treatment and care of AD costs Americans around $300 billion each year (Wong, 2021)! As you can see, this neurodegenerative disorder is devastating. Individuals with AD initially experience losses in memory. As the disease progresses, there are increased deficits in their decision-making, reasoning, and executive functioning. Eventually, the disease leads to difficulties in swallowing, which often leads to aspiration pneumonia (food/drink getting caught in the lungs and causing infection) and subsequent death (Mayo Clinic, 2021). Today, scientists are working diligently to better understand what causes AD, why people develop it, and most importantly, how can we treat it! Today we are going to break down the current body of research on Alzheimer’s Disease.
Let’s start by discussing the etiology, or cause of the condition. There are several things that are seen as risk factors for developing AD. The primary risk factor is age. The rate of AD cases doubles every 5 years after an individual turns 65. That being said, there are cases of AD that occur earlier in life (between ages 30-60), however these cases are rarer (What Causes Alzheimer’s Disease?, 2019).
Another important risk factor to consider is genetic makeup. There are many identified genes that contribute to the risk of developing AD, however, scientists agree that the APOE gene, which is involved in the transport and metabolism of lipids (fats), seems to be the most closely related to risk of Alzheimer’s development. Each individual carries 2 APOE genes and there are 3 possible variations (or isoforms) that each of the 2 genes can carry. APOE2 is a variation that seems to be protective against AD, APOE3 is the most common variation and does not add or subtract from the risk of developing AD, and the APOE4 variation increases the risk of developing AD (Alzheimer’s Disease Genetics Fact Sheet, 2019).The actual cause of the neurodegeneration seen in Alzheimer’s is unknown. However, there are many different hypotheses on how AD occurs and progresses (See pt. 2). While there may not be many pharmacological interventions to prevent AD onset and progression, there are things we can all do to reduce our risk of developing the condition. Regular exercise, healthy diet, social engagement, and adequate sleep are all considered protective factors against AD (Mattson, 2004; Sadeghmousavi et al., 2020)!