A study published online in The Laryngoscope reveals that current studies do not support the use of olfactory identification tests (smell tests) for predicting Alzheimer’s dementia.
Alzheimer’s is a progressive disease that causes loss of brain function and is the most common cause of dementia. The disease is expected to double every 20 years through the year 2040.
The study, conducted by Robert Wood Johnson Foundation (RWJF) Clinical Scholars at the University of Michigan and the VA Center for Clinical Management Research, is the first systematic review of the quantity and quality of these tests as prognostic tools for Alzheimer’s.
Gordon Sun, M.D., a general otolaryngologist and RWJF/US Department of Veterans Affairs Clinical Scholar at the University of Michigan, Ann Arbor, explains:
“Smell tests have been touted as a possible way of predicting Alzheimer’s dementia because of a reported association with decreased sense of smell. Our team set out to determine whether these beliefs are based on existing high-quality evidence.”
Of the 1,200 studies the researchers examined, only 30 cross-sectional studies and 2 prospective longitudinal cohort studies met inclusion criteria. According to the researchers, longitudinal studies are more significant than cross-sectional studies as they represent the gold standard study design for prognostic evaluations and track patients over time.
Although the team found evidence that loss of smell is associated to Alzheimer’s, there is not enough to conclude that loss of smell is a predictor for developing the disease. The researchers note that medical problems are also associated with loss of smell, and there are several other possible explanations for this association.
Sun explains:
“A nonspecific association between poor smell function and Alzheimer’s dementia is not the same as actually being able to use a smell test to predict Alzheimer’s.
Unfortunately, this misinterpretation of the research has led to the promotion of these tests by the media and public figures like Dr. Oz. This study helps set the record straight about where the evidence currently stands.”
Sun continues:
“Understandably, researchers, clinicians, and the public are eager for a simple, accurate, and inexpensive way to predict or diagnose Alzheimer’s early, but we’re not there yet.
My concern is that by promoting smell tests at this point, we create false hope or even false alarm among seniors and their families. Additional research is needed before we can rely on smell tests to predict the later onset of Alzheimer’s.”
The researchers note that if there are any concerns that you or your loved one may be at risk for developing Alzheimer’s dementia, you should should consult with your primary care physician first. For more information visit the Alzheimer’s Association by clicking here.
Written By Grace Rattue