Acute smell loss is one of the most common symptoms of COVID-19, but for two decades it has been linked to other diseases, including Parkinson’s disease and dementia. Now, a sense of poor smell can mean an increased risk of pneumonia in older adults, a team of researchers from Michigan State University (MSU) explains.
This is the first study of its kind to find a possible link between a poor sense of smell and an increased risk of hospitalization for pneumonia, and for this 13 years of health data from 2,494 adults over 71 to 82 years of age were analyzed. During the research, which was recently published in the medical journal The Lancet Healthy Longevity, participants received an odor identification kit containing common fragrances such as lemon and gasoline to determine whether the sense of smell was good, moderate, or poor. Participants were then monitored over the next 13 years through clinical examinations and phone calls to identify the number of hospitalizations related to pneumonia. They found that compared to participants who had a good sense of smell, those with a poorer one were about 50% more likely to be hospitalized for pneumonia at any time during the 13-year follow-up. Moreover, among participants with a defective sense of smell who had never had pneumonia before, the risk of pneumonia for the first time was about 40% higher.” As far as we know, this study provides the first epidemiological evidence that poor smell is associated with an increased long-term risk of pneumonia in older adults,” said Yaqun Yuan, a postdoctoral fellow in the Department of Epidemiology and Biostatistics at the MSU School of Human Medicine and one of the study’s authors.” This is just one example of how little we know about this common sensory deficit,” adds Honglei Chen, a professor in that same department and co-author. “Whether as a risk factor or as a marker, the bad sense of smell in older adults can presage multiple chronic diseases beyond what we know. We have to think outside the box.”
