Diminished Sense of Smell May Indicate Risk of Pneumonia

An acute loss of smell is one of the most common symptoms of COVID-19, but for two decades, it has been linked to other maladies, among them Parkinson's disease and dementia. Now, a poor sense of smell may signify a higher risk of pneumonia in older adults, stated a team of Michigan State University (MSU) researchers on May 11, 2021.

In a first-of-its-kind study, this MSU team found a possible link between a poor sense of smell and a higher risk of pneumonia hospitalization.

They analyzed 13 years of health data from 2,494 older adults, ages 71-82, from metropolitan areas of Pittsburgh, Pennsylvania, and Memphis, Tennessee. This study aimed to examine whether a poor sense of smell in older adults is associated with a higher future risk of developing pneumonia.

"About a quarter of adults 65 years or older have a poor sense of smell," said Honglei Chen, a professor in the Department of Epidemiology and Biostatistics within MSU's College of Human Medicine press statement.

"Unlike vision or hearing impairment, this sensory deficit has been largely neglected; more than two-thirds of people with a poor sense of smell do not know they have it."

'To the best of our knowledge, this study provides the first epidemiological evidence that poor olfaction in older adults is associated with a higher risk of pneumonia. It is estimated that 15–25% of older adults in the USA have poor olfaction.'

'Our study also has several limitations. First, our study participants were older than 70 years at the time of olfaction testing, which might limit the generalisability of our study findings to older adults who are relatively younger. Future studies should independently confirm this observation, investigate potential mechanisms, and understand its implications on the health of older adults.'

A start-up fund from the MSU supported this study. The NIA supported the Health ABC study, the National Institute of Nursing Research, the Intramural Research Program of the NIA/National Institutes of Health, and NIA contracts N01AG62101, N01AG62103, N01AG62106, NIA grant R01AG028050, and NINR grant R01NR012459.

Chen's research was published in the journal The Lancet Healthy Longevity on May 6, 2021.