A recent study from the Karolinska Institute in Sweden has highlighted the potential of a simple smell test to predict an increased risk of death in older adults. The research demonstrates a significant association between the ability to accurately identify odors and the likelihood of mortality within the subsequent six years, suggesting that olfactory function could serve as a valuable early indicator of overall health.
Previous studies have linked a decline in the sense of smell to a higher risk of mortality in older populations. This new research delves deeper into this connection, revealing that the more frequently an older adult misidentifies smells, the greater their risk of death within a six-year period. Specifically, the study found that each incorrect answer on a smell identification test was associated with a 6% increase in the risk of mortality within six years.
The study involved 2,524 adults aged between 60 and 99 years. Participants underwent the Sniffin’ Sticks Odour Identification task, a standardized test where they were presented with 16 distinct odors via felt-tip pens. They had five seconds to smell each and were then asked to either name the odor or choose the correct option from four possibilities.
Scores on the test ranged from 0 to 16, with one point awarded for each correct identification. Participants scoring six or less were classified as having anosmia (smell blindness), while those correctly identifying 11 to 16 odors were considered normosmic (having a normal sense of smell).
Over a six-year follow-up period, 18% of the participants had died, and 9% had developed dementia. After twelve years, the mortality rate had reached 39%, and 15% had been diagnosed with dementia.
By comparing this data with the participants’ initial smell test results, the researchers were able to establish a clear correlation between olfactory performance and mortality risk. They found that for each incorrect answer on the smell test, the risk of death increased by 6% after six years and by 5% after twelve years.
This means that an individual who scored only six on the smell test, indicating ten incorrect answers, faced a 42% higher risk of death from any cause within six years and a 34% higher risk over twelve years compared to someone who correctly identified all the smells.
These findings emphasize the potential of a straightforward smell test as a readily available tool for identifying older adults who may be at an elevated risk of mortality. While the precise biological mechanisms linking olfactory function to longevity require further investigation, this study provides compelling evidence that a decline in the sense of smell can serve as an early warning sign of underlying health issues and increased vulnerability.
