Read loss of smell and mortality research by its population, measurement and comparison. The tables below keep the reported numbers beside their study context.
Start with the test, then the statistic. Use the care and safety sections for questions to discuss with a healthcare professional.
The featured kitchen scene illustrates an everyday smell experience, not a research participant or a diagnostic test.
Three smell studies, three different comparisons
Read each row as a separate investigation. Note who was tested, how identification was assessed, what comparison was reported and how long follow-up lasted.
| Study | People and measurement | Reported comparison |
|---|---|---|
| Pinto and colleagues, 2014 | US adults aged 57 to 85; five-odor test; 2,918 in the main analysis | Adjusted odds ratio 3.37 for the most impaired category versus normal identification, over five years |
| Liu and colleagues, 2019 | 2,289 US adults aged 71 to 82; 12-item identification test | Ten-year cumulative mortality risk ratio 1.46 for poor versus good identification |
| Ruane and colleagues, 2025 | 2,524 Swedish adults aged 60 to 99; 16-item identification test | Six-year adjusted mortality hazard ratio 1.06 per additional incorrect answer |
The 2014 study began with 3,005 participants, but exclusions left the smaller analysis sample shown above. Its short test and lack of cause-of-death data limited what it could explain.
An odds ratio of 3.37 is not a statement that 337% of participants died.
What the 46% figure means
The 2019 cohort reported the modeled average risks below.
| Follow-up | Poor identification | Good identification | Reported risk ratio |
|---|---|---|---|
| Ten years | 44% | 30% | 1.46 |
| Thirteen years | 61% | 47% | 1.30 |
These adjusted group estimates are not personal risks. Rounded ten-year values differ by 14 percentage points, not 46 points.
The association was clearer among those reporting excellent to good health. Smell was measured only at baseline, not how changes influenced mortality.
What the newer Swedish study adds
The 2025 study excluded baseline dementia and followed mortality at six and twelve years.
Its adjusted hazard ratios per incorrect answer were 1.06 and 1.05 at those respective follow-ups. A hazard ratio compares modeled rates during follow-up, not the percentage of participants who died.
In its mediation models, incident dementia accounted for 23% of the association at six years, but it was not a meaningful mediator at twelve years. The authors measured frailty and malnutrition at baseline while tracking subsequent dementia, an important limitation when interpreting pathways.
Clinical usefulness needs further research. This study did not test smell training, supplements or other treatments for extending life.
Why this is not a personal forecast
Write the statistic label before comparing numbers. Beside it, record whether the contrast concerns categories or an additional test error.
Next, copy the population, follow-up period and adjustments into separate columns. Ask which differences would complicate a comparison.
Then ask whether an intervention was assigned and what outcome it tested. Leave treatment questions unanswered when a study cannot answer them.
Do not recreate a research score with kitchen ingredients or turn a missed odor into a survival estimate. A clinical assessment addresses why smell changed and what help is appropriate.
What a smell change is useful to discuss
The National Institute on Deafness and Other Communication Disorders lists several possible causes, including infections, nasal growths, injury, medicines and nervous-system conditions. A smell problem does not identify which cause applies.
An assessment can involve a health history, an ear, nose and throat examination, and supervised smell testing. Discuss persistent or unexplained changes with a healthcare professional rather than using the mortality table to decide their cause or urgency.
- Describe when the change began and whether odors are absent, weaker or distorted.
- Bring information about recent illness, injury, nasal symptoms and medication changes.
- Mention appetite, weight changes and effects on cooking, eating or daily activities.
This information supports an appointment; it is not a home diagnostic checklist. Ask the prescriber about a suspected medicine effect instead of changing treatment on your own.
Keep everyday safety separate from a mortality headline
NHS guidance notes that smell changes commonly follow infections, allergies or nasal problems, and some improve. It also warns that reduced smell can make gas leaks, fires and spoiled food harder to notice.
Review practical detection and food-safety arrangements rather than relying on your nose as the only warning. Ask for help with concerns affecting eating or home safety while the cause is being assessed.
Smell loss can affect enjoyment of food, and some people eat more while others eat less. Mention an unintended weight change rather than assuming it is an inevitable part of aging.
Bring those questions to a healthcare professional. Keep the research table and your description of a smell change together, without assigning yourself a survival score.
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References
- Pinto JM, et al. Olfactory dysfunction predicts 5-year mortality in older adults. PLOS ONE. 2014;9:e107541.
- Liu B, et al. Relationship between poor olfaction and mortality among community-dwelling older adults: A cohort study. Annals of Internal Medicine. 2019;170:673 to 681.
- Ruane R, et al. Olfactory deficits and mortality in older adults. JAMA Otolaryngology, Head & Neck Surgery. 2025;151:558 to 566.
- NIDCD. Smell disorders. NHS. Lost or changed sense of smell. Official patient guidance linked above.
Medical disclaimer: This article provides general health and research information, not a diagnosis, treatment plan or personal prognosis. Consult a qualified healthcare professional about persistent or unexplained smell changes, especially when eating or safety is affected.
