Association Between Perceived Olfactory Dysfunction and All-cause Mortality in Chinese Adults: A Prospective Community-based Study

Background: Olfactory dysfunction has been suggested to be associated with all-cause mortality. Yet, there is a lack of large-scale cohorts to study this relationship.

Methods: Using data from the Kailuan cohort, we assessed 97 327 Chinese adults for perceived olfactory dysfunction at baseline and gathered mortality data from government records. We used Cox proportional hazards regression models to analyse the risk of all-cause mortality associated with perceived olfactory dysfunction, yielding hazard ratios (HRs) and 95% confidence intervals (CIs) with adjustment for multiple potential confounders.

Results: Over a median follow-up of 6.4-year, we recorded a total of 3903 deaths. Individuals reporting perceived olfactory dysfunction had a higher risk of mortality (adjusted HR = 1.42; 95% CI = 1.02-2.00) compared to those without the dysfunction. In sensitivity analyses, we found similar results after excluding participants with pre-existing obesity, cardiovascular diseases, those younger than 50 years old, individuals diagnosed with cancer or stroke during follow-up, and those who died within two years of follow-up.

Conclusions: Perceived olfactory dysfunction was associated with a high risk of all-cause mortality among Chinese adults. Our study is limited by failure to include a national-representative sample and misclassification of exposure assessment due to use of a subjective question to assess olfactory dysfunction. Further studies with objective are warranted to replicate our findings and understand the underlying mechanisms.