Findings from a new study have highlighted a unique link between poor smell and a greater likelihood of 10-year mortality. The association was independent of the presence of dementia, which has previously been linked to loss of smell.
For the study, olfactory performance, using the Scandinavian Odour-Identification Test (SOIT) and self-reported olfactory function, was measured in 1,774 participants aged 40 to 90 years.
At 10 years, 411 participants (23 per cent) had died. The authors found individuals who performed at chance level on tests (indicating complete olfactory loss) were at a 19 per cent higher risk of death in the following, 10 years compared to individuals with normal smell function. Each additional correctly identified odour lowered the risk of mortality by 8 per cent.
Writing in the Journal of the American Geriatrics Society , the authors said “this study is the first to show that mortality can be predicted from subjective olfactory impairment, with participants with impairment being 30 per cent more likely to die. Although the predictive variance was largely shared between subjective and objective olfactory assessments, subjective assessments might give additional information about subtle intra-individual olfactory changes that objective tests do not capture.”