Sense of smell and mortality

Being unable to smell in older adults could be a predictor of increased risk of death within five years. In a study of more than 3,000 people aged 57 to 85, 39 per cent of subjects who failed a simple smelling test died within five years, according to results published in the journal PLOS One.
"Compared to a person with a normal sense of smell, a person with an absent sense of smell has three times greater risk of dying within a five-year span," says the study's lead author Dr Jayant Pinto of the University of Chicago. If one's sense of smell is in decline, it could be a warning for your GP to look further.

Pinto, Jayant M. [et al] (2014). Olfactory Dysfunction Predicts 5-Year Mortality in Older Adults. Plos One. DOI: 10.1371/journal.pone.0107541