Background: Olfaction plays an important role in our daily and social lives, both as adults and as children. This study assessed whether the ability to identify odours increases with age, as well as the ability in various age groups and the factors involved. Methods: The survey was performed in 2017 on 697 Japanese children (366 girls and 331 boys) aged 6–18 years who lived in Tsunan, Niigata Prefecture, Japan by using the ‘Open Essence’, a card-type odour identification test. We collected information regarding age, sex, and physical characteristic. We also inquired whether participants had siblings or if members of the family smoked, and whether they had conversations about odour at home. Statistical analysis was performed to evaluate the factors affecting odour identification abilities. Results: The results showed that the odour identification abilities of children increase with age, and children who have daily conversations about odours at home have better odour identification abilities. Conclusions: Odour identification ability increases with age. In addition, our findings suggest that conversation may positively affect odour identification. Hence, it is important for children to be exposed to an environment where they develop an interest in smells for better growth of their olfactory identification ability.

Post-traumatic olfactory dysfunction is known to have a poor prognosis. Traumatic olfactory dysfunction is commonly associated with parosmia, which is an often neglected symptom due to difficulty with its assessment using standard olfactory testing. We report a case of a patient diagnosed with post-traumatic olfactory loss and parosmia. Olfactory loss recovered within one year, but parosmia persisted for five years before disappearing.

Introduction: Olfactory dysfunction has been shown to be an early sign of neurodegenerative disease, but the incidence of neurodegenerative disease in patients with olfactory dysfunction in Japan is unknown. Moreover, olfactory dysfunction has been suggested to be a predictor of mortality. The goal of the present study was to investigate the long term olfactory prognosis, incidence of neurodegenerative disease and mortality in patients with olfactory dysfunction.