A clinical survey on patients with taste disorders in Japan: A comparative study.

Objective: To investigate changes in the clinical state of taste disorders between 1990, 2003, and 2019 using the same methodology as that in previous studies.

Materials And Methods: In June 2019, we mailed a questionnaire to 1100 otolaryngologists belonging to the Japan Society of Stomato-pharyngology and investigated three question categories: "Institution", "Number of patients for 3 months", and "Treatment". In addition, we analyzed some results by the class of institution.

Results: The rate of patients who complained of taste disorders in the 2019 survey (220/100,000 persons/year) was twice that of the 1990 survey (110/100,000 persons/year), and slightly higher than that of the 2003 survey (192/100,000 persons/year). The rate of female patients was higher than that of male patients in all age groups. The number of patients was correlated with age up to 70 years of age in both genders. The rates of performing taste tests to assess taste function in the 2019 survey were significantly decreased compared with a 2003 survey (electrogustometry: p<0.001, filter paper disk method: p<0.05 in university). The rate of examination of the serum zinc in the 2019 survey was increased compared with the 1990 survey (p<0.001). Zinc oral therapy was used for the treatment of taste disorders in 239/299 (79.9%) patients/institutes for 3 months. In addition, 213 institutions (69.6%) answered that zinc oral therapy was efficacious for taste disorders.

Conclusion: The patients who complained of taste disorder have increased. The zinc administration is an appropriate clinical treatment for taste disorders in Japan. To enhance treatment for taste disorders, simpler methods for assessing taste function need to be developed, and the pathological mechanisms of taste disorders other than zinc deficiency need to be clarified.