Investigation of the sniffin' sticks olfactory test in Taiwan and comparison with different continents

Background: The Sniffin' Sticks test is a well-developed olfactory test, with normative data having been derived from more than 3,000 subjects in central-northern Europe and Australia. However, as environment affects olfactory function, the purposes of this study were to establish normative data for the Sniffin' Sticks olfactory test in Taiwan, where the climate is different from that of Europe, and to determine whether or not the olfactory function of Taiwanese is different from that of Europeans. Methods: One hundred and forty-five subjects with normal self-rated olfactory function were enrolled. The Sniffin' Sticks olfactory test was used to score olfactory threshold (OT), odor discrimination (OD) and odor identification (OI), and a composite TDI score was calculated. Results: All of the tasks related to the Sniffin' Sticks olfactory test correlated significantly and inversely with age. The 10^th percentiles of OT, OD, OI and TDI in the 16-35 years age group were 4.50, 9.70, 12.00 and 30.00, respectively. These data were the criteria used to separate normosmia from hyposmia. Conclusion: The diagnostic criteria to separate normosmia from hyposmia in Taiwan are similar to those in Europe.