BACKGROUND: Previous reports indicated that self-reports of olfactory function are unreliable. The occurrence of measured olfactory dysfunction is approximately 20% in the general population and consistently higher than that of self-reported olfactory dysfunction. To further understand the frequencies of self-rated olfactory function in different age groups and its relation with measured olfactory function, a prospective investigation of self-rated and measured olfactory function was performed.

METHODS: One thousand five subjects were enrolled from the health care center, where subjects underwent a physical checkup for possible preclinical diseases. The subjects completed a questionnaire about demographic data and medical and surgical histories and self-rated their olfactory function. Then, they received a modified "Sniffin' Sticks" odor identification test.

RESULTS: The self-rated olfaction function did not correlate significantly with measured olfactory function. The frequencies of self-rated olfactory dysfunction (9-14%) were similar among various age groups. However, the frequencies of measured olfactory dysfunction in the three age groups, i.e., 18 to 35, 36 to 55, and > 55 years, were 3.7%, 17.4%, and 35.6%, respectively.

CONCLUSIONS: Self-ratings of olfactory function were unreliable at all ages. The frequencies of self-rated olfactory function in various age groups did not differ significantly, in contrast to the decrease of measured olfactory function with age.