BACKGROUND/OBJECTIVES: Loss of olfactory function is largely found with aging. Such a reduction in olfactory function affects quality of life and enhances likelihood of depressive symptoms. Furthermore, it has been shown that reduction in olfactory function is associated with cognitive impairment and several diseases such as major depression. Because several studies suggest that discontinuous exposure to odors may improve general olfactory function, the primary aim of this study was to investigate whether such "olfactory training" has positive effects on subjective well-being and cognitive function.

DESIGN: We performed a controlled, unblinded, longitudinal study SETTING: The study took place at an outpatients' clinic of a Department of Otorhinolaryngology at a Medical University.

PARTICIPANTS: A total of 91 participants (age 50 to 84 years) completed testing. They were randomly assigned to an olfactory training (OT) group (N = 60) and a control group (N = 31). The study included two appointments at the Smell and Taste Clinic.

MEASUREMENTS: Olfactory and cognitive function as well as subjective well-being was tested using standardized tests.

INTERVENTION: During the 5-month interval between sessions, the OT group completed daily olfactory exposure. During the same time, the control group completed daily Sudoku problems.

RESULTS: Analyses show a significant improvement of olfactory function for participants in the OT group and improved verbal function and subjective well-being. In addition, results indicated a decrease of depressive symptoms.

CONCLUSION: Based on the present results, OT may constitute an inexpensive, simple way to improve quality of life in older people. Copyright © 2017 John Wiley & Sons, Ltd.