Perspectives on population-based epidemiological studies of olfactory and taste impairment.

Epidemiological studies of the senses of olfaction (smell) and gustation (taste) are needed since impairments in these senses have important implications for health. Only a few attempts have been made to measure the prevalence of olfactory and gustatory or taste dysfunction, and many methodological challenges remain to be addressed. These challenges differ from those faced in studies based in the clinic or research laboratory. Epidemiological studies of smell and taste represent translational research, because they can be used to understand how findings from laboratory or clinical studies apply to the general population. This paper briefly reviews existing methods for "how" to measure smell and taste dysfunction and then illustrates findings based on prior epidemiological studies to indicate "why" we wish to measure smell and taste functioning in population-based samples. Self-reported information collected on smell and taste loss in a national sample, the 1994-1995 Disability Sample (phase I screening) of the National Health Interview Survey, is contrasted with results provided by an exam-based measure of olfactory impairment in an epidemiological study conducted in Beaver Dam, WI. The comparison of self-reported and exam-based measures of smell or taste loss leads to the question of how to best define smell or taste impairment in population samples, since unlike other sensory domains (namely, vision and hearing), there are no internationally accepted standards of impairment for the chemosenses. In addition to highlighting existing epidemiological studies, the current development of an NIH Toolbox of brief exam measures is described. Through this symposium, we hope to advance the nascent field of olfactory and taste epidemiology.