New chemosensory component in the U.S. National Health and Nutrition Examination Survey (NHANES): first-year results for measured olfactory dysfunction

Abstract

The U.S. NHANES included chemosensory assessments in the 2011-2014 protocol. We provide an overview of this protocol and 2012 olfactory exam findings. Of the 1818 NHANES participants aged ≥40 years, 1281 (70.5 %) completed the exam; non-participation mostly was due to time constraints. Health technicians administered an 8-item, forced-choice, odor identification task scored as normosmic (6-8 odors identified correctly) versus olfactory dysfunction, including hyposmic (4-5 correct) and anosmic/severe hyposmic (0-3 correct). Interviewers recorded self-reported smell alterations (during past year, since age 25, phantosmia), histories of sinonasal problems, xerostomia, dental extractions, head or facial trauma, and chemosensory-related treatment and changes in quality of life. Olfactory dysfunction was found in 12.4 % (13.3 million adults; 55 % males/45 % females) including 3.2 % anosmic/severe hyposmic (3.4 million; 74 % males/26 % females). Selected age-specific prevalences were 4.2 % (40-49 years), 12.7 % (60-69 years), and 39.4 % (80+ years). Among adults ≥70 years, misidentification rates for warning odors were 20.3 % for smoke and 31.3 % for natural gas. The highest sensitivity (correctly identifying dysfunction) and specificity (correctly identifying normosmia) of self-reported olfactory alteration was among anosmics/severe hyposmics (54.4 % and 78.1 %, respectively). In age- and sex-adjusted logistic regression analysis, risk factors of olfactory dysfunction were racial/ethnic minority, income-to-poverty ratio ≤ 1.1, education <high school, and heavy drinking. Moderate-to-vigorous physical activity reduced risk of impairment. Olfactory dysfunction is prevalent, particularly among older adults. Inexpensive, brief odor identification tests coupled with questions (smell problems past year, since age 25, phantosmia) could screen for marked dysfunction. Healthcare providers should be prepared to offer education on non-olfactory avoidance of hazardous events.

Keywords: Epidemiology; Health status; Olfaction disorders; Public health surveillance; Risk factors; Taste.

Fig. 1

a Depiction of the aqueous tastants (provided by the Laboratory of Dr. John Hayes, Pennsylvania State University, PA) and b application to the tongue tip (top panels) in the taste testing. c One of the two 4-item, odor identification tests (Pocket Smell Tests™, Sensonics, Inc., Haddon Heights, NJ) and d four microencapsulated scent strips (with odor choices for each of them) to illustrate the materials used in olfactory testing in the NHANES 2012–2014

Fig. 2

Distribution of the length of time elapsed since respondents experienced a change in their ability to smell (< 3 months [M], 3–12 M, 1–4 years [Y], 5–9 Y, 10 Y or more, unknown), based on whether they reported: a any alteration in their ability to smell (includes during last 12 months, since age 25, and/or phantosmia), b a smell problem in the last year, or c demonstrated a smell problem based on the measured exam results. This question on length of time was asked only if subjects self-reported an alteration in their sense of smell during the home interview prior to the olfactory exam in the MEC

Fig. 3

Reported frequency of smell-related problems based on whether they reported: a any alteration in their ability to smell (includes during last 12 months, since age 25, and/or phantosmia), b a smell problem in the last year, or c demonstrated a smell problem based on the measured exam results. This question about constant versus fluctuating smell problems was asked only if subjects self-reported an alteration in their sense of smell during the home interview prior to the olfactory exam in the MEC