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.

Olfactory function evaluation in a 1102 community-dwelling 20-90-year old Japanese population in relation with age, sex and mental decline

“…The comparison between self-reported and mPST-based smell dysfunction indicates the validity to use mPST because of high accuracy between these ( Table 2). The trend in our study is similar to NHANES outcomes [8]. Thus, mPST appears to be an unbiased tool to understand the status of smell function.…”

“…It has been reported that olfactory dysfunction is one of the earliest sign of neurodegeneration in AD [7]. The impairment of olfactory function was thoroughly investigated in the National Health and Nutrition Examination Survey (NHANES) in US using the Pocket Smell Test™ (PST) as the olfactory function identification test [8]. The NHANES confirmed the relationship between age, gender, race, education, general health, physical activity, smoking, drinking, and the loss of olfactory function.…”

Prevalence and risk factors of taste and smell impairment in a nationwide representative sample of the US population: a cross-sectional study

“…Our nationally representative estimate of the overall prevalence of smell dysfunction (13.5%) was quite similar to the estimate based on a single-year NHANES survey (12.4%) 21. These estimates were somewhat lower than that reported in other populations whose prevalence ranged from 18.0% to 24.5%,8 9 11 17 and somewhat higher than that reported by some other studies (2.7% to 3.8%) 10…”

“…In two studies, being unable to identify 75% of either 4 or 12 odorants was defined as dysfunction 912 Other studies have set this criterion at 62.5% for either 8 or 16 odorants,6 14 21 and 40% for 5 odorants 9. Such variations in criteria significantly influence the estimated prevalence and likely explain much of the variation seen among prevalence studies.…”

“…An evaluation of the olfactory data collected during a single-year survey (2012) reported a 12.4% prevalence for smell dysfunction in the sampled population, although estimates of taste dysfunction were not presented 21. In the present study, based on a larger sample size from the NHANES 2013–2014 survey among US population aged 40 years and older, we aimed to estimate the prevalence of olfactory and taste dysfunction in the US population, and explore potential risk factors for these conditions.…”