Hyposmia Explained

Hyposmia, or microsmia,[1] is a reduced ability to smell and to detect odors. A related condition is anosmia, in which no odors can be detected. Some of the causes of olfaction problems are allergies, nasal polyps, viral infections and head trauma. In 2012 an estimated 9.8 million people aged 40 and older in the United States had hyposmia and an additional 3.4 million had anosmia/severe hyposmia.[2]

Hyposmia might be a very early sign of Parkinson's disease.[3] Hyposmia is also an early and almost universal finding in Alzheimer's disease and dementia with Lewy bodies.[3] Lifelong hyposmia could be caused by Kallmann syndrome[4] or Autism Spectrum Disorder.[5] Along with other chemosensory disturbances, hyposmia can be a key indicator of COVID-19.[6] [7]

Epidemiology

The National Health and Nutrition Examination Survey (NHANES) collected data on chemosensory function (taste and smell) in a nationally-representative sample of US civilian, non-institutionalized persons in 2012.[8] Olfactory function was assessed on persons aged 40 years and older with an 8-item, odor identification test (Pocket Smell Tests, Sensonics, Inc., Haddon Heights, NJ). Odors included food odors (strawberry, chocolate, onion, grape), warning odors (natural gas, smoke) and household odors (leather, soap). Olfactory function score was based on the number of correct identifications. Prevalence (%) of anosmia/severe hyposmia (scores 0 to 3) was 0.3 at age 40–49 rising to 14.1 at age 80+. Prevalence of hyposmia (scores 4 to 5) was much higher: 3.7% at age 40–49 and 25.9% at 80+. Both were more prevalent in individuals of African descent than in those of Caucasian descent.

Chemosensory data were also collected in a larger NHANES sample in 2013–2014. The prevalence of smell disorder (scores 0–5 out of 8 correct) was 13.5% in persons aged 40 years and over.[9] If the same prevalence occurred in 2016, an estimated 20.5 million persons 40 and over had hyposmia or anosmia. In addition multiple demographic socioeconomic, and lifestyle characteristics were assessed as risk factors for diminished smell. In statistical analyses, greater age and male sex, coupled with either black and/or non-Hispanic ethnicity, low family income, low educational attainment, high alcohol consumption (more than 4 drinks per day), and a history of asthma or cancer were independently associated with a greater prevalence of smell impairment.

See also

Notes and References

  1. Book: Hawkes, Christopher H.. 2002. Smell and taste complaints. Butterworth-Heinemann. Boston. 0-7506-7287-0. 49–50.
  2. Hoffman . Howard J. . Rawal . Shristi . Li . Chuan-Ming . Duffy . Valerie B. . New chemosensory component in the U.S. National Health and Nutrition Examination Survey (NHANES): first-year results for measured olfactory dysfunction . Reviews in Endocrine and Metabolic Disorders . 10 June 2016 . 17 . 2 . 221–240 . 10.1007/s11154-016-9364-1. 27287364 . 5033684 .
  3. Factor, Stewart A., & Weiner, William J., eds. (2008). Parkinson's Disease: Diagnosis and Clinical Management, 2nd ed., pp. 72-73. New York: Demos Medical Publishing.
  4. Arkoncel . ML . Arkoncel . FR . Lantion-Ang . FL . A case of Kallmann syndrome . BMJ Case Reports . March 2011 . 2011 . bcr0120113727 . 10.1136/bcr.01.2011.3727 . 22700069 . 3070321 . Kallmann syndrome (KS), a rare genetic disorder, refers to the association between hypogonadotropic hypogonadism and anosmia or hyposmia due to abnormal migration of olfactory axons and gonadotropin-releasing hormone producing neurons..
  5. Tonacci . Alessandro . Billeci . Lucia . Tartarisco . Gennaro . Ruta . Liliana . Muratori . Filippo . Pioggia . Giovanni . Gangemi . Sebastiano . Olfaction in autism spectrum disorders: A systematic review . Child Neuropsychology . 2 January 2017 . 23 . 1 . 1–25 . 10.1080/09297049.2015.1081678 . 26340690 . 143375600 . 0929-7049.
  6. Lechien JR, Chiesa-Estomba CM, De Siati DR, Horoi M, Le Bon SD, Rodriguez A, Dequanter D, Blecic S, El Afia F, Distinguin L, Chekkoury-Idrissi Y, Hans S, Delgado IL, Calvo-Henriquez C, Lavigne P, Falanga C, Barillari MR, Cammaroto G, Khalife M, Leich P, Souchay C, Rossi C, Journe F, Hsieh J, Edjlali M, Carlier R, Ris L, Lovato A, De Filippis C, Coppee F, Fakhry N, Ayad T, Saussez S . 6 . Olfactory and gustatory dysfunctions as a clinical presentation of mild-to-moderate forms of the coronavirus disease (COVID-19): a multicenter European study . European Archives of Oto-Rhino-Laryngology . 277 . 8 . 2251–2261 . August 2020 . 32253535 . 7134551 . 10.1007/s00405-020-05965-1 . free .
  7. Xydakis MS, Dehgani-Mobaraki P, Holbrook EH, Geisthoff UW, Bauer C, Hautefort C, Herman P, Manley GT, Lyon DM, Hopkins C . 6 . Smell and taste dysfunction in patients with COVID-19 . The Lancet. Infectious Diseases . 20 . 9 . 1015–1016 . September 2020 . 32304629 . 7159875 . 10.1016/S1473-3099(20)30293-0 . free .
  8. Hoffman . Howard J. . Rawal . Shristi . Li . Chuan-Ming . Duffy . Valerie B. . New chemosensory component in the U.S. National Health and Nutrition Examination Survey (NHANES): first-year results for measured olfactory dysfunction . Reviews in Endocrine and Metabolic Disorders . 10 June 2016 . 17 . 2 . 221–240 . 10.1007/s11154-016-9364-1. 27287364 . 5033684 .
  9. Liu . Gang . Zong . Geng . Doty . Richard L . Sun . Qi . Prevalence and risk factors of taste and smell impairment in a nationwide representative sample of the US population: a cross-sectional study . BMJ Open . 9 November 2016 . 6 . 11 . e013246 . 10.1136/bmjopen-2016-013246. 28157672 . 5129069 . free .