Prevalence of Olfactory Dysfunction: The Skövde Population‐Based Study

Abstract

Objectives/Hypothesis Patients with olfactory dysfunction appear repeatedly in ear, nose, and throat practices, but the prevalence of such problems in the general adult population is not known. Therefore, the objectives were to investigate the prevalence of olfactory dysfunction in an adult Swedish population and to relate dysfunction to age, gender, diabetes mellitus, nasal polyps, and smoking habits. Study Design Cross‐sectional, population‐based epidemiological study. Methods A random sample of 1900 adult inhabitants, who were stratified for age and gender, was drawn from the municipal population register of Skövde, Sweden. Subjects were called to clinical visits that included questions about olfaction, diabetes, and smoking habits. Examination was performed with a smell identification test and nasal endoscopy. Results In all, 1387 volunteers (73% of the sample) were investigated. The overall prevalence of olfactory dysfunction was 19.1%, composed of 13.3% with hyposmia and 5.8% with anosmia. A logistic regression analysis showed a significant relationship between impaired olfaction and aging, male gender, and nasal polyps, but not diabetes or smoking. In an analysis of a group composed entirely of individuals with anosmia, diabetes mellitus and nasal polyps were found to be risk factors, and gender and smoking were not. Conclusion The sample size of the population‐based study was adequate, with a good fit to the entire population, which suggests that it was representative for the Swedish population. Prevalence data for various types of olfactory dysfunction could be given with reasonable precision, and suggested risk factors analyzed. The lack of a statistically significant relationship between olfactory dysfunction and smoking may be controversial.

Association between diabetes mellitus and olfactory dysfunction: current perspectives and future directions

“…Previous studies have further reported a relationship between olfactory dysfunction and diabetes [13][14][15][16][17][18], as well as an inverse relationship between olfactory identification and discrimination scores and the presence of diabetic complications [13,14,16,19,20]. Some authors have suggested that screening for olfactory dysfunction could serve as an early detector for the presence of diabetic microvascular complications, such as diabetic neuropathy [16,19].…”

Anosmia after exposure to a pyrethrin-based insecticide: A case report

“…The sensation of the smell of burnt or metallic smell in the absence of the stimulus is sometimes defined as 'torqosmia' [9]. In a large Swedish study, overall prevalence of hyposmia and anosmia in the general population were 13.3% and 5.8%, respectively [6], and similar proportions were reported in Germany [8]. One of the main factors related to olfactory dysfunction is aging [11], but several other causes are also known.…”

“…The prevalence of subjects with the impairment of olfactory perception in the general population ranges from 1 up to 20% [6][7][8]. However, this is likely an underestimation, especially considering the fact that many people with a reduced olfactory sensitivity are unaware of their situation [3].…”

“…Approximately 10-25% of all smell impairments in the general population are currently classified as 'idiopathic' [6,9,21]; some of these idiopathic olfactory losses are likely to be related to unnoticed chemical exposure. Accordingly, more attention is needed to airborne chemicals as a cause of olfactory dysfunction [1,20].…”

A possible correlation between vitamin D deficiency and loss of smell: 2 case reports

“…23,24 Similarly, 19% of Swedes were found to have hyposmia or anosmia. 25 Many times, the ability to smell diminishes gradually over time, making self-reported olfactory impairment substantially underestimated. 23 Patients frequently do not discuss their olfaction difficulties; however, the loss of smell can lead to depression and a lower quality of life.…”