A Study on the Effects of Hypothyroidism on the Senses: A Comprehensive Narrative Review

Abstract

Hypothyroidism has been found to have long-term effects on each of the senses, but with proper treatment, many of them can be significantly minimized. This paper analyzes the research on the impact of hypothyroidism on the senses of smell, taste, hearing, vision, and thermoregulation. Data were collected from the National Library of Medicine, PubMed, and Google Scholar databases using the keywords "hypothyroidism," "taste," "smell," "vision," "hearing," and "thermoregulation." Approximately 413 articles were found when searching with these parameters, and 30 were used in this paper. Studies were excluded if they were outside this paper's scope or older than 2012. Studies were included if they specifically focused on hypothyroidism and one of the five listed senses. Patients with hypothyroidism had a significantly increased risk of sensorineural hearing loss, decreased perception of the blue-yellow color axis, decreased sense of olfaction and number of olfactory bulbs, and decreased thermogenesis. Hypothyroidism was also found to show increased length of COVID-19-induced anosmia and decreased bitter taste perception. It can be concluded that hypothyroidism has many effects on the senses, particularly an increased risk of sensorineural hearing loss. More studies need to be done on these effects.