Thyroid Hormone Replacement Therapy Improves Olfaction and Taste Sensitivity in Primary Hypothyroid Patients: A Prospective Randomised Clinical Trial.

Smell and taste are known to be influenced by thyroid function changes. However, many hypothyroid patients and physicians are unaware of their dysosmia and dysgeusia. The present study was performed to shed more light on the relation between hypothyroidism and olfactory loss. 32 primary hypothyroid patients and 31 controls enrolled in the prospective randomized interventional study. Newly diagnosed Primary hypothyroid patients were treated with L-thyroxine for 3–6 months. The control group was selected on the basis of the biochemical evidence of a normal thyroid function. Psychophysiological olfactory testing was performed using odor dispensers similar to felt-tip pens (“Sniffin’ Sticks”, Burghart, Wedel, Germany). Taste function tests were made using “Taste Strips” (Burghart, Wedel, Germany) which are basically tastant adsorbed filter paper strip. Smell identification, threshold, discrimination, TDI scores, bitter and sweet taste scores were significantly lower in untreated hypothyroid patients compared to controls (12.31±1.09 vs. 14.03±1.05, p