Evaluation of olfactory function in adults with primary hypothyroidism

Area of Science:

• Endocrinology
• Neuroscience
• Otorhinolaryngology

Background:

• Limited clinical data exist on hypothyroidism's impact on adult olfactory function.
• Primary hypothyroidism affects various bodily systems, but its effect on smell is understudied.
• This study addresses the knowledge gap regarding olfactory deficits in adult hypothyroidism.

Purpose of the Study:

• To investigate and evaluate the olfactory function in adult patients with primary hypothyroidism.
• To compare olfactory test results between hypothyroid patients and healthy controls.
• To explore the relationship between thyroid hormone levels and olfactory parameters.

Main Methods:

• A cohort of 45 adult primary hypothyroidism patients (18-60 years) and 45 healthy controls were recruited.
• The Sniffin' Sticks olfactory test was administered to all participants.
• Thyroid function tests (TSH, FT4, FT3) were analyzed alongside olfactory test results.

Main Results:

• Hypothyroid patients exhibited significantly lower odor threshold, identification, and discrimination scores compared to controls (p < 0.001).
• A significant positive correlation was observed between free triiodothyronine (FT3) levels and all olfactory parameters (p < 0.001).
• No significant relationship was found between thyroid-stimulating hormone (TSH) or free thyroxine (FT4) and olfactory function.

Conclusions:

• Adult hypothyroidism is associated with diminished olfactory function.
• Free triiodothyronine (FT3) levels show a stronger association with olfactory parameters than TSH or FT4.
• These findings highlight the importance of thyroid hormone balance for maintaining olfactory acuity.