Selenium and goiter prevalence in borderline iodine sufficiency

Area of Science:

• Endocrinology
• Nutritional Science
• Thyroid Research

Background:

• Selenium (Se) is crucial for selenocysteine protein synthesis, including thyroid selenoenzymes like deiodinases that regulate thyroid hormones.
• Investigating Se's role in goiter is complex due to population variations in Se intake and bioavailability, and confounding iodine deficiency in prior studies.

Purpose of the Study:

• To assess the influence of selenium on thyroid volume in an iodine-sufficient population.
• To determine if selenium status is an independent risk factor for goiter development.

Main Methods:

• Evaluated urinary iodine (UI) and creatinine, and prevalence of goiter/nodules via ultrasonography in randomly selected individuals.
• Compared urinary Se excretion (USe) in goiter patients versus controls, adjusting for age, gender, thyroid history, smoking, and UI.

Main Results:

• The study population exhibited borderline selenium and iodine sufficiency (mean USe: 24 µg/L; mean UI: 96 µg/L).
• Individuals with goiter (n=89) had significantly higher USe levels than those with normal thyroid volume (n=83; P < 0.05).
• Urinary Se excretion was not affected by smoking or pregnancy.

Conclusions:

• Urinary Se was not found to be an independent risk factor for goiter development.
• The observed higher USe in goiter patients is likely coincidental.
• Iodine status appears to be the more critical determinant of thyroid volume in this population, rather than selenium.