Iodized salt induced thyrotoxicosis: Bangladesh perspective

Area of Science:

• Endocrinology
• Public Health
• Nutritional Science

Background:

• Iodine is essential for thyroid hormone synthesis.
• Iodized salt programs aim to prevent iodine deficiency disorders.
• The impact of long-term iodized salt consumption on thyroid function in specific populations requires investigation.

Purpose of the Study:

• To evaluate the effects of iodized versus non-iodized salt on thyroid hormones (T3, T4) and TSH.
• To assess the potential risk of iodinated salt induced thyrotoxicosis (ISIT) in residents of plain areas.

Main Methods:

• Cross-sectional study of 200 individuals from greater Mymensingh district.
• Categorization into study (iodized salt users, n=150) and control (non-iodized salt users, n=50) groups.
• Serum T3 and T4 measured by radioimmunoassay (RIA); TSH measured by immunoradiometric assay (IRMA).

Main Results:

• Iodized salt users showed significantly higher mean T3 (2.633 nmol/L vs 2.223 nmol/L) and T4 (122.444 nmol/L vs 110.355 nmol/L) compared to non-iodized salt users.
• Mean TSH was significantly lower in the iodized salt group (5.044 mIU/L vs 9.622 mIU/L).
• Results were statistically significant (p<0.05).

Conclusions:

• Long-term consumption of iodized salt in plain areas of Bangladesh can alter thyroid hormone levels and suppress TSH.
• Mandatory iodized salt consumption without screening may pose a risk for ISIT.
• Regular monitoring of thyroid function and urinary iodine is recommended for iodized salt consumers.