Goitrogenic anions, thyroid-stimulating hormone, and thyroid hormone in infants

Area of Science:

• Environmental health
• Endocrinology
• Pediatric toxicology

Background:

• Infant exposure to environmental goitrogens like perchlorate, thiocyanate, and nitrate may disrupt thyroid function.
• Previous studies in U.S. women show higher perchlorate exposure correlates with elevated thyroid-stimulating hormone (TSH) and reduced thyroxine (T4).
• Limited data exists on individual thyroid function measures alongside goitrogen exposure in infants.

Purpose of the Study:

• To investigate the association between urinary perchlorate, nitrate, iodide, and thiocyanate levels and urinary T4 and TSH in infants.
• To determine if these associations differ based on infant sex or iodide status.

Main Methods:

• Utilized data from the Study of Estrogen Activity and Development, including 92 full-term infants (birth to 1 year).
• Analyzed 206 urine samples for perchlorate, thiocyanate, nitrate, and iodide.
• Measured TSH and T4 in urine and 50 blood samples.

Main Results:

• Higher urinary perchlorate, nitrate, or thiocyanate correlated with elevated urinary TSH in infants, after adjusting for covariates.
• When all three chemicals were modeled, higher nitrate and thiocyanate remained associated with increased TSH.
• Higher perchlorate was linked to increased TSH specifically in infants with low urinary iodide.
• Unexpectedly, exposure to these three chemicals was generally associated with higher T4 levels.

Conclusions:

• Findings confirm the association between perchlorate exposure and increased urinary TSH in infants with low iodide, aligning with prior research.
• Elevated thiocyanate and nitrate exposure in infants were also found to be associated with higher TSH levels.
• These results highlight potential environmental impacts on infant thyroid regulation.