The Claim

At moderate urinary iodine levels (≤300 μg/L), higher fluoride exposure is associated with lower serum total triiodothyronine (TT3) levels in school-age children, indicating a potential disruption in thyroid hormone production under specific iodine conditions.

Source: Iodine Modifies the Susceptibility of Thyroid to Fluoride Exposure in School-age Children: a Cross-sectional Study in Yellow River Basin, Henan, China

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
44score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Correlation
1 study reviewed
In plain English

When kids have just enough iodine in their urine but are exposed to more fluoride, their bodies might make less of an important thyroid hormone called TT3 — like their thyroid is struggling a bit under those conditions.

See the scientific wording

At moderate urinary iodine levels (≤300 μg/L), higher fluoride exposure is associated with lower serum total triiodothyronine (TT3) levels in school-age children, indicating a potential disruption in thyroid hormone production under specific iodine conditions.

What the research says

1 study
  1. Study: Iodine Modifies the Susceptibility of Thyroid to Fluoride Exposure in School-age Children: a Cross-sectional Study in Yellow River Basin, Henan, China

    This study found that when kids have a normal amount of iodine in their urine, too much fluoride makes their thyroid produce less of an important hormone called TT3. So yes, fluoride can mess with thyroid function—but only when iodine isn’t too high or too low.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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