New Study Links Fluoride Exposure With Hypothyroidism In Pregnancy and Lower IQ of Children

SUTTON, N.H., Feb. 15, 2023 /PRNewswire/ -- Researchers say healthy thyroid function is crucial for fetal brain development and their latest research may explain earlier findings that pre-natal fluoride exposure lower's children's IQ, according to the Fluoride Action Network.

A new study led by scientists from Toronto's York University was published this week in the journal Science of the Total Environment and found that fluoride exposure was strongly associated with an increased risk of hypothyroidism–impaired thyroid function–in pregnant women. Fluoridated water was the main source of fluoride in the women. The study also found that hypothyroid pregnant mothers had boys with lower IQ scores than mothers with normal thyroid function.

This study is the strongest to date finding fluoride is associated with hypothyroidism and also that hypothyroidism in the mother is associated with lower IQ in the child. According to one study author, neuropsychologist Christine Till, PhD, "the findings are concerning because hypothyroidism is a known cause of brain-based disorders in children."

The study found that a 0.5 milligram per liter increase in water fluoride levels, which was roughly the difference in exposure level between the fluoridated and non-fluoridated communities, was associated with a 1.65 times increased odds of having hypothyroidism in pregnancy. This increased risk is substantial at the population level because hypothyroidism during pregnancy is well established as a cause of reduced IQ in children.

Women are more at risk of developing hypothyroidism, which in addition to causing pre-natal harm can cause symptoms such as fatigue, weight gain and depression. In pregnancy, demands put on the thyroid system increase substantially, especially in the first trimester when the fetus is solely reliant on maternal thyroid hormones.

The study was funded by the U.S. National Institute of Environmental Health Sciences (NIEHS) and Health Canada and followed more than 1,500 mother-child pairs participating in a multi-year study (MIREC) to investigate the impact of environmental chemicals on vulnerable populations.

Approximately 40% of Canadians and 70% of Americans have fluoridated drinking water. The study's authors say they hope that policy makers will consider this new research when evaluating the safety of community water fluoridation.

SOURCE Fluoride Action Network