British study finds an association, but unable to prove cause-and-effect
WEDNESDAY, Feb. 25, 2015 (HealthDay News) — A British study has found a correlation between the amount of fluoride in public drinking water and a rise in incidence of hypothyroidism. The findings were published online Feb. 24 in the Journal of Epidemiology & Community Health.
The new study was led by Stephen Peckham of the University of Kent in Canterbury, U.K. The authors compared 2012 national data on levels of fluoride in drinking water to trends for hypothyroidism as diagnosed by family physicians across England.
The researchers found that in locales where tap water fluoride levels exceeded 0.3 mg/L, the risk for having an underactive thyroid rose by 30 percent. Peckhams’s team also found that hypothyroidism rates were nearly double in urbanized regions that had fluoridated tap water, compared with regions that did not.
But a representative of the American Dental Association (ADA) took issue with the British report. “Public health policy is built on a strong base of scientific evidence, not a single study,” Edmond Hewlett, D.D.S., ADA spokesman and a professor at the UCLA School of Dentistry, told HealthDay. “Currently, the best available scientific evidence indicates that optimally fluoridated water does not have an adverse effect on the thyroid gland or its function.”
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