Water fluoridation above a certain level linked to higher rates of underactive thyroid

http://www.eurekalert.org/pub_releases/2015-02/b-wfi022015.php

Public Release: 23-Feb-2015
BMJ

Water fluoridation above a certain level is linked to 30 per cent higher than expected rates of underactive thyroid (hypothyroidism) in England, suggests research published online in the Journal of Epidemiology & Community Health.

The findings prompt the researchers to call for a rethink of public health policy to fluoridate the water supply in a bid to protect the nation's tooth health.

In England, around 10 per cent of the population (6 million) live in areas with a naturally or artificially fluoridated water supply of 1 mg fluoride per litre of drinking water.

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In areas with fluoride levels above 0.7 mg/l, they found higher than expected rates of hypothyroidism than in areas with levels below this dilution.

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"Consideration needs to be given to reducing fluoride exposure, and public dental health interventions should stop [those] reliant on ingested fluoride and switch to topical fluoride-based and non-fluoride-based interventions," they conclude.