Dear Editor,

It is no surprise to find that the Centre for Health Services, University of Kent, found a clear association between communities with artificial fluoridation of drinking water in the UK and thyroid dysfunction (IMT, March 06, 2015).

Their finding, in a current study published in the Journal of Epidemiology & Community Health (doi:10.1136/jech-2014-204971), supports the epidemiological evidence from numerous other studies worldwide that have similarly found that fluoride in drinking water can impair thyroid function. While the study was conducted in the UK and was remarkably the first ever population-level study to investigate this association, many people in Ireland appear to be unaware that hypothyroidism is a major public health problem in this country, with prevalence rates much more serious than the UK.

This, however, is to be expected, as in the UK less than 10 per cent of public water supplies are artificially fluoridated, while in the Republic of Ireland under mandatory national legislation, the vast majority of consumers are provided with artificially fluoridated water.

Pro-fluoridation advocates in this country appear unaware that according to the National Centre for Pharmacoeconomics, the third most prescribed drug in Ireland is levothyroxine — a drug that is used to treat hypothyroidism. The fourth most prescribed medication is one to treat calcium deficiency.

Calcium deficiency is also acknowledged to increase the toxic effects of fluoride ingestion.

The authors of the study at Kent University recommended that in fluoridated areas, testing for hypothyroidism should be routinely considered, yet remarkably in Ireland neither the HSE nor primary care physicians record hypothyroid prevalence in the community. Perhaps their thoughts are that by not measuring the prevalence of this condition, they can continue to say that fluoridation of water is a safe and effective public health measure.

It’s easy to say it’s safe if you don’t bother to look for the evidence of harm in the first place.

Declan Waugh,
Environmental Auditor and Risk Management Consultant,
Co Cork.