February 23, 2015

expert reaction to study on fluoridated water and hypothyroidism

A study published in the journal Journal of Epidemiology & Community Health has analysed a possible association between fluoride levels in water supplies and prevalence of hypothyroidism, suggesting that there is a correlation between the two.

Dr Sandra White, Director of Dental Public Health at Public Health England, said:

“Public Health England regularly reviews the evidence base for water fluoridation. The totality of evidence, accumulated over decades of research, tells us that water fluoridation is a safe and effective public health measure, and shows no association with reduced thyroid function. PHE’s own assessment of water fluoridation programmes in England found evidence of lower tooth decay rates in children living in fluoridated compared to non-fluoridated areas, and greater reductions among those living in the most deprived areas.”

Prof. David Coggon, Professor of Occupational and Environmental Medicine, University of Southampton, said:

“As epidemiological evidence goes, this is about as weak as it gets. Essentially the researchers have shown that after limited adjustment for demographic differences, there are somewhat higher rates of hypothyroidism (which can result from a number of different diseases) in four areas of England that have higher concentrations of fluoride in drinking water.  It is quite possible that the observed association is a consequence of other ways in which the areas with higher fluoride differ from the rest of the country. There are substantially more rigorous epidemiological methods by which the research team could have tested their idea”

‘Are fluoride levels in drinking water associated with hypothyroidism prevalence in England? A large observational study of GP practice data and fluoride levels in drinking water’ by Peckham et al. published in Journal of Epidemiology & Community Health on Monday 23rd February. 

Declared interests

None declared