Controversial study links fluoridated water to lower IQ scores in kids
WASHINGTON: A study published on Monday linked the consumption of fluoridated tap water during pregnancy to lower IQ scores in infants, a finding at odds with decades of public health messages extolling the mineral's benefits in reducing cavities.
"We realised that there were major questions about the safety of fluoride, especially for pregnant women and young children," said Associate Professor Christine Till of Canada's York University, the paper's senior author.
The study, published in the influential Jama Pediatrics journal, analysed data from 512 mother-child pairs across six Canadian cities, with 40 per cent living in communities supplied with fluoridated water.
They found that an increase in concentration of fluoride in a pregnant woman's urine of one milligram a litre was associated with a 4.5-point lower IQ score in boys - but not girls - at age three or four.
When estimating the daily maternal fluoride intake instead of fluoride in urine, a one milligram increase in intake was associated with a deficit of 3.7 IQ points for both boys and girls.
Anticipating controversy, the journal took the unusual step of issuing an editor's note that said the decision to publish was "not easy" and that it had been subject to additional scrutiny.
But experts in fields ranging from statistics to toxicology to neuroscience expressed reservations.
"The key words in the paper are 'higher levels'," said Associate Professor Oliver Jones, an environmental chemist at Australia's RMIT University, who noted that fluoride intake appeared to be below one milligram a litre for most people in the study.
He nevertheless called the work "interesting" and said it justified future research - a conclusion shared by Professor David Bellinger, an epidemiologist at Harvard University who told AFP said the results were "highly credible" but would need to be replicated before policy changes were in order. - AFP