Drinking fluoridated tap water during pregnancy could lead to lower IQ scores among children when they reach three or four years of age.
That’s among the findings of a new study conducted at Canada’s York University and published in the influential JAMA Pediatrics journal.
Researchers from York University (Rivka Green, MA, David Flora, PhD, Raichel Neufeld, and Christine Till, PhD), the University of British Columbia (Bruce Lanphear, MD), the Cincinnati Children’s Hospital Medical Center (Richard Hornung, PhD) Indiana University (E. Angeles Martinez-Mier, DDS) and Laval University (Pierre Ayotte, PhD) conducted the study.
The study followed 601 pairs of mothers and their children born from 2008 to 2012. Women were part of the Maternal-Infant Research on Environmental Chemicals program.
Under half (41 percent) of the mothers were in communities where fluoride was added to drinking water. Some 512 mothers were tested for fluoride levels during the study duration and during each of their three trimesters of pregnancy; 400 answered questionnaires about consumption of beverages such as tea and coffee (which used tap water) as well as drinking water in general.
The researchers then calculated the amount of fluoride consumed on average each day during pregnancy.
The children born were tested for their IQ scores upon reaching the ages of 3 to 4.
The study found that for every 1 milligram increase in the daily intake of fluoride, there was on average a corresponding 3.66 decline in the children’s IQ score.
After taking into consideration other toxins in their analysis, the researchers found that an increase in concentration of fluoride in pregnant mother’s urine of one milligram per liter was associated with a 4.5-point lower IQ score in boys – but not girls – when they reach age three or four, Agence France Presse reported.
And therein lies part of the controversy surrounding the study.
For example, the inconsistency raised questions from Dr. Stuart Ritchie, a psychologist at King’s College London, who was not part of the study. It was “inconsistent” that the study’s first analysis only found a significant result for boys and not girls, while the second analysis found an overall effect with no sex differences, and deemed the findings “pretty weak,” he told the AFP.
“We realized that there were major questions about the safety of fluoride, especially for pregnant women and young children,” Christine Till, an Associate Professor at Canada’s York University, told the news agency.
Dr. Till believes there must be science on whatever conclusions are made. “We’ve had many moments in history where we got new knowledge and changed decisions: look at thalidomide and look at recommendations for hormone replacement therapy,” which was once advised for all menopausal women, Dr. Till, the senior author of the study, told the news agency.
The results were “highly credible,” Dr. David Bellinger, an epidemiologist at Harvard University, told AFP. However, it needs to be validated by further studies, he added.
JAMA Pediatrics issued an Editor’s Note saying the decision to publish was “not easy.” It said the study was subjected to additional peer review./WDJ