Letters to the editor

Study looks at fluoride in pregnant mothers

A study published in September in the journal Environmental Health Perspectives has linked high urine fluoride levels in pregnant mothers to lower intelligence in their children. This study, which analyzed data collected since 1994 in Mexico, is noteworthy for a number of reasons.

One of the lead researchers, Dr. Howard Hu of the University of Toronto School of Public Health noted the importance of measuring individual urine fluoride levels: "This is significant because previous studies estimated exposures based on neighborhood measurements of drinking water fluoride levels, which are indirect and much less precise measures of exposure."

The data was controlled for a high number of potential confounders, including gestational age at birth, birthweight, birth order, sex, maternal marital status, smoking history, age at delivery, IQ, education, socioeconomic status and lead exposure.

There is limited data on fluoride levels in pregnant mothers in Canada and the US, but the negative effects were found to occur at urine levels common in non-pregnant North American adults. The IQ loss was up to between 5-6 points.

While one study cannot be considered proof of harm and Dr. Hu called for more research, he was not hesitant to recognize the implications of the team's findings: "This is a very rigorous epidemiology study. You just can't deny it. It's directly related to whether fluoride is a risk for the neurodevelopment of children."

The disturbing results shouldn't be surprising, given previous research from China that showed IQ loss in children from high water fluoride areas. Those 50-plus studies prompted Harvard researcher Phillipe Grandjean to comment: "Fluoride seems to fit in with lead, mercury, and other poisons that cause chemical brain drain"¦".

Given Health Canada's promotion of fluoridation as "safe and effective", the odds of them recommending caution by suggesting a suspension of fluoridation until further research is completed, is low. The responsibility to act lies with councillors in fluoridated cities. I recommend that you contact your councillors and ask them to end this experiment until the research that should have been done before fluoridation began, is completed.

David Green 

Peterborough