Research: Childhood fluoride exposure has no effect on IQ

About a year ago, the city of Portland, Oregon, was in the news because of its water supply—and not because a teenager decided to relieve himself into a reservoir. Instead, the issue was fluoridation, the addition of trace amounts of fluorine to municipal drinking water. Fluoridation is widespread in the US, as copious evidence indicates it improves oral hygiene.

That evidence prompted the Portland City Council to approve fluoridation—only to see voters reject that plan by a wide margin. While some of the opposition focused on the finances of the deal for the fluoridation process, concerns about the safety of fluoridation also played a major role in organizing the opposition.

It turns out that a similar drama had been playing out in New Zealand, where the city of Hamilton reversed course on water fluoridation several times over the past two years. Now, in response to the kerfuffle, some New Zealand researchers (combined with a ringer from Duke) have looked into one of the supposed health threats posed by fluoridation: it stunts the mental development of children. Their new report finds no evidence of this, however. In fact, children who grew up with fluoridated water had slightly higher IQs than their peers, though the difference wasn't statistically significant.

The fears about fluorine's impact on intellectual development appear to derive from a meta-analysis of natural exposure to fluorine in China, where levels in the water can reach several times those generated by intentional fluoridation. Although the study found a link between high fluorine and reduced IQ, the relevance of the study to the levels used in the US and elsewhere wasn't clear.

That, however, hasn't stopped anti-fluoridation activists from latching on to the paper as an indication that fluorine represents a threat. Not surprisingly, the paper makes appearances at the Fluorine Free Hamilton website. That group helped convince the city council of Hamilton to stop fluoridating its waters. After a public outcry, a referendum showed that this measure had the support of only 30 percent of Hamilton's citizens. After a national court ruled in favor of fluoridation in a different city (suggesting opposition may be widespread in New Zealand), the city council restored fluoridation.

In the mean time, however, public health experts were motivated to look into the health impact of fluoridation. Conveniently, they had a study population on hand: the Dunedin Multidisciplinary Health and Development Study has been tracking more than 1,000 children born in that city on New Zealand's South Island since their births in the early 1970s. Conveniently, fluoridation was not uniform in Dunedin, creating experimental and control populations. The cohort also had its IQ tested at ages from seven to 13 years old, and the study tracked whether the children had used fluoride-containing toothpaste or tablets.

Overall, nothing made any difference to IQ. "No statistically significant difference in IQ existed between participants who had or had not resided in areas with [fluoridation], used fluoride toothpaste, or used fluoride tablets, both before and after adjusting for potential confounding variables," the authors conclude. In fact, the children in areas with fluoridation had slightly higher IQs (although, again, this difference was not statistically significant).

Given that New Zealand uses fluoride levels that are similar to those in the US and Australia, the study appears to indicate that the high levels seen in some water in China are not relevant to controlled administration of fluoride in water. The authors also raise the prospect that any effects on IQ were the result of something other than fluorine, given that the Chinese studies didn't always take confounding variables into account.

Will this end public resistance to fluoridation? Certainly not; people who are convinced of something aren't often swayed by evidence that runs contrary to their beliefs. But it will provide some assistance to public health authorities who have to deal with anxious legislators when this issue comes up.

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Big Pat said:

Counterpoint:

My house has a well. If I drink the 100% natural water that comes out of it, I'll most likely be violently ill, since it contains a LOT of micro-organisms. It also killed one of my cats, since it has so much mineral in it it clogged her kidneys.

So I would much rather have trace amounts of chemicals in it if it meant I didn't have to buy fucking water at the grocery store.

And yes I will be changinfg my water treatment apparatus, it is not really working up to par, but that shit is expensive as well...

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Casino said:

Not even gonna read the article because I know it's bullshit. Just gonna post a couple facts that 100% non-debatable, and leave on that note.

Fluoride in drinking water is poison and always will be.
Most people have no clue what they consume on a daily basis and just take everything blindly up the ass by the government (goes for vaccinations, too).

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lord_galathon said:

Buy a filter.

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Big Pat said:

I'll do that as soon as I find a filter that will filter out micro-organisms, iron and calcium and whatever else is in this "natural" cesspool.

Seriously, the water cannot be treated with a common filter, otherwise I would have done it a long time ago. I need a water treatment apparatus and it is expensive, and it requires the addition of chemicals to the water. And I'll have to do it, as soon as I finish paying the million other things that are wrong with my money pit. Tom Hanks and Shelley Long have nothing on my girlfriend and I... (you're old enough to understand the reference... )

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diplomat128 said:

2 words: Reverse Osmosis.

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