I thought I would post this here as I found the evidence compelling, but could not locate any quality stats on diabetes/metabolic-syndrome pre-1970s. Before getting into the details, it's worth noting that there's a lot of conspiracy theorists and nut-jobs blaming fluoride for everything from autism to alzheimers. Hopefully we can avoid such baseless discussion here, and focus solely on facts and evidence.
Since 1965 the US has been up-regulating fluoride in most water supplies to the "optimal" level of 1mg/L (you can verify this on your local government website). After discovering some studies related to hypothyroidism, it seems that chronic exposure to fluoride in those with compromised thyroid function (or those with insufficient dietary iodine intake) can result in deleterious effects at doses between 0.01 - 0.05mg/kg of body mass (and around 0.15-0.3mg/kg in healthy individuals).
Now, the RDA for water is roughly 3L, which would be roughly 3mg of fluoride. This would be completely fine for most people, but assuming an average weight of 70kg, the safe dose of fluoride for those with insufficient iodine intake and/or compromised thyroid function would be around 0.7mg.
Considering that the American diet is typically deficient in iodine, it seems like there should be evidence of a significant positive trend in hypothyroidism, diabetes, and metabolic syndrom since the introduction of regulated fluoridation.
Unfortunately the introduction of processed foods and fructose-derived syrups has led to an exponential rise of these conditions in recent years making this variable harder to measure, but I'm still curious as to whether fluoridation could be a statistically-significant factor at least somewhat responsible for the American obesity epidemic.
Anyone have any data or ideas on how to prove/disprove the correlation?
Edited by lmlj, 01 August 2012 - 01:45 AM.