For over fifty years, there have been concerns that fluoridated water and fluoride from other sources may weaken bones and increase the risk of bone fractures. To date, scientific studies have focused on bone fractures in the elderly, especially hip fractures in older women, which are a leading cause of disability and death. This week, the first scientific study of artificial water fluoridation and broken bones in children was published. The article’s title is “Community Water Fluoridation and Rate of Pediatric Fractures” (Lindsay et al 2023).
Researchers from Oregon Health & Science University found that US states with a high proportion of their population receiving fluoridated water averaged twice the rate of common types of childhood bone fracture as states with relatively little fluoridation. They also looked at the level of fluoride in the water and found that in the group of states with an average concentration of around 0.7 mg/L – the level used in artificial fluoridation – rates of child forearm fractures were 2.5 times greater than in the group of states with the lowest average concentration, which was about 0.4 mg/L.
The study used nationwide bone fracture data from over 100,000 children aged 4 to 10 years old, at the state level, obtained from insurance records. Water fluoridation information came from CDC public data. The authors concluded, “community water fluoridation proportion by both state and fluoridation levels are associated with the increased rate of fracture in children”.
The largest increase was found in the most common type of childhood bone fracture called a Both Bone Forearm Fracture (BBFFx), an example of which is shown in the x-ray image.
For this type of broken arm, the study’s findings are illustrated by two graphs, drawn from data reported in the paper:
The graphs show highly significant large-magnitude associations between child forearm fractures and the percent of people fluoridated (left graph) and the average state water fluoride concentration (right graph).
While the study was a relatively simple design, based on state-level rather than individual-level exposure data, it raises new red flags about fluoride’s effect on skeletal development in young children.
FAN’s Michael Connett predicted back in 2012, based on a study in Iowa, that fluoride may increase risk of bone fractures in children [Connett 2012a, Connett 2012b]. The Iowa study found evidence of decreased Bone Mineral Density (BMD) in girls in fluoridated areas, especially cortical bone which is the outer layer that gives structural strength to long bones like those in the forearm. Connett said the finding was: “… particularly significant when considering that reductions in cortical bone density are a key mechanism by which fluoride can increase fracture rates.”
Twenty-one years ago, long before recent higher-quality studies became available, FAN’s Paul Connett made broader predictions of the effects of fluoridated water on bone:
“… the weight of evidence would suggest that it is highly plausible that exposure to water at 1 ppm … over a whole lifetime will damage human bones and ligaments. It is also probable that this damage will at least lead to the sub-clinical symptoms of skeletal fluorosis, possibly arthritis as well as to hip fractures.”
Those predictions from 10 and 20 years ago are being born out. Two years ago the evidence that long-term fluoride exposure increases risk of broken bones in older adults was greatly advanced by a high-quality study from Sweden. Last week’s first-ever study on childhood bone fractures now raises concern that just a few years of exposure to fluoridation, during ages when children’s bones are rapidly growing, may substantially increase rates of childhood bone fractures.
Chris Neurath
Research Director, Fluoride Action Network