Thursday, May 14, 1998
To Whom It May Concern:

It has been proposed to add fluoride to the water supply of the larger communities of Utah to prevent dental caries. This proposal will undoubtedly generate debate about the benefits and risk of low level ingestion of fluoride on human health.

I wanted to comment on some possible untoward side effects associated with the ingestion of low levels of fluoride. In 1991 three colleagues and myself published a paper in the Journal of the American Medical Association entitled "Hip fractures and fluoridation in Utah's elderly population." (See JAMA 1991; 268: 746-748) suggesting that there was a 27% (rate ratio = 1.27) increase in hip fractures among women, and a 41% (rate ratio = 1.41) increase in hip fractures among men age 65+ living in Brigham City, the largest fluoridated community in Utah, compared to Logan and Cedar City. The study covered fractures occurring between 1984-1990.

We undertook the study because of reports in the medical literature of increased hip fractures among women who had received high doses (75 mg/ day) of fluoride for the treatment of osteoporosis. We were surprised to find and effect at the much lower dose from a fluoridated water system (between 1-2 mg/d).

Since our study was published, three additional reports have appeared in medical literature. Sower et al., (American Journal of Epidemiology 1991; 133: 649-660) reported a more than 100% increased risk of hip fracture among women ages 55+ living in Iowa communities with 15+mg/l of fluoride compared to communities with 1mg/l of fluoride.

Jacobsen-Gadda et al., (JAMA 1995; 273: 775, letters to the editor) reported on hip fractures among 3,578 people age 65+ living in southwestern France, and drinking fluoridated water. They were able to calculate an individual dose for each subject, and control for body mass, and cigarette smoking. They reported an 86% increase in hip fractures (rate ratio 1.86) among those with the highest levels of fluoride intake (0.11 – 1.83mg/L), and no effect for calcium in water, nor for other sites of fractures besides the hip.

Of the four published scientific studies on the association of hip fracture with fluoride consumption in drinking water, all found an increased risk of hip fracture among those age 65+.

Department of Family and Preventive Medicine
50 North Medical Drive
Salt Lake City, Utah 81132
801-581-7234 Ext. 801-581-2759

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