Fluoride Supplementation and Vertebral Fractures in the Elderly

Source: Tufts University
January 11, 2002 (Reviewed: January 26, 2004)

We have known for decades that fluoride helps build strong teeth, and that it contributes to bone health. A study recently published in the Archives of Internal Medicine adds to what we know of its benefits to bone.

A measure of strength

Researchers from the University of Texas recruited 85 ambulatory women at least 65 years old. All showed at least one vertebral compression fracture in baseline lateral thoracic and lumbar x-rays. The women were randomized to a daily dose of 25 mg sodium fluoride or placebo in 3 year-long cycles, with a 2-month period separating each cycle. In addition, all the women supplemented their diets with 945 mg calcium and 600 IU cholecalciferol (vitamin D). The vertebral fracture rate was measured over the study period. Biochemical markers - serum PTH, bone-specific alkaline phosphatase, osteocalcin - and bone mineral density of the spine, hip, and femoral neck were measured periodically throughout the 42-month trial.

The risk of spine fracture was reduced by 60% in the women who took sodium fluoride, compared with placebo (RR= 0.40, 95% CI, 0.17-0.95). Biochemical analyses of those in the fluoride group showed a significant increase in the markers of bone formation.

There was no significant between-group difference in femoral neck or total hipbone mineral density. All participants, though, ended the study with greater vertebral bone density; there was an increase of 5.4% (95% CI, 2.7%-8.2%) for the fluoride group and 3.2% (95% CI, 0.8%-5.6%) in the control group - the between-group differences were not significant. This positive outcome was attributed to the use of calcium and vitamin D supplements.

Potential drawbacks

The authors note that the long-term use of sodium fluoride may have some drawbacks. It can cause gastrointestinal distress, and some participants of earlier studies have complained of leg pain, which researchers suspect might result from bones weakened by excessive bone remodeling. There is also some evidence that fluoride supplementation increases the risk of non-vertebral fractures, despite increases in bone mineral density. However, none of these problems was a significant issue in the current study.

Bones are in a constant state of remodeling - a process influenced by hormones, diet, and age. In women, estrogen helps to preserve bone strength, so maintaining healthy bones becomes a particularly pressing problem after menopause. Fluoride acts as an anabolic agent to enhance bone formation. In combination with an adequate intake of calcium and vitamin D, it can help slow the mineral erosion that leads to osteoporosis.

Speaking points

Osteoporosis is called the 'silent disease' because many people don't know they have it until they suffer a fracture. It's important to prompt patients - especially women, who are hardest hit by this disease - to get a bone mineral density test to detect osteoporosis before a fracture occurs. Sodium fluoride, used in this study, is still in the testing phase in the U.S. Other medications that can help preserve bone density are available, but it is important to educate patients to the fact that medication alone won't do it. A diet rich in calcium and vitamin D and regular weight-bearing exercise should be part of everyone's osteoporosis prevention program.

Source

• Sustained-release sodium fluoride in the treatment of the elderly with established osteoporosis. C. Rubin, C. Pak, B. Adams-Huet,  et al., Arch Intern Med, 2001, vol. 161, pp. 2325--2333

Related Links
What Are the Chances of Preventing Osteoporosis?
An Occasional Drink May Aid Bone Strength
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