THE QUESTION Machines with a vibrating platform, producing what’s called whole-body vibration, are being marketed as a way to prevent bone loss. Studies done with rats found such benefits. Might they help older women, who often experience bone density declines after menopause?
THIS STUDY involved 202 post-menopausal women (average age, 60) who had some bone loss but not enough to need prescription medication; all participants took calcium and Vitamin D supplements. They were randomly assigned to stand on a whole-body vibration (WBV) machine, erect but relaxed, for 20 minutes every day for a year at home or to not use such machines. All WBV machines were low-magnitude, with a vibration frequency of either 30 or 90 hertz (Hz). A series of standardized bone measurements, taken at the start and end of the study found essentially no differences in the rate of bone loss between women who used the WBV machines and those who did not. Differences in vibration frequency showed no effect, either. The machines were well tolerated, although more women who used them reported foot pain or numbness, dizziness and nausea.
WHO MAY BE AFFECTED? Post-menopausal women. Though bone loss often begins earlier, it usually increases rapidly after menopause and can lead to osteoporosis. Thinner, weaker bones can contribute to falls and fractures. After age 50, about half of all women break a bone because of osteoporosis.
CAVEATS Whether the participants followed directions about posture was not confirmed. A variety of WBV machines are sold; whether different machines would produce different results is unknown. Testing did not include high-magnitude machines, which the researchers described as potentially dangerous for long-term use. Whether WBV would help men, who also experience bone loss but generally to a lesser degree than women, was not tested.
FIND THIS STUDY Nov. 15 issue of Annals of Internal Medicine (www.annals.org).
The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.