A study concludes that people who experience vertigo, which is the feeling of spinning or falling even when the body is at rest, are more likely to have thinning bones than those who don’t experience the sensation.

Korean researchers measured the bone mineral density at the hip and spine of 209 patients with a diagnosis of benign positional vertigo, one of the most common causes of dizziness in older adults, and in 202 people without vertigo who served as controls.

Both men and women who experienced vertigo were more likely to also have brittle bones, but the association was most pronounced in women – nearly three-quarters of those with a diagnosis of vertigo had osteopenia or osteoporosis compared with only about 43 percent of patients who did not experience dizziness.

Those findings agreed with an earlier study that found osteoporosis in 75 percent of 32 women between 50 and 85 years of age who also had a diagnosis of vertigo.

Vertigo is believed to be caused by loose calcium carbonate crystals moving through the sensing tubes of the inner ear, the area of the body that governs the sense of balance.

Researchers speculate that drop in estrogen that accompanies menopause may cause bones to release more calcium into the blood. The increase in “free” calcium, then prevents the body from clearing the crystals out of the inner ear as it normally would.   

“Women most often have their first case of vertigo in their 50s, when they are also having a drop in bone mass due to loss of estrogen,” says study author Ji Soo Kim, MD, PhD, of Seoul National University College of Medicine in Korea. “Estrogen is one of the main hormones that influence calcium and bone metabolism.”

Though Dr. Kim also notes that the link between estrogen, bone loss and vertigo is probably incomplete since men with vertigo were also more likely to have thinning bones.

The study was published in the March 24, 2009, issue of the journal Neurology.