Patients with osteoporosis or osteopenia are more likely to suffer from benign positional vertigo (BPV) than individuals with normal bone mineral density (BMD), Korean researchers report.
Vertigo is an inner ear disorder that is a common cause of dizziness. In BPV, brief episodes of vertigo and nystagmus are produced by certain changes of head position, explain Ji-Soo Kim (Seoul National University Bundang Hospital) and colleagues.
The causes of BPV are mostly unknown, but may be due to loose calcium carbonate crystals (otoconia) moving in the sensing tubes of the inner ear.
Since otoconia are deposits of calcium carbonate in the form of composite calcite crystals, and bone contains 99% of calcium found in the body, Kim and team investigated the association between osteoporosis and idiopathic BPV.
They measured the BMD at the lumbar spine and femur of 209 consecutive patients (68% women, mean age 60 years) with a confirmed diagnosis of idiopathic BPV and 202 controls with no history of dizziness.
The researchers report that the mean BMD of both women and men with BPV was significantly lower than that of the controls.
Furthermore, the rates of osteopenia and osteoporosis were higher in both women and men with BPV than in controls.
In women, 25% of BPV patients had osteoporosis, compared with 9% of controls, and 47% of BPV patients had osteopenia, compared with 33% of controls. For men, 12% of BPV patients had osteoporosis, compared with 6% of controls, and 40% of BPV patients had osteopenia, compared with 37% of controls.
Multiple logistic regression analyses adjusted for age, gender, alcohol, smoking, and hyperphosphatemia showed that osteopenia and osteoporosis were associated with a 2- and 3-fold increased likelihood for BPV, respectively.
“These findings suggest an [unbalanced] calcium metabolism in idiopathic BPV,” write Kim and co-authors in the journal Neurology.
The researchers observe that, in women, the incidence of BPV increases rapidly after the age of 50 years, which may be linked to estrogen deficiency and bone loss around menopause.
However, since BMD was also decreased in men with BPV, other non-hormonal factors must also play a role, they add.