The thyroid gland makes hormones that regulate metabolism. An over-active thyroid can increase the risk of osteoporosis and fractures. A new study examined whether the risk of these fractures also increases among patients with only mild abnormalities of the thyroid, those who have not yet developed any physical symptoms. Anne Cappola, MD, endocrinologist and professor at the University of Pennsylvania School of Medicine, and co-authors examined the results of 13 individual reseach studies that included more than 70,000 people from all over the world. All patients had thyroid testing and were followed for an average of 12 years to see whether or not they experienced fractures. The study appears in JAMA, Journal of the American Medical Association.