Efficacy of Pioglitazone on Bone Metabolism in Postmenopausal Women With Impaired Fasting Glucose.

The World Health Organization has estimated that 30% of all women aged over 50 years (postmenopausal) have osteoporosis according to a definition of Bone Mineral Density at any site being more than 2.5 standard deviations below the mean for young healthy adult women. A known risk factor for development of osteoporosis and fracture is diabetes mellitus, with correlations to duration of disease and poor glycemic control. Pioglitazone is a thiazolidinedione developed by Takeda Pharmaceuticals for the treatment of type 2 diabetes. Preclinical studies to date on the bone effects of thiazolidinediones have not clearly identified a mechanism of bone loss. While there is evidence of increased bone fractures in postmenopausal diabetic females treated with a thiazolidinedione, the mechanism is not known. Initial studies with thiazolidinediones in humans have focused on short term exposure (12 to 14 weeks) and non-diabetic females. These studies have shown acute changes in circulating bone markers and bone density, but have been questioned because they may not represent bone metabolism in states of abnormal glucose metabolism. Impaired glucose tolerance has been identified not only as a risk factor for developing type 2 diabetes, but also at higher risk for known complications of diabetes. Examination of the effect of thiazolidinediones on bone metabolism in IGT patients will provide data in patients with abnormal glucose tolerance, but without the potential confounding effects of oral hypoglycemic medications to treat type 2 diabetes. The primary objective of this study is to evaluate the effect of pioglitazone on bone mass and metabolism in postmenopausal women with impaired fasting glucose or impaired glucose tolerance. Total participation time in this study is approximately 1 year and six months.