Ippei Kanazawa obtained Ph.D. degree in 2009 from Shimane University Graduate School of Medicine and completed postdoctoral studies at McGill University in Canada. He is now an assistant professor of the division of Endocrinology and Metabolism in Shimane University Faculty of Medicine. He has published more than 45 papers in international journals and serving as an editorial board member of Journal of Diabetes & Metabolism.
Accumulating evidence has shown that the risk of osteoporotic fracture is increased in type 2 diabetes mellitus (T2DM). Since the risk is independent of bone mineral density (BMD) reduction, measurement of BMD, which is a gold standard to detect primary osteoporosis, is not useful for screening diabetes-related bone fragility. It is known that insulin-like growth factor-I (IGF-I) has anabolic effects on bone, and that serum IGF-I level is decreased in poorly controlled diabetic patients. We thus hypothesized that IGF-I was involved in the etiology of diabetes-related bone fragility and its serum levels might be a clinically useful marker for assessing fracture risk in T2DM. To examine the relationship between serum IGF-I level and incidence of fracture, we conducted a cross-sectional study and a longitudinal study in postmenopausal women with T2DM. In the cross-sectional study, serum IGF-I level was decreased when the number of vertebral fractures (VFs) was increased. Multiple logistic regression analysis adjusted for confounding factors including age and BMD showed that serum IGF-I level was inversely associated with the presence of one VF [odds ratio (OR) = 0.67], two VFs (OR = 0.40), as well as three and more VFs (OR = 0.27). In the longitudinal study, basal serum IGF-I levels were inversely associated with the newly incidence of clinical non-vertebral fracture (OR = 0.49) as well as all-cause death (OR = 0.45). These findings indicate that serum IGF-I could be clinically useful for assessing the severity and incidence of osteoporotic fracture as well as mortality in the population.