There is some controversy about the effects of diabetes inellitus on bone metabolism and bone mineral density. Since diabetes and osteopenia are very common and of great socioeco-nomic relevance, interactions between both have become an ever increasing topic of interest. This raises the question whether diabetes mellitus is a risk factor for developing osteopenia and osteoporosis and/or whether osteoporosis is a complication of diabetes mellitus. Aibright and Reifenstein 1948 (1) first reported the coincidence of diabetes mellitus and osteo—penia, whereas Meetna and Meemo 1967 (2) and others claimed that diabetes is an antiosteoporotic condition. These historical statements have reflected the confusing and conflicting discussion up to the present day. The heterogenity of results might be explained by the hcterogenity of diabetic pa-tients without distinction between insulin dependence or in-dependence. Moreover, one has to take into account the differ-ent methods for determining bone mineral density, by which either more cortical or more trabecular bone is measured, the variance of measuring sites varying from peripheral to axial sites, the different study types (retrospective versus prospective) with different numbers of enclosed patients with result-ing statistical difficulties.

In order to illuminate the role of diabetes mellitus in osteope—nia, it seems essential to distinguish between IDDM and NIDDM to the extent that they show a completely different pathogenesis. IDDM is characterized by insulin deficiency in normal weight subjects due to an autoimmune process, whereas NIDDM is characterized by insulin resistance and hyperinsulinemia in overweight subjects. Obesity itself is negatively correlated with ostoepenia. Besides this, one has to dif-ferentiate between local and systemic forms of alterations on bone metabolism by diabetes mellitus. Local affections, such as osteomyelitis and Charcot osteoarthropathia summarized as" diabetic toot syndrome", will not be discussed here.