Norwegian Epidemiological Osteoporosis Studies. Why does the risk of osteoporotic fractures vary within Norway?

Norway has the world’s highest incidence of osteoporotic fractures. This large public health problem has severe consequences for the individual and for society. Bone mineral density (BMD) is the most widely used measure of bone strength. In spite of larg e regional differences in fracture risk, few comparative studies have been conducted, and little is known about the causes of these differences. Are they caused by differences in bone strength or tendency for falls? The 4 large epidemiological osteoporos is studies in Norway have established the NOREPOS research collaboration (Tromsø. North Trøndelag county, Hordaland county and Oslo). BMD has been measured at all study sites, validation and calibration studies have been conducted, and data are now ready for analyses. A substantial amount of work has been laid down in order to make the data from the 4 sites comparable. All NOREPOS studies have applied standardized questionnaires including CONOR (COhort of NORway) questions. NOREPOS data will be used to validate a method for standardizing BMD measurements across sites, investigate differences in BMD and fracture rates between geographic regions, as well as try to explain differences between sites by adjustment for potential confounders. A PhD dissertat ion project is defined, and this application also includes request for funding for the continued NOREPOS network collaboration.