This paper reports on a questionnaire study based on 4,960 women who had had DXA-measurements of bone mineral mass performed in Oslo and Trondheim. There was a great variation in bone mass in all age groups. The age-adjusted bone mass was a major contributing factor in all the fractures. Fractures in the femoral neck and other appendicular locations were most strongly related to femoral bone mass, while the spinal fractures were most strongly related to bone mass measured in the lateral projection of the spine. Clinical risk factors were only slightly related to bone mass and even less so to fractures. These relationships were of too little significance to adequately predict individual bone mass or the likely occurrence of fractures.