Epidemiology of osteoporosis and prediction of fractures : a 9-year population based follow-up study

The investigation that is the subject of this thesis intended to evaluate the clinical value of risk factors of osteoporosis for prediction of fractures. Osteoporosis and related fractures constitute a frequently occurring and expanding medical problem in the elderly population. The occuiTence of skeletal fractures is approximately five times more frequent in women aged 85 years as compared to women aged 45 years. 1 Osteoporosis. a condition characterised by a reduced amount of bone tissue in the skeleton. may be a major cause of the age related increase in fracture risk. Although osteoporosis is by no means a new disease. it has become a significant public health problem only recently. In the past decade, the absolute number of elderly fracture patients has grown considerably. In I 972 approximately 6000 subjects aged 65 years and over were admitted to Dutch hospitals for treatment of a limb fracture. Ten years later, in 1982 the number of hospital treated fracture patients of this age had increased by 65 per cent. to more than 10.000 patients.2 These figures represent only a small fraction of all fracture patients. since the majority of fractures will have been treated in outpatient facilities. The rise in the absolute number of fractures may be explained from two factors. Firstly. there has been some increase in the age specific incidence of (hip) fractures.3 Secondly. the size of the population with a high risk of fractures. has grown considerably. Between I 972 and 1982. the size of the Dutch population of subjects aged 65 years and over increased by 20 per cent: the population aged 75 years and over increased by 35 per cent: and the female population aged 75 years and over increased by more than 45 per cent. In the latter group the risk of fractures is particularly high.4 ·5 For the future it is expected that the absolute number of elderly subjects will continue to increase. 6 As a consequence the "epidemic" of fractures among the elderly will fwiher expand. The financial consequences of the large number of fractures may be considerable. For the USA. the financial costs of osteoporosis has been estimated at 6. I billion dollar in 1983.7 In the past few years osteoporosis has become a major health issue for the general public. The condition has been frequently discussed: both m the professional and in the lay press. News papers and popular magazines have regularly devoted their pages to inform the public about the disease. For the same reason several popular books have been published. some of which had provoking titles such as: "Osteoporosis: your head start on the prevention and treatment of brittle bones". 8 All this publicity may add to the impression of an epidemic disease threatening the integrity of our bones.