Osteoporose – risikofaktor eller sykdom? Definisjon, utbredelse, årsaker, diagnostisering og forebyggende tiltak

Abstract

ENGLISH SUMMARYAt present we do not know the distribution of osteoporosis in the Norwegian population -i.e. bone mineral density (BMD) below 2.5 standard deviations of the mean of young females. Nor do we know whether or not there has been any increase in the prevalence of osteoporosis the last decades. This paper reviews research about osteoporosis -focusing on risk factors and preventive measures, and discusses the WHO definition of osteoporosis. Osteoporosis is, in accordance to this definition, both a risk factor for fracture and the notion of a condition which presuppose a fracture (established osteoporosis). The definition implies that the diagnosis of osteoporosis depend upon the material of reference we compare with, and entail that a large majority of women above 70 years of age will have osteoporosis. This medicalization may lead to more frequent visits to physicians for control, more anxiety and less frequent physical activity because of fear of falling. Osteoporosis does not cause pain or loss of function before a fracture has occurred, and the diagnosis is not meant to initiate therapy. Nevertheless we worry that the diagnosis may have its own momentum in that direction, and enforce demands for more medicine for the purpose of prevention. This is problematic because there is a large overlap in BMD between those who will have a future fracture -and those who will not. However, measuring BMD is the best single method to predict future fracture, and is just as good as a measure of blood pressure is to predict stroke. To assess individual risk, one should, however, use more than one fracture risk factor. The most important risk factors for low BMD are: low weight/low body mass index, weight reduction, low intake of calcium/vitamin-D, smoking, early menopause, inactivity, high alcohol consumption and genetic factors.Interventions focusing on some of these factors have been effective in increasing/not reducing BMD.Mange hevder at osteoporose er blitt en moderne folkesykdom. Men hva er egentlig osteoporose? Vet vi hvor mange nordmenn som har osteoporose -og vet vi at det er mer osteoporose nå enn før? Hva vet vi om risikofaktorene, og hvordan kan vi forebygge osteoporose?