Is the prevalence of Paget's disease of bone decreasing?

UNLABELLED: Secular trends in the severity and prevalence of Paget's disease over a 30-year period are described. Paget's disease has become less prevalent and patients are presenting later, with less severe disease than previously. These data suggest that environmental factors are important in the etiology of Paget's disease.
INTRODUCTION: Data from several countries support the view that there are important secular trends in the prevalence and severity of Paget's disease. In this paper, recent trends in the epidemiology of Paget's disease are described.
MATERIALS AND METHODS: A database of all newly referred patients (n = 1487) with Paget's disease (1973-2002 inclusive, 30 years) was examined. Of these subjects, 56% had scintiscans. Plasma total alkaline phosphatase (total ALP) activity and disease extent on scintiscan were used as indices of severity. A radiographic prevalence survey of 1019 subjects of European origin >55 years of age in Dunedin was undertaken- approximately 20 years after an earlier survey had shown New Zealand to be a high prevalence area.
RESULTS: The number of new referrals with Paget's disease declined sharply from 1994 onward, to one half the rate seen 20 years earlier, whereas the mean age at presentation increased by 4 years per decade (p < 0.0001). Total ALP at diagnosis, disease extent on scintiscan, and the number of bones involved were all negatively correlated with both date of birth (p < 0.0001) and year of presentation (p < 0.0001), indicating that more recently born and presenting subjects had substantially less severe bone disease. The radiographic survey showed that the current prevalence was only approximately 50% of that in the 1983 survey (p = 0.012).
CONCLUSIONS: Although there are a number of potential biases, these data are consistent with a continued secular trend to presentation in older subjects with less extensive skeletal involvement and a declining prevalence of Paget's disease.