National Institute of Rheumatology and Physiotherapy, Budapest, Hungary and
1 ARC Epidemiology Research Unit Manchester, UK
SIR, Diffuse idiopathic skeletal hyperostosis (DISH) is a musculoskeletal disease of unknown aetiology, characterized by the presence of ligamentous ossification of the anterolateral aspect of the spinal column. The condition is recognized in many parts of the world, including North and South America, Europe, the Middle East, Africa, Asia and Australia [15]. There are, however, relatively few population-based studies concerning the population prevalence of the disease and, to our knowledge, no studies from central Europe [1, 2]. Such data are important in order to characterize the burden of the disease. The aim of our study was to determine the prevalence of DISH in a population sample of men and women in Budapest, Hungary.
Men and women were recruited from a health register covering 120 000 inhabitants in the third district of Budapest. Stratified random sampling was used, with a target of recruiting 50 men and women in each of six 5-yr age groups (5054 yr, 5559 yr, 6064 yr, 6569 yr, 7074 yr and 75 yr of age). The selected subjects were invited by letter to attend, and to complete a lifestyle questionnaire and undergo lateral radiographs of the dorsal and lumbar spine. Radiographs were taken using a standard protocol, which specified aspects of patient positioning and radiographic technique. All of the radiographs were evaluated for the presence of DISH by an experienced radiologist (M.Sz.) and a rheumatologist (C.K.) using the modified Resnick criteria [1]. In the modified criteria, individuals with ligamentous calcification continuously overbridging two or more intervertebral spaces (rather than the three as suggested by Resnick) were classified as DISH [6].
In total, 307 men (mean age 64±14.9 yr) and 328 women (mean age 64.3±14.1 yr) were recruited. Eighty-four (27.3%) men and 42 (12.8%) women had DISH according to the modified Resnick criteria. The prevalence of DISH increased with age: in men, from 10% at age 5054 yr, rising to 36% at age 75 yr; and in women, from 1.9% at age 5054 yr, rising to 26% at age
75 yr. With increasing age, the male to female ratio decreased gradually.
The prevalence of DISH reported here is higher than in previous population studies in Finland. It is similar though to results from a more recent large scale survey in the USA, based on assessment of lateral chest X-rays, where the prevalence of DISH among men aged 50 yr was 25%, and in women it was 15% [7]. In the latter study, the frequency appeared higher in Caucasians than in blacks, native Americans and Asians, suggesting racial differences in occurrence.
Our data are consistent with most previous reports suggesting a higher prevalence of DISH in men than in women. The aetiology of DISH is unknown, although there is an association with metabolic factors including diabetes mellitus and obesity. Any aetiological model, however, needs to be consistent with the higher frequency in men and the relatively high prevalence of the disease in central Europe.
In summary, our data highlight the frequent occurrence of the condition in Budapest, particularly in men, and the rise in frequency of the disease with age.
Notes
Correspondence to: C. Kiss, National Institute of Rheumatology and Physiotherapy, Frankel Leo Street 3840, Budapest, Hungary.
References
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