Hyperostosis of the spine in an adult population. Its relation to hyperglycaemia and obesity.

Osteoarthritis is a common disorder in middle-aged and older people (Kellgren and Lawrence, 1958; Lawrence, de Graaff and Laine, 1963; Anderson and Duthie, 1963; Roberts and Burch, 1966; Lawrence, 1969). Hyperostosis of the spine is a special form of osteoarthritic spondylosis. This condition was first described in the 19th century, but became better known after Forestier and RotesQuerol (1950) rediscovered this clinical entity and called it 'senile ankylosing hyperostosis of the spine'. Hyperostotic spondylosis occurs mostly in elderly people and is characterized by the formation of prominent bony bridges between the vertebrae. The thoracic spine is most frequently affected, but involvement of the cervical and lumbar spine is not uncommon. The bony bridges are usually most marked on the anterior surfaces of the vertebrae and differ from the bridges occurring in ankylosing spondylitis, which are flatter in contour. Boulet, Serre, and Mandin (1953) and Ott, Schwenckenbecher, and Iser (1963) reported that the prevalence of hyperostotic spondylosis was high in middle-aged and elderly patients with diabetes mellitus, and this finding has been corroborated by several other studies of hospitalized patients. The prevalence of hyperostotic spondylosis in middleaged and elderly diabetics has been reported to be 20 to 50 per cent. (Schilling, Schacherl, Camp, and Bopp, 1965; Haijkova, Streda, and gkrha, 1965; Julkunen, Karava, and Viljanen, 1966). The prevalence of hyperostosis in diabetics has been reported to increase with age and duration of disease (Hajkova and others, 1965; Bywaters, Doyle, and Oakley, 1966). On the other hand, a manifest or 'chemical' diabetes mellitus has been found in 40 to 60 per cent. of patients with hyperostotic spondylosis (Einaudi and Viara, 1960; Ott and others, 1963; Schilling and others, 1965). In contrast to the results of the studies mentioned above, Klunker (1964) did not find any definite correlation between the occurrence of hyperostosis and decreased glucose tolerance in an unselected series of patients attending a rheumatological clinic. In a series of 1,258 policemen, aged 30 to 69 yrs, Julkunen, Pyorala, and Lehtovirta (1968) did not find a significant relationship between the occurrence of hyperostotic spondylosis and the degree of hyperglycaemia defined by means of 2-hour blood glucose level in an oral glucose tolerance test, although there was a trend to an increased occurrence of the disease in those men who had a 2-hour blood glucose level of 120 mg./100 ml. or more. Hyperostotic spondylosis is often found also in acromegaly with or without diabetes (Julkunen and others, 1966). Hyperostotic spondylosis and endocranial hyperostosis have been found to occur more often together than expected (Schoen, Eggstein, and Vogt, 1969a; Hajkova, Streda, and gkrha, 1971). This may refer to some metabolic disorder causing hyperostotic manifestations. Schilling and others (1965) suggested that hyperostotic spondylosis is associated with obesity. Schoen, von Oldershausen, and Vogt, (1969b) reported an increased occurrence of hyperostotic spondylosis, particularly in obese diabetics. Julkunen and others (1966), however, found no definite association between obesity and hyperostotic spondylosis in hospitalized patients with diabetes mellitus. It is well known that there is a high degree of correlation between obesity and disorders of carbohydrate metabolism. Most relevant information about the relative contributions of obesity and hyperglycaemia in the pathogenesis of hyperostotic spondylosis can be obtained from a study of a nonselected population sufficiently large to yield an adequate number of subjects with this condition. The present study, which records an epidemiologic approach to this problem, was carried out in connection with a multiphasic screening examination in six communities in Finland.