38() URIST, MACDONALD, MOSS, AND SKOOG 



osteoporosis is recognized by hone failure or spontaneous collapse 

 of vertebral bodies, ballooned discs, and thin cortex in radiographs 

 of the dorsal and lumbar regions of the spine. After a thorough 

 clinical and laboratory study of the patient, it is easy to identif\' 

 osteoporosis as a disease by these three radiographic changes. Pa- 

 tients with osteomalacia and hyperparathyroidism may present the 

 same radiographic picture, l^ut the clinical and laboratory findings 

 are different and the number of cases is relatively small. Patients 

 with diffuse decrease in radiographic bone density (a highly sub- 

 jective observation), without anv deformity of the vertebrae, are 

 classified as examples of physiologic atrophy of bone of old age. 

 Patients in an early stage of the disease process of osteoporosis can- 

 not be diagnosed by clinical or laboratory methods that are now 

 available to physicians.* 



Controversy exists about whether the osteoporosis is an endocrine 

 (metabolic) disorder, a degenerative disease, or an integral part of 

 the time-dependent process of aging. Some investigators claim that 

 osteoporosis is simply mild chronic osteitis fibrosa generalisata 

 caused by prolonged calcium deficiency (Fraser, 1962); others con- 

 tend that osteoporosis consists of generalized bone atrophy that is 

 complicated by either osteitis fibrosa or osteomalacia ( Clerkin et ah, 

 1962) or both (Meroney ef ah, 1959) and, therefore, is not a dis- 

 crete condition; others (Little et al., 1962; Casuccio, 1962) postulate 

 that osteoporosis is primarily a degenerative disease of bone tissue. 

 A larger number of cases were reported in 1961-1962 than in the 

 preceding 5 years, and more new information was obtained about 

 pathogenesis of the disorder than in all of previous time. The etiol- 

 ogy, however, is not known and treatment is unsatisfactory. 



" Osteoporosis may be present or absent in individuals with a number of diverse 

 conditions, as, for example, acromegaly, diabetes, hyperthyroidism, gonadal agenesis, 

 Cushing's syndrome (endogenous and exogenous), pernicious anemia, starvation, 

 tumors, cirrhosis, von Gierke's disease of the liver, posttraumatic metabolic syndrome, 

 and postpregnancy state. The proportion of these diagnoses in the total number of 

 patients with osteoporosis is 19 per cent. The proportion of osteoporosis in otherwise 

 healthy individuals, between 50 and 75 years of age, generally classified in hospital 

 records as postmenopausal or senile types is 81 per cent (Moon and Urist, 1962). 

 Osteoporosis is frequently more severe in patients with than in patients without the 

 above diseases, but the causative relation is indirect and involves poorly understood 

 complex reactions of bone tissue. 



