[Idiopathic osteoporosis in middle-aged men--a "new" disease?].

Idiopathic osteoporosis is uncommon in middle-aged men. We discuss nine otherwise healthy men aged from 35 to 57 years, eight of whom were shown to be osteoporotic when subjected to detailed investigation because of back pain. None had suffered fractures of the appendicular skeleton as adults. All had an ordinary life style and ate a normal diet. Lumbar spine bone density was greatly reduced in all nine patients, while six of them showed normal values for cortical bone density in the forearm. Bone histomorphometry showed high turnover of bone tissue, with high bone resorption and lower than average bone formation. Serum osteocalcin levels were low in all nine patients, but alkaline phosphatase was higher than the upper normal limit in six of them. The etiology of the disease is unknown, but the pathogenesis is a result of disparity between formation and resorption of bone tissue. Unidentified environmental factors may be one of the reasons for the appearance of idiopathic osteoporosis as a "new" disease among middle-aged men.