Role of insulin-like growth factor-I in primary osteoporosis: a correlative study.

Osteoporosis is characterized by impairment of bone mass and deterioration of bone microscopic structure, resulting in increased bone fragility and susceptibility to fracture. Recent reports have indicated that reduced plasma levels of IGF-I are associated with osteoporosis in both males and females. Moreover, there is accumulating clinical evidence that treatment with GH or IGF-I has beneficial effects on bone mass and bone remodeling in men with idiopathic osteoporosis, in the elderly and in hypopituitary patients. As correlative studies on IGF-I, IGF-BP3 and bone mass in the elderly are lacking, we studied the relationships between serum IGF-I, IGF-BP3, bone mineral density (BMD), body mass index (BMI), calciotropic hormones and age in 102 premenopausal and postmenopausal women. Our study indicates that the reduction of the anabolic processes mediated by IGF-I may account for the slow and progressive loss of bone mass that take place after the age of 40-50 years. In addition, nutritional caloric or proteic deficit may add to the effects of GH, age and other factors in decreasing IGF-I synthesis and therefore further contribute to the development of primary osteoporosis.