Photon absorptiometry provides an accurate measurement of bone mineral content. In acromegaly, the bone mineral content is normal, whereas the bone mineral content is reduced by acidosis. Decreased bone mineral content occurs in alcoholics due to osteomalacia and also in anticonvulsant therapy for the same reason. In hyperparathyroidism, there is decreased bone mineral content. Corticosteroids reduce bone mineral content especially in the central skeleton similar to Cushing's disease. Glutethimide causes osteomalacia with decreased bone mineral content.
Long-term heparin therapy causes bone resorption.
Immobilization causes decreased bone mineral content. Bedrest and space flight reduce lower limb bone mineral content with recovery on ambulation.
Conversely, activity increases bone mineral content even in the elderly and bone mineral content is greater in athletes than non-athletes.
Osteoporosis is a normal process occurring from age 45 years in females and 65 in males. Bone loss is related to menopause and lactation in females and may be arrested by estrogens, fluoride (with calcium and vitamin D), and possibly calcium carbonate. Decreased bone mineral content occurs at all stages of renal failure with rapid bone mineral content loss in azotemia and during dialysis and slower loss after transplant. Parathyroidectomy does not affect bone mineral content in renal osteodystrophy.
The bone mineral content is normal in compact bone but decreased in trabecular bone in patients with spinal cord injury, as well as in leprosy and diabetes. In hemiplegia, there is decreased bone mineral content on the paralyzed side. In thyrotoxicosis, there is increased formation and resorption of bone.