Bone Disease
A variety of diseases affect bones. One of the most common bone diseases is osteoporosis , which is characterized by a thinning of bone tissue, causing bones to become weak, brittle, and prone to fractures. Many factors can cause osteoporosis, including menopause, lack of exercise, low calcium intake, smoking, use of steroid drugs, and excessive consumption of alcohol. Dietary deficiencies of calcium, phosphorus, and vitamin D cause rickets , a disease characterized by abnormal bone formation and skeletal deformities. Rickets is most common in children. Dietary deficiencies of these nutrients in adults-or metabolic disorders that cause poor absorption of the nutrients-can result in an abnormal softening of bone, a condition called osteomalacia. Infections of bones called osteomyelitis usually are caused by bacteria, especially Staphylococcus, which enters the body through open wounds and may destroy bone tissues. Tumors, or abnormal growths, occur in bone tissue, though most are benign