Osteoporosis is a progressive skeletal disease in which bones become thin, weak, brittle, and prone to fracture. Osteoporosis literally means “porous bones.” Thinning bones are caused by loss of bone density. Osteoporosis is a condition characterized by progressive loss of bone calcium, thinning and weakening of bone tissue and increased vulnerability to fractures. Calcium and other minerals contribute to the bone mineral density that helps strengthen and protect bones. Low bone density increases the risk for fracture. Bone fractures are the most serious complication of osteoporosis. Spinal vertebral fractures are the most common type of osteoporosis-related fracture, followed by hip fractures, wrist fractures, and other types of broken bones.