Osteoporosis in Men: Osteoporosis (or porous bone) is a disease in which bones become weak and are more likely to break. Without prevention or treatment, osteoporosis can progress without pain or symptoms until a bone breaks. More than 2 million American men have osteoporosis and 12 million are at risk. Risk factors include smoking, low calcium and vitamin D intake, small body frame, and low testosterone levels. Medications can treat bone loss, and exercise can prevent osteoporosis.