Half of all older Americans will develop bone-thinning osteoporosis or be at high risk for getting it by 2020, the surgeon general warned late last week.

Osteoporosis affects about 10 million Americans and about 1.5 million of them each year suffer a related fracture. One of every five of those injured with fractures is placed in a nursing home, and their risk of death in the following months is nearly four times greater than similarly-aged Americans with healthy bones.

Doctors forget to check bone density levels when middle-aged or older patients suffer fractures, Surgeon General Richard Carmona said. Osteoporosis is highly under-diagnosed, even though the risk for osteoporosis increases after age 50 when it becomes more difficult for new bone to form. Both genders of all ages and races are susceptible to osteoporosis, especially white women.

Exercise, with a boost of calcium and vitamin D, will strengthen bones and lessen the risk of getting osteoporosis and sustaining injuries related to the disease, Carmona said.