If they do fall, people with osteoporosis are much more likely to break bones even after a small knock or fall - often in the forearm, wrist hip and back. The risk of having an osteoporotic fracture increases with age and is determined by the severity of the disease and if the person is affected by other risk factors (e.g. postural instability). Some people may not even know they have osteoporosis until they break a bone.