No studies directly evaluated whether patient outcomes improve after screening or what the best frequency of screening is. Dual-energy x-ray absorptiometry predicts fractures in both men and women. Ultrasonography of the heel also predicts fractures but is less well studied than DXA. In postmenopausal women, bisphosphonates, calcitonin, parathyroid hormone, raloxifene, and estrogen reduce fractures; studies of treatment in men are lacking. Although there are reports of stomach upset, ulcers, abnormal heart rhythms, and jaw problems associated with bisphosphonates, no proven relationship exists among bisphosphonates and these or more serious adverse effects. Thigh bone, or femur, fractures have been reported, especially in women using bisphosphonates for more than 5 years. Blood clots can occur with raloxifene and estrogen. Also, estrogen is linked to heart attacks, strokes, and breast cancer. Little is known about the adverse effects of calcitonin and parathyroid hormone.