Softening of the bones, usually caused by a vitamin D deficiency, sometimes for as simple a reason as not getting enough exposure to the sun. Vitamin D is essential for bone health; without it calcium cannot be properly absorbed. In Osteomalacia, which is more common in women than in men, particularly those prone to Osteoporosis, the bones can become so soft that they bend or even break under the body's weight. Osteomalacia is treated with a course of vitamin D.