Q & A Library

Updated on 6/22/2005

Osteomalacia is softening of the bones in adults. When it occurs among children the disorder is called rickets and usually is due to a deficiency of vitamin D. Rickets was a common disease among youngsters in northern latitudes before milk was fortified with vitamin D. Other causes of osteomalacia include inadequate exposure to the sun's ultra violet rays (which allow the body to make vitamin D from a derivative of cholesterol in the skin) and intestinal malabsorption of vitamin D. The following can all lead to osteomalaciah: hereditary or acquired disorders of vitamin D metabolism, kidney failure, acidosis (excess acid in body fluids), phosphate depletion, kidney disease, and, sometimes, the side effects of drugs used to treat seizures, as well as chronic use of aluminum containing antacids. Other risk factors include remaining indoors (this usually applies to shut-ins who rarely go out) and avoiding milk or other dairy products containing vitamin D because of lactose intolerance.

Symptoms of osteomalacia are bone pain (especially in the hips), muscle weakness, numbness around the mouth, numbness in the arms and legs and spasm of the hands and feet. Untreated, bones may become so soft that they actually bend under the weight of the body. Clinical signs may be subtle in adults; the skeletal deformities may be overlooked until fractures occur after minimal trauma.

Fortunately, osteomalacia responds well to treatment, which usually begins with large doses of vitamin D. A physician also may recommend calcium and phosphorus supplements if tests show that blood levels of these minerals are low and might be to blame for the bone softening. If intestinal malabsorption of vitamin D is the cause, larger doses of vitamin D may be recommend along with exposure to ultraviolet light.

With proper treatment, the condition of the bones begins to improve quickly and positive changes can be seen on bone X-rays within weeks. It usually takes about six months for complete recovery. I recommend that healthy adults take 2,000 IU of vitamin D a day, even if they live in sunny areas.

Andrew Weil, M.D.