Hypovitaminosis D - Signs and Symptoms

Signs and Symptoms

Vitamin D deficiency is known to cause several bone diseases including:

• Rickets, a childhood disease characterized by impeded growth, and deformity, of the long bones. The earliest sign of subclinical vitamin D deficiency is Craniotabes, abnormal softening or thinning of the skull.
• Osteomalacia, a bone-thinning disorder that occurs exclusively in adults and is characterized by proximal muscle weakness and bone fragility.
• Osteoporosis, a condition characterized by reduced bone mineral density and increased bone fragility.
• Muscle aches and weakness (in particular proximal limb girdle)
• Muscle twitching (Fasciculations)

The role of diet in the development of rickets was determined by Edward Mellanby between 1918–1920. In 1921 Elmer McCollum identified an anti-rachitic substance found in certain fats that could prevent rickets. Because the newly discovered substance was the fourth vitamin identified, it was called vitamin D. The 1928 Nobel Prize in Chemistry was awarded to Adolf Windaus, who discovered the steroid 7-dehydrocholesterol, the precursor of vitamin D.

Prior to the fortification of milk products with vitamin D, rickets was a major public health problem. In the United States, milk has been fortified with 10 micrograms (400 IU) of vitamin D per quart since the 1930s, leading to a dramatic decline in the number of rickets cases.

Hypovitaminosis D is also considered a risk factor for the development of depressive symptoms in older persons.