Vitamin D, 25-Hydroxy

Description: The Vitamin D, 25-Hydroxy test is primarily ordered to measure the amount of 25-hydroxy vitamin in the bloodstream to rule out Vitamin D deficiency.
A significant deviation from the normal range may require further evaluation by your physician.

An adequate calcium intake and adequate body stores of vitamin D are important foundations for maintaining bone density and strength. However, vitamin D and calcium alone are not sufficient treatment for osteoporosis. They are given in conjunction with other treatments. Vitamin D is important in several respects:

·        Vitamin D helps the absorption of calcium from the intestines.

·        A lack of vitamin D causes calcium-depleted bone (osteomalacia), which further weakens the bones and increases the risk of fractures.

·        Vitamin D, along with adequate calcium (1200 mg of elemental calcium), has been shown in some studies to increase bone density and decrease fractures in older postmenopausal, but not in premenopausal or perimenopausal women.

Vitamin D comes from the diet and the skin. Vitamin D production by the skin is dependent on exposure to sunlight. Active people living in sunny regions (Southern California, Hawaii, countries around the equator, etc.) can produce most of the vitamin D they need from their skin. Conversely, lack of exposure to sunlight, due to residence in northern latitudes or physical incapacitation, causes vitamin D deficiency. In less temperate regions such as Minnesota, Michigan, and New York, skin production of vitamin D is markedly diminished in the winter months, especially among the elderly. In that population, dietary vitamin D becomes important.

Unfortunately, vitamin D deficiency is quite common in the United States. In a study of hospitalized patients in a general medical ward, vitamin D deficiency was detected in 57% of the patients. An estimated 50% of elderly women consume far less vitamin D in their diet than is recommended.