There's been much focus on vitamin D in the media recently as it's become apparent that this vitamin plays an important role in health and disease prevention. With increasing awareness that many Americans get insufficient quantities of this critical vitamin, you may wonder if you could be at high risk for a vitamin D deficiency.

Unfortunately, there are no symptoms of early stage deficiency of vitamin D. By the time you develop significant symptoms such as bone pain and muscle weakness, the deficiency state is usually quite advanced. A standard blood test won't identify vitamin D deficiency since most doctors don't request this test. In some cases when there are abnormally low levels of vitamin D calcium levels may be low as well. This can lead your doctor to prescribe vitamin D testing but testing isn't routine in an asymptomatic individual person of normal risk.

If you're in a higher risk group for being vitamin D deficient, it's a good idea to ask your doctor to perform the blood test needed to check vitamin D levels. This is known as the 25 OH Vitamin D test which is sent to a special lab to assess vitamin D levels. How do you know if you're at high risk for being vitamin D deficient? Here are some characteristics that may place you at risk for being deficient in vitamin D:
Having dark skin or living in area deficient in sunlight

One of the most important natural sources of vitamin D is conversion of a vitamin D precursor, known as 7-dehydrocholesterol, found on the skin to its active form. This conversion requires exposure to sunlight. If you live in an area that gets reduced sunlight, this can increase your risk of being deficient in vitamin D. Likewise, if you have dark skin, you may be at higher risk since melanin acts as a sunlight filter reducing the amount of sunlight that reaches the skin for conversion of the vitamin D precursor to its active form.
Being older

Another risk factor for being vitamin D deficient is age. Persons over the age of sixty-five, particularly those living in nursing homes, are more susceptible to being vitamin D deficient. This is probably related to reduced sunlight and decreased skin conversion of vitamin D to its active form. Vitamin D is also processed by the kidney and liver and reduced kidney function in the elderly can contribute to lower blood levels of vitamin D. Persons over the age of sixty-five should have blood levels of vitamin D checked regularly since low levels can increase the risk of experiencing a fracture.
Having certain diseases

Certain diseases can make you more susceptible to being vitamin D deficient including liver and kidney disease, Parkinson's disease, as well as certain malabsorption states where vitamin D can't be adequately absorbed by the intestine. If you have any of these diseases, ask your doctor about vitamin D supplementation.
Being overweight

If you're overweight or obese, you're more at risk for vitamin D deficiency. This is because fat cells tend to “hang onto” vitamin D which can reduce levels of the active vitamin in the blood stream. This type of vitamin D deficiency can usually be corrected by weight loss, dietary supplementation, and increased sun exposure.
Pregnancy