Healthnotes Newswire (November 9, 2006)—As the evidence of vitamin D’s importance for good health continues to grow, a new study has found that teenage girls are at high risk of vitamin D deficiency.

Most of the vitamin D we need is made in the body through a reaction between sunlight and skin. Foods such as eggs, fish, and vitamin D–fortified foods such as milk supply the rest. Vitamin D is necessary for proper absorption and use of dietary calcium. Bone pain, bone deformities, muscle spasms, and weakness are the hallmarks of rickets, the name used for vitamin D deficiency in children. In adults, vitamin D deficiency may cause softening of the bones and an increased risk of falling due to poor balance and muscle weakness, among other symptoms.

In modern times, awareness about the importance of supplementing with vitamin D at critical times in life—early childhood, pregnancy, and while nursing—has led to a decline in deficiency. Recent evidence, however, has suggested that its incidence is on the rise again. This trend might be partly due to successful campaigns to decrease sun exposure and use sunscreen in order to prevent skin cancer.

A new study, published in Archives of Diseases of Childhood, looked at the vitamin D status of 51 girls between the ages of 14 and 16. Of the girls, 73% had inadequate vitamin D levels, and 17% had levels low enough to be associated with rickets and bone deformities. Vitamin D deficiency was more pronounced in nonwhite girls than in white girls. None of the girls reported symptoms that were clearly related to deficiency, and none showed signs of muscle weakness.

Using questionnaires, the researchers determined that the low levels of vitamin D were due to lack of sun exposure, rather than poor diet. A number of the girls reported wearing concealing clothing and restricting outdoor activities due to cultural or religious beliefs, but they were not questioned about their use of sunscreens or their concern about skin cancer.

“Our bodies are designed to be outside, to be exposed to the sun. There is clearly some minimum exposure that is necessary for both physical and mental health,” commented chiropractor Michael Mundy. “It would be helpful to see studies that identify safe levels of sun exposure for different parts of the world and for people with different skin types.”

Adolescence has not been considered a critical time of vitamin D need, but vitamin D deficiency during childhood and adolescence can reduce the maximum bone mass that is achieved around the time of puberty, increasing the risk of osteoporosis later in life. More research is needed to understand the implications of widespread vitamin D deficiency in adolescent girls so that proper recommendations can be made regarding vitamin D intake and sunlight exposure.

(Arch Dis Child 2006;91:569–72)