Dec. 19 (HealthDay News) -- Almost 75 percent of children and adolescents with type 1 diabetes have insufficient levels of vitamin D, researchers at the Joslin Diabetes Center in Boston report.

A deficit in vitamin D can lead to bone problems later in life, especially among those with type 1 diabetes. While vitamin D is usually gotten from exposure to sunlight or from the diet, researchers suggest that supplements are needed to boost vitamin D levels.

"We found in children with type 1 diabetes a pretty significant level of vitamin D insufficiency -- much more than we had expected to find," said lead researcher Dr. Britta Svoren, an instructor in pediatrics.

Diabetes is associated with a reduction in bone mineral density, which can make bones more fragile, Svoren noted. Vitamin D deficiency can increase the risk of fracture in these children later in life, she added. In addition, vitamin D may have a role in the risk for developing type 1 diabetes.

Moreover, many children throughout the world without type 1 diabetes have vitamin D deficiency, Svoren said.

The report was published in the January issue of The Journal of Pediatrics.

For the study, Svoren's team measured vitamin D levels in 128 children with type 1 diabetes. The children were between 1.5 and 17.5 years old.

The researchers found that 61 percent of the children had insufficient levels of vitamin D, and 15 percent had a deficiency in vitamin D, meaning their vitamin D levels were severely low.

In fact, only 24 percent of the children had sufficient vitamin D levels.

The lowest vitamin D levels were seen among the oldest children. Among adolescents, 85 percent had inadequate levels of the vitamin, Svoren noted.

"One of the things that might be going on is that, for a lot of children and adolescents, the primary source of vitamin D is through vitamin D-fortified milk," Svoren said. "The problem is that a lot of teenagers with type 1 diabetes, rather than drinking milk, a lot of these individuals are probably drinking increased amounts of sugar-free colas."

Svoren recommended that these patients take a multivitamin and at least 400 IU of vitamin D daily.

Dr. David L. Katz, director of the Prevention Research Center at Yale University School of Medicine, said that vitamin D is important for all children.

"A growing body of research suggests the importance of vitamin D in many aspects of health, far beyond the long-established role in bone development and preservation," Katz said. "But the role of vitamin D in bone health remains crucial, and perhaps that much more so in groups at high risk of bone-thinning and injury. Such groups include postmenopausal women, those with kidney disease, and children with type 1 diabetes."

Whether or not supplementing vitamin D would prevent all diabetes-related bone disease in diabetic children, the practice makes sense, particularly in light of a recent American Academy of Pediatrics recommendation doubling the intake of vitamin D for all children, Katz said.

"All children should get ample vitamin D, at least 400 IU daily, from some combination of sun exposure, dairy products, and/or supplements," Katz said. "Those at high risk of deficiency, but not all children, should have levels monitored."

SOURCES: Britta Svoren, M.D., instructor, pediatrics, Joslin Diabetes Center, Boston; David L. Katz, M.D., M.P.H., director, Prevention Research Center, Yale University School of Medicine, New Haven, Conn.; January 2009, The Journal of Pediatrics