Medscape Medical News
ENDO 2010: The Endocrine Society 92nd Annual Meeting
June 22, 2010 (San Diego, California) — The current American Academy of Pediatrics (AAP) recommendation that all children receive 400 IU of vitamin D each day might not be adequate for all pediatric patients, researchers reported here at the ENDO 2010: The Endocrine Society 92nd Annual Meeting.
Investigators at the East Tennessee Children's Hospital in Knoxville reviewed 25-hydoxy vitamin D (25-[OH]D) levels and recommended doses of vitamin D for pediatric patients who had their vitamin D levels checked repeatedly over a recent 12-month period.
The study found that 400 IU of vitamin D daily might not be adequate for all pediatric patients, especially those known to have insufficient or deficient vitamin D levels.
In 2008, the AAP revised its daily vitamin D recommendation from 200 to 400 IU daily for children of all ages, from newborns to teenagers. Low vitamin D levels have been linked to bone disease and an increased risk for cancer, diabetes, cardiovascular disease, and autoimmune disorders.
"While more specific and controlled studies should be conducted, our research suggests that a universal recommendation for vitamin D supplementation may be inadequate for the entire pediatric population," Carmen D. Tapiador, MD, pediatric endocrinologist at the East Tennessee Children's Hospital, told Medscape Endocrinology.
She noted that although all children in the study were diabetic, the results might apply to the general pediatric population. "Studies have shown that even in Florida, where there is a lot of sun exposure, there is still a high percentage of kids with low vitamin D," she said. "So I think we can safely extrapolate our findings to the general pediatric population and not just the pediatric diabetic population."
Patients in the study were categorized by sex into 3 age groups: 0 to 5 years, 6 to 10 years, and 11 years and older.
The study was divided into 4 seasons: winter (January 1 to March 20), spring (March 21 to June 20), summer (June 21 to September 21), and fall (September 22 to December 22).
At the initial evaluation, baseline 25-(OH)D levels, an accepted measure of vitamin D status, were measured. Children were then classified as deficient (<20 ng/mL), insufficient (20 to 29 ng/mL), or sufficient (>30 ng/mL). The 3 groups were prescribed 2000 IU, 1000 IU, and 400 IU of vitamin D, respectively.
A review of patient charts revealed that vitamin D levels of 23 children (18%) were sufficient, of 74 children (59%) were insufficient, and of 28 children (23%) were deficient.
Treatment with 400 IU for those in the sufficient group prevented a marked decline in final 25-(OH)D levels. However, it did not "substantially increase" the vitamin D levels of these patients.
For those in the insufficient and deficient categories, 1000 IU and 2000 IU improved vitamin D levels. "Thus, recommendations above 400 IU appeared to be necessary for all groups," Dr. Tapiador said.
Of African American/biracial patients, 91% had insufficient or deficient 25-(OH)D levels, and the increase in their levels was only 54% of those of their white counterparts.
The study also found that vitamin D levels generally increased during spring and summer and declined in the fall. "This was expected and is known to be due to the increased ultraviolet exposure during the spring and summer months," Dr. Tapiador said.
Based on the study, she recommends that physicians consider increasing dosage recommendations for individual patients on the basis of age, race, season, and baseline vitamin D level, and that all patients receive at least 1000 IU during the winter months.
In addition, Dr. Tapiador recommends that 3 groups receive at least 1000 IU of vitamin D daily year-round: all children younger than 5 years of age, females 10 years of age and older, and all patients with darker skin pigmentation.
"The study adds to the growing body of evidence demonstrating that more people are vitamin D–deficient than we had originally thought," James L. Rosenzweig, MD, endocrinologist and associate professor of medicine at Boston University School of Medicine in Massachusetts, told Medscape Endocrinology.
He cited research showing that vitamin D deficiency is more pronounced in the northern United States because of the lack of sun exposure. "People living in northern states have to compensate with adequate vitamin D intake or increased sun exposure," he said.
Dr. Tapiador emphasized that more research is needed to confirm his study's findings.
Dr. Tapiador and Dr. Rosenzweig have disclosed no relevant financial relationships.
ENDO 2010: The Endocrine Society 92nd Annual Meeting. Abstract P1-170. Presented June 19, 2010.