Low vitamin D levels common in children with type 1 diabetes

Children and adolescents with type 1 diabetes are more likely to have low levels of 25-hydroxyvitamin D — including white and healthy-weight children, who were previously considered to have a low risk for the deficiency, recent study finding show.

“To our knowledge, this is the first study that has been adequately powered to examine the association between [25-(OH)D] and HbA1c in children and adolescents with type 1 diabetes,” Terri Lipman, PhD, CRNP, FAAN, the Miriam Stirl endowed term professor of nutrition, professor of nursing of children and assistant dean for community engagement at the University of Pennsylvania School of Nursing, said in a press release. “These data suggest the need for monitoring of vitamin D in all youth with this disorder.”

Lipman, Sarah Al Sawah, PhD, a former doctoral student at University of Pennsylvania School of Nursing, and colleagues analyzed data from 197 children and adolescents with type 1 diabetes recruited from the Diabetes Center for Children at The Children’s Hospital of Philadelphia between January and June 2011 (57% boys; 55% white; mean age, 13 years; 55% adolescents; 36% on insulin pump therapy). Within the cohort, 65% were considered to have a healthy BMI (< 85th percentile); 23% were overweight (85th-95th percentile); 13% had obesity (> 95th percentile); mean HbA1c was 8.6%. Researchers collected nonfasting blood samples to measure 25-(OH)D and blood glucose levels; other variables were abstracted from medical records.

Mean 25-(OH)D level for the cohort was 54.6 nmol/L. Researchers found that 90% of participants had a 25-(OH)D level less than 75 nmol/L (40.6% of participants with levels 50 nmol/L; 49.2% with levels 51-75 nmol/L). Black children had the lowest mean 25-(OH)D level (45 nmol/L), followed by Hispanic children (55.9 nmol/L) and white children (59.3 nmol/L).

There were no differences in HbA1c levels across vitamin D levels. The bivariate relationship between 25-(OH)D and HbA1c approached, but did not reach, statistical significance (P = .057), according to researchers.

“Although the benefit of normal 25-hydroxyvitamin D levels in [type 1 diabetes] is yet to be established, the negative effects of vitamin D deficiency have been demonstrated,” Sawah told Endocrine Today. “These data emphasize the importance of screening 25-hydroxyvitamin D levels in all youth with [type 1 diabetes].” 

“These additional findings challenge the common perceptions that only obese, [black] children and adolescents have the highest risk of presenting with low levels of [25-(OH)D],” the researchers wrote. “As this study confirms, there may be an alarmingly high prevalence of [25-(OH)D] levels 50 nmol/L and below in healthy weight [white] children and adolescents with [type 1 diabetes] that should not be dismissed.” – by Regina Schaffer

Disclosure: The researchers report no relevant financial disclosures.