NEW YORK (Reuters Health) – As in adult diabetics, hemoglobin (Hb) A1c levels are higher in black children with type 1 disease than in white children, independent of mean blood glucose, according to a February 25th online report in Diabetes Care.
The authors of the report have long been interested in between-individual differences in HbA1c levels. Spurred by reports indicating a role for race and ethnicity in adult diabetic variables, lead author Dr. Jodi L. Kamps and colleagues at Louisiana State University Health Sciences Center in New Orleans looked for a similar pattern in their pediatric patients.
Their study included 276 children (72% Caucasian, 28% African-American) with an average age of 12.5 years and an average disease duration of 4.9 years. Slightly more than half were girls.
Mean blood glucose was determined by averaging data downloaded from patient glucose meters for periods of 30 days or more. Predicted HbA1c was calculated with the following equation:
HbA1c % = (mean blood glucose x 0.021) + 4.3
Hemoglobin glycation index was then calculated by subtracting the predicted HbA1c from the observed HbA1c.
The hemoglobin glycation index was significantly higher in the African-American children (p < 0.001), the authors report. They note that the highest tertile (index > 0.26) contained 57.5% of the African American children but only 24.2% of the Caucasian children. The adjusted mean hemoglobin glycation index values were 0.64 in black children and -0.15 in whites (p < 0.001).
Furthermore, average HbA1c was significantly higher among African Americans than Caucasians after controlling for mean blood glucose, age, and diabetes duration: 9.1% vs 8.3%, respectively (p < 0.001).
These findings may help explain why African Americans are at increased risk of diabetes complications, the authors suggest.
Also, they caution, “Given that mean blood glucose-independent disparity in HbA1c is unlikely to be modifiable by glucose lowering agents, simply increasing insulin doses in order to achieve a lowered target HbA1c could lead to greater risk of hypoglycemia in African American patients.”
Dr. Kamps and her associates advise that both HbA1c and mean blood glucose be taken into account when making therapeutic decisions for diabetics, especially for African Americans.
Diabetes Care 2010.