HbA1c is a blood test that reflects average blood sugar levels over the previous months, and it is widely used to diagnose diabetes using a single cut-off value for everyone. However, HbA1c levels appear to differ between ethnic groups. Because most earlier studies included people with diabetes, whose blood sugar varies more, this systematic review focused only on people without diabetes.
The review combined the results of 12 studies with a total of 49,238 adults. Compared with White participants, HbA1c levels were significantly higher in Black participants (by 0.26 percentage points), Asian participants (by 0.24 points) and Latino participants (by 0.08 points).
The authors conclude that, although these differences are small, they may affect the use of a single HbA1c threshold to diagnose diabetes in all ethnic groups.
Learn more about this review here: https://doi.org/10.1371/journal.pone.0171315
Reference:
Cavagnolli, G., Pimentel, A.L., Freitas, P.A.C., Gross, J.L., & Camargo, J.L. (2017). Effect of Ethnicity on HbA1c Levels in Individuals without Diabetes: Systematic Review and Meta-Analysis. PLOS ONE, 12(2), e0171315.