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Integrated Diabetes Services

Researchers Have Found That Glucose Concentrations and A1c Levels Vary by Race


Researchers wanted to learn if there is a racial difference in the relationship of average glucose and A1c, so they conducted a 12 week long prospective, observational study across 10 diabetes centers in the US.  The Helmsley Charitable Trust was the primary source of funding for this research.

Of the 208 patients in this study, 104 were black and 104 were white.  To participate, subjects needed to be at least eight years old, have Type 1 diabetes for a minimum of two years, and have an A1c level of 6.0-12.0%

Using Continuous Glucose Monitoring (CGM), researchers determined mean glucose concentration and compared it by race with the A1c, glycated albumin, and fructosamine levels.  In the black patients, the mean A1c level was 9.1%, while in white patients it was 8.3%.  The mean glucose concentration was significantly lower in blacks than in whites for a given A1c level.  This was evidenced by mean A1c levels 0.4 percentage points higher in blacks than in whites for a given mean glucose concentration.  However, significant differences based upon race were NOT found in the relationship of glycated albumin and fructosamine levels with the mean glucose concentration.

Bear in mind, there weren’t enough study participants who had A1c levels <6.5% to be able to generalize the results to that population.

The Bottom Line:

The take-home message from this study is that in black persons, A1c levels overestimate the mean glucose concentration compared to whites.  This may stem from racial differences in the glycation of hemoglobin.  But since is only a partial explanation of the noted A1c differences between black participants and white participants, more research should be conducted to identify and modify the barriers which hinder improved glycemic control in black persons with diabetes.

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