Diabetes and Hemoglobin A1C
- A1C is the other name for the glycated hemoglobin which is a measure of the glucose irreversibly combined with the pigment hemoglobin found in red blood cells.
- A1C is the most important measure of glucose control for the past 120 days in diabetic patients. It makes it easier to monitor and control blood sugar over a long period of time. Approximately 75% of the diabetic patients do not know about this test, let alone its importance.
- Recently, hemoglobin A1C has been added to the diagnostic criteria for diabetes. Those with hemoglobin A1C > 6.5 would now qualify for the diagnosis of diabetes regardless of blood sugar level.
- An A1C of 5.7-6.4 is considered prediabetic even if the blood sugar level is normal. Sedentary lifestyle and weight gain will lead to overt diabetes in these individuals. Conversely, weight loss and increased physical activity can significantly decrease A1C and postpone the development diabetes by 10 to 20 years. Combination of aerobic and resistance training is necessary to improve A1C in diabetic subjects.1
- An elevated A1C level suggests inadequately controlled blood sugar, which is associated with a high risk of microvascular complications such as kidney, eye, and nerve damage.2, 3
- The risk of heart disease is increased not only among diabetics at blood sugar levels in the ranges considered normal with 82% of heart attack occurring in people with AIC concentrations of 5%-6.9% ─ considered normal or in the acceptable range for diabetic subjects. 4
- An absolute 1% decrease in A1C levels is associated with a 15-20% decrease in cardiovascular disease (CVD) events and 37% decrease in microvascular complications.2, 3 These data add to the evidence supporting the use of A1C as a diagnostic test for diabetes.5
- Among people without diabetes, A1C is similarly associated with a risk of development of diabetes and more strongly associated with risks of CVD and death from any cause as compared with fasting glucose.
1. Church TS, Blair SN, Cocreham S, et al. Effects of aerobic and resistance training on hemoglobin A1c levels in patients with type 2 diabetes: a randomized controlled trial. JAMA. Nov 24 2010;304(20):2253-2262.
2. Selvin E, Marinopoulos S, Berkenblit G, et al. Meta-analysis: glycosylated hemoglobin and cardiovascular disease in diabetes mellitus. Annals of internal medicine. Sep 21 2004;141(6):421-431.
3. Stratton IM, Adler AI, Neil HA, et al. Association of glycaemia with macrovascular and microvascular complications of type 2 diabetes (UKPDS 35): prospective observational study. Bmj. 2000;321(7258):405-412.
4. Khaw KT, Wareham N, Luben R, et al. Glycated haemoglobin, diabetes, and mortality in men in Norfolk cohort of European Prospective Investigation of Cancer and Nutrition (EPIC- Norfolk). BMJ. 2001;322(7277):15.
5. Selvin E, Steffes MW, Zhu H, et al. Glycated hemoglobin, diabetes, and cardiovascular risk in nondiabetic adults. N Engl J Med. Mar 4 2010;362(9):800-811.