An A1C test measures a person’s average blood sugar levels over the preceding two to three months. It is used to diagnose and monitor conditions like prediabetes and diabetes. Maintaining healthy A1C levels is important for overall well-being and can reduce the risk of various health complications.
Understanding A1C
The A1C test, also known as glycated hemoglobin or HbA1c, measures the percentage of hemoglobin in red blood cells coated with sugar. Hemoglobin is a protein that transports oxygen throughout the body. When glucose enters the bloodstream, it attaches to hemoglobin, a process called glycation. The more glucose present, the more it binds to hemoglobin.
Because red blood cells live for about three months, the A1C test provides a longer-term average of blood sugar levels than daily readings. A normal A1C level is below 5.7%. Levels between 5.7% and 6.4% indicate prediabetes. A diagnosis of diabetes is typically made when the A1C level is 6.5% or higher on two separate tests.
The Link Between A1C and Stroke Risk
Consistently elevated A1C levels can significantly damage blood vessels throughout the body, including those that supply the brain. This damage is a primary mechanism contributing to an increased risk of stroke. High blood sugar can lead to atherosclerosis, a condition where fatty deposits and plaque build up in the arteries, causing them to harden and narrow. This narrowing restricts blood flow, and if a piece of plaque breaks off, it can cause a blockage.
High blood sugar also increases the risk of blood clot formation. These clots can travel to the brain and block blood supply, resulting in an ischemic stroke, the most common type. High blood pressure, often co-occurring with uncontrolled diabetes, further contributes to blood vessel damage. This can increase the likelihood of both ischemic and hemorrhagic strokes, which occur when blood vessels in the brain leak or rupture.
Identifying “Stroke Level” A1C
While there isn’t a single, universally defined “stroke level” A1C, the risk of stroke escalates significantly as A1C levels rise, particularly into and above the diabetic range. For individuals with diabetes, an A1C consistently above 7% is associated with an increased risk of complications, including stroke. Studies indicate that for every 1% increase in A1C in people with diabetes, there is a corresponding increased risk of stroke. For instance, A1C levels of 7.0% to 7.9% show an increased risk for total stroke, and this risk continues to climb with higher A1C levels, particularly at 10% or higher.
The risk for ischemic stroke also increases with A1C levels above 7%. Some research suggests A1C levels as low as 5.6% can predict a future risk of ischemic stroke, even in individuals without a diabetes diagnosis. Maintaining glucose levels below 5.7% is important for stroke prevention, especially for those with other cardiovascular risk factors. An A1C of 6.5% or higher, signifying diabetes, is linked to a significant increase in stroke risk compared to normal A1C levels.
Managing A1C for Stroke Prevention
Managing A1C levels effectively reduces stroke risk. Lifestyle interventions are the foundation of A1C management. Adopting a balanced diet that prioritizes whole foods, vegetables, and fruits while limiting refined carbohydrates and added sugars helps regulate blood glucose. Regular physical activity also improves insulin sensitivity and lowers blood sugar.
Weight management through diet and exercise is important, as excess weight can contribute to insulin resistance and higher A1C levels. For individuals with diabetes, adherence to prescribed medications is essential for maintaining target A1C levels. Regular A1C monitoring, every three to six months, allows healthcare providers to assess treatment effectiveness and make adjustments. This ensures a personalized management plan.