Blood sugar levels and diabetes

Although other factors affect whether you develop complications from diabetes, keeping blood sugar levels as close to normal as possible (tight or strict blood sugar control) seems to help reduce your risk of complications. Two major studies in adults-the Diabetes Control and Complications Trial (people with type 1 diabetes) and the United Kingdom Prospective Diabetes Study (people with type 2 diabetes)-found that improved blood sugar control lowers the risk of diabetic eye disease (retinopathy), kidney disease (nephropathy), and nerve disease (neuropathy).¹

The American Diabetes Association (ADA) recommends that you keep your blood sugar levels at:¹

• 80 mg/dL to 120 mg/dL before meals and less than 160 mg/dL 1 to 2 hours after meals when using a blood sample drawn from a vein (a whole-blood sample).
• 90 mg/dL to 130 mg/dL before meals and less than 180 mg/dL 1 to 2 hours after meals when using a blood sample drawn from a fingertip (plasma blood sample).

The ADA also recommends a hemoglobin A1c (HbA1c) target level of less than 7% in adults. Some people may be able to achieve an even lower level of less than 6%.¹ For children, the ADA recommends higher target levels of A1c. In children younger than 6 years old, the recommended level is from 7.5% to 8.5%. In children 6 to 12 years old, the recommended level is less than 8%. And in teens-13 to 19 years old-the recommended level is less than 7.5%.² The lower the A1c, the lower the rate of complications. HbA1c is a measure of how well blood sugar levels have remained within a safe range over the previous 2 to 3 months. Keeping blood glucose levels less than 180 mg/dL after meals may help in achieving a hemoglobin A1c of less than 7%.

Low blood sugar (hypoglycemia) episodes are a possible complication in people who tightly control their blood sugar by taking insulin or some oral diabetes medicines. Some people who have tight control of their blood sugar may not be able to sense when they have low blood sugar. Some people need to have a higher target blood sugar level because of the danger of low blood sugar. Work with your health professional to establish your own target blood sugar. This will help you achieve the best control possible without having a high risk of hypoglycemia.

People who may need a higher blood sugar level include:³

• Children younger than age 7. Low blood sugar levels may harm brain development in young children. The risk of very low blood sugar from tightly controlling blood sugar levels is higher in these children because their food intake and activity level vary from day to day. In addition, very young children are unable to describe the symptoms of low blood sugar when they experience them.
• Children before they have reached puberty. These children seem to be protected from complications from diabetes. As a child grows older and can recognize early symptoms of low blood sugar, his or her blood sugar level can be lowered closer to the safe range for adults.
• People who already have severe diseases, such as kidney failure, from complications of diabetes. They may not benefit from such control of their blood sugar level.
• Older adults who have atherosclerosis and are at risk for permanent injury (a heart attack or stroke) from low blood sugar levels.

The ADA recommends that when a woman with diabetes is trying to become pregnant, her target blood sugar level range should be a little lower than that for other people with diabetes.⁴

• Between 70 mg/dL and 100 mg/dL before meals when a whole blood sample is used and between 80 mg/dL and 110 mg/dL when a plasma blood sample is used
• Less than 140 mg/dL two hours after meals when a whole blood sample is used and less than 155 mg/dL when a plasma blood sample is used

Other health organizations may recommend a different target blood sugar range for a woman with diabetes who wants to become pregnant. Talk to your health professional about the best blood sugar level for you.

Citations

1. American Diabetes Association (2007). Standards of medical care in diabetes. Clinical Practice Recommendations 2007. Diabetes Care, 30(Suppl 1): S4–S41.

2. American Diabetes Association (2005). Care of children and adolescents with type 1 diabetes. Diabetes Care, 28(1): 186–212.

3. American Diabetes Association (2003). Implications of the diabetes control and complications trial. Clinical Practice Recommendations 2002. Diabetes Care, 26(Suppl 1): S25–S27.

4. American Diabetes Association (2004). Preconception care of women with diabetes. Clinical Practice Recommendations 2004. Diabetes Care, 27(Suppl 1): S76–S78.