What You Need to Know About Insulin Resistance and Cardiometabolic Risk
1. Insulin is a hormone produced by the pancreas that works in liver cells, muscle cells, and fat cells (adiposetissue) to regulate glucose and energy metabolism.
2. Insulin sensitive (IS) individuals have cells that normally react to insulin. In contrast, insulin resistance (IR) is a condition in which liver cells, muscle cells, and fat cells are progressively more resistant to insulin over time.
3. As IR increases, many cardiometabolic risk factors worsen together, including abdominal obesity, blood pressure, blood glucose, blood lipid (cholesterol and triglyceride), and atherogenic particle number (LDL particle number and apolipoprotein B) levels.1-3
4. IR significantly increases the risk of cardiovascular events, risk of developing diabetes, and can limit the effectiveness of therapies used to treat other risk factors.4,5
5. Unfortunately, it is common for IR to be present for many years before blood glucose values, blood pressure, or other clinical features appear abnormal.6
What You Need to Know About Insulin Resistance and Risk of Diabetes
1. The risk for development of diabetes is most commonly determined by measurement of blood glucose levels. In the fasting state, glucose values less than 100 mg/dL are considered “normal,” while values 100-
125 mg/dL are considered “pre-diabetic.” Diabetes is diagnosed at fasting glucose values greater than or equal to 126 mg/dl on two separate occasions.7
2. While the risk of diabetes increases as glucose levels rise, there is a wide range of individual diabetic risk at any given glucose value.8,9 This can be seen in men and women followed in the Multi-Ethnic Study of Atherosclerosis (MESA).
As a result, blood glucose is an insensitive predictor of individual risk for developing diabetes.
3. Insulin resistance (IR) is the principal metabolic disorder that leads to increased blood glucose levels and progression to type 2 diabetes mellitus.10,11 As cells become resistant to insulin, blood glucose levels rise.12
4. Insulin resistance is a condition that progresses over time. As IR worsens, the pancreas releases increasing amounts of insulin in an attempt to “force” liver cells, muscle cells, and fat cells to respond and maintain normal blood glucose levels.12,13
5. Over time, fasting blood glucose values reach “prediabetic” levels (100 - 125 mg/dL) and usually stay in this range for many years. As long as the pancreas produces higher levels of insulin needed to overcome cellular insulin resistance, glucose levels remain relatively stable.12
6. Eventually, the pancreas is unable to maintain high levels of insulin production. The combination of cellular IR and declining insulin levels lead to progressively higher blood glucose levels and risk for developing type 2 diabetes.12
7. Your risk of developing diabetes depends on your degree of insulin resistance and fasting glucose levels.14,15 As you move from being insulin sensitive (IS) to insulin resistant (IR), your diabetes risk increases at any given fasting glucose value. Likewise, as fasting glucose increases, the risk of diabetes increases at a given level of IR.15
The graph below shows the risk of developing diabetes over 8 years for men (white bars) and women (pink bars) followed in the Multi-Ethnic Study of Atherosclerosis.
