Insulin Resistance, Type 2 Diabetes, and Metabolic Syndrome
Type 2 Diabetes and Insulin Resistance. Most people with type 2 diabetes are obese and, in fact, studies strongly suggest that weight loss may be the key in controlling the current epidemic in diabetes type 2. The connection between obesity and diabetes is not entirely clear, since most obese people are not diabetic.
The common factor appears to be insulin resistance. Insulin is a critical hormone in the metabolism of sugar. In type 2 diabetes, different factors cause the body to become insulin resistant--that is, it can no longer use it. This has the effect of increasing blood glucose (sugar in the blood), the hallmark of diabetes. Both obesity and insulin resistance at different phases are marked by elevated levels of certain chemicals (e.g., free fatty acids and the hormones resistin and leptin). It is not known yet if the higher levels are simply a product of obesity or play some causal role in diabetes.
Insulin resistance is also associated with high blood pressure and abnormalities in blood clotting. Some research indicates that obesity, in fact, is the one common element linking insulin resistance, diabetes type 2, and high blood pressure. [See In-Depth Report #60, Diabetes - type 2.]
Metabolic Syndrome. Metabolic syndrome (also called syndrome X) is a pre-diabetic condition that is significantly associated with heart disease and higher mortality rates from all causes. The syndrome consists of obesity marked by abdominal fat, unhealthy cholesterol levels, high blood pressure, and insulin resistance. A 2002 study estimated that nearly a quarter of the U.S. population now has this condition. Even worse, according to a 2003 study, nearly a million American teenagers have this syndrome. A combination of weight loss and exercise is an effective treatment for this syndrome.
Cancer
Obesity has been associated with a higher risk for cancer in general and specific cancers in particular. Studies have also suggested that restricting calories reduces the risk for cancer. Some experts believe that effective weight control for children and adults could reduce cancer rates by 30 -40%. One way obesity may increase the risk for cancer is its association with high levels of hormones called growth factors, which can trigger rapid cell proliferation leading to cancer.
Uterine Cancers. Women who are obese appear to have two to three times the risk for uterine cancer as thinner women.
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