Type 2 DM is primarily due to lifestyle factors and genetics. A number of lifestyle factors are known to be important to the development of type 2 DM, including obesity (defined by a body mass index of greater than 30), lack of physical activity, poor diet, stress, and urbanization. Excess body fat is associated with 30% of cases in those of Chinese and Japanese descent, 60–80% of cases in those of European and African descent, and 100% of Pima Indians and Pacific Islanders. Even those who are not obese often have a high waist–hip ratio.
The prevailing opinion is that all of these markers are signs of insulin resistance, meaning the diminished ability of a given amount of insulin to exert its normal effect. When insulin resistance develops, it can impact metabolic processes in many ways, resulting in the specific markers listed above. However, different individuals respond to insulin resistance in different ways. Also, the time frame in which certain signs develop varies. This variability makes defining—and treating—metabolic syndrome tricky.
The Mediterranean diet is palatable and easily sustained. In addition, recent studies have shown that when compared to a low fat diet, people on the Mediterranean diet have a greater decrease in body weight, and also had greater improvements in blood pressure, cholesterol levels, and other markers of heart disease -- all of which are important in evaluating and treating metabolic syndrome.
Resistant hypertension is defined as high blood pressure that remains above a target level, in spite of being prescribed three or more antihypertensive drugs simultaneously with different mechanisms of action. Failing to take the prescribed drugs, is an important cause of resistant hypertension. Resistant hypertension may also result from chronically high activity of the autonomic nervous system, an effect known as "neurogenic hypertension". Electrical therapies that stimulate the baroreflex are being studied as an option for lowering blood pressure in people in this situation.
The oral glucose tolerance test (OGTT), or glucose tolerance test is a blood test used (not routinely however) to diagnose diabetes, and gestational diabetes. Information in regard to reliability of the oral glucose tolerance test is important, as some conditions (common cold), or food (caffeine), or lifestyle habits (smoking) may alter the results of the oral glucose tolerance test.
According to the Mayo Clinic, doctors may use other tests to diagnose diabetes. For example, they may conduct a fasting blood glucose test, which is a blood glucose test done after a night of fasting. While a fasting blood sugar level of less than 100 milligrams per deciliter (mg/dL) is normal, one that is between 100 to 125 mg/dL signals prediabetes, and a reading that reaches 126 mg/dL on two separate occasions means you have diabetes.