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What Causes Diabetes: Genes or Environment?

Is diabetes more likely to be caused by your genes or your environment? A study from the University of Wisconsin shows that Pima Indians in America are more than five times more likely to develop diabetes than their relatives in Mexico (Diabetes Care, August 2006). Pima Indians in Arizona have been shown by DNA typing to be very closely related to Pima Indians in the Sierra Madre mountains of Mexico. However, only 8.9 percent of Mexican Pimas developed diabetes, compared to 38 percent of those in the United States.

Obesity is a major risk factor for diabetes, but both populations were similarly obese. About eight percent of the Pima men and 20 percent the Pima women suffered from obesity. However, the Mexican Pimas were far more active than the American ones and ate far fewer refined carbohydrates. This study show that diabetes is more an environmental disease than just a genetic one. Your genes determine how you respond to the environment. Since this study agrees with hundreds of others, everyone should exercise and limit refined carbohydrates such as flour and sugar, whether or not there is a family history of diabetes.

Another recent study shows that the best predictor of diabetes is a test called Hemoglobin A1C (HBA1C), which measures the amount of sugar stuck on cell membranes. At the American Diabetes Association meeting in June 2006, Dr. Peter Baginsky of Santa Rosa, California showed that HBA1C can be used not only to identify people who already have diabetes, but also as a screening test to predict which people are likely to develop diabetes in the future. This allows doctors to treat pre-diabetes before people suffer their heart attacks, strokes and other side effects that can be the first sign that the person has diabetes.

He also showed that people who have HBA1Cs above 5.8 have a 92 percent chance of being diabetic as determined by a fasting glucose tolerance test. The HBA1C test does not require fasting and can be done with only one draw of blood, while the glucose tolerance test takes seven. It is less expensive and has the potential to save a lot of lives by getting diabetics into treatment earlier.