NurseWeek: For Mexican-Americans, diabetes may be genetic

For Mexican-Americans, diabetes may be genetic
Disease also sparked by unhealthy lifestyle

By E'Louise Ondash
HealthScout Reporter
December 5, 2000


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(HealthScout). Mexican-Americans may be genetically more susceptible to developing diabetes than non-immigrants to this country, suggests a new study.

Through specially designed tests to measure metabolism, researchers at the Baylor College of Medicine in Houston discovered that even healthy Mexican-Americans who have no risk factors for diabetes have a metabolic abnormality that's a precursor for the disease.

This "glitch," they say, causes the production of sugar by the liver to shut down more slowly during eating than it does in people of Northern European descent.

"We believe this could be one of the earliest markers of insulin resistance," which causes more than 90 percent of all diabetes cases in Mexican-Americans, says Ashok Balasubramanyam,MD, an endocrinologist and assistant professor of medicine at Baylor.

"We ran many tests, and for most parameters, there was no difference between the two groups except for one: the ability of Mexican-Americans to suppress glucose," he says. "We found no difference in the two groups when they were fasting, but there was a significant difference while they were eating."

The findings confirm a genetic predisposition that many have long suspected, says Dr. Gerald Bernstein, an endocrinologist at Beth Israel Medical Center in New York City and past president of the American Diabetes Association.

"The genetics are already there," Bernstein says. "If we examine the relatives of Mexican-American diabetics, they have these abnormalities. Even though they don't have diabetes, they demonstrate insulin resistance."

Genetics aren't a problem, however, until you add obesity and other unhealthy lifestyle habits to the mix.

"For instance, look at the Pima Indians in Mexico and Arizona," Bernstein says. "They are the same people with the same genetics. The ones who live in Arizona are obese and live a sedentary life, and they have tons of diabetes. But those that live in Mexico behave differently, and they don't have diabetes."

The growing number of diabetics within the Mexican-American population is a huge problem, say U.S. health officials. Overall, nearly 11 percent of all Mexican-Americans have Type II diabetes, roughly one in four Mexican-Americans between the ages of 45 and 74 has Type II diabetes, and growing numbers of Mexican-American children are developing this type of diabetes as well. Type II diabetes once was seen only in people at middle-age and older.

The number of costly and serious diabetic complications is high, too, says the American Diabetes Association. Nearly two in five Mexican-American diabetics have retinopathy, a serious eye disease that can lead to blindness. Mexican-Americans also can be as much as 6.6 times more likely to suffer from end-stage kidney disease because of diabetes.

Changing this situation requires a "massive public health campaign," Bernstein says, "but it's going to be very difficult to change the habits of Americans."

Mexican-Americans are not alone in their propensity for diabetes.

"Every immigrant group that has come to this country in the last 20 years increases their risk for obesity and diabetes five-fold once they reach this country," Balasubramanyam says. "It is probably due to some mix between genetic background and environment."

This is a News story from HealthScout, a service of Rx Remedy, Inc.