Minority Children Show Risk of Heart Disease, Study Finds

Many Mexican American and African American children as young as 9 are already beginning to acquire risk factors for heart disease in later life, according to a new analysis of health data on more than 7,000 U.S. residents ages 6 to 24.

Stanford University researchers found that excess weight, high blood pressure, fat-rich diets and other indicators tended to be more common among African American and Mexican American youths than among whites, and showed up earlier in life than researchers generally believed.

At the same time, the 16% smoking rate among white teenage girls was four times that of Mexican American girls and eight times that of African American girls. The study, said to be the most thorough comparison of cardiovascular disease risk factors in youths of different ethnic groups, suggests that parents and professionals need to tailor heart-healthy messages to children. Those include encouraging more exercise, less junk food and less smoking, among other things.

The data, published today in the Journal of the American Medical Assn., are quite alarming, said Dr. Teri Manolio, director of epidemiology and biometry at the National Heart, Lung and Blood Institute.

“If 6- to 9-year-olds are already overweight, they’re going to be in some trouble as adults because that will translate into a higher risk of cardiovascular disease,” she said.

Although previous studies have looked at heart disease risk factors in youths from different ethnic groups, this study is the first to directly compare whites, African Americans and Mexican Americans in a nationally representative sample. Latino groups other than Mexican Americans were not part of the study.

Moreover, a strength of the study, researchers said, is that the three groups were drawn from all walks of life at 89 sites nationwide. That overcomes a flaw of previous research, which tended to emphasize minorities from poorer or less educated families in localized communities, Manolio said.

The study did not address the possible causes of the observed differences among the groups in weight gain, blood pressure or other factors. As a result, they could not attribute the differences specifically to genetics, behaviors or attitudes.

The findings “highlight the need for information about heart disease prevention to be made available sooner, maybe as early as kindergarten,” said Marilyn Winkleby, an epidemiologist at the Stanford Center for Research in Disease Prevention and the lead author of the study.

Information about heart disease is not as well marketed to African American and Mexican American communities as is information about cancer, AIDS and childhood vaccinations, she said. And yet heart disease takes a greater toll on those communities than do other diseases.

The research is part of an effort to identify the earliest possible signs of the different heart disease rates long known to prevail among ethnic communities. For instance, the cardiovascular disease death rate for African Americans 45 to 64 years old is about twice that of whites the same age.

The Stanford researchers say that less definitive data are available for Mexican Americans. But compared to whites, they are “more likely to be overweight and physically inactive, to have diabetes, and to have higher levels of untreated or uncontrolled” high blood pressure, the researchers wrote.

The study is based on dietary surveys and medical exams given to 7,686 African American, Mexican American and white youths between 1988 and 1994 as part of the National Health and Nutrition Examination Survey.

The researchers analyzed six different heart disease risk factors: the proportion of fat in the diet, body weight, blood pressure, cigarette smoking, an early sign of diabetes, and blood cholesterol.

Among the 6- to 9-year-olds, the most significant difference was between black and white girls. African Americans were about 4% heavier than white girls for their size, and they also had slightly higher blood pressure and consumed a higher proportion of calories as dietary fat.

Those differences were more pronounced with age. Among women 18 to 24, blacks and Mexican Americans were an average of 12 pounds heavier than whites, assuming an average height of 5 feet, 4 inches.

However, Mexican American and white females were virtually the same in the other risk measures, except smoking. Among 18- to 24-year-olds, 38% of whites smoked, 18% of African Americans, and only 14% of Mexican Americans.

As for males, the differences among the groups were less marked and tended to appear later in life. Overall, blacks tended to be heavier for their height, consumed more fat and had higher blood pressure measurements than whites and Mexican Americans.

Among males 14 to 17 years old, 13% of Mexican Americans and whites smoked, compared with just 3% of blacks. For the older age group, the smoking rates were 41% for whites, 28% for Mexican Americans and 23% for African Americans.

In the past, social critics have said that attributing disease risk factors to certain ethnic groups can be stigmatizing.

But Winkleby, of Stanford, said it would be unethical for scientists not to compare the health status of ethnic groups as a way of reducing the disparities.