Ethnicity Alters Diabetes Risks

Changes in Weight, Diet May Affect Blacks, Asians, Hispanics Differently Than Whites

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July 13, 2006 -- Blacks, Asians, and Hispanics in the U.S. are more likely to get type 2 diabetesdiabetes than whites. But, according to a new study, it may be easier for these minorities to cut their diabetes risk through better eating habits.

Also, the study found, adding extra pounds may be especially dangerous for Asians.

Those are the findings in a new study in the July issue of Diabetes Care. Like plenty of past research on race, ethnicity, and diabetes, this study confirmed the greater diabetes risk for blacks, Asians, and Hispanics.

But the report has three new twists:

  • BMI (body mass index) doesn't fully explain the racial gap in diabetes risk.
  • Healthy eating habits may lower diabetes risk more for blacks, Asians, and Hispanics than for whites.
  • Gaining weight may be a particularly strong diabetes risk factor for Asians.

The researchers included Iris Shai, PhD, of the Harvard School of Public Health and Israel's Ben- Gurion University.

Diabetes, Then and Now

Shai's data came from the Nurses' Health Study, a long-term study of 121,700 female registered nurses.

When the Nurses' Health Study started in 1976, the nurses were 30 to 55 years old. Every two years, they completed surveys about their medical history and lifestyle.

Shai and colleagues concentrated on about 78,400 nurses who were apparently in good health and didn't have diabetes in 1980. Those nurses filled out diet questionnaires in 1980, 1984, 1986, 1990, 1994, and 1998.

The researchers followed the women until 2000. During that 20-year period, the group had 3,844 new cases of type 2 diabetes, which is the most common type of diabetes and is often linked to being overweight.

Diabetes and Race

Aging Aging by itself raises the risk of developing type 2 diabetes. So the researchers took that into account.

But, compared to whites, age-adjusted diabetes risk was more than 120% greater for blacks, about 76% greater for Hispanics, and 43% greater for Asians, the study shows.

Age isn't the only diabetes risk factor. Being overweight also worsens the odds. So Shai's team adjusted for participants' BMI.

That adjustment affected the risk lineup. After considering both BMI and age, blacks were just 34% more likely than whites to have diabetes, while Hispanics were 86% more likely and Asians were 126% more apt to have diabetes than whites.

Continued

Squaring the Numbers

What do all those numbers mean? Here's what the researchers found when they took a closer look at the data.

Asians had the lowest average BMI. But they had the steepest rise in diabetes risk of any ethnic group if they gained weight after age 18.

"Weight gain is particularly detrimental for Asians," the researchers write. They suggest "lower cutoff BMI values are needed to identify Asians at a higher risk of diabetes."

Meanwhile, blacks had the highest average BMI. But BMI seemed to have less impact on diabetes risk for them than it did for whites, according to the study.

Still, "In conclusion, after accounting for BMI, our study indicates that Asians, Hispanics, and blacks were all at higher risk for type 2 diabetes than whites," the researchers write.

Healthy Diet Helps

The diet surveys added more clues.

Healthy diets -- those that emphasized fiber and unsaturated fats while minimizing trans fats and items that spike blood sugar -- apparently cut diabetes risk more for blacks, Hispanics, and Asians than for whites.

"These results suggest that dietary intervention may be particularly effective for diabetes prevention among minorities, although this hypothesis needs to be tested in future studies," Shai's team writes.

The researchers note two limits to their study: The nurses might not have reported their information perfectly, and they may not represent all women in their age group.

WebMD Health News Reviewed by Louise Chang, MD on July 13, 2006

Sources

SOURCES: Shai, I. Diabetes Care, July 2006; vol 29: pp 1585-1590.
© 2006 WebMD, Inc. All rights reserved.

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