Asian-Americans typically develop type 2 diabetes at a lower body mass index (BMI) than the rest of the population. As a result, the American Diabetes Association (ADA) has reduced its threshold for screening this demographic group. In January, the ADA is set to release its updated guidelines in the journal Diabetes Care.
The ADA recommends that Asian-Americans get tested when their BMI reaches 23 or higher. The general population should still be tested at a BMI of 25 or higher. The recommendation does not lay out new definitions for Asian-Americans’ overweight or obesity standards.
"Given that established BMI cut points indicating elevated diabetes risk are inappropriate for Asian-Americans, establishing a specific BMI cut point to identify Asian-Americans with or at risk for future diabetes would be beneficial to the potential health of millions of Asian-American individuals," the ADA said in its position statement.
BMI is a number calculated using a person’s weight and height. BMI provides a reliable estimate of body fat for most people. It is used as a guideline for when to screen patients for various health problems.
The change in the ADA standard was suggested by the Asian-American, Native Hawaiian, and Pacific Islander Diabetes Coalition (AANHPI-DC). The group noted that Asian-Americans are more likely to have type 2 diabetes than white Americans, even though Asian-Americans have a lower rate of obesity.
Fat Around the Waist Is One Risk Factor
Medical professionals think that Asian-Americans develop diabetes at lower BMI levels because excess weight tends to accumulates around their waists. That is where adiposity, or fat, is most harmful and most likely to cause disease. In the general population, fat is more common in the thighs and other parts of the body.
"Clinicians have known this intuitively for quite some time," said lead study author Dr. William C. Hsu, vice president of international programs at the Joslin Diabetes Center and an assistant professor at the Harvard Medical School. "They can see that Asian-Americans are being diagnosed with diabetes when they do not appear to be overweight or obese according to general standards. But if you use the previous Association standard for diabetes screening of being age 45 or older, with a BMI of 25 or above, you will miss many Asian-Americans who are at risk."
Do Genes Play a Role?
David Robbins, director of the Diabetes Institute at the University of Kansas Hospital, said that American Indians and Hispanics seem to share some of the early risk that is also present in Asian-Americans.
Many professionals believe this is because Asians carried a gene that predisposes them to diabetes when they migrated across the Bering Strait. This gene is now seen in their descendants.
“There has been speculation that the genetic trait was one that helped protect people from periods of starvation,” Robbins said. He noted that the genes or genes are now triggers for diabetes, hypertension, and heart disease.
“It’s important to modify the standards so that interventions, such as exercise and weight loss, can be started at the appropriate level of weight gain,” Robbins said.
The New ‘Normal’
According to Jane Chiang, the ADA’s senior vice president for Medical Affairs and Community Information, Asian-Americans are not as commonly represented in medical studies as people in other ethnic groups.
“Clearly, we need more research to better understand why these distinctions exist,” Chiang said.
“A thin Asian person may be at risk for developing diabetes. Research has shown that BMI may not be the best marker in this population,” said Dr. Ho Luong Tran, president of the National Council of Asian Pacific Islander Physicians, and the lead coordinator of AANHPI-DC.
Tran said that while the new guidelines are a smart move, she agreed that more clinical data on Asian Americans are needed.
“This practice recommendation is a timely reminder,” said Ronald Tamler, clinical director of the Mount Sinai Diabetes Center at The Mount Sinai Hospital in New York City. “It highlights what experienced doctors have known all along. Sometimes ‘normal’ is not normal.”
Tamler concluded that true diabetes prevention goes beyond merely measuring height and weight. “Healthcare providers need to have a deeper understanding of culinary and cultural traditions that profoundly impact metabolic health,” he said.