Asia, which covers an area almost twice the size of North America and is home to three billion people-half of humanity-is often seen as a homogenous entity in the minds of many Westerners, even scientists. But a land that stretches 6,000 miles from east to west is anything but homogenous. The Israelis and Arabs in western Asia, for example, are far different ethnically from the Hmong mountain people in Southeast Asia, the Ainu in northern Japan, or the Filipinos in the southwestern Pacific.

When it comes to tracking diabetes, Asia's great ethnic diversity hasn't always been taken into account. Until now, Asians have been lumped together in studies of diabetes, making it hard for doctors and scientists to know what the diabetes risk factors are for specific Asian ethnic groups.

That is going to change, however, thanks to a $2.5 million grant from the National Institutes of Health to the Palo Alto Medical Foundation's Research Institute. The California-based institute, located south of San Francisco, will use the money to fund a five-year study on how to prevent and treat diabetes in the state's six largest Asian ethnic groups: Asian Indians, Chinese, Filipinos, Japanese, Koreans, and Vietnamese. 

The study, to be called the Pan Asian Cohort Study (PACS), will examine existing clinical records of more than 60,000 Asians and Asian-Americans in California to ascertain their risk of diabetes. The cohort will be the largest group of ethnic Asians ever assembled for a medical study. 

The goal of the PACS will be to identify diabetes risk factors that may be unique to Asian-Americans in general and to specific Asian ethnic groups in particular. Because obesity is a common risk factor for type 2 diabetes, the PACS will attempt to determine if the current body mass index measures recommended by the World Health Organization to define obesity among Asians should be revised for Asians living in the United States. 

Preliminary studies by the Palo Alto Medical Foundation indicate that Asian Indians and Filipinos run a much higher risk for diabetes than the other groups in the study. This finding reinforces the need to study the six ethnic groups separately in order to arrive at useful conclusions regarding their relative risks of acquiring type 2. 

Another useful outcome will be a sort of "map" of racial and ethnic differences in how people metabolize glucose and insulin under similar living conditions. Being able to take into account such subtle differences will be a handy tool for doctors, especially in the San Francisco Bay Area, where 20 percent of the seven million residents belong to one of the six Asian ethnic groups under study. 

For more information about the study and its preliminary findings, visit www.pamf.org/pacs.