People, especially minorities, who are at a “healthy” weight may still be at increased risk for diabetes and heart disease, a new study reports.

Researchers gathered data on 7,617 white, Chinese-American, African-American, South Asian and Hispanic Americans aged 45 to 84. In addition to tracking body mass index, physical activity, and demographic and behavioral characteristics, they assessed four risk factors for cardiovascular disease: LDL cholesterol, triglycerides, blood pressure and glucose tolerance.

They found that compared to whites of normal weight, South Asians of normal weight were twice as likely to have abnormal readings in two or more of these risk factors. Normal weight Chinese-Americans were 53 percent more likely to have abnormal readings, African-Americans 48 percent more likely, and Hispanics 83 percent more likely. The differences were independent of age, sex, educational level, exercise and smoking.

“Race is a factor in the risk for heart disease, even at normal weight,” said the lead author, Unjali P. Gujral, a postdoctoral fellow at Emory University. “A heart healthy diet and lots of exercise is important regardless of weight.”

The study, in the Annals of Internal Medicine, found that to have the same number of abnormalities as a white person with a B.M.I. of 25, an African-American would have to have a B.M.I. of 22.9, a Hispanic 21.5, a Chinese-American 20.9 and a South Asian 19.6.