Black parents are twice as likely as white parents to distrust medical research, according to a study released yesterday by researchers at Children's Hospital of Pittsburgh and the University of Pittsburgh.

That distrust, they said, means many of those parents keep their children from participating in clinical trials. And that makes it more difficult for doctors to find treatments that someday could help close the gap between blacks and whites in the quality and quantity of health care they receive.

The civil rights movement isn't over -- it just has a new venue in the health disparity gap researchers are working to eliminate, said Dr. Stephen Thomas, director of the Center for Minority Health in the University of Pittsburgh's Graduate School of Public Health.

"We definitely cannot have segments of our community suffering from conditions that are totally preventable or diseases that are not being treated properly because people don't trust the care," he said. "It's totally unacceptable."

In a voluntary research survey of 140 black people and 50 white people, black parents more often reported distrust of medical research (67 percent vs. 50 percent). And they more often believed doctors prescribe medications as a way of experimenting on unknowing patients (40 percent vs. 28 percent).

They also were more likely to believe that medical research involves too much risk to the participant (46.8 percent vs. 28 percent), that doctors would not make full disclosures regarding their child's participation (24.6 vs. 10 percent) and that research participants would be favored and receive better medical care (48.6 percent vs. 28 percent).

Education level also was associated with distrust, with high distrust scores among 74 percent of those with less than a high school education, compared with 44 percent of college graduates. Even among people of similar education, blacks were more likely to distrust medical research.

Dr. Kumaravel Rajakumar, a pediatrician at Children's Hospital and the study's co-author, said the participation of black children in medical studies gives researchers essential information that can help those children and others like them.

In one recent study, researchers found that black children are at greater risk of vitamin D deficiency, which can cause rickets, a disease that bows the legs, because the darker pigmentation of their skin keeps sunlight from entering their bodies and generating the vitamin. Knowing that information helps doctors monitor their black pediatric patients' intake of vitamin D supplements, especially during the winter when sunlight is weakest. "Across the health spectrum, when we're talking about the benefits of research, it's important that it be beneficial to everybody," Dr. Rajakumar said.

Suspicion of the medical establishment has been inscribed on the consciousness of many black people because of events such as the Tuskegee Syphilis Experiment, researchers said. In that study, 399 black men with syphilis were left untreated -- and prevented from seeking treatment even after penicillin, which could have cured them, was discovered -- for 40 years, between 1932 and 1972, so that the effects of the disease could be studied.