Over a 30-year period, African Americans in California died of asthma at a rate up to four times higher than whites, researchers at UC Davis have found in a recent study. Further research shows that the difference in asthma death rates between African Americans and whites is increasing, says occupational health and pulmonary physician Dr. Marc B. Schenker. "The increase among African Americans is of particular concern, and increased attention should be focused on the causes of asthma morbidity and mortality in this group," he says. Researchers analyzed data from the California State Department of Health from 1960 to 1989 and the 1979-81 California Occupational Mortality Study. They also analyzed asthma deaths among Hispanics and Asians from 1985-89. Schenker and his colleagues found that overall asthma deaths were cut in half from 1960 to 1970, but showed a marked increase between 1975 and 1989. "No single cause for the increase has been identified," he says, "and it is likely that the increase reflects many different causes."