Researchers have found more evidence that suggests a relationship between race and rates of lung cancer among smokers. A new study shows that black people and Native Hawaiians are more likely to develop lung cancer from smoking. It compared their risk to whites, Japanese, Americans and Latinos. The study, however, found almost no racial or ethnic differences among the heaviest smokers. These were people who smoked more than thirty cigarettes each day. Other comparisons have shown that blacks are more likely than whites to get lung cancer from smoking. But the scientists say few studies have compared the risks among Native Hawaiians, Asians and Latinos. Researchers at the University of Southern California and the University of Hawaii did the new study. The New England Journal of Medicine published the findings. The eight-year study involved more than 180,000 people. They provided details about their tobacco use and their diet as well as other information. They included current and former smokers and people who never smoked. Almost 2,000 people in the study developed lung cancer. Researchers say genetics might help explain the racial and ethnic differences. There could be differences in how people's bodies react to smoke. But environmental influences, including the way people smoke, could also make a difference. African-Americans and Latinos in the study reported smoking the fewest cigarettes per day. Whites were the heaviest smokers. But the scientists note that blacks have been reported to breathe cigarette smoke more deeply than white smokers. This could fill their lungs with more of the chemicals in tobacco that cause cancer. Many researchers disagree not only about the effect of race on the risk of disease, but even about the meaning of race. Yet scientists know that some diseases affect different groups differently. And some drug companies have begun to develop racially targeted medicines. Last June, the United State Food and Drug Administration approved a drug designed to treat heart failure in black patients. The name is BiDil. The agency called it "a step toward the promise of personalized medicine". The subjects that the smoking researchers investigate are made up of    _   .
heavy smokers in America the black and white people the Asians and Hawaiians smokers and non-smokers