Lung Cancer Risk Higher for African-American Smokers
African Americans who smoke face a higher risk of developing lung cancer than smokers of other races, indicating that genes "might help explain the racial differences long seen in the disease," according to a study in Thursday's New England Journal of Medicine, the AP/Detroit Free Press reports (Chang, AP/Detroit Free Press, 1/26).
In the largest study on the topic to date, researchers from the University of Southern California and the University of Hawaii followed 183,000 study participants over an eight-year period beginning in 1993. Over the course of the study, 1,979 enrollees developed lung cancer.
Among African-American men who smoked, there were 264 cases of lung cancer per 100,000 individuals, compared with 264 cases among native Hawaiian men, 158 cases among white men, 121 cases among Japanese-American men and 79 cases among Latino men. The study, which did not include other ethnic groups, found that women overall had lower incidences of lung cancer, but ethnic disparities generally "followed the same pattern," the Wall Street Journal reports (Bulkeley, Wall Street Journal, 1/26).
Overall, whites who smoked up to one pack of cigarettes daily had a 43% to 55% lower risk of developing lung cancer than blacks who smoked the same amount. Latinos and Japanese Americans were 60% to 80% less likely than blacks to develop lung cancer if they smoked up to a pack a day, according to the study (AP/Detroit Free Press, 1/26).
The disparities -- which persisted even after researchers considered factors such as diet, socioeconomic status and occupation -- disappeared among participants who were the heaviest smokers, likely because the damage caused by smoking at that level overwhelmed other factors, according to lead author Christopher Haiman, an assistant professor at the Keck School of Medicine at USC.
Haiman said the study could not rule out the possibility that the findings resulted from unidentified environmental factors but noted that there could be "differences in how [African Americans] metabolize nicotine, which would influence smoking behaviors such as the depth and frequency of inhalation of tobacco smoke." He added, "There could be genetic factors on how they metabolize tobacco smoke" (Stein, Washington Post, 1/26).
In an editorial accompanying the study, Neil Risch, director of the Institute for Human Genetics at the University of California-San Francisco, said the results of the study "provide an example of how ethnicity can interact with environmental factors in terms of the risk of disease." He added that the findings could help doctors diagnose and treat some illnesses (Wall Street Journal, 1/26).
Esteban Gonzalez Burchard, an assistant professor at the UCSF School of Medicine, said, "If this happens with tobacco, what about other drugs? Tobacco is a drug. What about the drugs we give to patients, such as cancer medications or heart medications or lung medication? There could be important biologic differences that help to explain the differences we see in disease prevalence, severity and mortality, as well as response to therapies."
Jeffrey Kahn, a bioethicist at the University of Minnesota, said he is concerned that the findings could lead to discrimination, noting that "[t]he danger would be to sort of view lung cancer as a minority disease, and so something we don't have to worry as much about."
Troy Duster, a professor of sociology at New York University, said, "This feeds into the 19th-century notion that these categories really separate people in terms of their physical and biological characteristics. The reason why black people may be getting cancer more has to do with a combination of forces, not just their biologic makeup."
M. Gregg Bloche, a health law and policy professor at Georgetown University, said the study should encourage more research into understanding the role of genetics in how different races react to medicines, adding, "The biggest danger here is ideology on both sides getting in the way of trying to understand this phenomenon" (Washington Post, 1/26).
The study is available online.
The editorial is available online.