By Leslie Harris O'Hanlon
Smoking and Ethnicity
Blacks, native Hawaiian smokers have higher risk of lung cancer
By Leslie Harris O'Hanlon
Smoking can cause lung cancer in anyone, but African-American and native Hawaiian smokers might have a higher risk of developing the disease.
That's the conclusion of a study of lung cancer incidence among 183,813 men and women living in California and Hawaii. Compared with African-Americans who smoked less than 10 cigarettes or between 11 and 20 cigarettes per day, Latinos and Japanese who smoked the same number of cigarettes were 61 percent to 79 percent less likely to develop lung cancer, and white men and women were 43 percent to 55 percent less likely to have the disease. Lung cancer risk among native Hawaiians was similar to that of African-Americans.
Differences in occupation, diet or socioeconomic status could not explain the different lung cancer rates, but the study's authors note that they couldn't completely rule those factors out.
Members of these two groups tend to have lower socioeconomic status and "may be subject to an armful of environmental exposures more often than individuals of other groups," says Loïc Le Marchand, an epidemiologist at the Cancer Research Center of Hawaii in Honolulu and co-author of the study, which appeared in the Jan. 26 New England Journal of Medicine. "But so [do many] Latinos, and they had lower lung cancer risk."
Another possible explanation is that people in different ethnic groups absorb or process tobacco's harmful chemicals differently. "The uptake of tobacco smoke constituents could be greater in African-Americans and native Hawaiians," says Le Marchand. "They may also be able to better metabolize the carcinogens from tobacco smoke into more reactive and toxic byproducts. Or, they may be less able to eliminate these carcinogens."
Earlier research found that blacks have higher amounts of cotinine, a nicotine byproduct, in their blood after smoking the same number of cigarettes as whites and Hispanics. If nicotine metabolism is different in this group, it's possible that exposure to and metabolism of other tobacco chemicals may also be different.
Nevertheless, factors such as where people work and live and whether they have access to fresh fruits and vegetables may be just as important as any possible biological links in determining cause and effect, says Michael Christopher Gibbons, a public health professor at Johns Hopkins Urban Health Institute in Baltimore.
"To really understand disparities and lung cancer, you have to, at some level, have a handle on all these things," he says. "Very few, if any, diseases are attributable only to genetic causes. For the vast majority of diseases, even those that have a strong genetic component, something else has to happen."