Black smokers more susceptible to lung cancer

By Anthony J. Brown, MD

NEW YORK (Reuters Health) - African Americans and Native Hawaiians who smoke cigarettes have a higher risk of lung cancer than do their white counterparts, who, in turn, have a higher risk than Japanese American and Latino smokers, new research shows.

The findings, which are based on an analysis of data from a large multiethnic group, support what has been shown in smaller studies, according to the report in The New England Journal of Medicine.

"What we found interesting and striking is that there appeared to be modification of the ethnic differences by the number of cigarettes smoked per day," lead author Dr. Christopher A. Haiman, from the University of California at Los Angeles, told Reuters Health. "At high levels of smoking, the racial disparities essentially disappear."

The study included 183,813 African-American, Japanese-American, Latino, Native Hawaiian, and white subjects living in California or Hawaii. A total of 1979 cases of lung cancer were identified between 1993 and 2001.

African Americans and Native Hawaiians had a higher risk of lung cancer among the subjects who smoked less than 30 cigarettes per day.

The racial gap was particularly evident among subjects who smoked 10 or fewer cigarettes per day. White smokers and Japanese American/Latino smokers were 55 percent and 79 percent less likely, respectively, to develop lung cancer than black smokers.

The racial differences in smoking-related lung cancer risk were observed in both genders and for all lung cancer subtypes, the report indicates.

"There may be differences between the ethnic groups in how nicotine is metabolized," Dr. Haiman suggested. "This could influence rates of inhalation, which, in turn affect cancer risk."

Haiman and colleagues are planning additional studies, including genetic studies, in an effort to better understand the reasons for these racial differences.

SOURCE: The New England Journal of Medicine, January 26, 2006.