Associated Press
WASHINGTON — Chinese American smokers absorb less nicotine per cigarette but retain the addictive chemical longer in the blood, which may explain why they smoke less and have less lung cancer than white Americans, according to a new study.
The study analyzed how the body processes nicotine and found the chemical remains in the blood longer in Chinese American smokers than among American Hispanics and Caucasian smokers. Chinese American smokers also tended to take in less of the chemical when they smoked.
Dr. Neal Benowitz of the University of California, San Francisco, said this difference in nicotine metabolism may be one reason Chinese American smokers tend to smoke fewer cigarettes per day than white smokers. But it is not the final answer smoking differences, he cautioned, noting that American Hispanic smokers also tend to use fewer cigarettes.
The study is part of an effort to learn why Asian smokers tend to have less lung cancer than whites or American Hispanics. The risk of lung cancer for Asian smokers is about four times greater than for nonsmoking Asians. However, among white and Hispanic smokers, the lung cancer risk is 10 to 20 times greater than among nonsmokers.
For African American smokers, who were not included in this study, the lung cancer risk is even higher, 20 to 40 times greater than for nonsmokers. In 1998, Benowitz’s research showed that blacks take in more nicotine than whites.
The latest research appears Tuesday in the Journal of the National Cancer Institute.
Benowitz said earlier studies have shown that Chinese Americans tend to have less of the liver enzyme CYP2A6, which metabolizes chemicals from cigarette smoke. He said this enzyme also turns some of the chemicals into carcinogens, or cancer-causing compounds.
"We hypothesize that the reason they have lower lung cancer risk is that they activate fewer carcinogens because they have less of this enzyme in the liver," Benowitz said.
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