Source: Seattle Times (WA) Contact: http://www.seattletimes.com/ Pubdate: Wed, 08 Jul 1998 Author: John Schwartz, The Washington Post STUDIES SHOW BLACKS MAY ABSORB MORE NICOTINE Blacks who smoke absorb more nicotine than white or Hispanic smokers, a difference that explains why blacks tend to suffer more from tobacco-related disease and have more trouble kicking the habit, researchers reported yesterday. The new data emerges from two studies in today's edition of the Journal of the American Medical Association that constitute the broadest effort ever to understand racial differences in smoking. "It's really important research," said Jack Henningfield, an expert on nicotine addiction at Johns Hopkins University. "It raises a whole bunch of serious questions that need to be answered" about the biology of smoking and proper cessation treatment. "The bad news is, it's 1998 and we're just finding this out." African American adults historically have smoked at higher rates than the general population, but in recent years they have smoked at about the same rates as other groups. More than 31 percent of black men smoke, compared to nearly 28 percent of white men; 22.7 percent of black women smoke, compared to 24.4 percent of white women. Since 1976, smoking rates among black teenagers declined dramatically, but in recent years the rate has begun to climb again. The two new studies focus on bloodstream levels of cotinine, the most common chemical produced by the body from nicotine. In the first study, researchers at the federal Centers For Disease Control and Prevention in Atlanta measured the amount of cotinine in the blood of 7,182 subjects, 2,136 of whom said they had smoked in the previous five days. "For each level of cigarette smoking, the levels for African Americans were substantially higher," said lead author Ralph Caraballo of the CDC. Black participants in the study had cotinine levels in their blood that were between 12 percent and 50 percent higher than those of white subjects, and 32 percent to 56 percent higher than Mexican Americans. The researchers called the results "intriguing" because, they wrote, cessation experts say blacks "are more likely to try to quit but have a lower success rate than white smokers." The higher levels of cotinine suggest that blacks absorb more nicotine from cigarettes than whites. The researchers compensated for the fact that blacks tend to smoke fewer cigarettes than whites, though Caraballo said that they could not take into account possible behavioral differences in the ways that people of different races smoke. Previous studies have shown that black smokers tend to take more smoke into their lungs or hold it in the lungs for a longer time. Caraballo noted that such studies have tried to account for the greater popularity of menthol cigarettes among blacks, and the possibility that the anesthetizing effect of menthol "could allow you to smoke more deeply." But he said the structure of his study made such inquiries impossible. The second study found that blacks also keep cotinine in their bodies longer than whites. Keeping nicotine in the body longer could enhance smoking's pleasurable effects. Researchers at the University of California in San Francisco studied 79 smokers and found that an African American who smoked 12 to 15 cigarettes a day gets as much nicotine as whites who smoke a full pack of 20 cigarettes a day - a difference that Henningfield calls "small but real," with important implications for those who would help African Americans quit smoking. That study solved the issue of behavioral differences by infusing cotinine directly into the bloodstreams of the test subjects. - --- Checked-by: (Joel W. Johnson)