Friday, March 16, 2007

Tobacco toxicants are significantly higher in African-Americans

Jennifer Stawarz:

New research suggests that a child's race may be a factor in determining his/her susceptibility to tobacco toxins associated with environmental tobacco smoke (ETS). The study, published in the March issue of CHEST, the peer-reviewed journal of the American College of Chest Physicians (ACCP), reveals that African American children with asthma, who are exposed to ETS, have significantly higher toxin levels when compared to their Caucasian counterparts.

"African American children suffer from higher rates of tobacco-related disorders, such as asthma, sudden-infant death syndrome, and low birth weight, and we need to know why," said lead author Stephen Wilson MD, University of Cincinnati. "So our goal is to understand how certain populations - particularly those groups who are most susceptible - respond to ETS exposure."

Dr. Wilson and colleagues from the Cincinnati Children's Hospital Medical Center examined 220 tobacco-exposed children with asthma, who had previously participated in the Cincinnati Asthma Prevention study. Researchers studied a bi-racial, community-based sample (55% African American) of children ranging in ages 5 to 12. All of the children had physician-diagnosed asthma, symptoms consistent with persistent asthma, and were exposed to at least five cigarettes per day in or around the home.

Researchers tested for levels of cotinine, a nicotine metabolite, by collecting serum and hair samples at baseline, 6 months, and 1 year. Serum samples accounted for short-term tobacco exposure and hair samples accounted for long-term tobacco exposure.

"Cotinine is a product of nicotine metabolism. When people inhale or ingest nicotine, the body uses proteins to convert it into cotinine," said Dr. Wilson, "and, currently, measuring cotinine in various biologic specimens is a widely used method for assessing nonsmokers' exposure to ETS."

Researchers also avoided reporting parental bias by actively measuring levels of tobacco smoke in the home. Each study participant had a nicotine dosimeter placed in his or her home at baseline and at the 6-month visit. These dosimeters were removed at the 6-month and 1-year visits, and were used to objectively measure each child's level of ETS exposure.

No racial differences were reported in levels of ETS exposure outside of the home or in air nicotine levels at the 6-month or 1-year study visits. But, results indicated that while African-American children spent less time exposed to ETS, they showed significantly higher levels of cotinine compared to Caucasian children. On average, serum cotinine levels in the African-American participants were 32 percent higher than in the Caucasian participants, and hair cotinine levels were 4 times that of the Caucasian participants.

"Previous studies of adult smokers, as well as cross-sectional studies of nonsmokers have demonstrated similar racial differences in serum cotinine, however, we were surprised at the magnitude of the racial differences in the hair continine," said Dr. Wilson. "African-American children may "handle" environmental tobacco smoke differently than white children, so these results raise questions as to whether there are racial differences in other tobacco toxicants, as well."

Second-hand smoke riskier for black children: study

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