Posted on March 16, 2007

Race Affects Tobacco Absorption In Children

Medical News Today (Cancun), March 13, 2007

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.”

“Exposure to tobacco smoke is dangerous for everyone, regardless of age or race,” said Mark J. Rosen, MD, FCCP, President of the American College of Chest Physicians. “These findings underline the importance of eliminating environmental tobacco smoke in every setting, especially those where children are present.”

CHEST is a peer-reviewed journal published by the ACCP. It is available online each month at The journal’s website also provides public access to thousands of archived studies, dating back to 1946-a newly added feature that is free of charge. The ACCP represents 16,600 members who provide clinical respiratory care, sleep medicine, critical care, and cardiothoracic patient care in the United States and throughout the world. The ACCP’s mission is to promote the prevention and treatment of diseases of the chest through leadership, education, research, and communication. For more information about the ACCP, please visit the ACCP Web site at

Objective: African-American children have higher rates of tobacco-associated morbidity. Few studies have objectively measured racial differences in the exposure of children to tobacco smoke. The objective of this study was to test whether African-American children have higher levels of cotinine compared to white children while accounting for ambient measures of tobacco smoke.

Setting: Community-based sample of asthmatic children (n = 220) enrolled in an environmental tobacco smoke (ETS) reduction trial.

Participants: A biracial sample (55% African American) of children with asthma aged 5 to 12 years who were routinely exposed to ETS.

Measurements: We measured cotinine levels in serum and hair samples at baseline, 6 months, and 12 months. We measured the level of ETS exposure over a 6-month period by placing air nicotine dosimeters in the homes of the children at baseline and at 6-month study visits.

Results: African-American children had significantly higher levels of cotinine at all time points in the study. At the 12-month visit, African-American children had higher levels of serum cotinine (1.39 µg/dL vs 0.80 µg/dL, p = 0.001) and hair cotinine (0.28 ng/mg vs 0.08 ng/mg, p < 0.0001) when compared with white children. In a repeated-measures analysis, African-American children had significantly higher levels of serum cotinine (ß = 0.28, p = 0.04) and hair cotinine (ß = 1.40, p < 0.0001) compared with white children. Air nicotine levels and housing volume were independently associated with higher levels of cotinine.

Conclusions: Among children with asthma, African-American children have higher levels of serum and hair cotinine compared with white children.