Low Levels of Tobacco Smoke Exposure Tied to Lung Disease

Study links low-level exposure to alteration of gene function in the lungs

FRIDAY, Aug. 20 (HealthDay News) -- Individuals exposed to even low levels of tobacco smoke may be at increased risk for developing lung diseases, according to a study published online Aug. 6 in the American Journal of Respiratory and Critical Care Medicine.

Yael Strulovici-Barel, of Weill Cornell Medical College in New York City, and colleagues evaluated small airway epithelium samples obtained by bronchoscopy from 121 individuals to determine whether there were biologic changes related to exposure to low levels of tobacco smoke. Individuals were categorized as "nonsmokers," "active smokers," and "low-exposure smokers" using urine nicotine and cotinine.

The researchers found that there was no threshold of urine nicotine that did not have a small airway epithelial response, and there was no level of cotinine that did not correlate with genetic abnormalities. The induction half maximal level for urine nicotine was 25 ng/mL, and it was 104 ng/mL for cotinine.

"Overall, the data demonstrates, at the biologic level, the high sensitivity of the small airway epithelium to low levels of tobacco smoke. These observations have implications for the exposure of individuals in regard to their risk to lung health, as well as implications for public health, as large populations of individuals worldwide have exposure to low levels of cigarette smoke," the authors write.

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