Carcinogen exposure during short-term switching from regular to "light" cigarettes.

OBJECTIVES: "Light" cigarettes are extremely popular and are perceived by many smokers as less hazardous than higher-yield cigarettes. The objectives of this study were (a) to assess a battery of biomarkers of tobacco smoke exposure that includes tobacco smoke carcinogens, (b) to examine the behavioral nature of compensation, and (c) to examine the consistency of an individual's tobacco smoke exposure when smoking the same cigarette at different times. METHODS: The study was a 3-week crossover study in which smokers smoked their usual cigarettes during weeks 1 and 3, and a light cigarette, with a machine-determined nicotine yield of about 50% of the usual cigarette, during week 2. Blood and urine biomarkers of exposure and subjective questionnaires were collected weekly. RESULTS: Based on cotinine and carboxyhemoglobin levels, compensation averaged 78% and 83%, respectively. Urinary excretion of 4-(methylnitrosamino)-1-(3-pyridyl)-butanol, a metabolite of the tobacco specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-butanone, and a number of polycyclic aromatic hydrocarbon metabolites was similar in all conditions. Compensation was accomplished both by smoking cigarettes more intensively and by smoking more cigarettes per day. Exposures to various tobacco smoke constituents while smoking the usual brand of cigarette in weeks 1 and 3 were highly correlated. CONCLUSION: Our findings support the idea that smokers compensate to a high degree when switched from their usual brand to a light cigarette. Short-term switching resulted in no significant reduction in carcinogen exposure. Our assessment, based on measures of biochemical exposures, supports the idea that switching to light cigarettes is unlikely to reduce the health risks of cigarette smoking.