Reduced tar, nicotine, and carbon monoxide exposure while smoking ultralow- but not low-yield cigarettes.

An unresolved public health issue is whether some modern cigarettes are less hazardous than others and whether patients who cannot stop smoking should be advised to switch to lower-yield cigarettes. We studied "tar" (estimated by urine mutagenicity), nicotine, and carbon monoxide exposure in habitual smokers switched from their usual brand to high- (15 mg of tar), low- (5 mg of tar), or ultralow-yield (1 mg of tar) cigarettes. There were no differences in exposure comparing high- or low-yield cigarettes, but tar and nicotine exposures were reduced by 49% and 56%, respectively, and carbon monoxide exposure by 36% while smoking ultralow-yield cigarettes. Similarly, in 248 subjects smoking their self-selected brand, nicotine intake, estimated by blood concentrations of its metabolite cotinine, was 40% lower in those who smoked ultralow but no different in those smoking higher yields of cigarettes. Our data indicate that ultralow-yield cigarettes do deliver substantial doses of tar, nicotine, and carbon monoxide, but that exposures are considerably less than for other cigarettes.