Smoking high tar cigarettes increases risk of death from lung cancer, but no differences in risk for smokers of very low, low and medium tar cigarettes

Question

What is the relationship between lung cancer mortality and tar rating of smoker's cigarette brand?

Study Design

Multivariate analysis of data from prospective cohort study.

Main results

Risk of death due to lung cancer was significantly higher in smokers of high-tar cigarettes compared with people smoking low, very low and medium tar cigarettes (see Table 1). There were no significant differences in the risk of lung cancer mortality for people smoking very low or low tar cigarettes compared with smokers of medium tar cigarettes. Stopping smoking considerably reduced risk of lung cancer. People quitting before age 35 years had a very similar risk to those who had never smoked.

Table 1 Risk of mortality from lung cancer by tar level of cigarette smoked in the whole cohort
Tar level	Males	Females
	Hazard ratio (95% CI)	Hazard ratio (95% CI)
0–7 mg	1.17 (0.95 to 1.45)	0.98 (0.80 to 1.21)
8–14 mg	1.02 (0.90 to 1.16)	0.95 (0.82 to 1.11)
15–21 mg	1.0	1.0
⩾22 mg	1.44 (1.20 to 1.73)	1.64 (1.26 to 2.15)
Unclassifiable	1.10 (0.97 to 1.25)	0.72 (0.56 to 0.93)

Authors’ conclusions

There was no detectable difference in risk of lung cancer among people who smoked very low, low or medium tar cigarettes. An increased risk was identified in people who smoked high tar cigarettes. These findings persisted after adjustment for demographics, diet and medical history and for cigarettes/day.