Researchers analysed the relation between the tar rating of the brand of cigarette smoked in 1982 and death from lung cancer over six years among 364,239 men and 576,535 women aged 30 years or more.
Irrespective of the tar level of their current brand, all current smokers had a far greater risk of lung cancer than people who had never smoked or who had quit.
Men and women who smoked very low tar (7 mg or less) and low tar (8-14 mg) brands had risks of lung cancer indistinguishable from those who smoked medium tar (15-21 mg) brands. This pattern did not change after demographic factors, dietary habits, and occupational and medical histories were taken into account.
Men and women who smoked non-filtered cigarettes with tar ratings of 22 mg or more had even higher risks of lung cancer.
These findings are consistent with other evidence that people smoke low tar cigarettes more intensively, and challenge the assumption that the link between tar rating and lung cancer risk is necessarily linear, say the authors.
They suggest that reducing the use of high tar non-filter cigarettes may provide limited public health benefits in those countries where these products are commonly used.