Evidence relating cigarette, cigar and pipe smoking to lung cancer and chronic obstructive pulmonary disease: Meta-analysis of recent data from three regions

ARTICLE HIGHLIGHTS

Research background

While there are extensive data on the risks from smoking, these risks may change over time, and up-to-date evidence is needed for cigarette, cigar and pipe smoking.

Research motivation

To obtain recent evidence comparing the risks of major smoking-related diseases due to the use of various tobacco products.

Research objectives

To summarize data relating current smoking of cigarettes, cigars and pipes in North America, Europe and Japan to the risk of lung cancer and chronic obstructive pulmonary disease (COPD).

Research methods

MEDLINE searches identified English publications in 2010-2020 providing data on risks of one or both diseases relating to current (vs never) smoking of cigarettes, cigars or pipes in the three regions. The studies had to be of cohort or nested case-control design or be randomized controlled trials, involve at least 100 cases of the diseases of interest, and not be restricted to specific types of the disease, to patients with specific medical conditions or report results superseded by later results from the same study. Relative risk estimates were extracted for each study and combined using random meta-analyses.

Research results

Results for lung cancer were available from 44 studies and for COPD from 18, predominantly from North America and Europe. For current cigarette smoking, overall RR estimates were 12.14 for lung cancer and 9.19 for COPD. Estimates were slightly but not significantly higher for males than females. Estimates were relatively low in Japan, particularly for lung cancer, where RRs of 3.61 for Japan compared with those of 15.15 for North America and 12.30 for Europe. No highly significant variations were seen for other factors studied, though for COPD estimates were higher (17.45) where the disease definition excluded bronchiectasis. Few of the studies provided evidence on current cigar or pipe smoking, all from the US or Europe. Estimated RRs for cigar smoking, 2.73 for lung cancer and 2.44 for COPD, and for pipe smoking, 4.93 for lung cancer and 1.12 for COPD, were lower than for cigarette smoking, though based on limited data, with notable heterogeneity for pipe smoking for lung cancer.

Research conclusions

Consistent with evidence from earlier studies, risks for cigar and pipe smoking are much less than for cigarette smoking, both for lung cancer and COPD. Risk of lung cancer from cigarette smoking is much less in Japan than in the US or Europe.

Research perspectives

Smoking significantly increases the risks of developing lung cancer and COPD, with risks highest for cigarette smoking. To most effectively reduce these risks, smokers should quit, though evidence suggests that using alternative nicotine-containing products, such as snus, e-cigarettes and heated tobacco products should also substantially reduce these risks.