Evidence relating cigarettes, cigars and pipes to cardiovascular disease and stroke: Meta-analysis of recent data from three regions

ARTICLE HIGHLIGHTS

Research background

While there are considerable data on risks from smoking, such risks may change with time, and recent evidence is required for smoking of cigarettes, cigars and pipes.

Research motivation

To take into account recent data on the risks of acute myocardial infarction (AMI), ischaemic heart disease (IHD) and stroke associated with current smoking of cigarettes, cigars and pipes.

Research objectives

To summarize recent data on the risk of AMI, IHD and stroke related to current cigarette, cigar and pipe smoking in North America, Europe and Japan.

Research methods

Searches on MEDLINE identified publications in English in 2015-2020 giving data on risks of the three diseases associated with current (vs never) cigarette, cigar or pipe smoking in studies conducted in the three regions. Studies were accepted which were of cohort or nested case-control design or were randomized controlled trials, which involved at least 100 cases of the disease of interest, and were not restricted to specific disease subsets, to patients with specific medical conditions or which reported results superseded by later reports of the study. Relative risk estimates were extracted from each study and overall estimates derived using random-effects meta-analyses.

Research results

There were available results from 10 studies for AMI, from 23 studies for IHD, and from 31 studies for stroke, the studies being mainly conducted in North America and Europe. Overall relative risk (RR) estimates for current cigarette smoking were 2.72 for AMI, 2.01 for IHD and 1.62 for stroke. Estimates were dose-related to daily cigarette consumption, and somewhat higher for females than males. Estimates were relatively low in Japan for stroke. RR estimates tended to be higher for studies starting later and with a shorter follow-up period and where adjusted for multiple covariates. Only a few studies in the United States provided findings for current cigar or current pipe smoking, and then only for IHD and stroke. There was no evidence from these studies that smoking either of these products increased risk of these diseases.

Research conclusions

Consistent with evidence from earlier studies, increased risks for all three diseases are clearly seen for current cigarette smoking, but not for current cigar or pipe smoking.

Research perspectives

Cigarette smoking increases the risks of developing AMI, IHD and stroke, though by a factor much lower than for lung cancer and chronic obstructive pulmonary disease. To reduce these risks most effectively, cigarette smokers should quit, though switching to other products containing nicotine, such as Swedish snuff (“snus”), may also materially reduce these risks.