Systematic Reviews
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Meta-Anal. Jun 28, 2022; 10(3): 130-142
Published online Jun 28, 2022. doi: 10.13105/wjma.v10.i3.130
Review with meta-analysis relating North American, European and Japanese snus or smokeless tobacco use to major smoking-related diseases
Peter Nicholas Lee, Katharine Jane Coombs, Janette Susan Hamling
Peter Nicholas Lee, Katharine Jane Coombs, Department of Medical Statistics and Epidemiology, P.N.Lee Statistics and Computing Ltd, Sutton SM2 5DA, Surrey, United Kingdom
Janette Susan Hamling, Department of Medical Statistics and Epidemiology, RoeLee Statistics Ltd, Sutton SM2 5DA, Surrey, United Kingdom
Author contributions: Lee PN planned the study; Literature searches were carried out by Coombs KJ and checked by Lee PN; Statistical analyses were carried out by Hamling JS and checked by Lee PN; Lee PN drafted the text, which was checked by Coombs KJ and Hamling JS.
Conflict-of-interest statement: The authors have carried out consultancy work for many tobacco organizations.
PRISMA 2009 Checklist statement: The authors have read the Prisma 2009 Checklist, and the manuscript was prepared and revised according to the Checklist's requirements.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Peter Nicholas Lee, MA, Senior Statistician, Department of Medical Statistics and Epidemiology, P.N.Lee Statistics and Computing Ltd, 17 Cedar Road, Sutton SM2 5DA, Surrey, United Kingdom. peterlee@pnlee.co.uk
Received: February 10, 2022
Peer-review started: February 10, 2022
First decision: April 13, 2022
Revised: April 25, 2022
Accepted: May 28, 2022
Article in press: May 28, 2022
Published online: June 28, 2022
Processing time: 144 Days and 20.1 Hours
ARTICLE HIGHLIGHTS
Research background

There are extensive data on the risks from cigarette smoking, but far less on the risks from moist snuff (“snus”) or smokeless tobacco (ST) as used in Western populations and Japan.

Research motivation

To obtain recent evidence as part of a project comparing risks from use of various tobacco products.

Research objectives

To summarize data relating snus and ST use in North America, Europe and Japan to risk of the four main smoking related diseases – lung cancer, chronic obstructive pulmonary disease (COPD), ischaemic heart disease (IHD) (including acute myocardial infarction (AMI) and stroke.

Research methods

Medline searches sought English publications in 1990-2020 providing data on risks of each of the diseases relating to current (or ever) use of snus or ST in the selected regions. The studies had to include at least 100 cases of the disease considered, and not be based on individuals with specific diseases. Relative risk estimates adjusted at least for age were extracted for each study and combined using random-effects meta-analyses.

Research results

Six United States studies provided ST results. For current vs. never use (4 studies), significant increases were seen for each disease, with the RRs higher for lung cancer (1.59) and COPD (1.57) than for IHD/AMI (1.26) and stroke (1.25). Including also results for ever vs. never use, increased the lung cancer RR to 1.80, but little affected the other RRs. Twelve Scandinavian studies provided snus results, with no data on COPD. For the other diseases, RRs for current vs. never use were never significant, the highest RR being 1.05 for stroke. There were no relevant studies in Japan.

Research conclusions

Risks from ST use in North America are much less than for smoking, while no risks were demonstrated for snus.

Research perspectives

The results suggest that smokers unwilling to give up nicotine may substantially reduce their risk of the four diseases by switching to ST (as used in North America) or snus.