Smokeless tobacco and waterpie use and risk of lunbg cancer

Abstract

Abstract Background Over 300 million people worldwide use smokeless tobacco (ST) with rates of use exceeding that of cigarette smoking in much of South-East Asia and amongst certain groups in the Middle East. This study investigated the association between consumption of ST use and waterpipe smoking and lung cancer risk. Methods A systematic review and meta-analysis was carried out to summarise the findings from the epidemiologic studies of the risk of lung cancer associated with ST use and waterpipe smoking. Search was carried out in MEDLINE, Embase, Web of Science and OpenSIGLE to identify studies published before 18th October 2018. A combination of MESH terms and keywords were used including lung cancer, smokeless tobacco, snuff, snus, betel quid, gutka, naswar, zarda, shisha. Only studies adjusted for cigarette smoking or conducted in non-smokers only were included in the analysis. Random effects meta-analysis was carried out to pool the risk estimates and subgroup analyses was carried out by tobacco type and in studies of non-smokers. Results The search yielded 1796 articles, of which 24 studies (19 studies of ST, four of waterpipes and one of both) including 6777 lung cancer patients were included in the meta-analysis. Lung cancer was found to be positively associated with waterpipe smoking (pooled OR 3·06 (95%CI 1·68 – 5·60) and betel quid tobacco chewing (pooled OR 1·77 (95%CI 1·06 – 2·95)). Among non-smokers, any type of ST use was associated with lung cancer (pooled OR 1·46 (95%CI 1·04 – 2·07). Conclusions Our study suggest positive associations between ST use and waterpipe smoking and lung cancer risk. Given the high prevalence of ST use in much of the developing world, public health policies and international tobacco control efforts should focus on aiming to reduce ST use in addition to cigarette smoking. Key messages The risk of lung cancer is approximately three times higher in waterpipe smokers than in non-smokers. International tobacco control efforts should focus on aiming to reduce smokeless tobacco use in addition to cigarette smoking.