Association between tobacco smoking and drug-resistant tuberculosis Ming-Gui Wang,1,* Wei-Wei Huang,1,* Yu Wang,1 Yun-Xia Zhang,1 Miao-Miao Zhang,1 Shou-Quan Wu,1 Andrew J Sandford,2 Jian-Qing He1 1Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan Province, People’s Republic of China; 2Centre for Heart Lung Innovation, University of British Columbia and St. Paul’s Hospital, Vancouver, BC, Canada *These authors contributed equally to this work Background: Tobacco smoking is a risk factor for tuberculosis but little is known about the relationship between tobacco smoking and drug-resistant tuberculosis (DR-TB). We undertook a systematic review and meta-analysis to quantitatively assess the association between DR-TB and tobacco smoking.Methods: We searched for relevant studies in the Ovid MEDLINE, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, WANFANG, and WEIPU databases from inception to September 1, 2017. Results were expressed as odds ratios (ORs) with accompanying 95% CIs, and subgroup analyses were performed by study design, smoking type, DR-TB type, and multivariate analysis.Results: Thirty-three studies related to tobacco smoking and DR-TB were included. We found substantial evidence that tobacco smoking is associated with an increased risk of DR-TB (OR 1.57, 95% CI 1.33–1.86). Associations were also found in subgroup analyses: for multidrug-resistant tuberculosis (OR 1.49, 95% CI 1.19–1.86) and for any DR-TB (OR 1.70, 95% CI 1.3–2.23); the pooled OR was 1.45 (95% CI 1.11–1.90) for current smoking, 2.25 (95% CI 1.46–3.47) for past smoking, and 1.56 (95% CI 1.22–1.98) for smoking history; and similar ORs were also observed in study design and multivariate analysis subgroup analysis.Conclusion: This study demonstrated that tobacco smoking is an independent risk factor for DR-TB. Keywords: tobacco smoking, drug-resistant tuberculosis, multidrug-resistant tuberculosis, MDR-TB, meta-analysis