Association between tobacco smoking and drug-resistant tuberculosis

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 data-bases 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.