The contextual details of subgroup analysis included in this meta-analysis.

Abstract

<p>HWE: Hardy-Weinberg Equilibrium; WBC: White blood cells; BALF: bronchoalveolar lavage fluid; NA: not available.</p><p>*: The HWE test results of <i>CYP1A1</i> Msp1 that could be calculated were shown in the table, and the items with * meant the result that had been reported in the articles.</p><p>: Due to different setting of smoking status in papers, people who had smoked were calculated as smokers.</p><p>OR^a: Adjusted OR. ED: Epidemiological Design; NED: Non-epidemiology Design; WBC: blood, White blood cell lymphocytes, and serum. ^ζ: Newcastle-Ottawa Scale (NOS).</p><p>: The OR 95% CI was captured from logistic analysis; I: Heavy-smoker; a: healthy control; b: hospital control.</p><p>: The <i>GSTM1</i> data of this study was omitted because of a bigger sample in the other study published in the same year.</p