Cigarette smoking and risk of celiac disease: A systematic review and meta-analysis

Background/Objectives A negative association between cigarette smoking and celiac disease has been observed but results were inconsistent across the published studies. A meta-analysis was conducted with the aim to identify all studies that investigated this association and to summarize the results of those studies. Methods A comprehensive literature review was conducted utilizing MEDLINE and Embase databases through March 2018 to identify all cohort studies and case-control studies that compared the risk of celiac disease among current and/or former smokers versus never-smokers. Effect estimates from each study were extracted and combined together using the random-effect, generic inverse variance method of DerSimonian and Laird. Results A total of seven studies with 307,924 participants fulfilled the eligibility criteria and were included in the meta-analysis. The pooled analysis found a significantly decreased risk of celiac disease among current smokers compared with never-smokers with the pooled odds ratio (OR) of 0.52 (95% confidence interval (CI), 0.32-0.84; I-2 86%). However, the risk of celiac disease among former smokers was not significantly different from never-smokers with the pooled OR of 1.10 (95% CI, 0.76-1.60; I-2 of 73%). Conclusions A significantly decreased risk of celiac disease among current smokers compared with never-smokers was demonstrated in this meta-analysis.