Testing the association between tobacco smoking, alcohol consumption, and risk of periodontitis: A Mendelian randomization study.

Aim To investigate the associations of tobacco smoking and alcohol consumption with periodontitis using Mendelian randomization (MR) analysis. Methods and materials We used 17 single nucleotide polymorphisms (SNPs) as instrumental variables for the number of cigarettes per day from a genome-wide association study (GWAS) of 337,334 individuals, 109 SNPs for a lifetime smoking index from GWAS of 462,690 participants, and 33 SNPs for the number of drinks per week from GWAS of 941,280 individuals. The periodontitis GWAS included 12,289 cases and 22,326 controls. Wald ratios were obtained by dividing the SNP-periodontitis effects by SNP-exposure effects and pooled using an inverse-variance weighted model. Results Genetic liabilities for higher number of cigarettes per day (odds ratio [OR] per one standard deviation (1-SD) increment = 1.56; 95 % CI: 1.18-2.07, P-value = 0.0018, Q-value = 0.0054), lifetime smoking index (OR per 1-SD = 1.26; 95 % CI: 1.04-1.53, P-value = 0.0161, Q-value = 0.0242) and drinks per week (OR per 1-SD = 1.41; 95 % CI: 1.04-1.90, P-value = 0.0265, Q-value = 0.0265) were associated with increased odds of periodontitis. Estimates were consistent across robust and multivariable MR analyses. Conclusions The findings of this MR analysis suggest an association between tobacco smoking and alcohol consumption with periodontitis. This article is protected by copyright. All rights reserved.