The causal association between smoking, alcohol consumption and risk of bladder cancer: A univariable and multivariable Mendelian randomization study
Menée à l'aide d'une méthode de randomisation mendélienne et de données issues de "FinnGen" et de la "UK Biobank" portant sur 591 961 témoins et 3 998 patients atteints d'un cancer de la vessie, cette étude analyse l'association entre tabagisme, la consommation d'alcool et le risque de développer la maladie
Smoking and alcohol consumption are associated with bladder cancer risk in observational studies. We conducted a two-sample univariable and multivariable Mendelian randomization (MR) analysis to determine whether those associations are causal. We used 21, 126, 360, 39 single nucleotide polymorphisms (SNPs) as instrumental variables for number of cigarettes per day, lifetime smoking index, smoking initiation, and drinks per week, respectively. A total of 1,115 cases with bladder cancer and 174,006 non-cases from FinnGen consortium and 2,883 cases with bladder cancer and 417,955 non-cases from UK Biobank study were obtained. Genetic predisposition to cigarettes per day, lifetime smoking index and smoking initiation were positively associated with an increased risk of bladder cancer in both the FinnGen and UK Biobank consortium. The summary odds ratio (OR) of bladder cancer was 1.79 (95% confidence interval [CI], 1.31-2.45; P= 0.0002), 2.38 (95% CI, 1.45-3.88; P = 0.0005) and 1.91 (95% CI, 1.46-2.50; P = 1.59×10-06) for one standard deviation increase in the number of cigarettes per day, lifetime smoking index and smoking initiation, respectively. The genetically instrumented number of drinks per week was not associated with bladder cancer (OR = 0.69; 95% CI, 0.44-1.10; P = 0.1237). Estimates were consistent in multivariable MR analyses by the adjustments of body mass index and education. Our study suggests a causal potential of the association of smoking but not alcohol consumption with bladder cancer according to current evidence.