The causal relationship between alcohol consumption, smoking, coffee, tea intake and cutaneous melanoma: a two-sample Mendelian randomization study

Abstract Background Alcohol consumption and smoking have been associated with high risk, but coffee intake with a lower risk of cutaneous melanoma in observational studies. However, it is unclear whether these lifestyles are causally associated cutaneous melanoma. Objectives This study aimed to investigate causal relationship of alcohol consumption, smoking, coffee and tea intake with cutaneous melanoma using the two-sample Mendelian randomization design. Methods We obtained the exposure data (alcohol consumption, alcoholic drinks per week, alcohol dependence, smoking initiation, cigarettes per day, smoking cessation, coffee intake and tea intake) and outcome data (cutaneous melanoma) from the IEU Open GWAS and GWAS catalog project. The SNPs independently associated with lifestyles at genome-wide significance levels ( P < 5×10 − 6 ). Linkage disequilibrium score regression was used to compute the genetic correlation (r 2 < 0.001, clump distance > 10000kb). We then performed two-sample Mendelian randomization (MR) to validate whether these lifestyles are causally associated with cutaneous melanoma. Results We found that the alcohol consumption (OR = 0.715, 95% CI: 0.322–1.587), alcoholic drinks per week (OR = 0.878, 95% CI: 0.591–1.305) and alcohol dependence (OR = 1.012, 95% CI: 0.957–1.071) was not causally associated with cutaneous melanoma. The result showed no significant evidence to support an increased risk of cutaneous melanoma on smoking initiation (OR = 0.927, 95% CI: 0.753–1.142), cigarettes per day (OR = 0.970, 95% CI: 0.802–1.174) and smoking cessation (OR = 1.862, 95% CI: 0.685–5.059). Likewise, no significant associations were observed between genetically predicted coffee intake (OR = 0.978, 95% CI: 0.586–1.633) and tea intake (OR = 0.696, 95% CI: 0.462–1.048) with cutaneous melanoma. Conclusions According to our MR analysis, we found no evidence to support a causal association between alcohol consumption, smoking, coffee intake and tea intake with cutaneous melanoma.