Macronutrients and Lung carcinoma: a Bidirectional Mendelian Randomization Study

Abstract Background The relationships of lung cancer with macronutrients are in an increasing number of research nowadays. However, the causal effects between them are still unclear. Methods The macronutrients summary statistics from the greatest genome-wide meta-analysis produced by DietGen and other cohorts, and the largest genome-wide association studies (GWAS) meta-summary analysis in lung cancer were used in this two-sample bidirectional mendelian randomization (MR) investigation. The causal relationships between macronutrients and lung cancer were investigated by using inverse variance weighting (IVW), MR-Egger regression, weighted median, weighted model, and simple mode methods. Results IVW estimates suggested that fat and protein had casual associations with lung cancer. As for lung cancer, the IVW estimate of the fat [OR:0.44, 95% CI: 0.38–0.51, P IVW =1.50×10 − 24 ]; As for lung adenocarcinoma, the IVW estimate of the fat [OR:0.25, 95% CI: 0.12–0.53, P IVW =2.40×10 − 4 ], protein [OR: 0.40, 95% CI: 0.22–0.73, P IVW =3.10×10 − 3 ]; As for lung cancer in never smokers, the IVW estimate of the fat [OR: 0.34, 95% CI: 0.13–0.86, P IVW =2.30×10 − 2 ], protein [OR: 0.09, 95% CI: 0.03–0.32, P IVW =1.90×10 − 4 ]; As for lung cancer in ever smokers, the IVW estimate of the fat [OR: 0.53, 95% CI: 0.29–0.96, P IVW =3.60×10 − 2 ]. Conclusions This MR investigation discovered that fat and protein were served as protective factors and causally linked to lung cancer. To fully understand how fat and protein affect lung cancer, more research is required.