CHRNA3 and lung cancer: The overall comparison of CHRNA3 gene rs1051730-A allele yielded a remarkably increased risk for lung cancer (OR = 1.33; 95% CI: 1.24–1.44; P<0.0005) relative to the rs1051730-G allele; however, there was moderate evidence of between-study heterogeneity (I2 = 57.8%; P = 0.003).