CHRNA5 and chronic obstructive pulmonary disease: In this extensively updated meta-analysis, eight SNPs were proven to be significantly related to LC and COPD risk; of these, six variants were graded to show strong cumulative evidence for LC or COPD predisposition (CHRNA3 rs1051730, CHRNA3 rs6495309, and CHRNA5 rs16969968 with COPD risk and CHRNA3 rs1051730, CHRNA3 rs578776, CHRNA3 rs6495309, CHRNA3 rs938682, CHRNA5 rs16969968, and CHRNA5 rs588765 with LC risk), and five SNPs were graded to show moderate cumulative evidence for LC or COPD risk.