ARMS: amplification refractory mutation system; FEV₁: forced expiratory volume in 1st second; HWE: Hardy-Weinberg equilibriu; NA: relative data were not available; PCR: polymerase chain reaction; Q-genie tool: Quality of genetic association studies; RFLP: restriction fragment length polymorphism.

Table 2. Meta-analysis of association among Arg16Gly polymorphism and salbutamol responsiveness.