Figure 1. Random effect (A) and fixed effect (B) pooled ORs for the recessive model.

Subgroup analyses in recessive model were also carried out (B). Studies were first divided by ethnicity, then Asian population studies were divided into two subgroups: ≤60 y old (lower median) and >60 y old (upper median). The fixed-effect model was used for the analysis in (B), because heterogeneity was reduced in subgroup analyses.