NOS3 and hypertensive disorder: The funnel plots for recessive model (TT vs GG + GT) seemed symmetrical, and the results of Egger’s tests showed that there was no publication bias (P = 0.102); however, the funnel plots were asymmetrical in other genetic models for the association between eNOS rs1799983 polymorphism with hypertension, and the results of Egger’s tests showed that there were publication bias (T vs G: P = 0.026; GT vs GG: P = 0.023; TT vs GG: P = 0.032; GT + TT vs GG: P = 0.011; GT vs GG + TT: P = 0.038) (Additional file 3: Figure S2).