Table 3: Determination of the genetic effect of IL-13 +1923C/T on asthma and subgroup analyses.

ComparisonStudySample sizeNumber of studiesTest of associationModelHeterogeneity
CaseControlOR (95% CI) value value (%)

TT versus CCOverall875824034121.47 (1.25–1.73)4.60<0.00001R15.510.2629.0
TC versus CCOverall1273535447121.21 (1.10–1.33)4.03<0.0001R15.480.1629.0
TT versus TCOverall589716889121.14 (1.04–1.25)2.690.007R8.810.640.0
TT versus CCAsian8201085551.67 (1.20–2.34)3.020.003R7.290.1245.0
TT versus CCCaucasian76901297851.45 (1.11–1.88)2.750.006R5.970.2033.0
TT versus CCHigh quality857523839101.33 (1.21–1.47)5.69<0.00001R7.640.570.0
TC versus CCAsian13341694851.27 (1.05–1.55)2.460.01R6.150.1935.0
TC versus CCCaucasian111341830151.17 (1.05–1.30)2.890.004R5.440.2427.0
TC versus CCHigh quality1243635146101.15 (1.09–1.22)5.13<0.00001R9.280.413.0

R: random-effects model.