Table 2 Interactive effect of age and PIR on infertility (All participants)

Model l

PIR

0.9 (0.8 ~ 1)

0.055

1.18 (1.09 ~ 1.28)

< 0.001

< 0.001

PIR<2

1(Ref)

1(Ref)

PIR ≥ 2

0.79 (0.56 ~ 1.12)

0.185

1.63 (1.23 ~ 2.14)

0.001

0.001

Model 2

PIR

0.94 (0.82 ~ 1.06)

0.313

1.13 (1.03 ~ 1.25)

0.014

< 0.001

PIR<2

1(Ref)

1(Ref)

PIR ≥ 2

0.95 (0.64 ~ 1.41)

0.799

1.38 (1 ~ 1.9)

0.047

0.004

Model 3

PIR

0.99 (0.87 ~ 1.13)

0.9

1.17 (1.06 ~ 1.29)

0.003

< 0.001

PIR<2

1(Ref)

1(Ref)

PIR ≥ 2

1.09 (0.73 ~ 1.63)

0.685

1.49 (1.07 ~ 2.06)

0.017

0.004

Model 4

PIR

0.99(0.86 ~ 1.13)

0.834

1.22 (1.1 ~ 1.36)

< 0.001

< 0.001

PIR<2

1(Ref)

1(Ref)

PIR ≥ 2

1.09 (0.71 ~ 1.65)

0.702

1.67 (1.19 ~ 2.35)

0.003

0.002

Model 5

PIR

0.99(0.86 ~ 1.13)

0.839

1.24 (1.12 ~ 1.39)

< 0.001

< 0.001

PIR<2

1(Ref)

1(Ref)

PIR ≥ 2

1.08 (0.71 ~ 1.64)

0.728

1.75 (1.24 ~ 2.47)

0.001

0.002