Table 3 Multivariate logistic regression analysis of RIS in 190 NPC patients without sinusitis before RT.

Time (months post-RT for NPC)

0.008

3 months after RT

0.589

1.193

0.629 ~ 2.262

6 months after RT

0.035

2.229

1.057 ~ 4.701

9 months after RT

0.131

1.854

0.831 ~ 4.136

12 months after RT

0.006

3.773

1.470 ~ 9.687

18 months after RT

0.007

4.036

1.472 ~ 11.068

24 months after RT

0.023

3.250

1.180 ~ 8.955

TNM staging

0.040

II

0.506

1.591

0.405 ~ 6.253

III

0.379

1.794

0.488 ~ 6.590

IV

0.823

0.862

0.235 ~ 3.167

Smoking history

0.000

2.949

1.721 ~ 5.052

constant

0.177

2.483