Table 2

Childhood factors and risk of Crohn's disease

Unadjusted (Asia only)Adjusted* (Asia only)Adjusted* (Asia and Australia)
OR95% CIp ValueOR95% CIp ValueOR95% CIp Value
Breast feeding§
 0–6 months11.0001
 7–12 months0.6240.360 to 1.0810.0930.6450.363 to 1.1480.1360.5420.310 to 0.9490.032
 >12 months0.1100.039 to 0.3080†0.1030.036 to 0.2980†0.0860.030 to 0.2430†
Tonsillectomy0.4230.055 to 3.2450.4080.4370.056 to 3.4000.4291.4090.568 to 3.5000.460
Appendectomy1.0350.352 to 3.0430.9501.0210.341 to 3.0630.9700.6750.236 to 1.9360.465
Eczema1.5620.915 to 2.6650.1021.3710.786 to 2.3920.2661.6540.968 to 2.8270.066
Antibiotic use§
 ≤15 years0.1990.072 to 0.5510.0020.1850.066 to 0.5150.0010.2000.072 to 0.5580.002
 >15 years0.6160.334 to 1.1370.1210.6280.339 to 1.1620.1390.6120.331 to 1.1320.117
Pet animals
 Dog0.5000.328 to 0.7610.0010.5400.352 to 0.8270.0050.6430.440 to 0.9410.023
 Cat0.9490.602 to 1.4960.8211.1410.714 to 1.8240.5821.2470.819 to 1.8980.303
 Rodents0.8990.372 to 2.1710.8120.6640.269 to 1.6370.3730.7280.319 to 1.6620.452
 Birds0.6360.311 to 1.3010.2150.5950.289 to 1.2250.1590.6140.327 to 1.1530.130
 Aquarium fish0.6940.430 to 1.1200.1340.5440.330 to 0.8970.0170.6610.422 to 1.0370.071
Vaccinations§
 BCG1.3310.616 to 2.8760.4670.8460.375 to 1.9060.6862.1361.033 to 4.4180.041
 Pertussis1.2810.650 to 2.5210.4740.8220.401 to 1.6830.5920.7580.387 to 1.4880.421
 Measles1.7790.860 to 3.6810.1211.0210.468 to 2.2300.9581.4130.697 to 2.8660.338
 Rubella1.4070.786 to 2.5200.2500.9860.519 to 1.8750.9660.9720.528 to 1.7900.928
 Diphtheria1.4760.732 to 2.9770.2771.0450.498 to 2.1930.9071.1250.555 to 2.2810.744
 Tetanus1.3520.707 to 2.5840.3620.9070.456 to 1.8020.7800.9980.516 to 1.9290.996
 Polio0.8290.441 to 1.5570.5590.8150.414 to 1.6030.5521.0090.519 to 1.9630.979
Childhood infections§
 Measles0.8400.444 to 1.5910.5931.1270.582 to 2.1830.7221.5700.895 to 2.7550.116
 Pertussis1.5890.333 to 7.5790.5612.6540.537 to 13.1200.2312.4860.505 to 12.2480.263
 Rubella1.0330.226 to 4.7230.9671.1050.237 to 5.1550.8982.3100.780 to 6.8430.131
 Chickenpox0.9600.638 to 1.4450.8450.7950.512 to 1.2340.3070.8490.558 to 1.2900.443
 Mumps0.5980.326 to 1.1000.0980.7440.398 to 1.3880.3520.8350.471 to 1.4810.538
 Scarlet fever000.999000.9992.2750.230 to 22.5120.482
Sanitary conditions
 Inhouse water tap1.2080.803 to 1.8190.3640.7630.477 to 1.2220.2610.8470.533 to 1.3440.480
 Hot water tap1.4781.028 to 2.1250.0351.0000.654 to 1.5270.9990.9400.622 to 1.4200.769
 Flush toilet1.7191.149 to 2.5710.0081.2130.766 to 1.9220.4111.2890.823 to 2.0210.267
  • Statistically significant results are shown in bold (p<0.05).

  • *Adjusted for sex, age and country income based on GNI.

  • †Significant at p<0.0006 level after Bonferroni adjustment.

  • §>20% ‘unsure’ responses for one of more subject categories.

  • GNI, gross national income.