Results for the entire child population stratified by birth cohort, HRs show the adjusted association between the studied risk factors and coeliac disease risk for the period of 1991–2009
| Risk factor | 1991–1996 (n=666 178) | 1997–2002 (n=529 060) | 2003–2009 (n=716 966) | |||
|---|---|---|---|---|---|---|
| HR (95% CI) | p Value | HR (95% CI) | p Value | HR (95% CI) | p Value | |
| Season of birth | ||||||
| Winter | 1.00 | 1.00 | 1.00 | |||
| Spring | 1.12 (1.00 to 1.24) | 0.04 | 1.01 (0.90 to 1.23) | 0.47 | 1.05 (0.90 to 1.21) | 0.55 |
| Summer | 1.10 (0.98 to 1.22) | 0.09 | 1.14 (1.02 to 1.27) | 0.02 | 1.14 (0.97 to 1.33) | 0.11 |
| Autumn | 1.04 (0.93 to 1.17) | 0.49 | 1.24 (1.10 to 1.39) | <0.001 | 1.78 (1.64 to 1.92) | 0.003 |
| Geographical regions | ||||||
| North | 1.00 | 1.00 | 1.00 | |||
| Central | 1.19 (1.06 to 1.34) | 0.004 | 1.06 (0.94 to 1.19) | 0.36 | 1.28 (1.07 to 1.53) | 0.008 |
| South | 1.51 (1.35 to 1.68) | <0.001 | 1.50 (1.34 to 1.69) | <0.001 | 1.79 (1.51 to 2.14) | <0.001 |
| Sex | ||||||
| Boys | 1.00 | 1.00 | 1.00 | |||
| Girls | 1.73 (1.59 to 1.87) | <0.001 | 1.78 (1.64 to 1.92) | <0.001 | 2.11 (1.89 to 2.37) | <0.001 |
Season of birth is grouped as follows: winter (December, January, February), spring (March, April, May), summer (June, July, August) and autumn (September, October, November). Region of birth is grouped according to the administrative division of nomenclature of territorial units for statistics (NUTS 1) regions.