Comparison of incidence densities of AC and HR between patients with and without type 1 diabetes mellitus by demographic characteristics and comorbidity
| Controls | Patients with type 1 diabetes mellitus | IRR (95% CI) | Adjusted IRR‡ (95% CI) | |||||
| Event | Person-years | Rate† | Event | Person-years | Rate† | |||
| All | 1470 | 109 298 | 13.5 | 601 | 26 122 | 23.0 | 1.71 (1.58 to 1.85)*** | 1.59 (1.47 to 1.71)*** |
| Sex | ||||||||
| Male | 909 | 57 662 | 15.8 | 394 | 13 375 | 29.5 | 1.87 (1.69 to 2.07)*** | 1.76 (1.59 to 1.94)*** |
| Female | 561 | 51 637 | 10.9 | 207 | 12 747 | 16.2 | 1.49 (1.32 to 1.69)*** | 1.32 (1.17 to 1.49)*** |
| Stratification by age | ||||||||
| <18 | 1001 | 54 591 | 18.3 | 413 | 15 915 | 26.0 | 1.41 (1.27 to 1.58)*** | 1.44 (1.30 to 1.60)*** |
| ≥18 | 469 | 54 707 | 8.57 | 188 | 10 207 | 18.4 | 2.15 (1.91 to 2.41)*** | 2.16 (1.92 to 2.42)*** |
| Urbanisation‡ | ||||||||
| 1 (Very high) | 473 | 30 591 | 15.5 | 191 | 7386 | 25.9 | 1.67 (1.45 to 1.94)*** | 1.56 (1.35 to 1.80)*** |
| 2 (High) | 446 | 32 252 | 13.8 | 204 | 8304 | 24.6 | 1.78 (1.54 to 2.04)*** | 1.62 (1.41 to 1.86)*** |
| 3 (Moderate) | 271 | 22 061 | 12.3 | 103 | 4633 | 22.2 | 1.81 (1.52 to 2.16)*** | 1.66 (1.39* to 1.97)*** |
| 4 (Low) | 280 | 24 395 | 11.5 | 103 | 5799 | 17.8 | 1.55 (1.30 to 1.84)*** | 1.51 (1.28 to 1.80)*** |
| Parental occupation | ||||||||
| White collar | 911 | 64 428 | 14.1 | 345 | 14 054 | 24.6 | 1.74 (1.56 to 1.93)*** | 1.52 (1.37 to 1.69)*** |
| Blue collar | 406 | 30 827 | 13.2 | 169 | 8701 | 19.4 | 1.47 (1.28 to 1.70)*** | 1.48 (1.28 to 1.70)*** |
| Others | 153 | 14 044 | 10.9 | 87 | 3367 | 25.8 | 2.37 (1.92 to 2.92)*** | 2.22 (1.80 to 2.73)*** |
| Comorbidity§ | ||||||||
| No | 871 | 71 020 | 12.3 | 377 | 17 209 | 21.9 | 1.79 (1.62 to 1.97)*** | 1.68 (1.52 to 1.85)*** |
| Yes | 599 | 38 279 | 15.7 | 224 | 8912 | 25.1 | 1.61 (1.41 to 1.83)*** | 1.43 (1.26 to 1.63)*** |
| Follow-up time | ||||||||
| 1 year | 258 | 15 881 | 16.3 | 157 | 3942 | 39.8 | 2.45 (2.25 to 2.68)*** | 1.54 (1.42 to 1.68)*** |
| >1 year | 1212 | 93 417 | 13.0 | 444 | 22 180 | 20.0 | 2.15 (1.97 to 2.34)*** | 1.44 (1.33 to 1.57)*** |
*p<0.05, ***p<0.001.
†Rate, incidence rate, per 1000 person-years.
‡Adjusted IRR: multivariable analysis including sex, age, urbanisation level, parental occupation, and comorbidities of rhinitis and urticaria.
§Comorbidity: patients with any one of the comorbidities (rhinitis or urticaria) were classified under the comorbidity group.
AC, allergic conjunctivitis; IRR, incidence rate ratio.