Table 1.
Proportional hazards models of HIN1 vaccination (yes vs no) on risk of islet autoantibodies, multiple islet autoantibodies and type 1 diabetes before age 10 years adjusting for factors in table and also stratified by the factor subgroups
| Factor and group | Total (N a) | H1N1 vaccination in relation to risk of islet autoantibodies | H1N1 vaccination in relation to risk of multiple islet autoantibodies | H1N1 vaccination in relation to risk of type 1 diabetes | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Events (n) | HR (95% CI) | p valueb | Events (n) | HR (95% CI) | p valueb | Events (n) | HR (95% CI) | p valueb | ||
| All children | 3401 | 232 | 0.76 (0.57, 1.02) | 148 | 0.92 (0.63, 1.35) | 96 | 0.68 (0.43, 1.06) | |||
| Country | ||||||||||
| Finland | 1438 | 97 | 0.50 (0.32, 0.78) | 67 | 0.56 (0.33, 0.96) | 49 | 0.41 (0.23, 0.76) | |||
| Sweden | 1963 | 135 | 1.01 (0.68, 1.50) | 0.008 | 81 | 1.41 (0.82, 2.46) | 0.01 | 47 | 1.10 (0.53, 2.24) | 0.02 |
| Sex | ||||||||||
| Female | 1659 | 103 | 0.91 (0.58, 1.43) | 63 | 0.80 (0.45, 1.43) | 46 | 0.60 (0.31, 1.16) | |||
| Male | 1742 | 129 | 0.67 (0.46, 0.99) | 0.46 | 85 | 1.03 (0.62, 1.72) | 0.43 | 50 | 0.77 (0.41, 1.45) | 0.35 |
| Family history | ||||||||||
| General population | 3123 | 199 | 0.69 (0.50, 0.94) | 122 | 0.83 (0.55, 1.26) | 78 | 0.64 (0.39, 1.06) | |||
| First-degree relative | 278 | 33 | 1.30 (0.54, 3.13) | 0.12 | 26 | 1.66 (0.59, 4.68) | 0.15 | 18 | 0.71 (0.24, 2.07) | 0.65 |
| HLA-DR | ||||||||||
| DR-4/4 | 665 | 41 | 0.85 (0.41, 1.78) | 27 | 1.40 (0.52, 3.74) | 20 | 0.55 (0.20, 1.49) | |||
| DR-4/8 | 695 | 47 | 0.61 (0.32, 1.17) | 25 | 0.62 (0.25, 1.56) | 13 | 0.13 (0.04, 0.49) | |||
| DR-3/4 | 1298 | 111 | 0.72 (0.47, 1.10) | 80 | 0.76 (0.46, 1.26) | 53 | 0.74 (0.40, 1.38) | |||
| DR-3/3 | 649 | 28 | 0.77 (0.32, 1.87) | 0.68 | 12 | 1.73 (0.41, 7.30) | 0.32 | 7 | 7.74 (0.80, 74.7) | 0.14 |
| Age on 1 March 2010 | ||||||||||
| < 1 year | 752 | 71 | 0.76 (0.46, 1.25) | 44 | 0.75 (0.40, 1.39) | 26 | 0.26 (0.10, 0.70) | |||
| 1 year | 646 | 50 | 1.13 (0.55, 2.33) | 33 | 1.52 (0.58, 4.01) | 16 | 2.00 (0.45, 8.97) | |||
| 2 year | 649 | 43 | 0.75 (0.36, 1.58) | 25 | 0.53 (0.20, 1.39) | 23 | 0.70 (0.26, 1.91) | |||
| 3 year | 587 | 34 | 0.76 (0.34, 1.70) | 23 | 1.07 (0.36, 3.17) | 17 | 0.61 (0.21, 1.83) | |||
| ≥ 4 years | 722 | 34 | 0.57 (0.26, 1.24) | 0.73 | 23 | 2.48 (0.57, 10.9) | 0.07 | 14 | 1.24 (0.27, 5.71) | 0.19 |
aTotal number of children on 1 October 2009 who were observed at risk of type 1 diabetes; 145 were no longer observed at risk of islet autoimmunity, and 72 no longer at risk of multiple islet autoantibodies
b p value test of multiplicative interaction between subgroups; all HRs are adjusted for factors in table