Analysis of age at first exposure to an influenza season in a study of leukemia risk among California children diagnosed between 1997 and 2007
| All cases and controls | First births | Second or subsequent births | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Controls (n = 31,460) | Cases (n = 1,573) | ORa (95% CI) | Controls (n = 12,226) | Cases (n = 585) | ORa (95% CI) | Controls (n = 19,222) | Cases (n = 988) | ORa (95% CI) | |
| All ALL cases combined | |||||||||
| Age at first exposure to influenza season, mo | |||||||||
| 0–3 | 9,792 | 455 | Ref | 3,814 | 163 | Ref | 5,973 | 292 | Ref |
| 3–6 | 8,018 | 416 | 1.12 (0.97–1.28) | 3,151 | 153 | 1.14 (0.91–1.42) | 4,864 | 263 | 1.11 (0.93–1.31) |
| 6–9 | 7,543 | 380 | 1.08 (0.94–1.25) | 2,896 | 130 | 1.05 (0.83–1.33) | 4,645 | 250 | 1.10 (0.93–1.31) |
| 9–12 | 5,444 | 294 | 1.16 (1.00–1.35) | 2,087 | 128 | 1.44 (1.13–1.82) | 3,355 | 166 | 1.01 (0.83–1.23) |
| >12 | 663 | 28 | 0.91 (0.62–1.34) | 278 | 11 | 0.93 (0.50–1.73) | 385 | 17 | 0.90 (0.55–1.49) |
↵aORs adjusted for birth year.