Table II.
Effect of environmental and host factors on duration of wheezy episodes in young children
| No. of episodes | No. of children | IRR (95% CI 95), P value | |
|---|---|---|---|
| Sex | 515 | 216 | |
| Female | 288 | 115 | 0.97 (0.72-1.30), .85 |
| Male | 227 | 101 | Reference |
| Age | 515 | 216 | |
| 0-1 y | 227 | 136 | 1.22 (0.82-1.81), .33 |
| 1-2 y | 205 | 139 | 1.13 (0.75-1.70), .56 |
| 2-3 y | 83 | 62 | Reference |
| Father with a diagnosis of asthma | 485 | 205 | |
| Yes | 100 | 33 | 0.93 (0.70-1.25), .65 |
| No | 385 | 172 | Reference |
| Maternal educational level | 505 | 210 | |
| At most college | 333 | 137 | 1.01 (0.73-1.41), .94 |
| Medium duration | 127 | 50 | 0.99 (0.60-1.62), .963 |
| University | 45 | 23 | Reference |
| Environmental tobacco exposure (nicotine in hair at age 1 y >1 ng/mg vs <1 ng/mg) | 491 | 207 | |
| Yes | 206 | 90 | 1.16 (0.86-1.56), .34 |
| No | 285 | 117 | Reference |
| Sensitization at any point (6 mo, 18 mo, and 4 y) | 512 | 214 | |
| Yes | 183 | 52 | 0.82 (0.64-1.04), .10 |
| No | 329 | 162 | Reference |
| Asthma during age 0-3 y (yes vs no) | 478 | 198 | |
| Yes | 183 | 52 | 1.74 (1.32-2.30), <.001 |
| No | 295 | 146 | Reference |
| Chromosome 17q21 gene variant | 509 | 211 | |
| TT | 170 | 72 | 1.05 (0.67-1.66), .83 |
| TC | 227 | 88 | 0.87 (0.56-1.35), .54 |
| CC | 112 | 51 | Reference |
IRR, Incidence rate ratio.