Table 2.
Incidence rates of first hospitalization for bronchiolitis in the first 18 months of age in premature infants, stratified for several characteristics, Rome, Italy, 2000-2006
| N |
Person Years (PY) |
Cases |
Rate (per 100 PY) |
95% CI | ||
| Age of the mother (years) | ≤ 32 | 1119 | 1359.4 | 68 | 5.00 | 3.94 -6.34 |
| >32 | 1288 | 1553.1 | 69 | 4.44 | 3.51 -5.63 | |
| Parity | 0 | 1457 | 1773.2 | 77 | 4.34 | 3.47 -5.43 |
| 1 | 679 | 807.77 | 45 | 5.57 | 4.16 -7.46 | |
| ≥ 2 | 271 | 331.55 | 15 | 4.52 | 2.73 -7.50 | |
| Years of education | ≤ 8 | 1085 | 1312.5 | 80 | 6.10 | 4.90 -7.59 |
| >8 | 1318 | 1597 | 56 | 3.51 | 2.70 -4.56 | |
| Unknown | 4 | 3 | 1 | 33.33 | 4.70 -236.64 | |
| Birth-country of the mother | Italy | 2049 | 2505 | 119 | 4.75 | 3.97 -5.68 |
| Other | 358 | 407 | 18 | 4.42 | 2.79 -7.02 | |
| Gender | Males | 1282 | 1535.2 | 85 | 5.54 | 4.48 -6.85 |
| Females | 1125 | 1377.3 | 52 | 3.78 | 2.88 -4.95 | |
| Birth weight (grams) | <1000 | 152 | 161.96 | 15 | 9.26 | 5.58 -15.36 |
| 1000-2000 | 786 | 911.71 | 60 | 6.58 | 5.11 -8.48 | |
| >2000 | 1469 | 1838.8 | 62 | 3.37 | 2.63 -4.32 | |
| Gestational age | <32 | 516 | 585.24 | 34 | 5.81 | 4.15 -8.13 |
| 32-35 | 1891 | 2327.3 | 103 | 4.43 | 3.65 -5.37 | |
| Apgar score | ≤ 7 | 395 | 456 | 36 | 6.57 | 4.74 -9.11 |
| >7 | 2012 | 2456 | 101 | 3.43 | 2.82 -4.17 | |
| Broncho dysplasia | No | 2346 | 2850 | 131 | 4.60 | 3.87 -5.46 |
| Yes | 61 | 63 | 6 | 9.54 | 4.29 -21.24 | |
| Congenital heart disease | No | 2373 | 2873 | 134 | 4.66 | 3.94 -5.52 |
| Yes | 34 | 40 | 3 | 7.58 | 2.44 -23.50 |