Table 2.
RR for asthma hospitalization in childhood according to birth weight, gestational age, and fetal growth
| Fetal development variables | Cases | Cumulative incidence (%) | Crude RR | Adjusted RR* (95% CI) |
|---|---|---|---|---|
| Birth weight |
|
|
|
|
| <1000 g |
542 |
8.35 |
3.03 |
2.33 (2.14-2.53) |
| 1000-1499 g |
897 |
5.93 |
2.21 |
1.81 (1.68-1.95) |
| 1500-1999 g |
1,423 |
4.51 |
1.69 |
1.48 (1.40-1.57) |
| 2000-2499 g |
3,823 |
3.67 |
1.38 |
1.33 (1.28-1.38) |
| 2500-2999 g |
14,992 |
2.98 |
1.12 |
1.15 (1.12-1.17) |
| 3000-3499 g |
41,716 |
2.73 |
1.02 |
1.05 (1.04-1.07) |
| 3500-3999 g |
44,451 |
2.67 |
1 |
1 (ref) |
| 4000-4499 g |
19,371 |
2.73 |
1.02 |
0.99 (0.97-1.01) |
| 4500-4999 g |
4,037 |
2.89 |
1.08 |
1.03 (0.99-1.06) |
| ≥5000 g |
531 |
2.87 |
1.08 |
1.01 (0.92-1.11) |
| Birth weight per 1000-g decrease |
- |
- |
1.18 |
1.17 (1.15-1.18) |
| Gestational age |
|
|
|
|
| 22-28 weeks |
737 |
8.07 |
2.89 |
2.26 (2.10-2.43) |
| 29-32 weeks |
1,416 |
5.16 |
1.88 |
1.63 (1.54-1.73) |
| 33-36 weeks |
6,471 |
3.50 |
1.28 |
1.26 (1.22-1.29) |
| 37-38 weeks |
23,062 |
2.98 |
1.09 |
1.10 (1.09-1.12) |
| 39-41 weeks |
91,055 |
2.73 |
1 |
1 (ref) |
| 42-45 weeks |
9,042 |
2.37 |
0.86 |
0.98 (0.95-1.00) |
| GA per reduced week |
- |
- |
1.07 |
1.05 (1.04-1.06) |
| Fetal growth |
|
|
|
|
| SGA |
4,878 |
3.38 |
1.23 |
1.20 (1.16-1.24) |
| AGA |
121,741 |
2.76 |
1 |
1 (ref) |
| LGA |
5,164 |
3.18 |
1.15 |
1.05 (1.02-1.09) |
| Z-score per decreased of SD | - | - | 1.00 | 1.03 (1.02-1.04) |
*Adjusted for country of residence, maternal age at delivery, maternal social status, parity, mode of delivery, sex of the child, calendar year of birth and family history of asthma.