Table 5.
Hazard ratios (HR) and 95% confidence interval for asthma in relation to age at exposure to any antibiotics in childhood in children with siblings
| Age (years) | Crude | Adjusted* | Adjusted† | |||||
|---|---|---|---|---|---|---|---|---|
| No of cases‡ | HR (95% CI) | No of cases‡ | HR (95% CI) | No of cases‡ | HR (95% CI) | |||
| 0-0.5 | 1109 | 1.89 (1.49 to 2.41) | 993 | 2.11 (1.61 to 2.76) | 830 | 2.23 (1.71 to 2.91) | ||
| 0.5-1 | 1704 | 1.51 (1.34 to 1.71) | 1541 | 1.46 (1.28 to 1.67) | 1337 | 1.47 (1.29 to 1.68) | ||
| 1-1.5 | 955 | 1.77 (1.53 to 2.04) | 859 | 1.82 (1.55 to 2.13) | 768 | 1.80 (1.53 to 2.11) | ||
| 1.5-2 | 547 | 1.46 (1.18 to 1.80) | 498 | 1.50 (1.19 to 1.89) | 462 | 1.51 (1.20 to 1.91) | ||
| ≥2 | 600 | 1.32 (0.99 to 1.76) | 556 | 1.32 (0.97 to 1.79) | 507 | 1.31 (0.96 to 1.78) | ||
*Adjusted for sex, birth weight, gestational age, mode of delivery, respiratory diagnoses as newborn, maternal age at delivery, parity, family situation, maternal antibiotic exposure in fetal life, age as analysis time scale, and parity included as interaction term with age. Individuals with missing information on included variables excluded.
†Additionally adjusted for antibiotic exposure defined from hospital diagnoses.
‡All families discordant on asthma are included in analyses, but only those also discordant on exposure contribute to estimates in table, therefore number of cases is number of families with siblings discordant for both antibiotic exposure and asthma.