Table 2.
Univariate and adjusted associations between early life risk factors and offspring adult respiratory disease (ARD)
| HRa (95% CI) | P | aHRb (95% CI) | P | aHRc (95% CI) | P | |
|---|---|---|---|---|---|---|
| Gestational age (weeks) | 1.0 (0.99–1.0) | 0.9 | 0.99 (0.95–1.0) | 0.6 | 0.99 (0.95–1.0) | 0.6 |
| Birth weight (100 g) | 1.0 (0.99–1.0) | 0.1 | 0.99 (0.98–1.0) | 0.4 | 1.0 (0.98–1.0) | 0.5 |
| Birth height (cm) | 1.0 (0.99–1.0) | 0.01 | 1.0 (1.0–1.0) | 0.2 | 1.0 (1.0–1.0) | 0.2 |
| Sex | ||||||
| Female | 1.6 (1.3–1.8) | < 0.001 | 1.5 (1.3–1.8) | < 0.001 | 1.5 (1.3–1.8) | < 0.001 |
| Male | Reference | Reference | Reference | |||
| Weight groups | ||||||
| Small for gestational age (SGA) | 1.2 (0.9–1.6) | 0.2 | 1.1 (0.9–1.4) | 0.3 | 1.1 (0.9–1.4) | 0.4 |
| Appropriate for gestational age (AGA) | Reference | Reference | Reference | |||
| Large for gestational age (LGA) | 1.1 (0.9–1.4) | 0.3 | 1.2 (0.9–1.5) | 0.2 | 1.2 (0.9–1.5) | 0.2 |
| Born during winter (1st Nov - 31st Jan) | 1.0 (0.9–1.2) | 0.8 | 1.0 (0.9–1.2) | 0.8 | 1.0 (0.9–1.2) | 0.8 |
| Prematurity (< 37 weeks) | 1.1 (0.8–1.5) | 0.4 | 1.2 (0.9–1.6) | 0.3 | 1.2 (0.9–1.6) | 0.3 |
| Maternal use of sedative drugs | ||||||
| No sedatives used during pregnancy | Reference | Reference | Reference | |||
| During 1st trimester | 0.8 (0.5–1.3) | 0.3 | 0.8 (0.5–1.3) | 0.3 | 0.8 (0.5–1.3) | 0.3 |
| During 2nd trimester | 2.2 (1.3–3.3) | 0.001 | 2.2 (1.4–3.4) | 0.001 | 2.2 (1.4–3.4) | < 0.001 |
| During 3rd trimester | 1.1 (0.9–1.3) | 0.2 | 1.1 (1.0–1.3) | 0.2 | 1.1 (0.9–1.3) | 0.3 |
| During all trimesters | 1.3 (0.9–1.9) | 0.1 | 1.4 (1.0–2.0) | 0.1 | 1.4 (1.0–2.0) | 0.08 |
| Maternal infections | ||||||
| No infections during pregnancy | Reference | Reference | Reference | |||
| Any infection during pregnancy | 0.9 (0.8–1.1) | 0.6 | 0.9 (0.8–1.1) | 0.5 | 0.9 (0.8–1.1) | 0.6 |
| Maternal smoking | ||||||
| No | Reference | Reference | Reference | |||
| Smoking during 1st trimester | 0.9 (0.6–1.3) | 0.5 | 0.8 (0.5–1.3) | 0.4 | 0.8 (0.5–1.3) | 0.4 |
| Smoking during most of pregnancy | 1.2 (1.0–1.4) | 0.02 | 1.2 (1.0–1.4) | 0.01 | 1.2 (1.0–1.4) | 0.02 |
| Mode of delivery | ||||||
| Vaginal | Reference | Reference | Reference | |||
| Sectio | 1.1 (0.7–1.9) | 0.7 | 1.3 (0.8–2.2) | 0.3 | 1.3 (0.8–2.2) | 0.3 |
| Vacum extraction | 1.1 (0.7–1.6) | 0.8 | 1.0 (0.7–1.6) | 0.9 | 1.0 (0.7–1.6) | 0.9 |
| Other | 1.0 (0.5–2.3) | 0.9 | 0.9 (0.4–2.2) | 0.9 | 0.9 (0.4–2.2) | 0.8 |
HR hazard ratio, 95% CI 95% confidence interval, aHR adjusted hazard ratio
aUnivariate logistic regression
bModel 1 (stepwise forward regression): adjusted HR for: sex, maternal sedative use, and maternal smoking
cModel 2 (common cause approach): adjusted HR for sex, maternal sedative use, maternal smoking, maternal age, and nulliparity
P < 0.05 was considered significant