Meta-analysis results of obstructive and restrictive phenotypes in Model 2# in different age groups
| Variables | Age groups | Number of cohorts | I2 | p-value for Q statistic | OR (95% CI) |
| Obstructive phenotype | |||||
| Preterm birth | <10 | 8 | 53.1 | 0.037 | 2.04 (1.24–3.34) 2.83 (1.73–4.46) 1.53 (1.06–2.22) 1.49 (0.94–2.36) 1.83 (1.31–2.57) |
| >10–15 | 6 | 21.0 | 0.28 | ||
| >15–20 | 8 | 7.1 | 0.38 | ||
| >20–25 | 4 | 0.0 | 0.47 | ||
| 5–25 | 10 | 40.1 | 0.06 | ||
| Maternal smoking during pregnancy | <10 | 9 | 0.0 | 0.70 | 1.06 (0.89–1.28) 1.28 (0.95–1.73) 1.48 (1.20–1.82) 1.23 (0.86–1.75) 1.13 (0.97–1.33) |
| >10–15 | 6 | 0.0 | 0.97 | ||
| >15–20 | 10 | 17.0 | 0.29 | ||
| >20–25 | 3 | 0.0 | 0.79 | ||
| 5–25 | 11 | 0.0 | 0.58 | ||
| Asthma family history | <10 | 9 | 21.9 | 0.25 | 1.09 (0.90–1.32) 1.17 (0.82–1.67) 1.28 (1.07–1.52) 1.33 (0.74–2.40) 1.21 (1.04–1.41) |
| >10–15 | 6 | 0.0 | 0.63 | ||
| >15–20 | 11 | 0.0 | 0.84 | ||
| >20–25 | 3 | 69.6 | 0.037 | ||
| 5–25 | 12 | 0.0 | 0.67 | ||
| BMI | <10 | 9 | 53.7 | 0.027 | 1.05 (1.00–1.11) 1.06 (1.04–1.09) 1.04 (1.03–1.06) 1.04 (1.01–1.07) 1.04 (1.03–1.06) |
| >10–15 | 8 | 0.0 | 0.50 | ||
| >15–20 | 12 | 16.5 | 0.28 | ||
| >20–25 | 4 | 0.0 | 0.88 | ||
| 5–25 | 13 | 34.4 | 0.071 | ||
| Former smoker | >10–15 | 2 | 0.0 | 0.72 | 0.67 (0.45–1.01) 0.83 (0.70–0.97) 1.55 (1.14–2.11) 0.96 (0.76–1.22) 0.89 (0.37–2.15) |
| >15–20 | 10 | 20.8 | 0.25 | ||
| >20–25 | 4 | 0.0 | 0.59 | ||
| 10–25 | 11 | 47.0 | 0.023 | ||
| Current smoker | >10–15 | 2 | 54.1 | 0.14 | |
| >15–20 | 11 | 45.1 | 0.052 | 1.18 (0.90–1.54) 1.28 (0.92–1.79) 1.18 (0.93–1.49) | |
| >20–25 | 4 | 0.0 | 0.67 | ||
| 10–25 | 11 | 37.6 | 0.07 | ||
| Restrictive phenotype | |||||
| Preterm birth | <10 | 8 | 0.0 | 0.70 | 1.08 (0.68–1.73) 1.80 (0.88–3.71) 1.17 (0.72–1.92) 0.76 (0.30–1.92) 1.13 (0.77–1.68) |
| >10–15 | 5 | 0.0 | 0.85 | ||
| >15–20 | 6 | 0.0 | 0.83 | ||
| >20–25 | 3 | 0.0 | 0.95 | ||
| 5–25 | 9 | 0.0 | 0.97 | ||
| Maternal smoking during pregnancy | <10 | 9 | 0.0 | 0.71 | 0.95 (0.75–1.22 1.19 (0.78–1.79) 0.98 (0.59–1.62 1.01 (0.61–1.69) 1.06 (0.86–1.32) |
| >10–15 | 6 | 0.0 | 0.98 | ||
| >15–20 | 9 | 43.8 | 0.076 | ||
| >20–25 | 4 | 0.0 | 0.99 | ||
| 5–25 | 11 | 0.0 | 0.59 | ||
| Asthma family history | <10 | 9 | 3.8 | 0.40 | 0.99 (0.77–1.27) 0.89 (0.54–1.46) 0.88 (0.69–1.12) 0.99 (0.63–1.56) 1.02 (0.83–1.25) |
| >10–15 | 5 | 0.0 | 0.88 | ||
| >15–20 | 10 | 25.9 | 0.21 | ||
| >20–25 | 4 | 0.0 | 0.61 | ||
| 5–25 | 12 | 0.0 | 0.84 | ||
| BMI | <10 | 9 | 75.0 | <0.001 | 0.86 (0.77–0.95) 0.79 (0.74–0.84) 0.80 (0.75–0.85) 0.84 (0.70–1.01) 0.81 (0.77–0.85) |
| >10–15 | 8 | 50.8 | 0.039 | ||
| >15–20 | 12 | 75.9 | <0.001 | ||
| >20–25 | 4 | 92.2 | <0.001 | ||
| 5–25 | 13 | 76.9 | <0.001 | ||
| Former smoker | >10–15 | 2 | 0.0 | 0.35 | 0.64 (0.40–1.04) 0.96 (0.77–1.20) 0.69 (0.43–1.08) 0.91 (0.75–1.11) |
| >15–20 | 9 | 40.3 | 0.12 | ||
| >20–25 | 4 | 46.7 | 0.13 | ||
| 10–25 | 11 | 35.2 | 0.11 | ||
| Current smoker | >10–15 | 2 | 62.8 | 0.10 | 0.89 (0.26–3.07) 0.74 (0.49–1.13) 0.73 (0.47–1.15) 0.87 (0.68–1.13) |
| >15–20 | 11 | 41.8 | 0.07 | ||
| >20–25 | 4 | 0.0 | 0.56 | ||
| 10–25 | 11 | 19.2 | 0.24 | ||
#: Model 2 was adjusted for asthma family history, maternal smoking during pregnancy, preterm birth, body mass index (BMI) and smoking status, as well as for current asthma.