Meta-analysis results of obstructive and restrictive phenotypes in Model 1# in different age groups
| Variables | Age groups | Number of cohorts | I2 | p-value for Q statistic | OR (95% CI) |
| Obstructive phenotype | |||||
| Preterm birth | <10 | 9 | 60.8 | 0.0089 | 1.82 (1.08–3.06) 2.73 (1.67–4.46) 1.61 (1.13–2.29) 1.37 (0.88–2.12) 1.84 (1.27–2.66) |
| >10–15 | 5 | 17.6 | 0.30 | ||
| >15–20 | 8 | 6.7 | 0.38 | ||
| >20–25 | 4 | 0.0 | 0.63 | ||
| 5–25 | 10 | 51.6 | 0.016 | ||
| Maternal smoking during pregnancy | <10 | 9 | 0.0 | 0.61 | 1.11 (0.94–1.30) 1.20 (0.90–1.59) 1.43 (1.14–1.78) 1.43 (1.07–1.93) 1.16 (1.01–1.35) |
| >10–15 | 6 | 0.0 | 0.98 | ||
| >15–20 | 10 | 9.1 | 0.36 | ||
| >20–25 | 3 | 0.0 | 0.41 | ||
| 5–25 | 11 | 0.0 | 0.53 | ||
| Asthma family history | <10 | 9 | 26.9 | 0.20 | 1.34 (1.14–1.58) 1.39 (1.01–1.93) 1.46 (1.24–1.72) 1.59 (1.22–2.07) 1.44 (1.25–1.66) |
| >10–15 | 6 | 0.0 | 0.55 | ||
| >15–20 | 11 | 0.0 | 0.52 | ||
| >20–25 | 3 | 29.6 | 0.24 | ||
| 5–25 | 12 | 0.0 | 0.83 | ||
| BMI | <10 | 9 | 40.6 | 0.097 | 1.06 (1.02–1.10) |
| >10–15 | 8 | 55.3 | 0.022 | 1.04 (1.00–1.09) 1.05 (1.04–1.07) 1.03 (1.01–1.05) 1.05 (1.03–1.06) | |
| >15–20 | 12 | 17.7 | 0.27 | ||
| >20–25 | 4 | 0.0 | 0.47 | ||
| 5–25 | 13 | 44.7 | 0.019 | ||
| Former smoker | >10–15 | 2 | 0.0 | 0.61 | 0.67 (0.45–1.01) 0.83 (0.71–0.98) 1.37 (1.04–1.82) 0.93 (0.75–1.16) |
| >15–20 | 10 | 28.9 | 0.18 | ||
| >20–25 | 4 | 0.0 | 0.63 | ||
| 10–25 | 11 | 41.3 | 0.048 | ||
| Current smoker | >10–15 | 2 | 51.0 | 0.15 | 0.88 (0.38–2.05) 1.21 (1.01–1.44) 1.34 (1.01–1.78) 1.24 (1.05–1.46) |
| >15–20 | 11 | 35.5 | 0.11 | ||
| >20–25 | 4 | 0.0 | 0.70 | ||
| 10–25 | 11 | 29.8 | 0.13 | ||
| Restrictive phenotype | |||||
| Preterm birth | <10 | 8 | 0.0 | 0.79 | 1.17 (0.78–1.75) 1.46 (0.72–2.97) 1.16 (0.72–1.87) 0.88 (0.41–1.92) 1.20 (0.84–1.70) |
| >10–15 | 5 | 0.0 | 0.92 | ||
| >15–20 | 6 | 0.0 | 0.79 | ||
| >20–25 | 3 | 0.0 | 0.87 | ||
| 5–25 | 9 | 0.0 | 0.98 | ||
| Maternal smoking during pregnancy | <10 | 9 | 0.0 | 0.92 | 0.91 (0.73–1.14) 1.16 (0.79–1.70) 0.98 (0.61–1.58) 0.84 (0.52–1.36) 1.00 (0.82–1.22) |
| >10–15 | 6 | 0.0 | 0.95 | ||
| >15–20 | 9 | 40.9 | 0.095 | ||
| >20–25 | 4 | 0.0 | 0.73 | ||
| 5–25 | 11 | 0.0 | 0.66 | ||
| Asthma family history | <10 | 9 | 3.8 | 0.40 | 0.92 (0.74–1.15) 0.91 (0.58–1.44) 0.89 (0.71–1.12) 0.97 (0.66–1.42) 0.96 (0.79–1.16) |
| >10–15 | 6 | 0.0 | 0.97 | ||
| >15–20 | 10 | 13.4 | 0.32 | ||
| >20–25 | 4 | 0.0 | 0.64 | ||
| 5–25 | 12 | 0.0 | 0.84 | ||
| BMI | <10 | 9 | 69.3 | 0.001 | 0.88 (0.80–0.96) 0.80 (0.75–0.85) 0.80 (0.75–0.85) 0.84 (0.70–1.00) 0.81 (0.78–0.85) |
| >10–15 | 8 | 51.6 | 0.035 | ||
| >15–20 | 12 | 78.8 | <0.001 | ||
| >20–25 | 4 | 92.6 | <0.001 | ||
| 5–25 | 13 | 75.1 | <0.001 | ||
| Former smoker | >10–15 | 2 | 0.0 | 0.35 | 0.65 (0.40–1.04) 0.98 (0.79–1.21) 0.57 (0.27–1.23) 0.93 (0.76–1.12) |
| >15–20 | 9 | 25.3 | 0.24 | ||
| >20–25 | 4 | 56.6 | 0.075 | ||
| 10–25 | 11 | 35.9 | 0.10 | ||
| Current smoker | >10–15 | 2 | 62.2 | 0.10 | 0.89 (0.27–2.97) 0.80 (0.60–1.05) 0.72 (0.48–1.06) 0.85 (0.67–1.08) |
| >15–20 | 11 | 27.3 | 0.18 | ||
| >20–25 | 4 | 0.0 | 0.54 | ||
| 10–25 | 11 | 19.6 | 0.23 | ||
#: Model 1 was adjusted for asthma family history, maternal smoking during pregnancy, preterm birth, body mass index (BMI) and smoking status.