Table 5.
Subgroup analysis of the prospective cohort studies.
| Subgroup | Number of studies (n) | RR (95% CI) | I2 (%) | P overall effect | P interaction |
|---|---|---|---|---|---|
| Region | 0.88 (0.82, 0.95) | 69 | 0.0007 | 0.11 | |
| Europe | 3 | 0.78 (0.63, 0.96) | 64 | 0.02 | |
| Asia | 3 | 0.93 (0.88, 0.99) | 52 | 0.03 | |
| Africa | 1 | 0.73 (0.43, 1.25) | – | 0.26 | |
| Across continents | 1 | 0.70 (0.51, 0.95) | – | 0.03 | |
| Follow-up duration | 0.88 (0.82, 0.95) | 69 | 0.0007 | 0.006 | |
| Infancy | 1 | 0.70 (0.51, 0.96) | – | 0.03 | |
| Toddlerhood | 4 | 0.93 (0.88, 0.98) | 50 | 0.01 | |
| Preschool age and above | 3 | 0.71 (0.60, 0.85) | 15 | 0.0001 | |
| Exposure type | 0.88 (0.82, 0.95) | 69 | 0.0007 | <0.001 | |
| Dietary intake | 6 | 0.75 (0.68, 0.82) | 2 | <0.001 | |
| Dietary intake and supplement intake | 2 | 0.95 (0.89, 1.01) | 59 | 0.10 | |
| Maternal age (years) | 0.86 (0.74, 1.00) | 47 | 0.05 | 0.16 | |
| <30 yr | 2 | 0.71 (0.54, 0.93) | 0 | 0.01 | |
| ≥30 yr | 2 | 0.89 (0.75, 1.06) | 52 | 0.20 | |
| Disease type | 0.88 (0.82, 0.95) | 70 | 0.001 | 0.03 | |
| Asthma | 6 | 0.81 (0.68, 0.96) | 78 | 0.02 | |
| Eczema | 5 | 0.93 (0.82, 1.07) | 52 | 0.31 | |
| Food allergy | 1 | 0.99 (0.94, 1.06) | – | 0.85 | |
| Rhinoconjunctivitis | 1 | 0.88 (0.82, 0.95) | – | 0.0007 |