Table 3 Results of subgroup analyses based on country, study type, diagnostic criteria, test sample, and cutoff values
Subgroup | Number (N) | OR (95% CI) | Heterogeneity (I2%) | P |
|---|---|---|---|---|
Country | ||||
China | 7 | 1.23 (0.92, 1.65) | 77 | 0.16 |
Canada | 2 | 3.76 (1.78, 7.94) | 0 | 0.0005 |
America | 1 | / | / | / |
Bangladesh | 1 | / | / | / |
Chile | 1 | / | / | / |
French | 1 | / | / | / |
Study Type | ||||
Cohort study | 5 | 1.59 (1.14, 2.22) | 66 | 0.006 |
Cross-sectional study | 4 | 1.43 (0.52, 3.92) | 76 | 0.49 |
Retrospective case-control study nested in a cohort | 2 | 2.04 (0.37, 11.32) | 92 | 0.41 |
Case-control study | 1 | / | / | / |
Semi-ecological study | 1 | / | / | / |
Diagnostic Criteria | ||||
ADA Criteria | 5 | 1.17 (0.90, 1.52) | 74 | 0.24 |
CDA-SOGC Criteria | 2 | 3.76 (1.78, 7.94) | 0 | 0.0005 |
MOH Criteria | 2 | 0.78 (0.46, 1.33) | 0 | 0.36 |
WHO Criteria | 3 | 3.93 (1.27, 12.22) | 62 | 0.02 |
CNGOF Criteria | 1 | / | / | / |
Test Samples | ||||
Blood | 3 | 1.61 (0.97, 2.68) | 78 | 0.07 |
Urine | 7 | 1.39 (0.82, 2.34) | 67 | 0.22 |
Hair | 1 | / | / | / |
Tap water | 1 | / | / | / |
Meconium | 1 | / | / | / |
Cutoffs | ||||
Tertile | 6 | 1.16 (0.85, 1.56) | 42 | 0.35 |
Quartile | 4 | 2.13 (1.11, 4.10) | 72 | 0.02 |
Not said | 2 | 3.47 (0.64, 18.81) | 84 | 0.15 |
Binary | 1 | / | / | / |
Median year of publication | ||||
Before 2018 | 7 | 2.61 (1.65, 4.13) | 59 | 0.0001 |
After 2018 | 6 | 1.02 (0.85, 1.24) | 39 | 0.82 |
Quality | ||||
Moderate | 7 | 2.51 (1.40, 4.50) | 77 | 0.002 |
High | 6 | 1.09 (0.81, 1.48) | 71 | 0.56 |