Table 2 Odds ratios for pooled surgery exposures using a random effects model
Exposure | Included studies (n) | MS case group (n) | Control group (n) | Total (n) | Level of heterogeneity I2(χ2 p) | Pooled OR (95% CI) | Test for overall effect |
|---|---|---|---|---|---|---|---|
Z ( p) | |||||||
Tonsillectomy ≤ 20 years | 12 | 4,414 | 4,422 | 8,836 | 44% (0.05) | 1.32 (1.08-1.61)* | 2.76 (0.006) * |
Tonsillectomy > 20 years | 9 | 1,801 | 1,618 | 3,419 | 32% (0.16) | 1.20 (0.94-1.53) | 1.45 (0.15) |
Appendectomy ≤ 20 years | 7 | 21,218 | 205,124 | 226,342 | 0% (0.54) | 1.16 (1.01-1.34)* | 2.06 (0.04) * |
Appendectomy > 20 years | 5 | 21,360 | 205,021 | 226,381 | 46% (0.11) | 1.26 (0.92-1.72) | 1.43 (0.15) |
Adenoidectomy ≤ 20 years | 3 | 458 | 636 | 1,094 | 35% (0.21) | 1.06 (0.68-1.68) | 0.27 (0.79) |
Surgery ≤ 20 years | 4 | 485 | 1,202 | 1,687 | 19% (0.30) | 0.95 (0.70-1.31) | 0.29 (0.77) |
Surgery > 20 years | 15 | 1,099 | 1,371 | 2,470 | 71% (0.0001) | 1.19 (0.83-1.70) | 0.94 (0.35) |