Table. Subgroup Meta-analyses for HDP-ASD and HDP-ADHD Associations.
| Variable | No. of Studies (No. of Estimates) | No. of Participants | No. of Outcomes | OR (95% CI) | I2, % | Test for Subgroup Differences P Value |
|---|---|---|---|---|---|---|
| Autism Spectrum Disorder | ||||||
| Overall unadjusted | 19 (23) | 941 285 | 9331 | 1.41 (1.22-1.64) | 55 | .80a |
| Overall adjustedb | 11 (13) | 777 518 | 6866 | 1.35 (1.11-1.64) | 63 | .33a |
| Category of HDPb | ||||||
| Preeclampsia | 6 (6) | 378 991 | 4254 | 1.50 (1.26-1.78) | 15 | .33 |
| Other | 7 (7) | 472 268 | 4621 | 1.25 (0.90-1.73) | 72 | |
| Study designb | ||||||
| Case-control | 6 (7) | 16 975 | 3812 | 1.47 (1.18-1.84) | 21 | .41 |
| Cohort | 5 (6) | 760 543 | 3054 | 1.26 (0.93-1.70) | 78 | |
| Locationb | ||||||
| North America | 6 (7) | 372 527 | 3555 | 1.39 (1.09-1.77) | 59 | <.001 |
| Europe | 4 (5) | 28 010 | 2859 | 1.53 (1.26-1.87) | 0 | |
| Australia | 1 (1) | 376 981 | 452 | 0.64 (0.43-0.95) | NA | |
| Study qualityc | ||||||
| Minimal to low risk of bias | 14 (16) | 873 772 | 8041 | 1.39 (1.17-1.65) | 47 | .46 |
| Moderate to high risk of bias | 5 (7) | 67 513 | 1263 | 1.18 (0.81-1.74) | 69 | |
| Exposure measurementb | ||||||
| Self-reported | 4 (5) | 81 242 | 2026 | 1.54 (1.07-2.22) | 68 | .39 |
| Medical records | 7 (8) | 696 276 | 4840 | 1.27 (0.99-1.64) | 65 | |
| Outcome measurementb | ||||||
| Maternal-reported | 2 (3) | 79 543 | 992 | 1.32 (0.91-1.91) | 72 | .86 |
| Medical records | 9 (10) | 697 975 | 5874 | 1.37 (1.07-1.75) | 63 | |
| Length of follow-up, yb | ||||||
| ≤7 | 5 (5) | 102 838 | 1823 | 1.71 (1.23-2.38) | 41 | .09 |
| ≤21 | 6 (8) | 674 680 | 5043 | 1.22 (0.98-1.52) | 64 | |
| Attention-Deficit/Hyperactivity Disorder | ||||||
| Overall unadjusted | 9 (12) | 1 428 209 | 37 635 | 1.32 (1.20-1.45) | 48 | .33a |
| Overall adjustedb | 6 (8) | 1 395 605 | 37 128 | 1.29 (1.22-1.36) | 0 | .24a |
| Category of HDPb | ||||||
| Preeclampsia | 5 (6) | 1 382 105 | 36 962 | 1.28 (1.22-1.36) | 0 | .24 |
| Other | 2 (2) | 1 185 896 | 2489 | 1.70 (1.06-2.72) | 0 | |
| Study designb | ||||||
| Case-control | 3 (4) | 124 988 | 26 728 | 1.34 (1.25-1.43) | 0 | .08 |
| Cohort | 3 (4) | 1 270 617 | 10 400 | 1.21 (1.10-1.32) | 0 | |
| Locationb | ||||||
| North America | 2 (2) | 166 399 | 21 524 | 1.27 (1.13-1.43) | 70 | .99 |
| Europe | 2 (3) | 1 185 896 | 2489 | 1.26 (1.06-1.49) | 0 | |
| Other | 2 (3) | 43 310 | 13 115 | 1.27 (0.95-1.70) | 0 | |
| Study qualityc | ||||||
| Minimal to low risk of bias | 7 (9) | 1 427 617 | 37 365 | 1.29 (1.22-1.36) | 0 | .57 |
| Moderate to high risk of bias | 3 (4) | 840 | 394 | 0.95 (0.32-2.76) | 67 | |
| Exposure measurementb | ||||||
| Self-reported | 2 (2) | 13 748 | 290 | 1.70 (1.06-2.72) | 0 | .24 |
| Medical records | 4 (6) | 1 381 857 | 36 838 | 1.28 (1.22-1.36) | 0 | |
Abbreviations: ADHD, attention-deficit/hyperactivity disorder; ASD, autism spectrum disorder; HDP, hypertensive disorders of pregnancy; NA, not applicable; OR, odds ratio.
a
Calculated using test for subgroup differences between preeclampsia and other HDP.
b
Includes all studies that adjusted for confounders in the analysis phase.
c
Includes all studies.