Table 2.
Details of associations supported by strong evidence in meta-analyses of cohort studies on obesity and risk of obstetric and gynaecological morbidity. Outcomes are incidences unless stated otherwise. All statistical tests were two sided
| Exposure | Outcome | No of studies | Sample size (cases/cohort | RR (95% CI) of largest study | Random effects summary RR (95% CI)* | Random P value† | 95% prediction interval | 10% credibility RR (95% CI)* | Egger’s P‡ | I2 (%) | Excess significance§ | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| O/E | P value | |||||||||||
| Gynaecological oncology | ||||||||||||
| WHR per 0.1 units | Endometrial CA | 5 | 2447/394 340 | 1.33 (1.18 to 1.51) | 1.21 (1.13 to 1.29) | 1.0−8 | 1.09 to 1.34 | 1.17 (1.04 to 1.31) | 0.54 | 0 | 3/4.4 | NA |
| BMI per 5kg/m2 increase | Endometrial CA PrMP | 6 | 5981/2 558 935 | 1.53 (1.48 to 1.58) | 1.49 (1.39 to 1.61) | 3.1−27 | 1.27 to 1.76 | 1.36 (1.11 to 1.67) | 0.56 | 20 | 5/4.2 | 0.67 |
| BMI >30 v <25 | Ovarian CA | 13 | 6947/20 560 388¶ | 1.27 (1.19 to 1.36) | 1.27 (1.17 to 1.38) | 2.6−8 | 1.09 to 1.47 | 1.16 (1.02 to 1.30) | 0.88 | 12 | 3/5.3 | NA |
| Obstetric, fetal | ||||||||||||
| BMI 30-40 v <25 | Apgar <7 at 1 minute | 4 | 16 187/230 884 | 1.27 (1.22 to 1.32) | 1.29 (1.23 to 1.36) | <1−100 | 1.10 to 1.52 | 1.28 (1.06 to 1.56) | 0.51 | 20 | 4/3.9 | 1.00 |
| BMI >40 v < 5 | Apgar <7 at 1 minute | 3 | 9958/153 104 | 1.63 (1.52 to 1.74) | 1.63 (1.53 to 1.74) | <1−100 | 1.08 to 2.47 | 1.64 (1.06 to 2.55) | 0.62 | 0 | 3/3.0 | 1.00 |
| GWG high v normal | Macrosomia risk: >4000 g | 11 | 25 985/401 803 | 2.00 (1.90 to 2.10) | 2.08 (1.92 to 2.26) | <1−100 | 1.72 to 2.52 | 2.06 (1.46 to 2.92) | 0.14 | 41 | 9/11.0 | NA |
| Obstetric, maternal | ||||||||||||
| BMI >30 v <25 | Antenatal depression risk | 23 | 6370/46 182 | 1.48 (1.32 to 1.67) | 1.48 (1.32 to 1.66 | 1.3−11 | 1.07 to 2.05 | 1.30 (1.13 to 1.49) | 0.97 | 39 | 7/12.0 | NA |
| BMI >30 v <25 | Caesarean section-emergency | 6 | 2301/18 749 | 1.51 (1.21 to 1.89) | 1.63 (1.40 to 1.89) | 4.0−10 | 1.31 to 2.02 | 1.63 (1.15 to 2.31) | 0.29 | 0 | 5/3.9 | 0.67 |
| BMI >30 v <25 | Caesarean section-total | 16 | 8413/62 277 | 2.02 (1.79 to 2.28) | 2.00 (1.87 to 2.15) | <1−100 | 1.86 to 2.16 | 1.86 (1.45 to 2.39) | 0.66 | 0 | 12/14.5 | NA |
| BMI 25-30 v <25 | Pre-eclampsia (adjusted)** | 12 | 30 001/1 091 624 | 1.74 (1.69 to 1.80) | 1.70 (1.60 to 1.81) | <1−100 | 1.49 to 1.95 | 1.59 (1.26 to 2.01) | 0.38 | 29 | 10/10.8 | NA |
| BMI >35 v <25 | Pre-eclampsia (adjusted)** | 5 | 12 614/901 409 | 4.28 (3.48 to 5.26) | 4.14 (3.61 to 4.75) | <1−100 | 3.32 to 5.17 | 3.96 (1.54 to 10.2) | 0.84 | 0 | 5/5.0 | 1.00 |
BMI=body mass index; WHR=waist to hip ratio; CA=cancer; NA=not applicable, because estimated number is larger than observed, and there is no evidence of excess significance based on assumption made for plausible effect size; PrMP=premenopausal; GWG=gestational weight gain.
*From random effects model. RR for categorical outcome measure.
†P value of summary random effects estimate.
‡From Egger’s regression asymmetry test.
§Expected number of significant studies with point estimate of largest study (smallest SE) as plausible effect size. O/E=observed/expected number of studies with significant results. P value for excess significance test.
¶Person years.
**Estimate based on studies that used adjusted risk estimates