Table I.
Characteristics of laparoscopically confirmed endometriosis cases and matched controls within the NHS II blood cohorta.
| Endometriosis cases (n = 350) | Controls (n = 694) | |
|---|---|---|
| Age at blood drawb | 41.7 (4.6) | 42.1 (4.5) |
| Racec | ||
| White | 346 (98.9%) | 689 (99.3%) |
| Black | 1 (0.3%) | 3 (0.4%) |
| Other | 3 (0.9%) | 2 (0.3%) |
| BMI at blood draw (kg/m2)c | ||
| <18.5 | 8 (2.3%) | 14 (2.0%) |
| 18.5–22.4 | 106 (30.5%) | 238 (34.4%) |
| 22.5–24.9 | 72 (20.7%) | 156 (22.5%) |
| 25–29.9 | 88 (25.3%) | 158 (22.8%) |
| 30–34.9 | 37 (10.6%) | 61 (8.8%) |
| 35–39.9 | 23 (6.6%) | 45 (6.5%) |
| 40+ | 14 (4.0%) | 20 (2.9%) |
| BMI at age 18 (kg/m2)c | ||
| <18.5 | 54 (15.6%) | 110 (16.0%) |
| 18.5–22.4 | 212 (61.1%) | 413 (59.9%) |
| 22.5–24.9 | 45 (13.0%) | 105 (15.2%) |
| 25–29.9 | 25 (7.2%) | 47 (6.8%) |
| 30–34.9 | 8 (2.3%) | 7 (1.0%) |
| 35–39.9 | 3 (0.9%) | 6 (0.9%) |
| 40+ | 0 (0.0%) | 1 (0.1%) |
| Parityc | ||
| Nulliparous | 105 (30.3%) | 147 (21.2%) |
| 1 | 45 (13.0%) | 97 (14.0%) |
| 2 | 122 (35.3%) | 249 (36.0%) |
| 3 | 55 (15.9%) | 154 (22.3%) |
| 4+ | 19 (5.5%) | 45 (6.5%) |
| Infertility historyc | ||
| Yes | 97 (27.7%) | 209 (30.1%) |
| No | 253 (72.3%) | 485 (69.9%) |
BMI, body mass index.
aLaparoscopically confirmed cases of endometriosis were matched 1:2 with controls of comparable age, race, infertility history, menopausal status at diagnosis, as well as month, time of day and fasting status at blood draw.
bResults expressed as mean (standard deviation). Age at blood draw ranges between 32 and 52 years.
cResults expressed as n (%). Some categories may not sum to 100 due to rounding. Additionally, four women were missing BMI at blood draw, eight women were missing BMI at age 18 and six women were missing parity.