Table 1.
Baseline (2003–2009) characteristics of Sister Study participants (n=50,201) according to their fibroid and endometriosis status at the end of follow-up (up to September 2020)
| Fibroid and Endometriosis Status at End of Follow-up | ||||||
|---|---|---|---|---|---|---|
| Baseline Characteristics3 | All Participants | Neither diagnosis | Fibroids | Fibroids diagnosed < 35 years | Endometriosis | Endometriosis diagnosed < 35 years |
| N = 50,201 | N = 26,547 (52.8%) | N = 19,9321 (39.7%) | N = 4,2301 (8.4%) | N = 8,9511 (17.8%) | N = 3,9701 (7.9%) | |
| Age at Baseline | 56 (9) | 55 (9) | 56 (9) | 56 (9) | 56 (9) | 54 (8) |
| Race | ||||||
| Non-Hispanic White | 42,038 (84%) | 22,996 (87%) | 15,773 (79%) | 2,891 (68%) | 7,547 (84%) | 3,316 (84%) |
| Non-Hispanic Black/ African American | 4,521 (9.0%) | 1,465 (5.5%) | 2,886 (14%) | 1,050 (25%) | 741 (8.3%) | 375 (9.4%) |
| Hispanic | 2,315 (4.6%) | 1,366 (5.1%) | 779 (3.9%) | 171 (4.0%) | 381 (4.3%) | 152 (3.8%) |
| Other | 1,327 (2.6%) | 720 (2.7%) | 494 (2.5%) | 118 (2.8%) | 282 (3.2%) | 127 (3.2%) |
| Education | ||||||
| High School | 7,683 (15%) | 4,284 (16%) | 2,781 (14%) | 617 (15%) | 1,345 (15%) | 553 (14%) |
| Some College | 16,930 (34%) | 8,606 (32%) | 6,956 (35%) | 1,559 (37%) | 3,314 (37%) | 1,538 (39%) |
| Undergraduate Degree | 13,556 (27%) | 7,418 (28%) | 5,208 (26%) | 1,035 (24%) | 2,223 (25%) | 998 (25%) |
| Graduate Degree | 12,032 (24%) | 6,239 (24%) | 4,987 (25%) | 1,019 (24%) | 2,069 (23%) | 881 (22%) |
| Body mass index (BMI) at Baseline (kg/m2) | ||||||
| <18.5 | 519 (1.0%) | 320 (1.2%) | 171 (0.9%) | 25 (0.6%) | 73 (0.8%) | 32 (0.8%) |
| 18.5–25 | 19,801 (39%) | 11,170 (42%) | 7,135 (36%) | 1,340 (32%) | 3,300 (37%) | 1,548 (39%) |
| 25–30 | 15,971 (32%) | 8,334 (31%) | 6,439 (32%) | 1,396 (33%) | 2,910 (33%) | 1,261 (32%) |
| >30 | 13,910 (28%) | 6,723 (25%) | 6,187 (31%) | 1,469 (35%) | 2,668 (30%) | 1,129 (28%) |
| Physical Activity Including Work | ||||||
| <10 hours/week | 18,901 (38%) | 9,907 (37%) | 7,620 (38%) | 1,610 (38%) | 3,285 (37%) | 1,471 (37%) |
| 10–20 hours/week | 20,738 (41%) | 11,083 (42%) | 8,126 (41%) | 1,652 (39%) | 3,655 (41%) | 1,616 (41%) |
| 20–30 hours/week | 8,403 (17%) | 4,406 (17%) | 3,345 (17%) | 779 (18%) | 1,583 (18%) | 691 (17%) |
| >30 hours/week | 2,159 (4.3%) | 1,151 (4.3%) | 841 (4.2%) | 189 (4.5%) | 428 (4.8%) | 192 (4.8%) |
| Alcohol | ||||||
| Non-Drinking | 9,538 (19%) | 4,939 (19%) | 3,885 (19%) | 965 (23%) | 1,804 (20%) | 815 (21%) |
| <7 drinks/week | 33,874 (67%) | 17,831 (67%) | 13,509 (68%) | 2,807 (66%) | 6,019 (67%) | 2,688 (68%) |
| 7+ drinks/week | 6,789 (14%) | 3,777 (14%) | 2,538 (13%) | 458 (11%) | 1,128 (13%) | 467 (12%) |
| Smoking (pack-years) | ||||||
| Never | 28,338 (56%) | 14,910 (56%) | 11,417 (57%) | 2,383 (56%) | 4,905 (55%) | 2,170 (55%) |
| <15 pack-years | 13,687 (27%) | 7,173 (27%) | 5,478 (27%) | 1,106 (26%) | 2,502 (28%) | 1,087 (27%) |
| 15–30 pack-years | 4,890 (9.7%) | 2,635 (9.9%) | 1,863 (9.3%) | 430 (10%) | 927 (10%) | 426 (11%) |
| >30 pack-years | 3,286 (6.5%) | 1,829 (6.9%) | 1,174 (5.9%) | 311 (7.4%) | 617 (6.9%) | 287 (7.2%) |
| Parity | ||||||
| No children | 9,079 (18%) | 4,374 (16%) | 3,828 (19%) | 811 (19%) | 2,180 (24%) | 1,018 (26%) |
| 1 child | 7,261 (14%) | 3,539 (13%) | 3,059 (15%) | 791 (19%) | 1,547 (17%) | 780 (20%) |
| 2 children | 18,450 (37%) | 9,882 (37%) | 7,242 (36%) | 1,483 (35%) | 3,107 (35%) | 1,388 (35%) |
| 3+ children | 15,411 (31%) | 8,752 (33%) | 5,803 (29%) | 1,145 (27%) | 2,117 (24%) | 784 (20%) |
| Age at First Pregnancy | ||||||
| Never Pregnant | 7,762 (15%) | 3,941 (15%) | 3,059 (15%) | 637 (15%) | 1,762 (20%) | 851 (21%) |
| <20 years old | 9,536 (19%) | 4,629 (17%) | 4,217 (21%) | 1,064 (25%) | 1,751 (20%) | 741 (19%) |
| 20–24 years old | 17,466 (35%) | 9,117 (34%) | 7,187 (36%) | 1,470 (35%) | 2,950 (33%) | 1,213 (31%) |
| 25–29 years old | 9,349 (19%) | 5,300 (20%) | 3,425 (17%) | 590 (14%) | 1,433 (16%) | 610 (15%) |
| 30+ years old | 6,088 (12%) | 3,560 (13%) | 2,044 (10%) | 469 (11%) | 1,055 (12%) | 555 (14%) |
| Breastfeeding | ||||||
| Never | 21,596 (43%) | 10,756 (41%) | 9,026 (45%) | 2,021 (48%) | 4,416 (49%) | 1,930 (49%) |
| <1 year | 16,407 (33%) | 8,556 (32%) | 6,628 (33%) | 1,393 (33%) | 2,927 (33%) | 1,323 (33%) |
| 1–2 years | 6,503 (13%) | 3,768 (14%) | 2,343 (12%) | 436 (10%) | 929 (10%) | 415 (10%) |
| >2 years | 5,695 (11%) | 3,467 (13%) | 1,935 (9.7%) | 380 (9.0%) | 679 (7.6%) | 302 (7.6%) |
| Age of Menarche | ||||||
| <12 years old | 10,254 (20%) | 4,847 (18%) | 4,606 (23%) | 1,123 (27%) | 2,093 (23%) | 965 (24%) |
| 12–14 years old | 28,194 (56%) | 15,027 (57%) | 11,109 (56%) | 2,304 (54%) | 4,874 (54%) | 2,124 (54%) |
| >14 years old | 11,753 (23%) | 6,673 (25%) | 4,217 (21%) | 803 (19%) | 1,984 (22%) | 881 (22%) |
| Years taking oral contraceptives | ||||||
| Never | 8,015 (16%) | 4,399 (17%) | 3,113 (16%) | 648 (15%) | 1,190 (13%) | 465 (12%) |
| 0–2 years | 7,948 (16%) | 3,916 (15%) | 3,415 (17%) | 763 (18%) | 1,559 (17%) | 696 (18%) |
| 2–10 years | 21,556 (43%) | 11,291 (43%) | 8,604 (43%) | 1,901 (45%) | 3,959 (44%) | 1,882 (47%) |
| 10+ years | 12,682 (25%) | 6,941 (26%) | 4,800 (24%) | 918 (22%) | 2,243 (25%) | 927 (23%) |
| Hormone Replacement Therapy | ||||||
| None | 28,056 (56%) | 16,404 (62%) | 10,044 (50%) | 2,038 (48%) | 3,832 (43%) | 1,728 (44%) |
| Estrogen and Progestin | 12,388 (25%) | 7,016 (26%) | 4,442 (22%) | 833 (20%) | 1,982 (22%) | 863 (22%) |
| Estrogen Only | 9,757 (19%) | 3,127 (12%) | 5,446 (27%) | 1,359 (32%) | 3,137 (35%) | 1,379 (35%) |
| Surgery2 | ||||||
| No Surgery | 34,241 (68%) | 21,940 (83%) | 10,482 (53%) | 1,765 (42%) | 3,716 (42%) | 1,685 (42%) |
| Hysterectomy Only | 6,929 (14%) | 2,374 (8.9%) | 3,913 (20%) | 1,259 (30%) | 1,763 (20%) | 865 (22%) |
| Bilateral Oophorectomy Only | 234 (0.5%) | 141 (0.5%) | 78 (0.4%) | 13 (0.3%) | 36 (0.4%) | 10 (0.3%) |
| Both | 8,797 (18%) | 2,092 (7.9%) | 5,459 (27%) | 1,193 (28%) | 3,436 (38%) | 2,092 (7.9%) |
1
Those subjects who have both fibroids and endometriosis contribute to the statistics of both the fibroids and endometriosis columns.
2
“Hysterectomy Only” indicates hysterectomy but not bilateral oophorectomy; “bilateral oophorectomy” indicates bilateral oophorectomy with or without hysterectomy; “no surgery” indicates neither hysterectomy nor bilateral oophorectomy. Partial/unilateral oophorectomies would either be classified under “no surgery” or “hysterectomy only”.
3
Characteristics are based on status at baseline, while fibroids and endometriosis refer to status at end of follow-up
Mean (SD) or Count (percentage)
Data represented here is the average of all 30 imputed data sets