TABLE 1.
Distributions of WHI participants’ characteristics by total long-chain ω-3 fatty acids (n = 87,360)1
| Energy-adjusted quintiles of total long-chain ω-3 PUFAs (mg/d) |
||||||
| Demographics and anthropometric measures | ≤56.8 (n = 17,472) | 56.9–91.2 (n = 17,472) | 91.3–133.9 (n = 17,472) | 134.0–205.2 (n = 17,472) | >205.2 (n = 17,472) | P |
| Age,2 y | 62.7 ± 7.3 | 63.3 ± 7.3 | 63.1 ± 7.2 | 62.9 ± 7.1 | 62.8 ± 7.0 | 0.175 |
| Race, n (%) | <0.001 | |||||
| White | 15,428 (88.3) | 15,067 (86.2) | 14,914 (85.4) | 14,836 (84.9) | 14,205 (81.3) | |
| Black | 707 (4.0) | 1058 (6.1) | 1215 (7.0) | 1270 (7.3) | 1495 (8.6) | |
| Hispanic | 858 (4.9) | 757 (4.3) | 634 (3.6) | 473 (2.7) | 443 (2.5) | |
| Asian/Pacific Islander | 177 (1.0) | 290 (1.7) | 443 (2.5) | 610 (3.5) | 1009 (5.8) | |
| Other race | 302 (1.7) | 300 (1.7) | 266 (1.5) | 283 (1.6) | 320 (1.8) | |
| Education, n (%) | <0.001 | |||||
| ≤High school graduate | 4393 (25.3) | 4282 (24.7) | 3664 (21.1) | 2884 (16.6) | 2260 (13.0) | |
| Some college | 6422 (37.0) | 6593 (38.0) | 6391 (36.8) | 5944 (34.3) | 5486 (31.7) | |
| College or advanced degree | 6548 (37.7) | 6480 (37.3) | 7301 (42.1) | 8524 (49.1) | 9575 (55.3) | |
| WHI enrollment, n (%) | <0.001 | |||||
| Observational study | 8403 (48.1) | 7916 (45.3) | 7747 (44.3) | 7498 (42.9) | 6893 (39.5) | |
| Clinical trials | 9069 (51.9) | 9556 (54.7) | 9725 (55.7) | 9974 (57.1) | 10,579 (60.5) | |
| Lifestyle characteristics, n (%) | ||||||
| BMI (kg/m2) | <0.001 | |||||
| <25.0 | 6265 (36.2) | 6567 (37.9) | 6574 (38.0) | 6700 (38.7) | 6758 (39.0) | |
| 25.0–29.9 | 5826 (33.6) | 5945 (34.3) | 5993 (34.6) | 5972 (34.5) | 5877 (33.9) | |
| 30.0–34.9 | 3202 (18.5) | 3063 (17.7) | 2990 (17.3) | 2864 (16.6) | 2859 (16.5) | |
| ≥35.0 | 2024 (11.7) | 1757 (10.1) | 1759 (10.2) | 1765 (10.2) | 1818 (10.5) | |
| Physical activity | <0.001 | |||||
| Inactive | 3198 (19.4) | 2865 (17.2) | 2351 (14.1) | 2046 (12.2) | 1735 (10.3) | |
| >0–7.2 MET-h/wk | 5023 (30.4) | 5087 (30.6) | 4963 (29.8) | 4489 (26.8) | 4072 (24.1) | |
| 7.3–17.2 MET-h/wk | 4292 (26.0) | 4653 (28.0) | 4723 (28.3) | 5084 (30.4) | 5000 (29.6) | |
| ≥17.3 MET-h/wk | 4014 (24.3) | 4042 (24.3) | 4630 (27.8) | 5119 (30.6) | 6070 (36.0) | |
| Smoking | <0.001 | |||||
| Never smoker | 9156 (54.0) | 9112 (53.9) | 8628 (51.2) | 8487 (50.5) | 8081 (48.2) | |
| >0–7.4 pack-years | 2469 (14.6) | 2501 (14.8) | 2743 (16.3) | 2781 (16.5) | 2910 (17.4) | |
| 7.5–23.0 pack-years | 2380 (14.0) | 2440 (14.4) | 2594 (15.4) | 2703 (16.1) | 2879 (17.2) | |
| ≥23.1 pack-years | 2953 (17.4) | 2856 (16.9) | 2895 (17.2) | 2849 (16.9) | 2896 (17.3) | |
| Alcohol (servings/wk) | <0.001 | |||||
| 0 | 8495 (48.6) | 7733 (44.3) | 6641 (38.0) | 5737 (32.9) | 5334 (30.6) | |
| >0–0.9 | 3356 (19.2) | 3685 (21.1) | 3708 (21.2) | 3656 (20.9) | 3373 (19.3) | |
| 1.0–4.0 | 2927 (16.8) | 3137 (18.0) | 3698 (21.2) | 3962 (22.7) | 4068 (23.3) | |
| ≥4.1 | 2684 (15.4) | 2897 (16.6) | 3408 (19.5) | 4105 (23.5) | 4675 (26.8) | |
| Medical history and reproductive health, n (%) | ||||||
| Family history of endometrial cancer | 0.012 | |||||
| No | 15,460 (94.7) | 15,420 (94.4) | 15,450 (94.3) | 15,533 (94.8) | 15,549 (95.1) | |
| Yes | 868 (5.3) | 907 (5.6) | 936 (5.7) | 850 (5.2) | 802 (4.9) | |
| Age at menarche (y) | <0.001 | |||||
| ≤10 | 975 (5.6) | 961 (5.5) | 995 (5.7) | 1102 (6.3) | 1170 (6.7) | |
| 11–12 | 6964 (40.0) | 6999 (40.2) | 7090 (40.7) | 7098 (40.7) | 7268 (41.7) | |
| 13–14 | 7732 (44.4) | 7621 (43.7) | 7657 (43.9) | 7570 (43.5) | 7390 (42.4) | |
| ≥15 | 1753 (10.1) | 1845 (10.6) | 1693 (9.7) | 1650 (9.5) | 1603 (9.2) | |
| Age at menopause ( y) | <0.001 | |||||
| <47 | 3236 (19.6) | 3164 (19.1) | 3054 (18.3) | 2803 (16.8) | 2622 (15.6) | |
| 47–51 | 6905 (41.9) | 6917 (41.8) | 6865 (41.1) | 6836 (41.0) | 6859 (40.9) | |
| ≥52 | 6353 (38.5) | 6469 (39.1) | 6766 (40.6) | 7053 (42.3) | 7274 (43.4) | |
| Parity | <0.001 | |||||
| Nulliparous or nulligravida | 2156 (12.4) | 2156 (12.4) | 2162 (12.4) | 2236 (12.9) | 2456 (14.1) | |
| 1 | 1525 (8.8) | 1448 (8.3) | 1543 (8.9) | 1531 (8.8) | 1574 (9.1) | |
| 2–4 | 10,935 (62.9) | 11,022 (63.3) | 11,154 (64.1) | 11,269 (64.8) | 11,463 (66.0) | |
| ≥5 | 2780 (16.0) | 2778 (16.0) | 2548 (14.6) | 2346 (13.5) | 1887 (10.9) | |
| Age at first birth | <0.001 | |||||
| Nulliparous or nulligravida | 2156 (13.5) | 2156 (13.6) | 2162 (13.6) | 2236 (14.1) | 2456 (15.5) | |
| <20 y | 2008 (12.6) | 1937 (12.2) | 1756 (11.1) | 1474 (9.3) | 1348 (8.5) | |
| 20–29 y | 10,263 (64.3) | 10,258 (64.8) | 10,428 (65.7) | 10,620 (66.8) | 10,437 (65.9) | |
| ≥30 y | 1543 (9.7) | 1472 (9.3) | 1523 (9.6) | 1571 (9.9) | 1608 (10.1) | |
| Duration of combined hormone therapy (y) | <0.001 | |||||
| <2.5 | 12,346 (70.7) | 12,387 (70.9) | 12,000 (68.7) | 11,831 (67.7) | 11,850 (67.8) | |
| 2.5–7 | 2632 (15.1) | 2551 (14.6) | 2697 (15.4) | 2776 (15.9) | 2824 (16.2) | |
| ≥8 | 2494 (14.3) | 2534 (14.5) | 2774 (15.9) | 2864 (16.4) | 2798 (16.0) | |
| Duration of unopposed estrogen therapy (y) | 0.032 | |||||
| <2.5 | 16,445 (94.1) | 16,411 (93.9) | 16,444 (94.1) | 16,483 (94.3) | 16,557 (94.8) | |
| 2.5–7 | 587 (3.4) | 584 (3.3) | 559 (3.2) | 526 (3.0) | 511 (2.9) | |
| ≥8 | 440 (2.5) | 477 (2.7) | 469 (2.7) | 462 (2.6) | 404 (2.3) | |
| Duration of oral contraceptive use (y) | 0.004 | |||||
| ≤4 | 14,066 (80.5) | 14,132 (80.9) | 14,008 (80.2) | 13,842 (79.3) | 13,907 (79.6) | |
| 5–12 | 2632 (15.1) | 2531 (14.5) | 2631 (15.1) | 2746 (15.7) | 2689 (15.4) | |
| >12 | 771 (4.4) | 807 (4.6) | 826 (4.7) | 874 (5.0) | 872 (5.0) | |
| Oophorectomy status | 0.139 | |||||
| No | 16,615 (95.5) | 16,592 (95.2) | 16,641 (95.6) | 16,599 (95.4) | 16,546 (95.1) | |
| Yes | 786 (4.5) | 830 (4.8) | 762 (4.4) | 798 (4.6) | 855 (4.9) | |
| History of diabetes | 0.007 | |||||
| No | 16,684 (95.5) | 16,571 (94.9) | 16,571 (94.9) | 16,615 (95.1) | 16,552 (94.8) | |
| Yes | 778 (4.5) | 890 (5.1) | 895 (5.1) | 850 (4.9) | 913 (5.2) | |
1
Sum of EPA (20:5ω-3), docosapentaenoic acid (22:5ω-3), and DHA (22:6ω-3). P value for age was derived from the F test; all other comparisons were derived from chi-square tests of independence. MET-h, metabolic equivalent task hours; WHI, Women’s Health Initiative.
2
All values are means ± SDs.