Table 1.
Baseline characteristics of participants in the Women's Health Initiative (WHI) Observational Study (OS) Cohort, stratified by smoking status
| Covariate | Smoking exposure category (number, %) |
Total | P-value (χ2 test) | |||
|---|---|---|---|---|---|---|
| Never, no passive | Never, passive | Former | Current | |||
| Total | 3636 4.77% |
36 135 47.36% |
31 804 41.68% |
4729 6.20% |
76 304 | |
| Person-years of follow-up (per 100 000) | 0.38 | 3.82 | 3.36 | 0.46 | ||
| Age group (at enrollment) | ||||||
| <50–59 | 1059 29.13% |
11 321 31.33% |
10 219 32.13% |
1981 41.89% |
24 580 | <0.0001 |
| 60–69 | 1524 41.91% |
15 679 43.39% |
14 487 45.55% |
2043 43.20% |
33 733 | |
| 70–79+ | 1053 28.96% |
9135 25.28% |
7098 22.32% |
705 14.91% |
17 991 | |
| BMI category | ||||||
| <25 | 1691 46.51% |
15 409 42.64% |
12 899 40.56% |
2226 47.07% |
32 225 | <0.0001 |
| 25–<30 | 1204 33.11% |
12 048 33.34% |
10 905 34.29% |
1525 32.25% |
25 682 | |
| ≥30 | 741 20.38% |
8678 24.02% |
8000 25.15% |
978 20.68% |
18 397 | |
| Ethnicity/race | ||||||
| American Indian or Alaskan Native | 15 0.41% |
140 0.39% |
112 0.35% |
36 0.76% |
303 | <0.0001 |
| Asian or Pacific Islander | 204 5.61% |
1529 4.23% |
508 1.60% |
82 1.73% |
2323 | |
| Black or African-American | 212 5.83% |
2528 7.00% |
2087 6.56% |
593 12.54% |
5420 | |
| Hispanic/Latino | 246 6.77% |
1403 3.88% |
741 2.33% |
186 3.93% |
2576 | |
| White (not of Hispanic origin) | 2905 79.90% |
30 126 83.37% |
28 057 88.22% |
3785 80.04% |
64 873 | |
| Other | 54 1.49% |
409 1.13% |
299 0.94% |
47 0.99% |
809 | |
| Prior history of lung cancer | ||||||
| No | 3630 99.83% |
36 104 99.91% |
31 678 99.60% |
4716 99.73% |
76 128 | <0.0001 |
| Yes | 6 0.17% |
31 0.09% |
126 0.40% |
13 0.27% |
176 | |
| Cancer, male relative | ||||||
| No | 2504 68.87% |
23 136 64.03% |
20 225 63.59% |
3123 66.04% |
48 988 | <0.0001 |
| Yes | 1132 31.13% |
12 999 35.97% |
11 579 36.41% |
1606 33.96% |
27 316 | |
| Cancer, female relative | ||||||
| No | 1982 54.51% |
18 371 50.84% |
15 926 50.08% |
2491 52.67% |
38 770 | <0.0001 |
| Yes | 1654 45.49% |
17 764 49.16% |
15 878 49.92% |
2238 47.33% |
37 534 | |
| Education | ||||||
| Primary | 100 2.75% |
538 1.49% |
252 0.79% |
79 1.67% |
969 | <0.0001 |
| Some high school | 104 2.86% |
1083 3.00% |
899 2.83% |
249 5.27% |
2335 | |
| High school | 455 12.51% |
6416 17.76% |
4534 14.26% |
840 17.76% |
12 245 | |
| Some college | 913 25.11% |
12 928 35.78% |
11 976 37.66% |
2012 42.55% |
27 829 | |
| College | 537 14.77% |
4129 11.43% |
3880 12.20% |
473 10.00% |
9019 | |
| Graduate school | 1527 42.00% |
11 041 30.55% |
10 263 32.27% |
1076 22.75% |
23 907 | |
| Supplemental and dietary vitamin D | ||||||
| <400 IU | 1822 50.11% |
19 047 52.71% |
16 374 51.48% |
2886 61.03% |
40 129 | <0.0001 |
| ≥400 IU | 1814 49.89% |
17 088 47.29% |
15 430 48.52% |
1843 38.97% |
36 175 | |
| Main occupation | ||||||
| Managerial/professional | 1746 48.02% |
15 289 42.31% |
14 652 46.07% |
1829 38.68% |
33 516 | <0.0001 |
| Technical/sales/admin | 638 17.55% |
10 629 29.41% |
9165 28.82% |
1483 31.36% |
21 915 | |
| Service/labor | 604 16.61% |
6298 17.43% |
4964 15.61% |
998 21.10% |
12 864 | |
| Full-time homemaker | 648 17.82% |
3919 10.85% |
3023 9.51% |
419 8.86% |
8009 | |
| Physical activity (MET hours per week) | ||||||
| 0–≤1.67 | 592 16.28% |
6917 19.14% |
5442 17.11% |
1408 29.77% |
14 359 | <0.0001 |
| >1.67–≤8.33 | 943 25.94% |
9812 27.15% |
7644 24.03% |
1458 30.83% |
19 857 | |
| >8.33–≤20 | 1130 31.08% |
10 811 29.92% |
9867 31.02% |
1121 23.70% |
22 929 | |
| >20 | 971 26.71% |
8595 23.79% |
8851 27.83% |
742 15.69% |
19 159 | |
| Alcohol intake | ||||||
| Non-drinker | 1026 28.22% |
6344 17.56% |
904 2.84% |
179 3.79% |
8453 | <0.0001 |
| Past drinker | 480 13.20% |
6338 17.54% |
6208 19.52% |
953 20.15% |
13 979 | |
| <1 drink/month | 437 12.02% |
4724 13.07% |
3141 9.88% |
630 13.32% |
8932 | |
| 1 drink/month–<1 drink/week | 686 18.87% |
7658 21.19% |
6177 19.42% |
876 18.52% |
15 397 | |
| 1–<7 drinks/week | 768 21.12% |
8263 22.87% |
9670 30.40% |
1170 24.74% |
19 871 | |
| ≥7 drinks/week | 239 6.57% |
2808 7.77% |
5704 17.93% |
921 19.48% |
9672 | |
| Hormone therapy use (estrogen or progesterone, not as part of WHI study) | ||||||
| Never used | 1590 43.73% |
14 806 40.97% |
11 818 37.16% |
2137 45.19% |
30 351 | <0.0001 |
| Past user | 516 14.19% |
5192 14.37% |
4898 15.40% |
689 14.57% |
11 295 | |
| Current user | 1530 42.08% |
16 137 44.66% |
15 088 47.44% |
1903 40.24% |
34 658 | |
| Oral contraceptives | ||||||
| No | 2400 66.01% |
22 180 61.38% |
17 956 56.46% |
2581 54.58% |
45 117 | <0.0001 |
| Yes | 1236 33.99% |
13 955 38.62% |
13 848 43.54% |
2148 45.42% |
31 187 | |
| Diet: red meat servings per day (avg, SD) | 0.55, 0.50 | 0.60, 0.56 | 0.58, 0.54 | 0.77, 0.70 | 0.60, 0.56 | <0.0001 |
| Diet: fruit medium servings per day (avg, SD) | 2.27, 1.34 | 2.11, 1.30 | 2.01, 1.26 | 1.47, 1.20 | 2.04, 1.29 | <0.0001 |
| Diet: vegetables medium servings per day (avg, SD) | 2.39, 1.40 | 2.27, 1.33 | 2.35, 1.36 | 1.85, 1.22 | 2.28, 1.35 | <0.0001 |
| Total MET hours per week (avg, SD) | 14.63, 14.81 | 13.39, 14.10 | 14.78, 14.60 | 9.74, 12.22 | 13.80, 14.29 | <0.0001 |
| General health construct (SF 36) (avg, SD) | 75.61, 17.71 | 74.23, 17.95 | 74.57, 18.10 | 71.28, 19.18 | 74.26, 18.10 | <0.0001 |
| Lung cancer during follow-up | ||||||
| No | 3620 99.56% |
35 999 99.62% |
31 273 98.33% |
4511 95.39% |
75 403 | <0.0001 |
| Yes | 16 0.44% |
136 0.38% |
531 1.67% |
218 4.61% |
901 | |
| Died during follow-up | ||||||
| No | 3334 91.69% |
33 201 91.88% |
28 368 89.20% |
3901 82.49% |
68 804 | <0.0001 |
| Yes | 302 8.31% |
2934 8.12% |
3436 10.80% |
828 17.51% |
7500 | |
χ2 test between different smoking categories. Significant for all categories.
METs, metabolic equivalent tasks; SD, standard deviation.