Table 1.
Characteristics of study participants at baseline according to coffee consumption in the Women’s Health Initiative Observational Study (n = 46,977).
| Daily total coffee consumption | ||||||||
|---|---|---|---|---|---|---|---|---|
| 0 or <1 cup/day | 1 cup/day | 2-3 cups/day | ≥4 cups/day | |||||
| Continuous | Mean | (SD) | Mean | (SD) | Mean | (SD) | Mean | (SD) |
| Age (years) | 62.7 | (7.5) | 64.0 | (7.4) | 63.3 | (7.2) | 62.9 | (7.1) |
| Physical exercise (MET/week) | 14.6 | (15.0) | 13.7 | (14.4) | 14.5 | (14.3) | 14.3 | (14.7) |
| Age at menopause | 50.3 | (4.9) | 50.3 | (5.1) | 50.3 | (5.1) | 50.0 | (4.8) |
| Body mass index | 27.1 | (6.1) | 26.8 | (5.6) | 26.8 | (5.4) | 26.8 | (5.3) |
| Total daily energy intake (kcal) | 1528 | (677) | 1501 | (689) | 1554 | (650) | 1642 | (716) |
| Categorical | n† | % | n† | % | n† | % | n† | % |
| Ethnicity | ||||||||
| White | 10,828 | (80.1) | 5347 | (78.6) | 16,737 | (88.5) | 7071 | (93.2) |
| Black | 1413 | (10.5) | 608 | (8.9) | 754 | (4.0) | 141 | (1.9) |
| Other | 1284 | (9.5) | 851 | (12.5) | 1428 | (7.6) | 374 | (4.9) |
| Body mass index | ||||||||
| Normal BMI (<25 kg/m2) | 5986 | (44.6) | 3028 | (44.9) | 8183 | (43.6) | 3177 | (42.1) |
| Overweight (25-30 kg/m2) | 4110 | (30.6) | 2186 | (32.4) | 6420 | (34.2) | 2711 | (36.0) |
| Obese (≥30 kg/m2) | 3327 | (24.8) | 1533 | (22.7) | 4157 | (22.2) | 1651 | (21.9) |
| Age at menarche | ||||||||
| Early menarche (<12 years) | 2822 | (20.9) | 1347 | (19.8) | 4044 | (21.4) | 1682 | (22.2) |
| Average (12-13 years) | 7395 | (57.7) | 3746 | (55.1) | 10,578 | (56.0) | 4190 | (55.4) |
| Late menarche (>13 years) | 3301 | (24.4) | 1710 | (25.1) | 4272 | (22.6) | 1694 | (22.4) |
| Number of full term births | ||||||||
| None | 2044 | (15.2) | 881 | (13.0) | 2468 | (13.1) | 1014 | (13.4) |
| 1-2 | 4891 | (36.3) | 2464 | (36.3) | 6586 | (35.0) | 2620 | (34.7) |
| 3 or more | 6541 | (48.5) | 3439 | (50.7) | 9782 | (51.9) | 3911 | (51.8) |
| Smoking status | ||||||||
| Never smoked | 8243 | (61.4) | 3752 | (55.7) | 8656 | (46.2) | 2855 | (37.1) |
| Past smoker | 4741 | (35.3) | 2698 | (40.1) | 8907 | (47.6) | 3664 | (48.9) |
| Current smoker | 444 | (3.3) | 282 | (4.2) | 1157 | (6.2) | 981 | (13.1) |
| Oral contraceptive use | ||||||||
| Never | 7859 | (57.9) | 4187 | (61.3) | 11,038 | (58.2) | 4430 | (58.3) |
| Ever | 5712 | (42.1) | 2643 | (38.7) | 7935 | (41.8) | 3173 | (41.7) |
| Diabetes Status | ||||||||
| No | 12,581 | (94.8) | 6457 | (94.6) | 18,128 | (95.7) | 7289 | (95.9) |
| Yes | 705 | (5.2) | 370 | (5.4) | 824 | (4.3) | 310 | (4.1) |
| Combined estrogen-progestin use | ||||||||
| Never used | 7917 | (58.4) | 3920 | (57.4) | 10,527 | (55.5) | 4385 | (57.7) |
| Past user | 1173 | (8.7) | 615 | (9.0) | 1657 | (8.7) | 653 | (8.6) |
| Current user | 4472 | (33.0) | 2290 | (33.6) | 6779 | (35.8) | 2562 | (33.7) |
| Unopposed estrogen use ‡ | ||||||||
| Never used | 11,957 | (88.1) | 5956 | (87.3) | 16,652 | (87.8) | 6722 | (88.5) |
| Past user | 1242 | (9.2) | 680 | (10.0) | 1832 | (9.7) | 698 | (9.2) |
| Current user | 368 | (2.7) | 190 | (2.8) | 482 | (2.5) | 179 | (2.4) |
| Family history of endometrial cancer ‡ | ||||||||
| No | 221 | (1.6) | 89 | (1.3) | 238 | (1.3) | 103 | (1.4) |
| Yes | 5670 | (41.8) | 2947 | (43.2) | 8274 | (43.6) | 3229 | (42.5) |
| Don’t know | 7680 | (56.6) | 3794 | (55.5) | 10,461 | (55.1) | 4271 | (56.1) |
† Numbers may not add to 46,977 because of missing values. Due to the large sample size p values for all variables were <0.0001, except for ‡ unopposed estrogen use (p = 0.19); and ‡ family history of endometrial cancer (p = 0.96).