Table 1.
Characteristics of the study population by BMI categories
| Characteristic | BMI |
All women | Women with adenocarcinoma | Women with squamous cell carcinoma | ||
|---|---|---|---|---|---|---|
| <25 kg/m2 | 25–<30 kg/m2 | 30+ kg/m2 | ||||
| n (%) | 584 515 (46.6) | 447 030 (35.6) | 223 984 (17.8) | 1 255 529 (100) | 1386 (0.1) | 1799 (0.1) |
| Age (years), mean (SD) | 55.9 (4.9) | 56.4 (4.9) | 56.2 (4.8) | 56.2 (4.9) | 57.5 (5.0) | 57.8 (5.0) |
| BMI ( kg/m2), mean (SD) | 22.6 (1.7) | 27.1 (1.4) | 34.0 (3.8) | 26.2 (4.7) | 28.1 (5.2) | 24.2 (4.0) |
| Highest socioeconomic quintile, n (%) | 131 595 (22.7) | 87 993 (19.8) | 34 232 (15.4) | 253 820 (20.4) | 220 (15.9) | 364 (20.4) |
| Current smoker, n (%) | 125 284 (21.6) | 80 606 (18.2) | 34 557 (15.5) | 240 447 (19.3) | 413 (31.4) | 607 (39.0) |
| Alcohol (drinks per week) among drinkers, mean (SD) | 6.6 (5.5) | 6.1 (5.4) | 5.5 (5.3) | 6.3 (5.5) | 5.7 (5.4) | 8.2 (7.1) |
| Non-drinkers, n (%) | 179 910 (31.0) | 157 245 (35.4) | 103 420 (46.6) | 440 575 (35.3) | 599 (43.8) | 665 (37.2) |
| Ever used OC, n (%) | 357 775 (61.8) | 257 832 (58.3) | 123 540 (55.9) | 739 147 (59.5) | 718 (52.4) | 946 (53.2) |
| Current MHT use, n (%) | 210 572 (36.4) | 145 065 (32.8) | 61 747 (27.9) | 417 384 (33.6) | 380 (27.7) | 507 (28.6) |
| Strenuous exercise at least twice per week, n (%) | 142 337 (25.2) | 83 642 (19.4) | 30 334 (14.1) | 256 313 (21.1) | 224 (16.8) | 385 (22.3) |
| Parity, mean (SD) | 2.1 (1.2) | 2.2 (1.2) | 2.4 (1.4) | 2.2 (1.2) | 2.3 (1.4) | 2.1 (1.3) |
| Age at menarche (years), mean (SD) | 13.2 (1.6) | 12.9 (1.6) | 12.6 (1.6) | 13.0 (1.6) | 12.8 (1.7) | 13.1 (1.6) |
| Postmenopausal, n (%) | 414 995 (84.7) | 328 034 (86.3) | 160 825 (84.6) | 903 854 (85.2) | 1110 (89.9) | 1521 (94.0) |
| Oesophageal cancers, n (%) | ||||||
| Adenocarcinoma | 435 (0.07) | 527 (0.1) | 424 (0.2) | 1386 (0.1) | ||
| Squamous cell carcinoma | 1151 (0.2) | 516 (0.1) | 132 (0.06) | 1799 (0.1) | ||
| Other | 190 (0.03) | 125 (0.03) | 71 (0.03) | 386 (0.03) | ||
BMI, body mass index; OC, oral contraceptive; MHT, menopausal hormone therapy; SD, standard deviation.