Table 1 Selected characteristics of the study population at blood collection (n cases/controls =1558/1558)
Variables | Cases | Controls |
|---|---|---|
Mean (SD) or N (%) | Mean (SD) or N (%) | |
Breast cancer cases characteristics | ||
Time between blood collection and diagnosis in years | 8.6 (2.8) | – |
Age at diagnosis in years | 61.4 (8.3) | – |
ER positive | ||
Negative | 305 (19.6) | – |
Positive | 1253 (80.4) | – |
PR status | ||
Negative | 509 (31.8) | – |
Positive | 1104 (68.2) | – |
HER2 status | ||
Negative | 1224 (78.6) | – |
Positive | 334 (21.4) | – |
Molecular status | ||
ER+PR±HER2+ | 210 (13.7) | – |
ER+PR±HER2− | 1043 (68.3) | – |
ER−PR−HER2− | 160 (10.5) | – |
ER−PR−HER2+ | 115 (7.5) | – |
Sociodemographic, lifestyle and reproductive factors | ||
Age at blood collection in years | 52.5 (7.9) | 52.5 (7.9) |
Education level (N missing=63) | ||
Primary/no schooling | 557 (37) | 571 (37) |
Technical/professional/secondary | 647 (42) | 638 (42) |
Longer education | 324 (21) | 316 (21) |
Time since last meal at blood collection in hours (N missing=49) | ||
< 3 h | 706 (46) | 712 (46) |
≥ 3–≤ 6 h | 273 (18) | 272 (18) |
> 6 h | 552 (36) | 552 (36) |
Physical activity index (N missing=27) | ||
Inactive | 349 (23) | 312 (20) |
Moderately inactive | 573 (37) | 610 (40) |
Moderately active | 346 (22) | 335 (22) |
Active | 282 (18) | 282 (18) |
Smoking status (N missing=25) | ||
Never | 875 (56) | 875 (56) |
Former | 351 (23) | 334 (22) |
Smoker | 319 (22) | 337 (22) |
Alcohol consumption at recruitment in g/day (N missing=4) | ||
Non drinker | 223 (14) | 220 (14) |
> 0–≤ 3 | 459 (29) | 423 (27) |
> 3–≤ 12 | 454 (29) | 434 (28) |
> 12–≤ 24 | 256 (16) | 270 (17) |
> 24 | 166 (11) | 207 (13) |
Age at first menstrual period in years (N missing=32) | ||
≤ 13 | 977 (63) | 961 (62) |
> 13 | 568 (37) | 578 (38) |
Number of full-term pregnancies and age at first full-term pregnancy* (N missing=91) | ||
Nulliparous | 243 (16) | 213 (14) |
Age <30 (1-2 children) | 714 (47) | 739 (47) |
Age <30 (≥3 children) | 340 (22) | 385 (25) |
Age ≥30 | 215 (14) | 176 (11) |
Ever breastfed among women with full-term pregnancy | ||
No | 199 (15) | 188 (14) |
Yes | 1034 (80) | 1,069 (80) |
Missing | 68 (5) | 77 (6) |
Use of exogenous hormones at blood collection | 489 (31.4) | 489 (31.4) |
Ever use of oral contraceptive at baseline (N missing=11) | 939 (50.5) | 919 (49.5) |
Ever use of menopausal hormone therapy at baseline among postmenopausal women (N missing=5) | 415 (49.7) | 420 (50.3) |
Menopausal status at blood collection (N missing=0) | ||
Premenopausal | 413 (26) | 413 (26) |
Perimenopausal | 307 (20) | 307 (20) |
Postmenopausal | 838 (54) | 838 (54) |
Anthropometric factors | ||
Weight in kg | ||
Among premenopausal women | 64.5 (10.7) | 64.8 (11.2) |
Among perimenopausal women | 67.9 (12.3) | 66.8 (10.4) |
Among postmenopausal women | 69.1 (12.6) | 66.8 (10.9) |
Height in cm | ||
Among premenopausal women | 161.9 (6.5) | 162.1 (6.6) |
Among perimenopausal women | 162.6 (6.6) | 161.8 (6.8) |
Among postmenopausal women | 162.1 (6.6) | 161.2 (6.5) |
Body mass index in kg/m2 | ||
Among premenopausal women | 24.7 (4.2) | 24.7 (4.1) |
Among perimenopausal women | 25.7 (4.6) | 25.6 (4.0) |
Among postmenopausal women | 26.3 (4.7) | 25.7 (4.1) |
Waist circumference in cm (N missing=78) | ||
Among premenopausal women | 77.8 (10.2) | 78.0 (10.2) |
Among perimenopausal women | 81.8 (11.3) | 80.3 (11.1) |
Among postmenopausal women | 83.3 (11.7) | 81.5 (10.2) |
Hip circumference in cm (N missing= 78) | ||
Among premenopausal women | 99.4 (8.2) | 99.9 (8.4) |
Among perimenopausal women | 102.0 (9.1) | 101.3 (8.3) |
Among postmenopausal women | 103.3 (9.5) | 101.3 (8.0) |
Waist to hip ratio (N missing= 78) | ||
Among premenopausal women | 0.78 (0.06) | 0.78 (0.06) |
Among perimenopausal women | 0.80 (0.07) | 0.79 (0.09) |
Among postmenopausal women | 0.81 (0.07) | 0.80 (0.07) |
Comorbidities | ||
History of diabetes (N missing=60) | 40 (3) | 22 (1) |
History of hypertension | ||
No | 1078 (35) | 1094 (35) |
Yes | 354 (11) | 323 (10) |
Missing | 126 (4) | 141 (5) |