Table 1 Selected characteristics in all cohort and breast cancer cases
From: Association between allostatic load and breast cancer risk: a cohort study
|  | All cohort (N = 181,455) | Breast cancer case (N = 5,701) | P value |
|---|---|---|---|
Age at recruitment, mean (SD) | 56.11 (8.01) | 56.85 (7.79) |  < 0.01 |
Median follow-up for cases, Years | Â | 6.21 | Â |
Race, N (%) |  |  |  < 0.01 |
 White | 171,379 (94.45%) | 5,457 (95.72%) |  |
 Black | 2,791 (1.54%) | 55 (0.96%) |  |
 Asian | 3,796 (2.09%) | 106 (1.86%) |  |
 Mixed or others | 2,977 (1.64%) | 66 (1.16%) |  |
 Missing | 512 (0.28%) | 17 (0.30%) |  |
Age of menarches, mean (SD) | 12.98 (1.62) | 12.93 (1.62) | 0.04 |
Age at first live birth, mean (SD) | 25.42 (4.63) | 25.49 (4.62) | 0.07 |
Ever taken oral contraceptive pill, N (%) | Â | Â | 0.93 |
 Yes | 147,276 (81.16%) | 4,634 (81.28%) |  |
 No | 33,667 (18.55%) | 1,056 (18.52%) |  |
 Missing | 512 (0.28%) | 11 (0.19%) |  |
Ever used hormone-replacement therapy, N (%) |  |  |  < 0.01 |
 Yes | 68,304 (37.64%) | 2,331 (40.89%) |  |
 No | 112,578 (62.04%) | 3,352 (58.80%) |  |
 Missing | 573 (0.32%) | 18 (0.32%) |  |
Had menopause, N (%) |  |  |  < 0.01 |
 Yes | 10,8513 (59.80%) | 3,532 (61.95%) |  |
 No | 44,780 (24.68%) | 1,285 (22.54%) |  |
 Missing | 28,162 (15.52%) | 884 (15.51%) |  |
Family History of breast cancer, N (%) |  |  |  < 0.01 |
 Yes | 10,3907 (57.26%) | 3,141 (55.10%) |  |
 No | 9,274 (5.11%) | 440 (7.72%) |  |
 Missing | 68,274 (37.63%) | 2,120 (37.19%) |  |
Education, N (%) | Â | Â | 0.14 |
 High school or less | 82,700 (45.58%) | 2,584 (45.33%) |  |
 College/professional | 67,244 (37.06%) | 2,174 (38.13%) |  |
 Missing | 31,511 (17.37%) | 943 (16.54%) |  |
Employment, N (%) |  |  |  < 0.01 |
 Unemployment | 16,706 (9.21%) | 487 (8.54%) |  |
 Employment | 101,377 (55.87%) | 3,094 (54.27%) |  |
 Retired | 61,651 (33.98%) | 2,077 (36.43%) |  |
 Missing | 1,721 (0.95%) | 43 (0.75%) |  |
Income, N (%) | Â | Â | 0.51 |
 < £30,999 | 75,416 (41.56%) | 2,506 (43.95%) |  |
 ≥ £30,999 | 74,697 (41.17%) | 2,262 (39.68%) |  |
 Missing | 31,341 (17.27%) | 933 (16.37%) |  |
Townsend deprivation score (Z-score, mean/SD) | − 1.39 (3.00) | − 1.43 (2.93) | 0.16 |
Cigarette smoking, N (%) | Â | Â | 0.03 |
 Never | 108,780 (59.95%) | 3,325 (58.32%) |  |
 Ever | 72,038 (39.70%) | 2,360 (41.40%) |  |
 Missing | 634 (0.35%) | 16 (0.28%) |  |
Total physical activity MET-hours/week ((Z-score, mean/SD)) | 42.02 (41.21) | 39.61 (39.93) |  < 0.01 |
Alcohol consumption, N (%) |  |  |  < 0.01 |
 Special occasions or never | 43,976 (24.24%) | 1,288 (22.59%) |  |
 Moderate | 70,460 (38.83%) | 2,103 (36.89%) |  |
 Heavy | 66,878 (36.86%) | 2,308 (40.48%) |  |
 Missing | 141 (0.08%) | 2 (0.04%) |  |
Sleep quality, N (%) | Â | Â | 0.48 |
 Never/rarely sleepless | 34,586 (19.06%) | 1,071 (18.79%) |  |
 Sometimes sleepless | 89,381 (49.26%) | 2,792 (48.97%) |  |
 Usual sleepless | 57,385 (31.62%) | 1,837 (32.22%) |  |
 Missing | 103 (0.06%) | 1 (0.02%) |  |
Standard PRS for breast cancer (Z-score, mean/SD) | − 0.17 (1.00) | 0.38 (1.00) | < 0.01 |