Table 2 Characteristics of participants from 19 cohort studies within the PBCCG (N = 783,830, breast cancer cases = 9,618)
From: Development and validation of a risk prediction model for premenopausal breast cancer in 19 cohorts
Characteristic | Mean (SD) or N (%)a |
|---|---|
Race/Ethnicity | |
 White | 455,286 (58%) |
 Black | 18,836 (2.4%) |
 Asian | 49,200 (6.3%) |
 Hispanic | 5,094 (< 1%) |
 Other/Unknown | 251,791 (32%) |
Age at baseline questionnaire (years) | 39.9 (6.9) |
Age at menarche (years) | 12.8 (1.5) |
Height (cm) | 164.2 (6.5) |
BMI (kg/m2) | 24.0 (4.5) |
Missing | 11,310 (1.4%) |
BMI age 18–21 (kg/m2)b | 21.2 (3.1) |
 Missing | 23,602 (3.0%) |
4-y weight change (kg)b | 0.5 (1.8) |
 Missing | 35,403 (4.5%) |
Current alcohol drinker (yes) | 393,978 (50%) |
 Missing current alcohol use | 241,439 (31%) |
Alcohol (drinks/week, among current drinkers)b | 4.2 (8.1) |
 Missing | 40,716 (65%) |
Family history of BCb | 77,747 (9.9%) |
 Missing | 55,482 (7%) |
History of benign breast diseaseb | 134,266 (17%) |
 Missing | 348,889 (44%) |
Parous | 618,405 (79%) |
 Parity (among parous) | 2.2 (1.1) |
  Missing | 6 (<0.1%) |
 Age at first birth (among parous) | 25.2 (4.5) |
  Missing | 4,670 (0.8%) |
 Breastfeeding months (among parous)b | 15 (11.8) |
  Missing | 120,085 (19%) |
Breast cancer cases | 9,618 (1.2%) |
Age at diagnosis (years) | 46.4 (4.8) |
In situ | 1673 (17%) |
Invasive | 7,914 (82%) |
  Stage I | 2393 (25%) |
  Stage II | 1843 (19%) |
  Stage III | 605 (6.3%) |
  Stage IV | 123 (1.3%) |
  Unknown | 3460 (32%) |
In situ vs. invasive status missing | 31 (0.3%) |
ER Status | |
 Positive | 4,735 (49%) |
 Negative | 1,517 (16%) |
Borderline/Unknown | 3,366 (35%) |
PR status | |
 Positive | 4,097 (43%) |
 Negative | 1,717 (18%) |
 Borderline/Unknown | 3,799 (39%) |
HER2 Status | |
 Positive | 657 (6.8%) |
 Negative | 2,877 (30%) |
 Borderline/Unknown | 6,084 (63%) |