Table 1 Selected age-standardized characteristics of the 109,239 members of the Nurses’ Health Study II throughout follow-up (1989–2011)
Characteristic | Mean (SD) or % |
|---|---|
Age (years)a | 44.39 (7.81) |
Physical activity (MET-hrs/week) | 19.58 (27.81) |
Body mass index (BMI) at age 18 (kg/m2) | 21.22 (3.17) |
Difference between current BMI and BMI at age 18 | 5.03 (5.15) |
White | 95 |
History of biopsy confirmed benign breast disease | 16 |
Family history of breast cancer | 11 |
Screening mammogram in past 2 years | 50 |
Age at menarche (years) | |
< 12 | 24 |
12 | 30 |
13 | 27 |
14+ | 18 |
Parity | |
Nulliparous | 18 |
Parous, by number of children | |
1–2 | 47 |
3–8 | 24 |
Height (inches) | |
50 < − < 62 | 9 |
62- < 65 | 37 |
65- < 68 | 38 |
68+ | 16 |
Oral contraceptive use | |
Never | 12 |
Past | 73 |
Current | 7 |
Menopausal status and hormone use | |
Premenopausal | 72 |
Postmenopausal never users | 4 |
Postmenopausal past users | 9 |
Postmenopausal current users | 8 |
Smoking status | |
Never | 65 |
Past | 24 |
Current | 9 |
Rotating Shift Work | |
Never | 32 |
1–9 years | 62 |
≥ 10 years | 6 |
Individual level socioeconomic status | |
Married | 56 |
Not Married | 44 |
Live alone | 7 |
Live with others | 93 |
Personal income in 2001 | |
less than 100,000 | 40 |
100–149,000 | 14 |
150,000+ | 8 |
Not reported | 38 |
Census tract level socioeconomic status | |
Median home value | 160,490 (121,757) |
Median income | 62,781 (23,818) |
Region of residence | |
Northeast | 31 |
Midwest | 34 |
West | 15 |
South | 20 |