Table 1.
Distribution of selected characteristics given as %a and mean (SD)b for postmenopausal women at baseline in 1993–96, by race/ethnicity and breast cancer status in the Multiethnic Cohort study, followed to 2013 (n = 67 313)
| African American (n = 12 776) |
Native Hawaiian (n = 4286) |
Japanese American (n = 19 043) |
Latina (n = 14 371) |
White (n = 16 837) |
||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Cases | Non-cases | Cases | Non-cases | Cases | Non-cases | Cases | Non-cases | Cases | Non-cases | |
| No. of participants | 754 | 12 022 | 375 | 3911 | 1306 | 17 737 | 667 | 13 704 | 1128 | 15 709 |
| Age at cohort entry, yearsb | 63.0 (7.4) | 62.8 (7.8) | 58.9 (7.4) | 59.1 (8.0) | 62.6 (7.1) | 63.2 (7.6) | 61.1 (6.7) | 60.7 (6.8) | 61.7 (7.6) | 61.3 (8.0) |
| Person-years of follow-up | 7790 | 207 873 | 3883 | 69 225 | 13 064 | 331 685 | 6848 | 254 293 | 11 007 | 284 427 |
| Follow-up yearsb | 9.3 (5.7) | 16.3 (5.8) | 9.3 (5.5) | 16.7 (5.1) | 9.0 (5.5) | 17.7 (4.1) | 9.3 (5.6) | 17.6 (4.4) | 8.8 (5.4) | 17.1 (4.8) |
| Incidence/100 000c | 247.5 | 402.6 | 325.8 | 216.8 | 288.0 | |||||
| Age at diagnosis, yearsb | 72.9 (8.5) | 68.7 (8.3) | 72.1 (8.6) | 70.8 (8.3) | 71.0 (8.5) | |||||
| Family history of breast cancera | 17.2 | 10.7 | 18.1 | 13.1 | 15.1 | 10.2 | 15.4 | 8.4 | 18.0 | 11.8 |
| Current smokera | 18.0 | 20.0 | 20.5 | 22.5 | 6.6 | 8.4 | 11.5 | 10.4 | 15.3 | 16.6 |
| Ever smokera | 56.2 | 56.3 | 55.7 | 55.8 | 30.9 | 30.5 | 36.4 | 36.2 | 57.4 | 55.7 |
| Age at smoking initiation, yearsb,d | 31.6 (11.2) | 31.5 (11.1) | 26.6 (11.1) | 27.3 (10.3) | 30.3 (9.8) | 30.7 (10.1) | 31.9 (10.6) | 33.1 (11.4) | 27.8 (9.9) | 27.8 (9.6) |
| Smoking duration, yearsb,d | 22.3 (12.6) | 23.4 (12.3) | 23.9 (11.8) | 23.9 (12.1) | 19.7 (12.3) | 21.0 (12.5) | 20.1 (12.3) | 18.7 (12.9) | 23.5 (12.6) | 23.5 (12.8) |
| No. of cigarettes smoked/dayb,d | 10.9 (6.3) | 11.4 (6.6) | 14.8 (7.7) | 14.0 (7.6) | 12.2 (6.5) | 12.3 (6.9) | 10.0 (6.5) | 9.2 (6.2) | 15.3 (8.3) | 15.8 (8.4) |
| Pack-years of smokingb,d | 14.0 (12.5) | 14.8 (12.8) | 19.5 (15.1) | 18.4 (14.9) | 13.9 (12.7) | 14.7 (13.3) | 11.5 (11.5) | 10.1 (11.5) | 20.4 (17.1) | 20.9 (17.3) |
| Smokers who started to smoke before the first childbirtha,d,e | 21.9 | 19.2 | 35.1 | 30.1 | 35.3 | 30.1 | 13.9 | 17.2 | 36.9 | 33.4 |
| Years of smoking before first childbirthb,d,e | 5.7 (3.9) | 5.1 (4.2) | 5.7 (5.0) | 5.1 (4.1) | 5.8 (3.8) | 5.4 (4.2) | 5.4 (5.2) | 5.5 (4.5) | 6.2 (4.3) | 5.5 (4.3) |
| Body mass index (kg/m2)b | 29.0 (5.4) | 28.8 (5.7) | 29.3 (6.2) | 28.2 (6.1) | 24.3 (3.9) | 23.4 (3.7) | 28.1 (5.2) | 27.8 (5.1) | 25.7 (4.9) | 25.7 (5.2) |
| ≥13 years of educationa | 65.8 | 59.0 | 41.9 | 41.1 | 59.6 | 52.9 | 32.8 | 27.7 | 69.1 | 68.2 |
| Age at menarche, yearsb | 13.1 (1.6) | 13.2 (1.7) | 12.8 (1.7) | 12.9 (1.7) | 13.1 (1.6) | 13.3 (1.7) | 13.3 (1.7) | 13.2 (1.7) | 13.1 (1.7) | 13.1 (1.6) |
| Parous womena | 85.8 | 86.6 | 90.7 | 93.1 | 84.9 | 87.1 | 89.2 | 91.7 | 83.1 | 84.2 |
| Number of childrenb,e | 3.2 (1.8) | 3.4 (1.9) | 4.0 (1.8) | 4.0 (1.8) | 2.7 (1.1) | 2.8 (1.2) | 3.9 (1.8) | 4.1 (1.9) | 2.8 (1.4) | 3.0 (1.5) |
| Age at first childbirth, yearsb,e | 21.8 (4.6) | 21.4 (4.6) | 21.6 (4.0) | 21.6 (3.8) | 25.7 (4.2) | 25.2 (4.1) | 22.6 (4.7) | 22.1 (4.5) | 24.0 (4.5) | 23.4 (4.4) |
| Ever postmenopausal hormone therapy usea | 49.7 | 46.0 | 54.9 | 51.7 | 67.0 | 59.2 | 52.8 | 47.7 | 72.3 | 66.5 |
| Age at menopause, yearsb,f | 48.7 (5.4) | 48.3 (5.4) | 48.6 (5.3) | 48.1 (5.4) | 50.2 (4.5) | 49.7 (4.7) | 48.5 (5.4) | 48.0 (5.3) | 49.4 (4.8) | 48.7 (5.0) |
| Menopause typea | ||||||||||
| Natural | 56.1 | 55.5 | 72.0 | 65.9 | 72.7 | 71.3 | 69.3 | 68.7 | 69.6 | 65.7 |
| Oophorectomy | 21.9 | 23.0 | 17.9 | 22.7 | 17.5 | 18.4 | 14.5 | 15.2 | 16.8 | 20.8 |
| Hysterectomy | 22.0 | 21.5 | 10.1 | 11.4 | 9.9 | 10.2 | 16.2 | 16.1 | 13.6 | 13.5 |
| Non-drinkersa | 63.3 | 63.4 | 65.1 | 64.6 | 78.1 | 79.2 | 60.9 | 64.7 | 35.2 | 40.9 |
| Alcohol consumption, g/dayg | ||||||||||
| Mean (SD) | 14.7 (28.1) | 12.1 (27.7) | 11.5 (20.7) | 12.4 (27.1) | 6.6 (12.3) | 6.1 (11.7) | 7.2 (15.2) | 7.1 (17.3) | 17.6 (24.3) | 15.4 (24.2) |
| Median (min, max) | 4.1 (0.4, 208) | 3.3 (0.0, 392) | 3.9 (0.2, 154) | 3.7 (0.0, 403) | 1.6 (0.4, 106) | 1.7 (0.2, 248) | 2.4 (0.4, 186) | 2.2 (0.0, 328) | 9.8 (0.4, 263) | 6.6 (0.2, 428) |
aValues are percents.
bValues are means (standard deviations).
cRates, truncated to ages 45–85, were adjusted to the 2000 US standard population.
dAmong ever smokers.
eAmong parous women.
fNatural menopause.
gAmong drinkers.