Table 1.
Characteristics of the Study Population by Diabetes Status
| Characteristica | Category | No diabetes | Type 2 diabetesb |
|---|---|---|---|
| Participants | Number | 89,163 | 14,558 |
| Person-years | Number | 1,325,439 | 205,002 |
| Breast cancer cases | Number | 5,703 | 896 |
| Age at cohort entry | Mean ± std | 59.7±8.9 | 61.6±8.1 |
| Age at diabetes diagnosis | Mean ± std | NA | 62.4±8.0 |
| Age at breast cancer | Mean ± std | 67.9±9.2 | 69.6±8.2 |
| Follow-up time | Mean ± std | 14.9±4.1 | 14.1±4.4 |
| Ethnicity | White | 23,219 (26.0) | 1,927 (13.2) |
| African American | 16,500 (18.5) | 3,755 (25.8) | |
| Native Hawaiian | 6,343 (7.1) | 1,338 (9.2) | |
| Japanese American | 24,578 (27.6) | 3,434 (23.6) | |
| Latina | 18,523 (20.8) | 4,104 (28.2) | |
| US-born | 9,051 (10.2) | 2,367 (16.3) | |
| Foreign-born | 9,472 (10.6) | 1,737 (11.9) | |
| Education, yrs | ≤12 | 40,815 (45.8) | 8,300 (57.0) |
| 13-15 | 26,405 (29.6) | 3,828 (26.3) | |
| ≥16 | 21,943 (24.6) | 2,430 (16.7) | |
| BMI (kg/m2) | <20 | 7,943 (8.9) | 332 (2.3) |
| ≥20 to <25 | 36,345 (40.8) | 2,761 (19.0) | |
| ≥25 to <30 | 27,795 (31.2) | 5,062 (34.8) | |
| ≥30 | 17,080 (19.2) | 6,403 (44.0) | |
| Family history of breast cancer | Number | 9,286 (10.4) | 1,619 (11.1) |
| Smoking status | Never | 48,837 (54.8) | 7,676 (52.7) |
| Past | 25,702 (28.8) | 4,674 (32.1) | |
| Current | 13,041 (14.6) | 1,902 (13.1) | |
| Alcohol intake, drinks | <1 mo | 54,277 (60.9) | 11,211 (77.0) |
| ≥1/mo-<1/day | 22,293 (25.0) | 2,049 (14.1) | |
| ≥1/day | 8,109 (9.1) | 468 (3.2) | |
| Physical activity | <30 min/day | 35,907 (40.3) | 7,282 (50.0) |
| ≥30 min/day | 51,112 (57.3) | 6,760 (46.4) | |
| Age at menarche, yrs | ≤12 | 42,781 (48.0) | 7,724 (53.1) |
| 13-14 | 33,925 (38.1) | 4,932 (33.9) | |
| ≥15 | 11,033 (12.4) | 1,632 (11.2) | |
| Parity | 0 | 11,516 (12.9) | 1,443 (9.9) |
| 1 | 10,361 (11.6) | 1,365 (9.4) | |
| 2-3 | 39,499 (44.3) | 5,291 (36.3) | |
| ≥4 | 26,704 (30.0) | 6,254 (43.0) | |
| Age at first live birth, yrs | ≤20 | 11,702 (13.1) | 1,476 (10.1) |
| 21-30 | 24,999 (28.0) | 5,271 (36.2) | |
| ≥31 | 44,294 (49.7) | 6,613 (45.4) | |
| Hormone therapy use | Never/pre | 45,822 (51.4) | 7,927 (54.5) |
| Past estrogen | 13,342 (15.0) | 2,590 (17.8) | |
| Current estrogen | 11,707 (13.1) | 1,673 (11.5) | |
| Combined | 14,201 (15.9) | 1,501 (10.3) |
a
N (%) unless otherwise indicated; percentages do not add to 100 due to missing values : 6,299 family history of breast cancer; 1,889 smoking status; 5,314 alcohol intake; 2,660 physical activity; 1,694 age at menarche; 1,288 parity; 2,820 age at first live birth; 4,958 hormone therapy; 9,358 age at menopause.
b
Women with self-reported type 2 diabetes confirmed by at least one administrative data source