Table 1.
Baseline characteristics of the pooled study populations of male breast cancer cases (n=449) and controls (n=13,855)
| Physical activity tertilea | |||
|---|---|---|---|
| Characteristic | Low | Medium | High |
| Cases/controls | 157/3884 | 177/5757 | 115/4214 |
| Age at entry (years), mean (SD)b, c | 61.0 (7.9) | 61.7 (7.6) | 62.1 (7.7) |
| Race, n (%) whiteb | 3499 (86.8) | 5293 (89.9) | 3882 (90.2) |
| Married, n (%) | 3316 (85.3) | 5064 (87.3) | 3625 (87.5) |
| Body mass index (kg/m2), mean (SD) | 27.3 (4.4) | 26.7 (3.8) | 26.0 (3.3) |
| Smoking status, n (%) | |||
| Never | 1269 (32.3) | 2006 (34.9) | 1479 (35.2) |
| Former | 1990 (50.7) | 3131 (54.4) | 2352 (56.0) |
| Current | 668 (17.0) | 615 (10.7) | 372 (8.9) |
| Diabetes, n (%) | |||
| No | 3333 (91.0) | 5280 (91.7) | 3832 (93.0) |
| Yes | 328 (8.9) | 480 (8.3) | 288 (7.0) |
| Alcohol (grams/day), mean (SD) | 17.3 (40.6) | 15.4 (33.7) | 15.7 (30.3) |
| Educational level, n (%) | |||
| Less than high school | 683 (17.3) | 457 (7.9) | 389 (9.2) |
| High school graduate | 625 (15.8) | 803 (13.8) | 650 (15.3) |
| Some college/vocational school | 914 (23.1) | 1485 (25.5) | 985 (23.2) |
| College graduate | 1728 (43.8) | 3069 (52.8) | 2229 (52.4) |
a
Physical activity tertiles were created from study specific distributions and then pooled.
b
Cohort control subjects were incidence-density matched to cases on sex, race, study center, date of birth, date of entry, and exit date.
c
Case-control subjects were frequency matched on age, and were sampled from provincial health insurance plans in Canada (coverage of >95% of Canadians).