General characteristics of the study population
| Lifetime cumulative number of menstrual cycles | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| ≤415 (n = 1,313) | 416-453 (n = 1,203) | 454-490 (n = 1,329) | ≥491 (n = 1,388) | Always irregular (n = 798) | ||||||
| Age at enrollment* | 59.45 (5.87) | 58.83 (5.51) | 59.56 (5.19) | 60.4 (4.9) | 59.2 (5.6) | |||||
| Body mass index* | 25.98 (4.23) | 25.89 (3.98) | 26.06 (3.95) | 26.44 (4.1) | 26 (4.3) | |||||
| Educational level (%) | ||||||||||
| Primary education | 401 (30.5) | 309 (25.7) | 308 (23.2) | 339 (24.4) | 217 (27.2) | |||||
| Lower technical, secondary | 583 (44.1) | 574 (47.7) | 623 (46.9) | 614 (44.2) | 368 (46.1) | |||||
| High technical, secondary | 162 (12.3) | 160 (13.3) | 176 (13.2) | 204 (14.7) | 102 (12.8) | |||||
| Academic | 167 (12.7) | 160 (13.3) | 222 (16.7) | 231 (16.6) | 111 (13.9) | |||||
| Ever married (%) | 1,257 (95.7) | 1,144 (95.1) | 1,241 (93.37) | 1,221 (88.0) | 729 (91.4) | |||||
| Cigarette smoking habits (%) | ||||||||||
| Never smoked | 625 (47.6) | 561 (46.7) | 632 (47.6) | 675 (48.6) | 350 (43.9) | |||||
| Past smoker | 382 (29.1) | 384 (31.9) | 444 (33.4) | 478 (34.4) | 282 (35.3) | |||||
| Current smoker | 306 (23.3) | 257 (21.4) | 253 (19.0) | 235 (16.9) | 166 (20.8) | |||||
| Mother or sister with breast cancer (%) | 153 (11.7) | 139 (11.6) | 182 (13.7) | 214 (15.4) | 101 (12.7) | |||||
↵* Mean ± SD.