Table 1.

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 education401 (30.5)309 (25.7)308 (23.2)339 (24.4)217 (27.2)
    Lower technical, secondary583 (44.1)574 (47.7)623 (46.9)614 (44.2)368 (46.1)
    High technical, secondary162 (12.3)160 (13.3)176 (13.2)204 (14.7)102 (12.8)
    Academic167 (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 smoked625 (47.6)561 (46.7)632 (47.6)675 (48.6)350 (43.9)
    Past smoker382 (29.1)384 (31.9)444 (33.4)478 (34.4)282 (35.3)
    Current smoker306 (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.