Table 1

Descriptive statistics of subjects stratified by case or control status (total observations with percentage in parentheses)

VariableCases (n = 428)Controls (n = 426)Total (n = 854)Pa
Age at entry (yrs)
 <5058 (13.5)86 (20.2)144 (16.9)
 50–5461 (14.3)76 (20.2)137 (16.0)
 55–5965 (15.2)65 (15.3)130 (15.2)
 60–6479 (18.5)59 (13.9)138 (16.2)
 65–6990 (21.0)83 (19.5)173 (20.3)
 70–7469 (16.1)51 (12.0)120 (14.1)
 ≥756 (1.4)6 (1.4)12 (1.4)0.05
Ethnicity
 African American117 (27.3)117 (27.5)234 (27.4)
 Japanese100 (23.4)100 (23.5)200 (23.4)
 Latina101 (23.6)99 (23.2)200 (23.4)
 White110 (25.7)110 (25.8)220 (25.8)0.9995
Family history of breast cancer
 Reported77 (18.0)42 (9.9)119 (13.9)0.0090
 Any <50 yrs33 (7.7)17 (4.0)50 (5.9)0.0015
Family history of ovarian cancer19 (4.4)21 (4.9)40 (4.7)0.8594
Age at first menstrual period (yrs)
 <13229 (54.1)211 (49.9)440 (52.0)
 13194 (45.9)212 (50.1)406 (48.0)0.2420
No. of children
 None29 (7.8)25 (6.7)54 (7.5)
 1–279 (21.2)104 (27.9)183 (25.3)
 2–3129 (34.6)141 (37.8)270 (37.3)
 4 or more114 (30.6)103 (27.6)217 (30.0)0.2475
Age of first full-term pregnancy (yrs)b
 <20108 (29.3)129 (34.6)237 (32.1)
 21–25129 (34.9)141 (37.8)270 (36.5)
 26–3087 (23.6)78 (20.9)162 (21.9)
 3145 (12.2)25 (6.7)70 (9.5)0.0356
  • a P was calculated by the χ2 test for heterogeneity (categorical variables) comparing cases with controls.

  • b Among parous women.