Table 1

Characteristics of study subjects

CharacteristicCases (n = 88)Controls (n = 168)Pa
Age at enrollment,b yr, mean (SD)58.7 (5.1)58.8 (5.0)
Age at menarche, yr, mean (SD)12.8 (1.6)12.9 (1.5)0.60
Age at first full-term pregnancy, yr, mean (SD)24.9 (6.0)24.8 (4.9)0.56
Age at menopause, yr, mean (SD)50.2 (4.4)48.8 (5.5)0.06
First-degree family history of breast cancer, n (%)
 No73 (83%)141 (85%)
 Yes15 (17%)25 (15%)0.57
Parity, n (%)
 Never pregnant23 (27%)29 (17%)
 Ever pregnant63 (73%)138 (83%)0.08
Oral contraceptive use, n (%)
 Never62 (70%)106 (63%)
 Ever12 (14%)36 (21%)0.07
 Unknown14 (16%)26 (16%)
Hormone replacement therapy, n (%)
 Never48 (55%)106 (63%)
 Ever26 (29%)42 (25%)0.34
 Unknown14 (16%)20 (12%)
Cigarette smoking, n (%)
 Never44 (50%)69 (41%)
 Ever28 (32%)65 (39%)0.08
 Unknown16 (18%)34 (20%)
Height (cm), mean (SD)161.0 (7.0)161.9 (5.7)0.32
Weight (kg), mean (SD)66.0 (11.0)69.9 (13.1)0.03
Body mass index (kg/m2) mean (SD)25.4 (3.9)26.6 (4.5)0.05
  • a Mixed effect linear regression model for continuous variables (after natural log-transformation); conditional logistic regression for categorical variables.

  • b Matching criteria.