Table 1.

Baseline characteristics of the subset of breast cancer cases and controls with plasma 25-OHD levels, Long Island Breast Cancer Study Project (1996-1997)

Baseline CharacteristicsCases (n = 1,026)Controls (n = 1,075)
Mean (SD)
Age (y)58.6 (12.5)56.1 (12.5)
Age at menarche (y)12.6 (1.5)12.5 (1.6)
Parity*2.4 (1.6)2.5 (1.6)
Age at first birth (y)*25.4 (4.6)25.1 (4.5)
BMI (kg/m2)26.6 (5.6)26.3 (5.8)
Plasma 25-OHD (ng/mL)27.1 (13.0)29.7 (15.1)
Percentage (%)
White94.492.4
Postmenopausal67.564.6
First-degree family history of breast cancer18.513.8
History of benign breast disease19.313.7
Ever breastfeeding34.236.2
Ever hormone replacement therapy29.727.5
  • *Among parous women (n = 890 cases and 955 controls).