Table 1.

Characteristic of breast cancer cases and controls at baseline

Cases (n = 2,414)*Controls (n = 2,414)*
Japanese American (%)26.716.9
White (%)26.917.2
African American (%)20.726.5
Latino (%)19.827.5
Hawaiian (%)5.811.8
Age at baseline (y)60.8 ± 8.458.3 ± 8.6
Age at blood draw (y)65.7 ± 8.563.0 ± 8.7
Age at menarche (y)12.6 ± 1.512.7 ± 1.5
Ever pregnant (%)89.991.6
Age at first birth(y)23.9 ± 5.022.9 ± 4.7
Parity2.6 ± 1.83.0 ± 1.9
Menopausal at baseline (%)87.282.3
Ever used HRT (%)57.447.7
Ever smoked (%)46.245.2
Current drinker (%)41.840.9
Family history(%)17.611.8
Body mass index (kg/m2)26.3 ± 6.127.0 ± 6.6
Folate from foods (μg/d)356 ± 204380 ± 252
Total folate§(μg/d)505 ± 327519 ± 354
Ethanol(g/d)4.9 ± 15.64.3 ± 14.6
  • NOTE: Mean ± standard deviation, except when specified as percentages.

  • * No. subjects was smaller for some risk factors due to missing data.

  • Among parous women only.

  • Family history of breast cancer in mother and sisters.

  • § Folate from foods and supplements.

  • Among drinkers the means were 11.7 ± 22.2 and 10.4 ± 21.2 g/d among cases and controls, respectively.