Table 1

Age-standardized characteristics by plasma total cysteine concentrations in 712 controls in the Nurses’ Health Studya

CharacteristicsQuintile
1 (lowest)2345 (highest)
Age (yrs)5456585960
Plasma folate (ng/ml)89999
Plasma vitamin B6 (pmol/ml)7673767178
Plasma vitamin B12 (pg/ml)448438485473446
Plasma total homocysteine (nmol/ml)910111113
Alcohol intake ≥15 g/day (%)9812119
Postmenopausal (%)6568697169
Age at menarche (yrs)1312121312
Age at first birth (yrs)2425252425
Parity (births)33333
Body mass index at age 18 years (kg/m2)2121212121
Body mass index at blood collection (kg/m2)2425252626
Mother or sister with breast cancer (%)1313131814
History of benign breast disease (%)4855455053
Multivitamin supplement use (%)3938403840
Folate from foods and supplements (μg/day)b412407399410397
Vitamin B6 from foods and supplements (mg/day)b89887
Vitamin B12 from foods and supplements (μg/day)b1010111010
  • a All factors except age are directly standardized. Values presented here are means unless indicated otherwise.

  • b Average intakes calculated from the 1980, 1984, 1986, and 1990 food frequency questionnaires. Nutrients are adjusted for total energy intake.