Table 4

Multivariate RR and 95% CIa of breast cancer for 125 nmol/ml increment in plasma total cysteine by levels of other breast cancer risk factors

Risk factorCases/controlsRR (95% CI)P for interaction
Menopausal status
 Premenopausal149/1550.33 (0.13–0.83)
 Postmenopausal487/4840.72 (0.47–1.12)0.22
Plasma folate
 <Median (7.5 ng/ml)394/3560.64 (0.41–1.02)
 ≥Median318/3560.69 (0.44–1.08)0.78
Plasma vitamin B6
 <Median (48.5 pmol/ml)405/3560.78 (0.50–1.24)
 ≥Median307/3560.57 (0.36–0.90)0.21
Plasma vitamin B12
 <Median (423 pg/ml)355/3560.67 (0.42–1.04)
 ≥Median357/3560.64 (0.41–1.00)0.88
Plasma total homocysteine
 <Median (10.2 nmol/ml)361/3560.79 (0.46–1.35)
 ≥Median351/3560.55 (0.35–0.88)0.23
Alcohol intake
 <15 g/day641/6410.67 (0.46–1.00)
 ≥15 g/day71/710.55 (0.22–1.35)0.65
Body mass index at age 18 years
 <23 kg/m2589/5600.65 (0.44–0.97)
 ≥23 kg/m2123/1520.66 (0.36–1.21)0.97
Body mass index at blood collection
 <25 kg/m2387/4010.52 (0.33–0.81)
 ≥25 kg/m2325/3110.88 (0.56–1.40)0.04
Age at menarche
 <12 yrs172/1620.51 (0.28–0.95)
 ≥12 yrs540/5500.70 (0.47–1.05)0.29
Parity
 <3 births285/2820.68 (0.43–1.09)
 ≥3 births427/4300.64 (0.41–0.98)0.78
Mother or sister with breast cancer
 No593/6370.67 (0.45–1.00)
 Yes119/750.53 (0.24–1.14)0.53
History of benign breast disease
 No299/4060.61 (0.39–0.97)
 Yes413/3060.69 (0.44–1.09)0.64
  • a Adjustments for matching factors, age at menarche, parity, age at first birth, history of breast cancer in mother or a sister, history of benign breast disease, alcohol intake, body mass index at age 18 years, body mass index at blood collection, and duration of postmenopausal hormone use.