Table 3

RR and 95% CI of breast cancer according to quintiles of plasma total cysteine concentrations in the Nurses’ Health Study

QuintileP for trend
1 (lowest)2345 (highest)
Total cysteine (nmol/ml)<259259–283284–311312–351>351
Invasive cancer and in situ
 Cases/controls152/142160/143147/142136/143117/142
 Simple RRa (95% CI)1.01.01 (0.72–1.42)0.88 (0.63–1.25)0.74 (0.50–1.09)0.54 (0.34–0.87)0.008
 Multivariate RRb (95% CI)1.00.96 (0.66–1.39)0.88 (0.60–1.28)0.68 (0.44–1.05)0.44 (0.26–0.74)0.002
 Multivariate RRc (95% CI)1.01.03 (0.70–1.51)0.99 (0.66–1.49)0.80 (0.49–1.31)0.51 (0.27–0.94)0.04
Invasive cancer only
 Cases/controls126/116131/119126/117119/12598/123
 Simple RRa (95% CI)1.00.98 (0.67–1.42)0.90 (0.62–1.30)0.73 (0.48–1.10)0.50 (0.30–0.84)0.006
 Multivariate RRb (95% CI)1.00.97 (0.64–1.47)0.90 (0.59–1.37)0.71 (0.45–1.13)0.38 (0.21–0.68)0.001
 Multivariate RRc (95% CI)1.01.02 (0.66–1.57)1.00 (0.64–1.56)0.80 (0.47–1.36)0.38 (0.19–0.76)0.01
  • a Adjustments for matching factors only.

  • b 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, body mass index at blood collection, and duration of postmenopausal hormone use.

  • c Additional adjustments for plasma concentrations of folate, vitamin B6, vitamin B12 and total homocysteine.