Plasma total cysteine and total homocysteine and risk of myocardial infarction in women: a prospective study.
BACKGROUND
Cysteine is a glutathione precursor, but is also a homocysteine byproduct. We prospectively evaluated relationships between fasting plasma concentrations of total cysteine and total homocysteine, and subsequent myocardial infarction (MI) in women.


METHODS
Among 32,826 women who provided blood samples between 1989 and 1990, 239 were diagnosed with incident MI after blood collection, but before July 1998. Of these women, 144 had provided a postfast sample. We matched controls to cases 2:1 by age, cigarette smoking status, and month and fasting status at the time of blood collection. We used conditional logistic regression to adjust for confounding.


RESULTS
Fasting total cysteine was positively related to MI risk in matching factor-adjusted analyses (rate ratio [RR] for highest vs lowest quartile 3.50 [95% CI 1.44-8.52]). However, after controlling for conventional risk factors of MI, it was not independently associated with risk (RR for highest vs lowest quartile 1.32 [95% CI 0.42-4.12, P trend = .10]). Fasting homocysteine was positively associated with MI risk; the multivariable adjusted RR for the highest versus the lowest quartile was 3.37 (95% CI 1.30-8.70, P trend = .014).


CONCLUSIONS
Fasting plasma concentration of total homocysteine, but not total cysteine, was positively associated with MI risk.
Page
John H
JH
Department of Epidemiology, Harvard School of Public Health, Harvard, MA, USA. john_page@post.harvard.edu
Ma
Jing
J
Chiuve
Stephanie E
SE
Stampfer
Meir J
MJ
Selhub
Jacob
J
Manson
Joann E
JE
Rimm
Eric B
EB
D000328:Adult; D016022:Case-Control Studies; D003545:Cysteine / Q000097:blood*; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood*; D012307:Risk Factors
D006710:Homocysteine; D003545:Cysteine