Plasma total cysteine, mortality, and cardiovascular disease hospitalizations: The Hordaland Homocysteine Study

Background: We have previously reported a positive association between tHcy and mortality and cardiovascular disease (CVD) hospitalizations in the Hordaland Homocysteine Study cohort. Using the same data set, we assessed the relationship between plasma total cysteine (tCys) and mortality from all causes and from cardiovascular and noncardiovascular conditions, and the association between tCys and the risk of hospitalizations from CVD. Methods: We measured plasma tCys in blood samples from 12 595 men and women 40-42 years of age and from 4766 men and women 65-67 years of age, collected as part of the Hordaland Homocysteine Study in the year 1992-1993. Follow-up data on mortality were collected through 1999. Data on CVD hospitalizations were collected from hospital records up to May 31, 1998. Results: After a follow-up time of 6.6-7.6 years, there were a total of 610 deaths, of which 243 were cardiovascular deaths and 367 were noncardiovascular deaths. There was no association between tCys and all-cause, cardiovascular, or noncardiovascular mortality. When we used tCys values <247.6 mumol/L (lowest quartile) as the reference category, the adjusted mortality ratio (MR) for all-cause mortality at tCys concentrations of 247.6-270.79, 270.8-295.79, and greater than or equal to295.8 mumol/L (highest quartile) were 1.0, 0.9, and 1.0, respectively. The adjusted MRs for cardiovascular mortality were 1.0, 1.1, and 1.1, respectively. There were no associations between tCys and 1275 CVD hospitalizations, except that tCys was significantly associated with hospitalizations from coronary artery bypass grafting. Conclusion: Plasma tCys is not associated with mortality or CVD hospitalizations. (C) 2003 American Association for Clinical Chemistry.