SERUM TOTAL HOMOCYSTEINE AND CORONARY HEART-DISEASE

Background. Several studies have observed high plasma levels of homocy steine among patients with coronary heart disease (CHD). The only pros pective study was based on US physicians, and concluded that homocyste ine was associated with subsequent myocardial infarction (MI). However , the association was limited to those above a threshold level of homo cysteine. Methods. We conducted a nested case-control study among the 21 826 subjects, aged 12-61 years, who were surveyed in the municipali ty of Tromso, Norway, Among those free from MI at the screening, 123 l ater developed CHD. Four controls were selected for each case. Results . Level of homocysteine was higher in cases than in controls (12.7 +/- 4.7 versus 11.3 +/- 3.7 mu mol/l (mean +/- SD); P = 0.002). The relat ive risk for a 4 mu mol/l increase in serum homocysteine was 1.41 (95% confidence interval (CI):1.16-1.71). Adjusting for possible confounde rs reduced the relative risk to 1.32 (95% CI:1.05-1.65). There was no threshold level above which serum homocysteine is associated with CHD events, Conclusions. In the general population serum total homocystein e is an independent risk factor for CHD with no threshold level.