Our data suggest that moderately elevated tHcy levels are prevalent in our population and are associated with an increased risk for CAD. This study provides evidence that the MTR A2756G and MTRR A66G polymorphisms significantly influence the circulating homocysteine concentration. In addition, the MTR and MTRR genes may interact to increase the risk for having hyperhomocysteinaemia.

Increased plasma total homocysteine (tHcy) levels have been shown to be a risk factor for coronary artery disease (CAD). The common methylenetetrahydrofolate reductase C677T (MTHFR C677T) polymorphism has been reported to be a strong predictor of mild hyperhomocysteinaemia (HHcy). We assessed whether this mutation was associated with increased risk of CAD and plasma levels of tHcy. We also evaluated interactions between this polymorphism, mild elevated tHcy levels and conventional risk factors of CAD. Method. Using PCR-RFLP analysis, we studied the frequency of the C677T genotypes and its effect on CAD and on tHcy concentrations in 400 subjects without and with CAD angiographically confirmed. There were 210 subjects with CAD and 190 subjects without CAD. Results. The frequencies of the C677T genotypes were 53% (59.5% in controls versus 48.1% in cases), 34.8% (32.1 in controls versus 37.1 in cases), and 11.8% (8.4% in controls versus 14.8% in cases), respectively, for 677CC, 677CT, and 677TT. The genotype frequencies were significantly different between case and control groups (P < .05). The 677T allele enhances the risk of CAD associated to HHcy (P < .01). In multivariate analysis models, MTHFR C677T polymorphism effect on CAD was masked by other risk factors. HHcy was only and independently influenced by MTHFR polymorphism and smoking habits, and it is a strong predictor of CAD independently of conventional risk factors. Conclusion. Our data suggest that HHcy is strongly and independently associated to CAD risk increase; and MTHFR C677T polymorphism and smoking habits were the main predictors of tHcy levels. The CAD risk increase is mainly associated with mild HHcy in 677TT, whereas in 677CT and 677CC it is mainly associated with the conventional risk factors.

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Prévalence et facteurs prédictifs de l'hypertension « de la blouse blanche » dans une importante base de données de mesure ambulatoire de la pression artérielle RÉSUMÉ Cette étude avait pour objectif de déterminer la prévalence de l'effet blouse blanche et de l'hypertension de la blouse blanche, et de recenser les variables cliniques qui sont des facteurs prédictifs de ce type d'hypertension. Au total, 2 462 sujets ont fait l'objet d'une mesure ambulatoire de la pression artérielle, en raison d'une hypertension légère (groupe 1), aux fins de l'évaluation d'un traitement antihypertenseur (groupe 2), ou en raison d'une hypotension (groupe 3). Dans la population générale, 33,0 % des sujets présentaient une hypertension de la blouse blanche, 32,8 % dans le groupe 1 et 37,0 % dans le groupe 2. Dans l'analyse multivariée, le sexe et le niveau d'hypertension étaient des facteurs prédictifs indépendants d'hypertension de la blouse blanche. ABSTRACT The objective of this study was to determine both the prevalence of white-coat effect and white-coat hypertension (WCH) and which selected clinical variables were predictors of WCH. A total of 2462 patients underwent ambulatory blood pressure monitoring either in borderline hypertension (group 1) or for assessment of antihypertensive treatment (group 2) or for hypotension (group 3). In the overall population 33.0% of patients showed WCH, 32.8% in group 1 and 37.0% in group 2. In multivariate analysis, sex and grade of hypertension were independent predictors of WCH in groups 1 and 2.

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