Sustained Homocysteine-Lowering Effect over Time of Folic Acid-Based Multivitamin Therapy in Stroke Patients despite Increasing Folate Status in the Population
Notice bibliographique
Résumé
BACKGROUND AND AIMS: It is uncertain what impact increasing voluntary folate fortification may be having on the statistical power of randomized trials testing the homocysteine hypothesis of atherothrombosis. The objective of this study was to determine whether there has been a change in folate status between 1998 and 2002 in stroke patients randomized into the VITAmins TO Prevent Stroke (VITATOPS) Study at a single center in Perth, Australia, and what impact this may have had on the magnitude of the homocysteine-lowering effect achieved over time with folic acid-based multivitamin therapy. METHODS: We conducted a randomized, double-blind, placebo-controlled study involving 285 patients with stroke or transient ischemic attack who were recruited between 1998 and 2002 and randomized to long-term folic acid 2.0 mg/day, pyridoxine 25 mg/day and cobalamin 0.5 mg/day (active VITATOPS medication) or placebo. Fasting plasma total homocysteine, red cell folate, serum cobalamin and serum pyridoxine levels were measured at baseline and 6 months, and the change in blood levels over 4 time quartiles and differences in levels between the two randomized treatments were examined. RESULTS: Between 1998 and 2002, there was a significant rise in baseline mean red cell folate levels over 4 time quartiles among the entire stroke cohort (723.3, 780.1, 922.6 and 1,023.7 nmol/l in the first, second, third and fourth quartiles, respectively; p < 0.0001), but this was not associated with a spontaneous reduction in mean baseline total homocysteine levels during the same time period (12.7, 14.3, 12.1 and 12.8 micromol/l in the first, second, third and fourth quartiles, respectively; p = 0.55). The homocysteine-lowering effect of the active VITATOPS trial medication at 6 months after randomization also did not change significantly between 1998 and 2002 (difference between randomized groups: -4.1, -4.1, -3.1 and -3.6 micromol/l in the first, second, third and fourth quartiles, respectively; p = 0.56). CONCLUSIONS: The homocysteine-lowering effect of the active VITATOPS trial medication has not attenuated significantly in the past 5 years despite increasing voluntary fortification of foods with folic acid as reflected by a progressive rise in baseline folate status. These data suggest that in the continuing absence of a program of mandatory folate fortification of food in populations served by centers participating in the VITATOPS trial, the study will remain adequately powered to test the homocysteine-lowering hypothesis for which it was designed.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».