RESUMO
BACKGROUND AND PURPOSE: The purpose of this case-cohort study was to examine urinary arsenic levels in relation to incident ischemic stroke in the United States. METHODS: We performed a case-cohort study nested within the REGARDS (REasons for Geographic and Racial Differences in Stroke) cohort. A subcohort (n=2486) of controls was randomly sampled within region-race-sex strata while all incident ischemic stroke cases from the full REGARDS cohort (n=671) were included. Baseline urinary arsenic was measured by inductively coupled plasma-mass spectrometry. Arsenic species, including urinary inorganic arsenic and its metabolites monomethylarsonic acid and dimethylarsinic acid, were measured in a random subset (n=199). Weighted Cox's proportional hazards models were used to calculate hazard ratios and 95% confidence intervals of ischemic stroke by arsenic and its species. RESULTS: The average follow-up was 6.7 years. Although incident ischemic stroke showed no association with total arsenic or total inorganic arsenic, for each unit higher level of urinary monomethylarsonic acid on a log-scale, after adjustment for potential confounders, ischemic stroke risk increased ≈2-fold (hazard ratio=1.98; 95% confidence interval: 1.12-3.50). Effect modification by age, race, sex, or geographic region was not evident. CONCLUSIONS: A metabolite of arsenic was positively associated with incident ischemic stroke in this case-cohort study of the US general population, a low-to-moderate exposure area. Overall, these findings suggest a potential role for arsenic methylation in the pathogenesis of stroke, having important implications for future cerebrovascular research.
Assuntos
Arsênio/toxicidade , Arsenicais/urina , Isquemia Encefálica , Acidente Vascular Cerebral , Idoso , Idoso de 80 Anos ou mais , Isquemia Encefálica/induzido quimicamente , Isquemia Encefálica/epidemiologia , Isquemia Encefálica/urina , Feminino , Seguimentos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Acidente Vascular Cerebral/induzido quimicamente , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/urina , Estados Unidos/epidemiologiaRESUMO
BACKGROUND/AIMS: In an attempt to find new predictors of stroke prognosis, we evaluated the association of albuminuria (AUr) and the estimated glomerular filtration rate (eGFR) with the recurrence of stroke and mortality. METHODS: We evaluated and followed for at least 7 months patients with first-ever stroke or transient ischemic attack admitted to a prospective cohort from March 2005 to December 2007. We analyzed traditional CV risk factors, albumin-to-creatinine ratio and eGFR (ml/min/1.73 m(2)) as predictors of mortality or recurrence. RESULTS: From a total of 185 patients included [57% (104/185) men, 64 ± 13 years], 38 patients suffered from a recurrent stroke or died, with a mean follow-up of 25.1 ± 8.7 months. AUr (≥30 mg/g) was found in 50.2% (93/185), and 38.9% (72/185) presented an eGFR <60. In univariate analysis, age >65 years, eGFR ≤50, atrial fibrillation (AF), no alcohol intake and AUr >17 mg/g were associated with the composite endpoint. In a multivariate analysis, AF and AUr >17 mg/g were independent predictors of the composite endpoints, but eGFR ≤50 was not. CONCLUSION: The presence of AUr >17 mg/g is independently associated with death or recurrence after stroke. Further studies should consider the AUr as a predictor for a worse prognosis in these patients.