Are myocardial infarction--associated single-nucleotide polymorphisms associated with ischemic stroke?

BACKGROUND AND PURPOSE: Ischemic stroke (IS) shares many common risk factors with coronary artery disease (CAD). We hypothesized that genetic variants associated with myocardial infarction (MI) or CAD may be similarly involved in the etiology of IS. To test this hypothesis, we evaluated whether single-nucleotide polymorphisms (SNPs) at 11 different loci recently associated with MI or CAD through genome-wide association studies were associated with IS. METHODS: Meta-analyses of the associations between the 11 MI-associated SNPs and IS were performed using 6865 cases and 11 395 control subjects recruited from 9 studies. SNPs were either genotyped directly or imputed; in a few cases a surrogate SNP in high linkage disequilibrium was chosen. Logistic regression was performed within each study to obtain study-specific ßs and standard errors. Meta-analysis was conducted using an inverse variance weighted approach assuming a random effect model. RESULTS: Despite having power to detect odds ratio of 1.09-1.14 for overall IS and 1.20-1.32 for major stroke subtypes, none of the SNPs were significantly associated with overall IS and/or stroke subtypes after adjusting for multiple comparisons. CONCLUSIONS: Our results suggest that the major common loci associated with MI risk do not have effects of similar magnitude on overall IS but do not preclude moderate associations restricted to specific IS subtypes. Disparate mechanisms may be critical in the development of acute ischemic coronary and cerebrovascular events.

Association of cardiorespiratory fitness and morphological brain changes in the elderly: results of the Austrian Stroke Prevention Study.

BACKGROUND: Physical activity and cardiorespiratory fitness relate to better cognitive performance. Little is known about the effects of fitness on structural brain abnormalities in the elderly. OBJECTIVE: Assess the association between maximal oxygen consumption (VO(2)max), white matter lesion (WML) volume and brain parenchymal fraction (BPF) in a large cohort of community-dwelling elderly individuals. METHODS: The study population consisted of 715 participants of the Austrian Stroke Prevention Study who underwent brain MRI with semi-automated measurement of WML volume (cm(3)) and automated assessment of BPF (%) by the use of SIENAX. A maximal exercise stress test was done on a bicycle ergometer. VO(2)max was calculated based on maximum and resting heart rate. RESULTS: After adjustment for possible confounders, VO(2)max was independently associated with WML volume (ß = -0.10; p = 0.02); no significant relationship existed with silent cerebral infarcts and BPF. Associations between VO(2)max and WML load were only significant in men, but not in women. CONCLUSION: Our findings may have important preventive implications because WMLs are known to be a major determinant of cognitive decline and disability in old age.

Association between higher plasma lutein, zeaxanthin, and vitamin C concentrations and longer telomere length: results of the Austrian Stroke Prevention Study.

OBJECTIVES: To examine the association between plasma concentrations of antioxidative micronutrients and leukocyte telomere length (LTL) in elderly adults. DESIGN: Cross-sectional cohort study. SETTING: Austrian Stroke Prevention Study, a population-based cohort study on brain aging. PARTICIPANTS: Individuals with a mean age of 66 ± 7 (n = 786; 58% female). MEASUREMENTS: Concentrations of vitamin C, lutein, zeaxanthin, ß-cryptoxanthin, canthaxanthin, lycopene, α- and γ-tocopherol, α- and ß-carotene, and retinol in plasma, advanced oxidation protein products as a measure of oxidative stress in serum, and LTL were measured. Vitamins and carotenoids were measured using high-performance liquid chromatography, advanced oxidation protein products using spectrophotometry, and telomere length using quantitative real-time polymerase chain reaction. RESULTS: Multiple linear regression analyses with adjustment for age and sex demonstrated that higher lutein, zeaxanthin, and vitamin C concentrations were strongly associated with longer telomere length. The associations were independent of body mass index, maximum oxygen uptake, and vascular risk factors and were not mediated by advanced oxidation protein products content. CONCLUSION: This study provides first evidence that higher lutein, zeaxanthin, and vitamin C concentrations in plasma are associated with longer LTL in normal elderly persons and suggest a protective role of these vitamins in telomere maintenance.