Family history and risk of subarachnoid hemorrhage: a case-control study in Nagoya, Japan

Neuroprotective effect of green and roasted coffee bean extracts on cerebral ischemia-induced injury in rats

Stroke is a lethal event with a high incidence in Egypt. Quick early intervention can be lifesaving. Transient global ischemia (TGI), a type of ischemic stroke, is mainly instigated by cardiac arrest. Ischemia followed by reperfusion causes further neuronal cell damage. In this study, we aimed to evaluate the potential apoptotic, anti-inflammatory, and neuroprotective effects of green (GCBE) and roasted (RCBE) coffee bean water extract against transient global ischemia-induced via a bilateral common carotid artery occlusion (CAO) in rats. Before CAO, 1.5 ml/kg body weight/day of GCBE or RCBE was administered for 14 days by oral gavage. Ischemia/reperfusion (I/R) and sham groups were treated with a vehicle. Oxidative stress biomarkers and antioxidant enzyme activities, such as MDA, NO, GSH, SOD, CAT, GR, GPx, inflammatory markers TNF-α, IL-1β, and NF-κB, and BDNF were investigated. Quantitative real-time PCR analysis of mitogen-activated protein kinase pathways, in addition to heme oxygenase 1, and nuclear factor erythroid 2-related factor 2 were determined. Apoptotic markers, including Bcl-2, Bax, and caspase 3, in addition to the vascular endothelial growth factor-a, were investigated, followed by an examination of hippocampal histopathology. Pre-administration of GCBE and RCBE improved neurological function and neuronal survival, suppressed the spread of oxidative stress, inflammation, and apoptosis, and reversed most of the pathological changes. However, green coffee bean extract was more effective than roasted coffee bean extract, perhaps due to the roasting process, which may affect active compounds. In conclusion, GCBE and RCBE represent a potential clinical strategy for pre-ischemic conditioning.

Epigenetic landscapes of intracranial aneurysm risk haplotypes implicate enhancer function of endothelial cells and fibroblasts in dysregulated gene expression

BACKGROUND

Genome-wide association studies have identified many single nucleotide polymorphisms (SNPs) associated with increased risk for intracranial aneurysm (IA). However, how such variants affect gene expression within IA is poorly understood. We used publicly-available ChIP-Seq data to study chromatin landscapes surrounding risk loci to determine whether IA-associated SNPs affect functional elements that regulate gene expression in cell types comprising IA tissue.

METHODS

We mapped 16 significant IA-associated SNPs to linkage disequilibrium (LD) blocks within human genome. Using ChIP-Seq data, we examined these regions for presence of H3K4me1, H3K27ac, and H3K9ac histone marks (typically associated with latent/active enhancers). This analysis was conducted in several cell types that are present in IA tissue (endothelial cells, smooth muscle cells, fibroblasts, macrophages, monocytes, neutrophils, T cells, B cells, NK cells). In cell types with significant histone enrichment, we used HiC data to investigate topologically associated domains (TADs) encompassing the LD blocks to identify genes that may be affected by IA-associated variants. Bioinformatics were performed to determine the biological significance of these genes. Genes within HiC-defined TADs were also compared to differentially expressed genes from RNA-seq/microarray studies of IA tissues.

RESULTS

We found that endothelial cells and fibroblasts, rather than smooth muscle or immune cells, have significant enrichment for enhancer marks on IA risk haplotypes (p < 0.05). Bioinformatics demonstrated that genes within TADs subsuming these regions are associated with structural extracellular matrix components and enzymatic activity. The majority of histone marked TADs (83% fibroblasts [IMR90], 77% HUVEC) encompassed at least one differentially expressed gene from IA tissue studies.

CONCLUSIONS

These findings provide evidence that genetic variants associated with IA risk act on endothelial cells and fibroblasts. There is strong circumstantial evidence that this may be mediated through altered enhancer function, as genes in TADs encompassing enhancer marks have also been shown to be differentially expressed in IA tissue. These genes are largely related to organization and regulation of the extracellular matrix. This study builds upon our previous (Poppenberg et al., BMC Med Genomics, 2019) by including a more diverse set of data from additional cell types and by identifying potential affected genes (i.e. those in TADs).

Screening for Intracranial Aneurysms in Individuals with a Positive First-Degree Family History: A Systematic Review

BACKGROUND

Subarachnoid hemorrhage secondary to rupture of an intracranial aneurysm (IA) is a devastating condition with high morbidity and mortality. Individuals with a positive family history of aneurysmal subarachnoid hemorrhage (aSAH) or IA can have an increased risk for aSAH or IA themselves. Screening is currently recommended in families with ≥2 affected first-degree relatives. We sought to assess the usefulness and cost-effectiveness of IA screening in individuals with a positive first-degree family history, relative to the number of family members affected.

METHODS

We performed a systematic literature search using PubMed and Google Scholar and identified additional studies by reviewing reference lists. Only original studies and review papers were considered. We excluded genetic diseases associated with IA and studies with unclear data concerning the number of first-versus second-degree relatives affected.

RESULTS

This review included 37 articles. Individuals with ≥2 affected first-degree relatives had a greater prevalence of IA (average 13.1% vs. 3% in the general population). Similarly, we found a greater prevalence of IA in individuals with ≥1 affected first-degree relative (average 4.8%, up to 19% in individuals with additional risk factors). The risk of aSAH also was increased in both categories. Recent studies stressed the importance of serial screening over time and suggested that such screening can be cost-effective in persons with only one first-degree relative with IA or aSAH.

CONCLUSIONS

While current guidelines do not recommend screening individuals with ≥1 first-degree relative affected, we found strong arguments in favor of this approach.

Characteristics of aneurysmal subarachnoid hemorrhage associated with rheumatic disease

Spontaneous subarachnoid hemorrhage (SAH) occurs due to intracranial aneurysm rupture in most cases. Rheumatic disease may cause vessel wall inflammation, which can increase the risk of rupture. However, the characteristics of SAH with rheumatic disease are unknown. This study aimed to evaluate SAH features in patients with rheumatic disease. We retrospectively analyzed clinical data of 5066 patients from the Nagasaki SAH Registry Study who had been diagnosed with aneurysmal SAH between 2001 and 2018. We evaluated the SAH characteristics in patients with rheumatic disease using multivariable logistic regression analysis. In total, 102 patients (2.0%, 11 men and 91 women, median age 69.0 [57.0-75.5]) had rheumatic disease. In these patients, univariate logistic regression analysis showed that sex, hypertension, family history of SAH, smoking history, World Federation of Neurosurgical Societies grade on admission, aneurysm size, multiple aneurysms, treatment, and symptomatic spasms were associated with SAH. Multivariable logistic regression analysis showed that characteristics independently associated with SAH in rheumatic disease were female sex (odds ratio [OR] 3.38; 95% confidence interval [CI] 1.81-6.93, P < 0.001), hypertension (OR 0.60; 95% CI 0.40-0.90, P = 0.012), family history of SAH (OR 0.18; 95% CI 0.01-0.80, P = 0.020), small ruptured aneurysms (OR 1.50; 95% CI 1.02-2.24, P = 0.048), and multiple aneurysms (OR 1.69; 95% CI 1.09-2.58, P = 0.021) in comparison with SAH without rheumatic disease. In conclusion, SAH in patients with rheumatic disease was characterized by small multiple aneurysms, regardless of the low incidence of hypertension and family history of SAH.

Management of unruptured incidentally found intracranial saccular aneurysms

Unruptured intracranial saccular aneurysms occur in 3-5% of the general population. As the use of diagnostic medical imaging has steadily increased over the past few decades with the increased availability of computed tomography (CT) and magnetic resonance imaging (MRI), so has the detection of incidental aneurysms. The management of an unruptured intracranial saccular aneurysm is challenging for both patients and physicians, as the decision to intervene must weigh the risk of rupture and resultant subarachnoid hemorrhage against the risk inherent to the surgical or endovascular procedure. The purpose of this paper is to provide an overview of factors to be considered in the decision to offer treatment for unruptured intracranial aneurysms in adults. In addition, we review aneurysm and patient characteristics that favor surgical clipping over endovascular intervention and vice versa. Finally, the authors propose a novel, simple, and clinically relevant algorithm for observation versus intervention in unruptured intracranial aneurysms based on the PHASES scoring system.

Sex differences in risk factors for aneurysmal subarachnoid haemorrhage: Systematic review and meta-analysis

BACKGROUND

Aneurysmal subarachnoid haemorrhage (aSAH) disproportionally affects women. We conducted a systematic review and meta-analysis to explore sex differences in aSAH risk factors.

METHODS

Case-control/cohort studies were searched to November 2017 with sex-specific risk factors for aSAH. Meta-analysis was performed when a risk factor was reported in ≥2 studies.

RESULTS

Of 31 studies, 22 were eligible for meta-analysis. Female sex was associated with greater odds of aSAH (HR_adjusted 1.90 [1.47-2.46]. There was no detectable difference between the sexes for hypertension (OR_adjusted: men 3.13 [2.26-4.34]; women 3.65 [2.87-4.63], p = .18), smoking (OR_adjusted: men 2.96 [1.68-5.21]; women 3.11 [1.21-7.97], p = .95), aSAH family history, systolic blood pressure, age and some genetic variations. Alcohol (OR_adjusted: men 1.50 [1.04-2.17]; women 0.83 [0.48-1.45], p = .003), high alanine aminotransferase levels, and some gene variants increased the risk of aSAH in men. Reproductive factors, divorce and some genetic variations increased the risk in women. High aspartate aminotransferase levels in men and, diabetes (OR_adjusted: men 0.57 [0.32-1.01]; women 0.24 [0.13-0.43], p = .01) and parity in women reduced aSAH risk.

CONCLUSION

We recommend sex-specific re-analysis of existing studies of aSAH risk factors. Known aSAH risk factors (hypertension, smoking and alcohol consumption) should be targeted to prevent aSAH in men and women. Registration PROSPERO (ID: CRD42018091521).

Different Types of Family History of Stroke and Stroke Risk: Results Based on 655,552 Individuals

BACKGROUND

Many studies concentrated on the relationships between different types of family history and stroke, but they have not arrived at an unified conclusion. We conducted a comprehensive systematic review to further evaluate the associations.

METHODS

Different databases were searched for related studies published from 1990 to August 2017. The relative risk was considered as the common measure of association across different studies. Heterogeneity of effects across studies was quantified by I².

RESULTS

Sixteen published studies (total participants: 655,552) were eligible in this study. The pooled multifactorial adjusted relative risk (RR) (95% confidence interval [CI]) was 1.40 (1.18, 1.67) for individuals with paternal history, 1.36 (1.20, 1.53) for those with maternal history, and 1.44 (1.17, 1.77) for those with sibling history. Based on cohort studies, the pooled adjusted RRs (95%CIs) for paternal, maternal, and sibling history were 1.33 (1.11-1.59), 1.28 (1.14-1.45), and 1.24 (1.01-1.51), respectively, all of which were smaller than those based on case-control and cross-sectional studies. In studies with large sample size, the respective adjusted RR (95%CI) of stroke for paternal, maternal, and sibling history was 1.30 (1.09, 1.56), 1.30 (1.18, 1.44), and 1.26 (1.02, 1.56), which was lower than that in studies with small sample size.

CONCLUSIONS

Each type of family history of stroke was associated with an increased stroke risk. We could not find significant differences among stroke risks relating to different types of family history of stroke. Thus, paternal, maternal, and sibling history require our equal attention in the stroke prevention and control work.

Identification of nine genes as novel susceptibility loci for early-onset ischemic stroke, intracerebral hemorrhage, or subarachnoid hemorrhage

Given that substantial genetic components have been shown in ischemic stroke, intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH), heritability may be higher in early-onset than late-onset individuals with these conditions. Although genome-wide association studies (GWASs) have identified various genes and loci significantly associated with ischemic stroke, ICH, or intracranial aneurysm mainly in European ancestry populations, genetic variants that contribute to susceptibility to these disorders remain to be identified definitively. We performed exome-wide association studies (EWASs) to identify genetic variants that confer susceptibility to ischemic stroke, ICH, or SAH in early-onset subjects with these conditions. A total of 6,649 individuals aged ≤65 years were examined. For the EWAS of ischemic or hemorrhagic stroke, 6,224 individuals (450 subjects with ischemic stroke, 5,774 controls) or 6,179 individuals (261 subjects with ICH, 176 subjects with SAH, 5,742 controls), respectively, were examined. EWASs were performed with the use of Illumina Human Exome-12 v1.2 DNA Analysis BeadChip or Infinium Exome-24 v1.0 BeadChip. To compensate for multiple comparisons of allele frequencies with ischemic stroke, ICH, or SAH, we applied a false discovery rate (FDR) of <0.05 for statistical significance of association. The association of allele frequencies of 31,245 single nucleotide polymorphisms (SNPs) that passed quality control to ischemic stroke was examined with Fisher's exact test, and 31 SNPs were significantly (FDR <0.05) associated with ischemic stroke. The association of allele frequencies of 31,253 or 30,970 SNPs to ICH or SAH, respectively, was examined with Fisher's exact test, and six or two SNPs were significantly associated with ICH or SAH, respectively. Multivariable logistic regression analysis with adjustment for age, sex, and the prevalence of hypertension and diabetes mellitus revealed that 12 SNPs were significantly [P<0.0004 (0.05/124)] related to ischemic stroke. Similar analysis with adjustment for age, sex, and the prevalence of hypertension revealed that six or two SNPs were significantly [P<0.0016 (0.05/32)] related to ICH or SAH, respectively. After examination of linkage disequilibrium of identified SNPs and results of previous GWASs, we identified HHIPL2, CTNNA3, LOC643770, UTP20, and TRIB3 as susceptibility loci for ischemic stroke, DNTTIP2 and FAM205A as susceptibility loci for ICH, and FAM160A1 and OR52E4 as such loci for SAH. Therefore, to the best of our knowledge, we have newly identified nine genes that confer susceptibility to early-onset ischemic stroke, ICH, or SAH. Determination of genotypes for the SNPs in these genes may prove informative for assessment of the genetic risk for ischemic stroke, ICH, or SAH in Japanese.

Association of intracranial aneurysm rupture with smoking duration, intensity, and cessation

OBJECTIVE

Although smoking is a known risk factor for intracranial aneurysm (IA) rupture, the exact relationship between IA rupture and smoking intensity and duration, as well as duration of smoking cessation, remains unknown.

METHODS

In this case-control study, we analyzed 4,701 patients with 6,411 IAs diagnosed at the Brigham and Women's Hospital and Massachusetts General Hospital between 1990 and 2016. We divided individuals into patients with ruptured aneurysms and controls with unruptured aneurysms. We performed univariable and multivariable logistic regression analyses to determine the association between smoking status and ruptured IAs at presentation. In a subgroup analysis among former and current smokers, we assessed the association between ruptured aneurysms and number of packs per day, duration of smoking, and duration since smoking cessation.

RESULTS

In multivariable analysis, current (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.89-2.59) and former smoking status (OR 1.56, 95% CI 1.31-1.86) were associated with rupture status at presentation compared with never smokers. In a subgroup analysis among current and former smokers, years smoked (OR 1.02, 95% CI 1.01-1.03) and packs per day (OR 1.46, 95% CI 1.25-1.70) were significantly associated with ruptured aneurysms at presentation, whereas duration since cessation among former smokers was not significant (OR 1.00, 95% CI 0.99-1.02).

CONCLUSIONS

Current cigarette smoking, smoking intensity, and smoking duration are significantly associated with ruptured IAs at presentation. However, the significantly increased risk persists after smoking cessation, and smoking cessation does not confer a reduced risk of aneurysmal subarachnoid hemorrhage beyond that of reducing the cumulative dose.

Prevalence of stroke and associated risk factors among middle-aged and older farmers in western China

Objectives

China has the world’s largest population and the stroke has become the leading cause of death in recent years. The purpose of this study was to explore the associations between hypertension, family history of stroke, diabetes mellitus, obesity and stroke among middle-aged and older farmers of western China. A population-based study was conducted from June 2014 to April 2015 in Shaanxi and Sichuan provinces.

Methods

Twenty thousand five hundred twenty-five Chinese middle-aged and older farmers (≥40 years) were recruited to the Qinling-Daba Mountains Region Stroke Study. A structured-questionnaire was used to collect data through face-to-face interviews. Demographic characteristics, risk factors, medical history, and other clinical characteristics were recorded for all participants. The association between hypertension, family history of stroke, diabetes mellitus, obesity and stroke were analyzed by using univariate and multivariate logistic regression analysis.

Results

The stoke prevalence rate was 1380/100,000 in middle-aged and older farmers of western China. The difference in hypertension, diabetes mellitus, obesity and family history between different age groups had statistical significance (p < 0.05). The prevalence rate of hypertension and family history of stroke were higher in male population than in the female population. The difference was statistically significant (p < 0.05). Univariate logistic regression analysis demonstrated age, gender, hypertension, obesity and family history of stroke were stroke risk factors (p < 0.05). Multivariate logistic regression analysis revealed that the odds ratios of family history of stroke, obesity and hypertension were 7.177, 4.389 and 3.647 respectively.

Conclusions

Family history is the strongest stroke risk factor in middle-aged and older farmers of western China.

Clinical management guidelines for subarachnoid haemorrhage. Diagnosis and treatment

OBJECTIVE

To update the Spanish Society of Neurology's guidelines for subarachnoid haemorrhage diagnosis and treatment.

MATERIAL AND METHODS

A review and analysis of the existing literature. Recommendations are given based on the level of evidence for each study reviewed.

RESULTS

The most common cause of spontaneous subarachnoid haemorrhage (SAH) is cerebral aneurysm rupture. Its estimated incidence in Spain is 9/100 000 inhabitants/year with a relative frequency of approximately 5% of all strokes. Hypertension and smoking are the main risk factors. Stroke patients require treatment in a specialised centre. Admission to a stroke unit should be considered for SAH patients whose initial clinical condition is good (Grades I or II on the Hunt and Hess scale). We recommend early exclusion of aneurysms from the circulation. The diagnostic study of choice for SAH is brain CT (computed tomography) without contrast. If the test is negative and SAH is still suspected, a lumbar puncture should then be performed. The diagnostic tests recommended in order to determine the source of the haemorrhage are MRI (magnetic resonance imaging) and angiography. Doppler ultrasonography studies are very useful for diagnosing and monitoring vasospasm. Nimodipine is recommended for preventing delayed cerebral ischaemia. Blood pressure treatment and neurovascular intervention may be considered in treating refractory vasospasm.

CONCLUSIONS

SAH is a severe and complex disease which must be managed in specialised centres by professionals with ample experience in relevant diagnostic and therapeutic processes.

Impact of LIMK1, MMP2 and TNF-α variations for intracranial aneurysm in Japanese population

Genetic factors are known to have an important role in intracranial aneurysm (IA) pathogenesis. The purpose of this study is to identify single-nucleotide polymorphisms (SNPs) that are associated with IA in Japanese population. A total of 2050 IA patients and 1835 controls recruited in Biobank Japan, The University of Tokyo were used in this study. In all, 45 SNPs in 24 genes encoding proteins, which have been considered to be possible risk factors to IA pathogenesis, were genotyped using multiplex PCR-invader assay. Association analysis was evaluated by logistic regression analysis before and after adjustment of age, smoking and hypertension status. This case-control association study revealed a SNP, rs6460071 located on LIMK1 gene (P = 0.00069) to be significantly associated with increased risk of IA. In addition, two SNPs, rs243847 (P = 0.00086) and rs243865 (P = 0.00090), on matrix metallopeptidase 2 (MMP2) gene and one SNP rs1799724 (P = 0.0026) on tumor necrosis factor-α (TNF-α) gene, are marginally associated with IA in male- and female-specific manner, respectively. In conclusion, a large-scale case-control association study was conducted to verify genetic variations associated with IA in Japanese population. This study gave insights on the importance of stratified analysis between genders, and suggested that the underlying mechanism of IA pathogenesis might differ between females and males.

Treatment of Intracranial Aneurysms

The management of intracranial aneurysms (IAs) remarkably improved due to the development of diagnostic and surgical procedures. Subarachnoid hemorrhage (SAH) from IA rupture constitutes a devastating event, whose prognosis remains unsatisfactory. At present, several researchs are targeted to individuate subjects harboring unruptured IAs and those presenting a higher risk for rupture. Numerous risk factors for the rupture of lAs have been individuated. The prevalence of intracranial saccular aneurysms in the general population is estimated from 0.2% to 6.8%, with an incidence of SAH at 10/100,000/year. The most relevant morbidity and mortality rates after SAH are related to rebleeding and vasospasm. The primary therapeutic target consists in prevention of rebleeding. At present, therapeutic opportunities for intracranial aneurysms are microsurgery and endovascular treatment.

Molecular Genetics of Human Intracranial Aneurysms

Intracranial aneurysms (IAs) are the dilatations of blood vessels in the brain and pose potential risk of rupture leading to subarachnoid hemorrhage. Although the genetic basis of IAs is poorly understood, it is well-known that genetic factors play an important part in the pathogenesis of IAs. Therefore, the identifying susceptible genetic variants might lead to the understanding of the mechanism of formation and rupture of IAs and might also lead to the development of a pharmacological therapy. To elucidate the molecular pathogenesis of diseases has become a crucial step in the development of new treatment strategies. Although extensive genetic research and its potential implications for future prevention of this often fatal condition are urgently needed, efforts to elucidate the susceptibility loci of IAs are hindered by the issues bewildering the most common and complex genetic disorders, such as low penetrance, late onset, and uncertain modes of inheritance. These efforts are further complicated by the fact that many IA lesions remain asymptomatic or go undiagnosed. In this review, we present and discuss the current status of genetic studies of IAs and we recommend comprehensive genome-wide association studies to identify genetic loci that underlie this complex disease.

Effects of meteorological factors on the onset of subarachnoid hemorrhage: a time-series analysis

Previous studies have suggested a possible association between meteorological factors and the onset of subarachnoid hemorrhage (SAH). We aimed to investigate the relationship between the onset of SAH and meteorological factors based on an hourly time-series analysis. We collected hourly data on transportation of patients with SAH using the ambulance records of the Tokyo Fire Department from January 1 to December 31, 2005. We also collected hourly meteorological data for Tokyo from the Japan Meteorological Agency during the same period. We performed a time-series analysis using the autoregressive integrated moving average (ARIMA) model to control for autocorrelations in the time-series data. There were 1729 patients with SAH (mean age 63.3 years; 60.2% women). We identified two circadian patterns in the onset of SAH: a daily peak at 10 am (p<0.001) and a seasonal peak in February (p<0.001). Based on the ARIMA time-series analysis, significant risk factors associated with the onset of SAH included: low temperature on the previous day (lag time 17h; p=0.005) and on the onset day (lag time 0h; p<0.001); high barometric pressure on the onset day (lag time 0h; p=0.001). Humidity was not associated with the onset of SAH. Among meteorological factors, low temperature and high barometric pressure may be risk factors for the onset of SAH.

Dietary antioxidant intake and risk of an aneurysmal rupture subarachnoid hemorrhage in Japan

The purpose of this study was to investigate the relationship between dietary antioxidant intake and the risk of subarachnoid hemorrhage (SAH) in a case-control study. An antioxidant intake score was calculated for individual values for each food group (soy products, green yellow-vegetables, fruits, boiled rice and tea) collected by a self-administered food frequency questionnaire. Incident SAH cases (n=201) were identified and individually matched for age (+/-2 years) and gender to community (n=201) controls from April 1992 to March 1997. The antioxidant intake score was inversely associated with the risk of SAH, even after adjusting for confounding factors (lowest vs highest score adjusted odds ratio, 0.54; 95% confidence interval, 0.30-0.99). These findings suggest that the development of SAH may be reduced by the frequent intake of various antioxidants in the diet. Prospective studies are needed to confirm the relationship of dietary antioxidants to SAH risk in Japanese men and women.

Soy products and risk of an aneurysmal rupture subarachnoid hemorrhage in Japan

BACKGROUND

The aim of this study was to explore the relationship between soy products and the risk of subarachnoid hemorrhage in a case-control study.

DESIGN

A case-control study was conducted.

METHODS

Incident subarachnoid hemorrhage cases (n = 201) were identified and individually matched on age (+/- 2 years) and sex to community (n = 201) controls from April 1992 to March 1997. A factor analysis was conducted to identify dietary patterns in relation to subarachnoid hemorrhage risk.

RESULTS

Soy-rich products were significantly associated with a decreased risk of subarachnoid hemorrhage (lowest versus highest quartile, adjusted odds ratio 0.46; 95% confidence interval 0.18-0.88).

CONCLUSION

The findings suggest that a diet high in soy products may be protective against the development of subarachnoid hemorrhage.

Habitual green tea consumption and risk of an aneurysmal rupture subarachnoid hemorrhage: A case–control study in Nagoya, Japan

BACKGROUND

Green tea, a popular beverage in Japan, contains many polyphenolic antioxidants, which might prevent cardiovascular disease. This study is designed to determine whether the consumption of green tea is associated with a reduced risk for subarachnoid hemorrhage (SAH) using a case-control study.

METHODS

Incident SAH cases (n=201) were identified and individually matched by age (+/-2 years) and gender to hospital (n=201) and community controls (n=201) from April 1992 to March 1997. Habitual regular tea consumption was assessed with a structured questionnaire. Conditional logistic regression models were used to compute odds ratios adjusted for smoking, history of hypertension, and educational levels.

RESULTS

The proportion of the consumption of one time or more of tea per day was higher in controls (70.9%) than in SAH patients (60.3%). Multivariate analyses showed that green tea consumption was inversely associated with SAH risk. Subjects consuming <1, and >or=1 time per day had adjusted ORs of 0.74 (CI: 0.34-1.58), and 0.56 (CI: 0.32-0.98) in comparison with non daily green tea drinkers, respectively (p-trend <0.001).

CONCLUSION

In a case-control study in Japan, we found that habitual green tea consumption may be strongly associated with a reduced risk for SAH. Our findings will be useful in targeting individuals and populations for the primary prevention of SAH.

Serum lipids as protective factors for subarachnoid hemorrhage

Identification of common serum lipid profiles in patients with subarachnoid hemorrhage (SAH) may allow a better understanding of its pathogenesis. We conducted a hospital-based case-control study in Japan. One hundred and fifty consecutive cases of spontaneous SAH during a 5-year period were examined and their lipid profiles assessed. Age- and gender-matched controls were identified for each case through random hospital sampling. Median serum total cholesterol was 161 mg/dl (range 77-288) in patients with SAH, and 209 mg/dl (134-441) in controls (p < 0.001). Median serum triglycerides were 95 mg/dl (range 28-589) in SAH and 122 mg/dl (31-371) in controls (p < 0.001). A high serum total cholesterol of more than 5.20 mmol/L (200 mg/dl) (odds ratio 0.22 [95% confidence interval 0.12-0.40]) and a high serum triglyceride of more than 1.70 mmol/L (150 mg/dl) (odds ratio 0.29 [95% CI 0.14-0.60]) were independent protective factors for SAH. In conclusion, higher values of both serum cholesterol and triglyceride may be inversely associated with the occurrence of SAH.

Risk factors for subarachnoid hemorrhage: an updated systematic review of epidemiological studies

BACKGROUND AND PURPOSE

After a 1996 review from our group on risk factors for subarachnoid hemorrhage (SAH), much new information has become available. This article provides an updated overview of risk factors for SAH.

METHODS

An overview of all longitudinal and case-control studies of risk factors for SAH published in English from 1966 through March 2005. We calculated pooled relative risks (RRs) for longitudinal studies and odds ratios (ORs) for case-control studies, both with corresponding 95% CIs.

RESULTS

We included 14 longitudinal (5 new) and 23 (12 new) case-control studies. Overall, the studies included 3936 patients with SAH (892 cases in 14 longitudinal studies and 3044 cases in 23 case-control studies) for analysis. Statistically significant risk factors in longitudinal and case-control studies were current smoking (RR, 2.2 [1.3 to 3.6]; OR, 3.1 [2.7 to 3.5]), hypertension (RR, 2.5 [2.0 to 3.1]; OR, 2.6 [2.0 to 3.1]), and excessive alcohol intake (RR, 2.1 [1.5 to 2.8]; OR, 1.5 [1.3 to 1.8]). Nonwhite ethnicity was a less robust risk factor (RR, 1.8 [0.8 to 4.2]; OR, 3.4 [1.0 to 11.9]). Oral contraceptives did not affect the risk (RR, 5.4 [0.7 to 43.5]; OR, 0.8 [0.5 to 1.3]). Risk reductions were found for hormone replacement therapy (RR, 0.6 [0.2 to 1.5]; OR, 0.6 [0.4 to 0.8]), hypercholesterolemia (RR, 0.8 [0.6 to 1.2]; OR, 0.6 [0.4 to 0.9]), and diabetes (RR, 0.3 [0 to 2.2]; OR, 0.7 [0.5 to 0.8]). Data were inconsistent for lean body mass index (RR, 0.3 [0.2 to 0.4]; OR, 1.4 [1.0 to 2.0]) and rigorous exercise (RR, 0.5 [0.3 to 1.0]; OR, 1.2 [1.0 to 1.6]). In the studies included in the review, no other risk factors were available for the meta-analysis.

CONCLUSIONS

Smoking, hypertension, and excessive alcohol remain the most important risk factors for SAH. The seemingly protective effects of white ethnicity compared to nonwhite ethnicity, hormone replacement therapy, hypercholesterolemia, and diabetes in the etiology of SAH are uncertain.

Risk of hemorrhagic stroke in Asian American ethnic groups

The sparseness of prospective data about hemorrhagic stroke (HS) risk among Asian American ethnic groups led to the investigation of 128,934 persons with self-classified ethnicity at health examinations in 1978-1985. Subsequently, 431 persons were hospitalized for HS; 31% for subarachnoid hemorrhage (SAH) and 69% for intracerebral hemorrhage (ICH). Ethnic predictors of HS were studied by Cox proportional hazard models with 7 covariates. With whites as reference, the adjusted relative risk (95% CI) of all Asians for HS was 1.6 (1.1-2.3, p = 0.01), due substantially to increased risks of SAH in Japanese people and ICH in Filipinos. These data mandate emphasis upon preventive measures in these groups.

The familial risk of subarachnoid haemorrhage

Relatives of people with aneurysmal subarachnoid haemorrhage (SAH) may be at increased risk of SAH, but precise data on the level of risk and which relatives are most likely to be affected are lacking. We studied two samples: 5478 relatives of patients from the whole of Scotland who had a SAH in one year and 3213 relatives of patients with a SAH admitted to the West of Scotland regional neurosurgical unit 10 years previously. Overall, 2% of all relatives in each sample had a SAH. In the Scotland-wide sample, the absolute lifetime risk of SAH (from birth to 70 years) was higher for first-degree relatives [4.7%; 95% confidence interval (CI): 3.1-6.3%] than for second-degree (1.9%; 95% CI: 1.0-2.9%). In the West of Scotland sample, the lifetime risks were very similar to the Scotland-wide sample. The 10-year prospective risk for first-degree relatives alive at the time of the index patient's SAH was 1.2% (95% CI: 0.4-2%) and for second-degree was 0.5% (95% CI: 0.1-0.8%). There was a trend for risk to be highest in families with two first-degree relatives affected and lowest with only one second-degree affected. Most living relatives of patients who suffer a SAH are at low absolute risk of a future haemorrhage; screening is inappropriate except for the few families in whom two or more first-degree relatives, i.e. index case plus one extra have been affected.

Genome-wide scan for Japanese familial intracranial aneurysms: linkage to several chromosomal regions

BACKGROUND

Genetic factors have an important role in the pathogenesis of intracranial aneurysm (IA). The results of previous studies have suggested several loci.

METHODS AND RESULTS

From 29 IA families with > or =3 individuals affected by IA, we used nonparametric (model-free) methods for linkage analyses, using GENEHUNTER and Merlin software. Genome-wide linkage analyses revealed 3 regions on chromosomes 17cen (maximum nonparametric logarithm of the odds score [MNS] = 3.00, nominal P=0.001), 19q13 (MNS=2.15, nominal P=0.020), and Xp22 (MNS=2.16, nominal P=0.019). We tested 4 candidate genes in these regions: the microfibril-associated protein 4 gene (MFAP4) and the promoter polymorphism of the inducible nitric oxide synthase gene (NOS2A) on chromosome 17cen, the epsilon genotypes of the apolipoprotein E gene (APOE) on chromosome 19q13, and the angiotensin I converting enzyme 2 gene (ACE2) on chromosome Xp22. Associations of their polymorphisms with IA were evaluated by a case-control study (100 cases: 29 probands from IA families and 71 unrelated subjects with IAs, 100 unrelated control subjects [unaffected members with IAs and absence of family history of IAs]). However, the case-control study showed that none of the polymorphisms of the examined genes had associations with IA.

CONCLUSIONS

A genome-wide scan in 29 Japanese families with a high degree of familial clustering revealed 1 suggestive linkage region on chromosome 17cen and 2 potentially interesting regions on chromosomes 19q13 and Xp22. These regions were consistent with previous findings in various populations.

Unruptured intracranial aneurysms: benign curiosity or ticking bomb?

15 years ago, the treatment of incidentally discovered intracranial aneurysms was straightforward with a good evidence base behind it. When intracranial aneurysms were identified, people were referred to neurosurgeons who would offer surgical repair if the patient was in reasonable health and had a good life expectancy. Since that time, several studies have given contradictory evidence for what should be done with these lesions, and a new technique for the repair of aneurysms, endovascular coil embolisation, has been developed. Here we review the research and make several recommendations. First, incidentally discovered aneurysms in the anterior circulation less than 7 mm in size in people with no personal or family history of subarachnoid haemorrhage should be left untreated. Second, people with remaining life expectancy of less than 20 years or so (ie, those over age 60 years) should be informed that from a statistical point of view the benefits of treatment do not outweigh the risks. Third, in all other cases treatment with surgical clipping or coil embolisation should be advised. And finally, if surgical treatment is not feasible then medical hypotensive treatment may be a viable alternative.