Risk Factors for Fatal Subarachnoid Hemorrhage

Higher cerebral blood flow on four-dimensional flow magnetic resonance imaging in young women

We investigated the reduction in regional brain volume and cerebral blood flow (CBF) with aging and explored potential sex differences in healthy brains. Three-dimensional (3D) T1-weighted magnetic resonance imaging (MRI), time-of-flight magnetic resonance angiography, and four-dimensional (4D) flow MRI were performed on 129 healthy volunteers aged 22-92 years. The brains of healthy volunteers were segmented into 21 subregions using 3D T1-weighted MRI and CBFs in 16 major intracranial arteries were measured using 4D flow MRI. The cortical gray matter volume decreased linearly with aging, whereas the cerebral white matter volume increased until the 40s and then decreased, and the subcortical gray matter volume changed little with aging. The cortical gray matter volume was significantly associated with the total CBF of the major intracranial arteries distal to the circle of Willis; however, the cerebral white matter and subcortical gray matter volumes were not. Generally, women have higher total CBF than men, particularly in their 40s and younger, despite the smaller intracranial volume and smaller diameters of intracranial arteries than men. This may contribute to the higher incidence of subarachnoid hemorrhage due to cerebral aneurysms and migraine in women.

Health effects associated with exposure to secondhand smoke: a Burden of Proof study

Despite a gradual decline in smoking rates over time, exposure to secondhand smoke (SHS) continues to cause harm to nonsmokers, who are disproportionately children and women living in low- and middle-income countries. We comprehensively reviewed the literature published by July 2022 concerning the adverse impacts of SHS exposure on nine health outcomes. Following, we quantified each exposure-response association accounting for various sources of uncertainty and evaluated the strength of the evidence supporting our analyses using the Burden of Proof Risk Function methodology. We found all nine health outcomes to be associated with SHS exposure. We conservatively estimated that SHS increases the risk of ischemic heart disease, stroke, type 2 diabetes and lung cancer by at least around 8%, 5%, 1% and 1%, respectively, with the evidence supporting these harmful associations rated as weak (two stars). The evidence supporting the harmful associations between SHS and otitis media, asthma, lower respiratory infections, breast cancer and chronic obstructive pulmonary disease was weaker (one star). Despite the weak underlying evidence for these associations, our results reinforce the harmful effects of SHS on health and the need to prioritize advancing efforts to reduce active and passive smoking through a combination of public health policies and education initiatives.

Secondhand smoking and neurological disease: a meta-analysis of cohort studies

BACKGROUND

The results of studies on the relationship between secondhand smoking and neurological disease remain controversial. We conducted a meta-analysis to explore the association between secondhand smoking and risk of neurological disease.

METHODS

Literature search was performed in PubMed, Embase and Web of Science through December 2019. We included cohort studies which examined the association between secondhand smoking and risk of neurological disease. According to the type of neurological disease, summary relative risks (RRs) with 95% confidence intervals (CIs) of stroke, cognitive impairment and Parkinson disease (PD) for secondhand smoking exposure were calculated.

RESULTS

A total of 14 unique articles (n=697,185 participants) were eventually included in the analysis. When all studies were pooled, the RR of stroke for secondhand smoking exposure was 1.20 (95% CI: 1.04, 1.38). When studies included only non-smokers, the pooled RR of stroke was 1.20 (95% CI: 1.05, 1.37). Summary RRs of cognitive impairment and PD for secondhand smoking exposure were 1.43 (95% CI: 1.02, 2.00) and 0.83 (95% CI: 0.72, 0.95), respectively. Summary RRs did not change significantly when excluding one study at a time.

CONCLUSIONS

Secondhand smoking was found to be positively associated with risks of stroke and cognitive impairment, while inversely associated with risk of PD. Overall, our finding is a reminder of the need to step up smoking bans to prevent health damage, and also suggests that more researches on biological mechanisms whereby secondhand smoking affect PD may be beneficial to PD prevention and treatment.

Low BMI and weight loss aggravate COPD mortality in men, findings from a large prospective cohort: the JACC study

To clarify how low BMI and weight loss were associated with risk of chronic obstructive pulmonary disease (COPD) mortality, in a large prospective cohort of the general population across Japan, the Japan Collaborative Cohort Study, conducted between 1988 and 2009. A total of 45,837 male residents were observed for a median period of 19.1 years. Self-administered questionnaires, collecting information on BMI, weight loss since the age of 20, lifestyles, history of diseases, as well as records of COPD mortality, were analysed at 2019. During follow-up, 268 participants died from COPD. The multivariate-adjusted hazard ratio (95% confidence interval) of COPD mortality associated with a 1-SD increment of body mass index (BMI) was 0.48 (0.41–0.57), while for weight change from age of 20 (+ 2.0 kg) it was 0.63 (0.59–0.68). These associations were persistently observed after stratifications with smoking status, excluding those having airway symptoms in the baseline survey, and excluding early COPD deaths within 5, 10 and 15 years. Our study suggests that BMI and weight change since the age of 20 could be markers for COPD prognosis, indicated by risk of COPD mortality.

Sex-Specific Associations of Smoking with Spontaneous Subarachnoid Hemorrhage: Findings from Observational Studies

BACKGROUND

Some studies have reported that women are at higher risk for spontaneous subarachnoid hemorrhage (SAH) compared with men, and smoking is the most important lifestyle risk factor for spontaneous SAH. However, it is still unknown whether the risk of SAH from smoking and smoking status is differential for women and men. We performed a meta-analysis to estimate the effect of smoking on SAH in women compared with men.

METHODS

PubMed (January 1, 1966 to February 19, 2020) and EMBASE (January 1, 1980 to February 19, 2020) were systematically searched. Studies that estimated sex-specific relative risks (RRs) of SAH were selected. We pooled sex-specific RRs, comparing women with men using random-effects meta-analysis.

RESULTS

Data from 20 observational studies that included 1,387,204 participants (563,898 women) and 7,838 SAHs (3,977 women) were analyzed. The combined women-to-men RRs of former smokers versus never smokers for SAH were 1.08 (95% confidence interval [CI] 0.62-1.89, p = 0.78). The pooled women-to-men RRs of current smokers versus never smokers were 1.39 (95% CI 1.05-1.83, p = 0.02). The combined women-to-men RRs of total smokers versus never smokers RRs were 1.15 (95% CI 0.88-1.52, p = 0.30).

CONCLUSIONS

Our study shows there is not enough evidence to suggest that women who smoke have a greater risk for SAH than men; however, women who persistently smoke have a greater risk. Smoking seems to be more susceptible in the increased SAH risk in women.

The Bilateral Ovariectomy in a Female Animal Exacerbates the Pathogenesis of an Intracranial Aneurysm

Considering the poor outcome of subarachnoid hemorrhage (SAH) due to the rupture of intracranial aneurysms (IA), mechanisms underlying the pathogenesis of IAs, especially the rupture of lesions, should be clarified. In the present study, a rat model of IAs in which induced lesions spontaneously ruptured resulting in SAH was used. In this model, the combination of the female sex and the bilateral ovariectomy increased the incidence of SAH, similar to epidemiological evidence in human cases. Importantly, unruptured IA lesions induced in female animals with bilateral ovariectomy were histopathologically similar to ruptured ones in the presence of vasa vasorum and the accumulation of abundant inflammatory cells, suggesting the exacerbation of the disease. The post-stenotic dilatation of the carotid artery was disturbed by the bilateral ovariectomy in female rats, which was restored by hormone replacement therapy. The in vivo study thus suggested the protective effect of estrogen from the ovary on endothelial cells loaded by wall shear stress. β-estradiol or dihydrotestosterone also suppressed the lipopolysaccharide-induced expression of pro-inflammatory genes in cultured macrophages and neutrophils. The results of the present study have thus provided new insights about the process regulating the progression of the disease.

Increased Body Mass Index Associated With Reduced Risk of Delayed Cerebral Ischemia and Subsequent Infarction After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Increased body mass index (BMI) may be protective against cerebral ischemia in certain clinical contexts.

OBJECTIVE

To investigate whether increased BMI was associated with delayed cerebral ischemia (DCI) and subsequent infarction after aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

We retrospectively reviewed the clinical course of patients presenting to our institution for management of aSAH. Patient were segregated according to BMI< or ≥29.4, a value determined by Classification and Regression Tree analysis. Predictors of DCI and delayed infarction were identified using stepwise multivariate logistic regression analysis.

RESULTS

There were 161 patients included for analysis. Average BMI within our patient cohort was 28.9, with 67 patients presenting with a BMI of ≥29.4 on admission. DCI occurred in 50 patients (31.1%) and was complicated by delayed infarction in 15 patients (9.3%). On stepwise multivariate analysis, BMI ≥ 29.4 was independently associated with reduced likelihood of DCI (odds ratio [OR] 0.42, 95% confidence interval [CI] 0.18-0.92) and delayed infarction (OR 0.13, 95% CI 0.02-0.61; P = .008). Increasing maximum flow velocity on transcranial Doppler ultrasound was independently associated with increased odds of both DCI (Unit OR 1.19, 95% CI 1.09-1.30; P < .001) and delayed infarction (Unit OR 1.31, 95% CI 1.13-1.56; P < .001), while intracerebral hemorrhage was independently associated with increased odds of delayed infarction (OR 6.99, 95% CI 1.82-30.25; P = .005).

CONCLUSION

We report an association between elevated BMI and reduced incidence of DCI and delayed infarction, suggesting a protective effect of increasing BMI on the risk of ischemic complications after aSAH.

Obesity paradox in subarachnoid hemorrhage: a systematic review

As the number of obese people is globally increasing, reports about the putative protective effect of obesity in life-threatening diseases, such as subarachnoid hemorrhage (SAH), are gaining more interest. This theory-the obesity paradox-is challenging to study, and the impact of obesity has remained unclear in survival of several critical illnesses, including SAH. Thus, we performed a systematic review to clarify the relation of obesity and SAH mortality. Our study protocol included systematic literature search in PubMed, Scopus, and Cochrane library databases, whereas risk-of-bias estimation and quality of each selected study were evaluated by the Critical Appraisal Skills Program and Cochrane Collaboration guidelines. A directional power analysis was performed to estimate sufficient sample size for significant results. From 176 reviewed studies, six fulfilled our eligibility criteria for qualitative analysis. One study found paradoxical effect (odds ratio, OR = 0.83 (0.74-0.92)) between morbid obesity (body mass index (BMI) > 40) and in-hospital SAH mortality, and another study found the effect between continuously increasing BMI and both short-term (OR = 0.90 (0.82-0.99)) and long-term SAH mortalities (OR = 0.92 (0.85-0.98)). However, according to our quality assessment, methodological shortcomings expose all reviewed studies to a high-risk-of-bias. Even though two studies suggest that obesity may protect SAH patients from death in the acute phase, all reviewed studies suffered from methodological shortcomings that have been typical in the research field of obesity paradox. Therefore, no definite conclusions could be drawn.

Determining rural risk for aneurysmal subarachnoid hemorrhages: A structural equation modeling approach

An aneurysmal subarachnoid hemorrhage (aSAH) carries a high disability burden. The true impact of rurality as a predictor of outcome severity is unknown. Our aim is to clarify the relationship between the proposed explanations of regional and rural health disparities linked to severity of outcome following an aSAH. An initial literature search identified limited data directly linking geographical location, rurality, rural vulnerability, and aSAH. A further search noting parallels with ischemic stroke and acute myocardial infarct literature presented a number of diverse and interrelated predictors. This a priori knowledge informed the development of a conceptual framework that proposes the relationship between rurality and severity of outcome following an aSAH utilizing structural equation modeling. The presented conceptual framework explores a number of system, environmental, and modifiable risk factors. Socioeconomic characteristics, modifiable risk factors, and timely treatment that were identified as predictors of severity of outcome following an aSAH and within each of these defined predictors a number of contributing specific individual predictors are proposed. There are considerable gaps in the current knowledge pertaining to the impact of rurality on the severity of outcome following an aSAH. Absent from the literature is any investigation of the cumulative impact and multiplicity of risk factors associated with rurality. The proposed conceptual framework hypothesizes a number of relationships between both individual level and system level predictors, acknowledging that intervening predictors may mediate the effect of one variable on another.

Recurrent Stroke and Bleeding Events after Acute Cardioembolic Stroke-Analysis Using Japanese Healthcare Database from Acute-Care Institutions

BACKGROUND

To understand the reality of patients who experienced a cardioembolic stroke (CES) is important because of the high incidence of recurrent stroke and the need to account for bleeding risk in relation to the need for anticoagulation treatment. We elucidated the current real-world medical care in patients who had a CES and identified the risk factors for recurrent stroke.

METHODS AND RESULTS

The study comprised 9804 patients who were diagnosed with CES between April 2008 and September 2013 as identified in a healthcare database used by acute-care institutions in Japan. We analyzed the incidence and risk factors of stroke and bleeding events in CES patients. The incidence of stroke was 10.3% during the median observation period of 68 days, mainly consisting of recurrent CES (8.5%). The incidence of bleeding events and intracranial bleeding was 10.3% and 7.0%, respectively. The recurrence of ischemic stroke was significantly lower, and brain hemorrhage was significantly higher in the anticoagulation treatment group. The factors related to an increased risk of stroke were a history of cerebral infarction or transient ischemic attack, diabetes, and increase of CHA₂DS₂-VASc and CHADS₂ scores. The risk factors for bleeding events were hypertension, renal dysfunction, and use of proton pump inhibitors (PPIs).

CONCLUSIONS

The patients who experienced CES had a high rate of recurrent stroke or CES, mainly consisting of recurrent CES. Although anticoagulation may be beneficial for reducing recurrence of ischemic stroke, careful management is required given consideration of increased risk of brain hemorrhage during anticoagulation treatment, especially for patients with hypertension, renal dysfunction, and use of PPIs.

Effect of body mass index on outcome after aneurysmal subarachnoid hemorrhage treated with clipping versus coiling

OBJECTIVE It has been suggested that increased body mass index (BMI) may confer a protective effect on patients who suffer from aneurysmal subarachnoid hemorrhage (aSAH). Whether the modality of aneurysm occlusion influences the effect of BMI on patient outcomes is not well understood. The authors aimed to compare the effect of BMI on outcomes for patients with aSAH treated with surgical clipping versus endovascular coiling. METHODS The authors retrospectively reviewed the outcomes for patients admitted to their institution for the management of aSAH treated with either clipping or coiling. BMI at the time of admission was recorded and used to assign patients to a group according to low or high BMI. Cutoff values for BMI were determined by classification and regression tree analysis. Predictors of poor functional outcome (defined as modified Rankin Scale score > 2 measured ≥ 90 days after the ictus) and posttreatment cerebral hypodensities detected during admission were then determined separately for patients treated with clipping or coiling using stepwise multivariate logistic regression analysis. RESULTS Of the 469 patients admitted to the authors' institution with aSAH who met the study's inclusion criteria, 144 were treated with clipping and 325 were treated with coiling. In the clipping group, the frequency of poor functional outcome was higher in patients with BMI ≥ 32.3 kg/m² (47.6% vs 19.0%; p = 0.007). In contrast, in the coiling group, patients with BMI ≥ 32.3 kg/m² had a lower frequency of poor functional outcome at ≥ 90 days (5.8% vs 30.9%; p < 0.001). On multivariate analysis, high BMI was independently associated with an increased (OR 3.92, 95% CI 1.20-13.41; p = 0.024) and decreased (OR 0.13, 95% CI 0.03-0.40; p < 0.001) likelihood of poor functional outcome for patients treated with clipping and coiling, respectively. For patients in the surgical group, BMI ≥ 28.4 kg/m² was independently associated with incidence of cerebral hypodensities during admission (OR 2.44, 95% CI 1.16-5.25; p = 0.018) on multivariate analysis. For patients treated with coiling, BMI ≥ 33.2 kg/m² was independently associated with reduced odds of hypodensities (OR 0.45, 95% CI 0.21-0.89; p = 0.021). CONCLUSIONS The results of this study suggest that BMI may differentially affect functional outcomes after aSAH, depending on treatment modality. These findings may aid in treatment selection for patients with aSAH.

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.

Alcohol Consumption and Aneurysmal Subarachnoid Hemorrhage

Alcohol consumption may be a modifiable risk factor for rupture of intracranial aneurysms. Our aim is to evaluate the association between ruptured aneurysms and alcohol consumption, intensity, and cessation. The medical records of 4701 patients with 6411 radiographically confirmed intracranial aneurysms diagnosed at the Brigham and Women's Hospital and Massachusetts General Hospital between 1990 and 2016 were reviewed. Individuals were divided into cases with ruptured aneurysms and controls with unruptured aneurysms. Univariable and multivariable logistic regression analyses were performed to determine the association between alcohol consumption and rupture of intracranial aneurysms. In multivariable analysis, current alcohol use (OR 1.36, 95% CI 1.17-1.58) was associated with rupture status compared with never drinkers, whereas former alcohol use was not significant (OR 1.23, 95% CI 0.92-1.63). In addition, the number of alcoholic beverages per day among current alcohol users (OR 1.13, 95% CI 1.04-1.23) was significantly associated with rupture status, whereas alcohol use intensity was not significant among former users (OR 1.02, 95% CI 0.94-1.11). Current alcohol use and intensity are significantly associated with intracranial aneurysm rupture. However, this increased risk does not persist in former alcohol users, emphasizing the potential importance of alcohol cessation in patients harboring unruptured aneurysms.

Passive smoking and stroke in men and women: a national population-based case-control study in China

An association between passive smoking and stroke is unclear in China, particularly the association with hemorrhagic stroke. This study included 16205 deaths due to stroke aged ≥30 years and 16205 non-stroke controls randomly selected and frequency-matched to cases on gender and age. Smoking of spouses, defined as ≥1 cigarette per day for up to 1 year, was taken as a measure of exposure to passive smoking of subjects that was retrospectively ascertained by interviewing surviving spouses. After adjustment for variables, passive smoking increased the risk of death by 10% (odds ratio (OR), 1.10; 95% confidence interval (CI), 1.05-1.16) for all strokes, by 10% (OR, 1.10; 95% CI, 1.04-1.16) for hemorrhagic stroke, and by 12% (OR, 1.12; 95% CI, 1.03-1.23) for ischemic stroke, compared with non-exposure. This finding was highly consistent in men or women and in smokers or non-smokers, and was generally consistent among zones of China despite geographic diversity. The risk significantly increased with exposure-years and quantity of cigarettes smoked daily by spouses. This study indicated that passive smoking is associated with deaths from all-type strokes. It is highly advisable for the government to promote strong tobacco prevention and cessation programs and smoke-free environments.

Environmental Tobacco Smoke Exposure and Risk of Stroke in Never Smokers: An Updated Review with Meta-Analysis

OBJECTIVES

The study aimed to review the epidemiological evidence relating environmental tobacco smoke exposure to stroke in never smokers.

METHODS

The study is similar to our review in 2006, with searches extended to March 2016.

RESULTS

Twelve further studies were identified. A total of 28 studies varied considerably in design, exposure indices used, and disease definition. Based on 39 sex-specific estimates and the exposure index current spousal exposure (or nearest equivalent), the meta-analysis gave an overall fixed-effect relative risk estimate of 1.23 (95% confidence interval: 1.16-1.31), with significant (P < .05) heterogeneity. There was no significant heterogeneity by sex, continent, fatality, disease end point, or degree of adjustment for potential confounding factors. Relative risks were less elevated in prospective studies (1.15, 1.06-1.24) than in case-control studies (1.44, 1.22-1.60) or cross-sectional studies (1.40, 1.21-1.61). They also varied by publication year, but with no trend. A significant increase was not seen in studies that excluded smokers of any tobacco (1.07, .97-1.17), but was seen for studies that included pipe- or cigar-only smokers, occasional smokers, or long-term former smokers. No elevation was seen for hemorrhagic stroke. Relative risk estimates were similar using ever rather than current exposure, or total rather than spousal exposure. Eleven studies provided dose-response estimates, the combined relative risk for the highest exposure level being 1.56 (1.37-1.79). Many studies have evident weaknesses, recall bias, and particularly publication bias being major concerns.

CONCLUSIONS

Although other reviewers inferred a causal relationship, we consider the evidence does not conclusively demonstrate this. We repeat our call for publication of data from existing large prospective studies.

Risk-factor profile for the incidence of subarachnoid and intracerebral haemorrhage, cerebral infarction, and unspecified stroke during 21 years' follow-up in men

Aims: To study the risk-factor profile for the incidence of non-fatal and fatal stroke among middle-aged men according to the stroke subtypes subarachnoid or intracerebral haemorrhage, cerebral infarction, and unspecified stroke. Methods: The study design is a prospective cohort study. A total of 16,209 men aged 40—49 years resident in Oslo were screened for cardiovascular disease risk factors in 1972—73. Of these, 14,403 men had no cardiovascular symptoms or diseases or diabetes. The incidence of stroke after 21 years of follow-up of all men was extracted from hospital records and linkage to Statistics Norway. Results: A total of 429 non-fatal and 107 fatal stroke events were registered. Case fatality within 28 days (number and percentage of cases) was 51% (41, 7.7%) for subarachnoid haemorrhage, 39% (67, 12.6%) for cerebral haemorrhage, 10% (246, 46.3%) for cerebral infarct, and 19% (177, 33.4%) for unspecified stroke. Risk of stroke (not subarachnoid haemorrhage) increased with the presence of symptoms or a history of cardiovascular disease or diabetes. In multivariate analysis of men without CVD or diabetes, high blood pressure was a risk factor for all subtypes of stroke; furthermore, daily smoking was a risk factor for all subtypes except subarachnoid haemorrhage. Serum cholesterol and glucose concentrations and height (inverse association) were independently associated with cerebral infarction. Smoking was a significantly stronger predictor of fatal than non-fatal events. Conclusions: The risk-factor profile differed according to the underlying subtype of stroke. Cerebral infarction clearly shared with myocardial infarction the classical risk factors, including non-fasting glucose concentration.

Alcohol consumption and risk of subarachnoid hemorrhage: A meta-analysis of 14 observational studies

The association between alcohol consumption and the risk of subarachnoid hemorrhage (SAH) is inconsistent. Thus, meta- and a dose-response analyses are presented with the purpose of assessing their associations. A systematic literature search was performed using Pubmed and Embase electronic databases for pertinent observational studies. Random-effects or fixed-effect models were employed to combine the estimates of the relative risks (RRs) with corresponding 95% confidence intervals (CIs). A dose-response pattern was conducted for further analysis. The current meta-analysis includes 14 observational studies reporting data on 483,553 individuals and 2,556 patients. The combined RRs of light alcohol consumption (<15 g/day) and moderate alcohol consumption (15–30 g/day) compared with teetotal individuals were 1.27 (95% CI: 0.95, 1.68) and 1.33 (95% CI: 0.84, 2.09), respectively, which indicated no significant association between light-to-moderate alcohol consumption and SAH. An increased risk of SAH was noted in heavy alcohol consumption (>30 g/day) when compared with no alcohol consumption, as demonstrated by a result of 1.78 (95% CI: 1.46, 2.17). Dose-response analysis showed evidence of a linear association (P=0.0125) between alcohol consumption and SAH. The risk of SAH increased by 12.1% when alcohol consumption was increased by 10 g/day. Therefore, heavy alcohol consumption was found to be associated with an increased risk of SAH. Furthermore, the association between SAH and alcohol consumption has clinical relevance with regard to risk factor modification and the primary and secondary prevention of SAH.

Alcohol intake and associated risk of major cardiovascular outcomes in women compared with men: a systematic review and meta-analysis of prospective observational studies

BACKGROUND

The prevalence of alcohol intake is increasing among women in some populations. Alcohol consumption plays an important role in the risk of major cardiovascular outcomes and total mortality. Here, we conducted a meta-analysis to estimate the association between alcohol intake and major cardiovascular outcomes or total mortality in women compared with men.

METHODS

We searched the PubMed, Embase, and the Cochrane Library databases for relevant articles published prior to June 2014. Among these potential included prospective studies, the different dose categories of alcohol intake were compared with the lowest alcohol intake or non-drinkers between women and men for the outcomes of major cardiovascular or total mortality.

RESULTS

We included 23 prospective studies (18 cohorts) reporting data on 489,696 individuals. The summary relative risk ratio (RRR; female to male) for total mortality was significantly increased with moderate alcohol intake compared with the lowest alcohol intake (RRR, 1.10; 95 % confidence interval [CI]: 1.00-1.21; P = 0.047); no such significance was observed with other levels of alcohol intake (low intake: RRR, 1.07; 95 % CI: 0.98-1.17; P = 0.143; heavy intake: RRR, 1.09; 95 % CI: 0.99-1.21; P = 0.084). There was no evidence of a sex difference in the relative risk for coronary disease, cardiac death, stroke, or ischemic stroke between participants with low to heavy alcohol intake compared with those who never consumed alcohol or had the lowest alcohol intake.

CONCLUSIONS

Women with moderate to heavy alcohol intake had a significantly increased risk of total mortality compared with men in multiple subpopulations. Control of alcohol intake should be considered for women, particularly for young women who may be susceptible to binge drinking.

Body Mass Index and Aneurysmal Subarachnoid Hemorrhage: Decreasing Mortality with Increasing Body Mass Index

BACKGROUND

Labeled the "obesity paradox," obesity has been shown to provide a survival advantage in coronary artery disease, stroke, and intracerebral hemorrhage. Studies on body mass index (BMI) in aneurysmal subarachnoid hemorrhage (SAH) show conflicting results and none examined a North American population with long-term follow-up.

METHODS

A total of 305 consecutive SAH patients (2002 to 2011) were retrospectively reviewed to collect demographics, BMI (kg/m(2)), comorbidities, Glascow Coma Scale, World Federation of Neurologic Surgeons Scale, aneurysm treatment, delayed cerebral ischemia, radiographic infarction, and short-term and long-term (> 24 months) morbidity, and mortality. Patients were stratified by BMI into category 1, < 25 kg/m(2); category 2, 25 -< 30 kg/m(2); and category 3, ≥ 30 kg/m(2).

RESULTS

Categories 1, 2, and 3 had 93, 100, and 87 patients with mean BMIs of 22.4 ± 1.8, 27.6 ± 1.4, and 35.7 ± 4.6 (P < 0.05), respectively. By category, 24-month follow-up was available in 92%, 85%, and 85%. Category 3 had more hypertension, diabetes mellitus, and clipping than category 1. Short-term mortality rates were 17%, 12%, and 8%; long-term mortality rates were 34%, 26%, and 19% (P > 0.05 at all points between categories 1 vs. 3, but not 1 vs. 2 or 2 vs. 3). On univariate analysis, BMI was inversely associated with short-term (odds ratio, 0.91; 95% confidence interval 0.84-0.98; P = 0.009) and long-term (odds ratio, 0.92; 95% confidence interval 0.87-0.97; P = 0.001) mortality. On multivariate analysis including age, World Federation of Neurologic Surgeons Scale, delayed cerebral ischemia, and radiographic infarction, BMI remained significant for short-term (odds ratio, 0.91; 95% confidence interval 0.81-0.99; P = 0.047) and long-term (odds ratio, 0.92; 95% confidence interval 0.85-0.98; P = 0.021) mortality. On Kaplan-Meier survival analysis, P > 0.05 for categories 1 versus 2 and 2 versus 3, but P = 0.005 for categories 1 versus 3.

CONCLUSIONS

In our SAH population, higher BMI resulted in less short-term and long-term mortality, but no difference in functional outcome.

Genetic study of intracranial aneurysms

BACKGROUND AND PURPOSE

Rupture of intracranial aneurysms (IAs) causes subarachnoid hemorrhage, leading to immediate death or severe disability. Identification of the genetic factors involved is critical for disease prevention and treatment. We aimed to identify the susceptibility genes for IAs.

METHODS

Exome sequencing was performed in 12 families with histories of multiple cases of IA (number of cases per family ≥3), with a total of 42 cases. Various filtering strategies were used to select the candidate variants. Replicate association studies of several candidate variants were performed in probands of 24 additional IA families and 426 sporadic IA cases. Functional analysis for the mutations was conducted.

RESULTS

After sequencing and filtering, 78 variants were selected for the following reasons: allele frequencies of variants in 42 patients was significantly (P<0.05) larger than expected; variants were completely shared by all patients with IA within ≥1 family; variants predicted damage to the structure or function of the protein by PolyPhen-2 (Polymorphism Phenotyping V2) and SIFT (Sorting Intolerance From Tolerant). We selected 10 variants from 9 genes (GPR63, ADAMST15, MLL2, IL10RA, PAFAH2, THBD, IL11RA, FILIP1L, and ZNF222) to form 78 candidate variants by considering commonness in families, known disease genes, or ontology association with angiogenesis. Replicate association studies revealed that only p.E133Q in ADAMTS15 was aggregated in the familial IA cases (odds ratio, 5.96; 95% confidence interval, 2.40-14.82; P=0.0001; significant after the Bonferroni correction [P=0.05/78=0.0006]). Silencing ADAMTS15 and overexpression of ADAMTS15 p.E133Q accelerated endothelial cell migration, suggesting that ADAMTS15 may have antiangiogenic activity.

CONCLUSIONS

ADAMTS15 is a candidate gene for IAs.

Rapid aneurysm growth and rupture in systemic lupus erythematosus

BACKGROUND

Subarachnoid hemorrhage (SAH) due to intracranial aneurysm rupture is a major neurosurgical emergency associated with significant morbidity and mortality. Rapid aneurysm growth is associated with rupture. Systemic lupus erythematosus (SLE) is a multi-system autoimmune disorder whose complications can include cerebral vasculitis and vasculopathy. Intracranial aneurysms are not known to occur more frequently in SLE patients than the general population; however, aneurysm growth rates have not been studied in SLE.

CASE DESCRIPTION

We present a 43-year-old female with SLE on prednisone, hydroxychloroquine, and azathioprine with moderate disease activity who presented with severe, acute-onset headache and was found to have Hunt and Hess grade II SAH due to rupture of an 8 mm saccular anterior communicating artery (ACoA) aneurysm. The patient developed severe vasospasm, re-ruptured, and was taken for angiography and embolization, which was challenging due to a high degree of vasospasm and arterial stenosis. Review of imaging from less than 2 years prior demonstrated a normal ACoA complex without evidence of an aneurysm.

CONCLUSION

We review the literature and discuss the risk factors and pathophysiology of rapid aneurysm growth and rupture, as well as the pathologic vascular changes associated with SLE. Although SLE patients do not develop intracranial aneurysm at an increased rate, these changes may predispose them to higher incidence of growth and rupture. This possibility-coupled with increased morbidity and mortality of SAH in SLE-suggests that SAH should be considered in SLE patients presenting with headache, and advocates for more aggressive treatment of SLE patients with unruptured aneurysms.

Stroke mortality associated with environmental tobacco smoke among never-smoking Japanese women: a prospective cohort study

OBJECTIVE

This study examined the association of exposure to environmental tobacco smoke (ETS) during adulthood with stroke and its subtypes using data from a large-scale prospective cohort study in Japan.

METHODS

The study population included 36,021 never-smoking Japanese women who were enrolled between 1983 and 1985 and were followed-up for 15 years. We used Cox proportional hazard regression models to estimate hazard ratios (HRs) for stroke death associated with ETS exposure at home during adulthood.

RESULTS

A total of 906 cases of stroke death were observed during 437,715 person-years of follow-up. Compared with never-smoking women without smoking family members, HRs for stroke mortality among never-smoking women living with smoking family members in all subjects, in those aged 40-79 years, and in those aged ≥ 80 years were 1.14 (95% confidence interval: 0.99-1.31), 1.24 (95% CI: 1.05-1.46), and 0.89 (95% CI: 0.66-1.19), respectively, after adjustment for possible confounders. The risk was most evident for subarachnoid hemorrhage [HR: 1.66 (95% CI: 1.02-2.70) in all subjects].

CONCLUSION

This study suggests that exposure to ETS at home during adulthood is associated with an increased risk of stroke among never-smoking Japanese women.

Blood pressure categories and long-term risk of cardiovascular disease according to age group in Japanese men and women

Blood pressure (BP) categories defined by systolic BP (SBP) and diastolic BP (DBP) are commonly used. However, the BP category-specific risk of cardiovascular disease (CVD) has not been thoroughly investigated in different age groups. The aim of this study was to assess long-term CVD risk and its impact according to BP categories and age group. Pooling individual data from 10 cohorts, we studied 67 309 Japanese individuals (40-89 years old) who were free of CVD at baseline: we categorized them as belonging to three age groups: 'middle-aged' (40-64 years), 'elderly' (65-74 years) and 'very elderly' (75-89 years). BP was classified according to the 2009 Japanese Society of Hypertension Guidelines. Cox models were used to estimate adjusted hazard ratios for CVD deaths. We observed 1944 CVD deaths over a mean follow-up of 10.2 years. In all age groups, the overall relationship between BP category and CVD risk was positive, with a greater strength observed for younger age groups. We observed a trend of increased risk from SBP/DBP ≥ 130/85 mm Hg in the very elderly, and a significant increase from SBP/DBP ≥ 120/80 mm Hg in the other age groups. The population attributable fractions (PAFs) of CVD death in reference to the SBP/DBP<120/80 mm Hg category ranged from 23.4% in the very elderly to 60.3% in the middle-aged. We found an overall graded increase in CVD risk with higher BP category in the very elderly. The PAFs suggest that keeping BP levels low is an important strategy for primary CVD prevention, even in an elderly population.

Sexual intercourse and cerebral aneurysmal rupture: potential mechanisms and precipitants

Aneurysmal subarachnoid hemorrhage (SAH) is a significant cause of death in young and middle-aged individuals and causes tremendous morbidity in affected patients. Despite the identification of various risk factors, the series of events leading to the formation, growth, and rupture of intracranial aneurysms is poorly understood. Cerebral aneurysm rupture has been associated with sexual intercourse and other forms of physical exercise. In fact, multiple case series reported that coitus was the immediate preceding activity in 3.8–14.5% of patients suffering from aneurysmal SAH. This may be related to the large elevations in mean arterial blood pressure that occur in both males and females during sexual intercourse (130–175 and 125–160 mm Hg, respectively). While coitus and physical exercise share important physiological similarities, each may differentially affect the probability that a preformed aneurysm will rupture. In this literature review and synthesis, the authors analyze the physiological human response to sexual intercourse in an effort to delineate those factors that may precipitate aneurysmal rupture. The authors' analysis is based on the original data collected by Masters and Johnson. To the authors' knowledge, this is the first review to address the link between sexual intercourse and intracranial aneurysmal rupture. While actual measurements of the physiological variables relevant to SAH were not performed in this article, the authors make reasonable assumptions based on the available data to help elucidate the mechanism of sexually induced aneurysmal rupture.

Medical complications after subarachnoid hemorrhage

The prevention and management of medical complications are important for improving outcomes after subarachnoid hemorrhage (SAH). Fever, anemia requiring transfusion, hyperglycemia, hyponatremia, pneumonia, hypertension, and neurogenic cardiopulmonary dysfunction occur frequently after SAH. There is increasing evidence that acute hypoxia and extremes of blood pressure can exacerbate brain injury during the acute phase of bleeding. There are promising strategies to minimize these complications. Randomized controlled trials are needed to evaluate the risks and benefits of these and other medical management strategies after SAH.

Excess body weight and incidence of stroke: meta-analysis of prospective studies with 2 million participants

BACKGROUND AND PURPOSE

A systematic review of the prospective studies addressing the relationship of overweight and obesity to major stroke subtypes is lacking. We evaluated the occurrence of a graded association between overweight, obesity, and incidence of ischemic and hemorrhagic stroke by a meta-analysis of cohort studies.

METHODS

A search of online databases and relevant reviews was performed. Inclusion criteria were original article in English, prospective study design, follow-up > or = 4 years, indication of number of subjects exposed, and number of events across body mass index categories. Crude unadjusted relative risk (RR) and 95% CI were calculated for each study for overweight or obese compared with normal-weight categories. Log-transformed values and SE were used to calculate the pooled RR with random effects models; publication bias was checked. Additional analyses were performed using the multivariate estimates of risk reported in the individual studies.

RESULTS

Twenty-five studies were included, with 2 274 961 participants and 30 757 events. RR for ischemic stroke was 1.22 (95% CI, 1.05-1.41) for overweight and 1.64 (95% CI, 1.36-1.99) for obesity, whereas RR for hemorrhagic stroke was 1.01 (95% CI, 0.88-1.17) and 1.24 (95% CI, 0.99-1.54), respectively. Subgroup and meta-regression analyses ruled out gender, population average age, body mass index and blood pressure, year of recruitment, year of study publication, and length of follow-up as significant sources of heterogeneity. The additional analyses relying on the published multivariate estimates of risk provided qualitatively similar results.

CONCLUSIONS

Overweight and obesity are associated with progressively increasing risk of ischemic stroke, at least in part, independently from age, lifestyle, and other cardiovascular risk factors.

Spontaneous spinal subarachnoid haemorrhage--a complication of alcohol withdrawal therapy

BACKGROUND

Non-traumatic spontaneous idiopathic spinal subarachnoid haemorrhage (SSH) is extremely rare. So far, only 12 cases have been described in the literature and there are no data regarding the association between alcohol dependence and SSH.

CASE SUMMARY

We report the first case of an alcohol-dependent patient with an idiopathic non-traumatic cervical subarachnoid haemorrhage after alcohol withdrawal therapy.

CONCLUSIONS

Clinicians should be aware of alcohol dependence as an independent risk factor for not only intracranial, but subarachnoid haemorrhage. We recommend performing spinal imaging in alcoholics with sudden onset of severe neck or back pain, even if neurological deficits are absent or coagulation parameters are normal.

Optimal hemoglobin concentration in patients with subarachnoid hemorrhage, acute ischemic stroke and traumatic brain injury

PURPOSE OF REVIEW

The review outlines recent clinical and experimental studies regarding the effects of red blood-cell transfusion on clinical outcome in neurocritical patients, including patients with subarachnoid hemorrhage, acute ischemic stroke and traumatic brain injury. Optimal hemoglobin transfusion trigger and the role of other transfusion indicators for neurocritical patients are discussed.

RECENT FINDINGS

Acute anemia (hemoglobin levels near 7 g/dl) is well tolerated by healthy subjects, but extreme anemia might negatively affect clinical outcome of neurocritical patients. Conversely, high hemoglobin levels, attained by means other than red blood-cell transfusion, improve clinical outcome, whereas red blood-cell transfusion is associated with poorer clinical outcome (mortality, length of stay and disability) in patients presenting subarachnoid hemorrhage, acute ischemic stroke and traumatic brain injury. Studies defining the optimal hemoglobin concentration in neurocritical patients are lacking, but a restrictive transfusion policy seems to be safe and is often recommended. In the near future, signals coming from the brain, such as brain tissue oxygen tension and regional cerebral oxygen saturation, might potentially be developed into transfusion triggers.

SUMMARY

Both severe anemia and red blood-cell transfusion may negatively influence clinical outcome in neurocritical patients. Acceptance of low hemoglobin concentrations may be justified by avoiding negative transfusion effects. No evidence-based transfusion trigger in neurocritical patients can be recommended.

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.

Association analyses confirming a susceptibility locus for intracranial aneurysm at chromosome 14q23

Previous linkage analyses of intracranial aneurysm (IA) have proposed several genetic susceptibility loci; however, some loci remain contradictory. The objective of this study was to confirm these loci in a Japanese population using allelic and haplotype association analyses. We set high-density single nucleotide polymorphism markers in previously suggested IA loci and conducted an association analysis in 29 cases and 35 controls from a small community in Akita, Japan. Genotyping was carried out using the GeneChip 10 K mapping array, and the association analysis was performed using GeneSpring GT2 software. The result was confirmed in a replication cohort consisting of 237 cases and 253 controls from all over Japan. Only one variant, rs767603, at chromosome 14q23, was significantly associated with IA, both in allelic analysis (p=0.00017, Bonferroni-corrected p=0.021) and haplotype analysis (p=0.00178, Bonferroni-corrected p=0.048). This association was confirmed in the replication cohort (p=0.0046 for allelic association, p=0.0060 for haplotype association). Our findings confirm 14q23 to be a susceptibility locus for intracranial aneurysm.

Risk and protective factors related to mortality from pneumonia among middleaged and elderly community residents: the JACC Study

BACKGROUND

There have been few systematic investigations into risk and protective factors for pneumonia related mortality for community residents. This study investigated these factors utilizing a large cohort study on Japanese community residents.

METHODS

Subjects, 110,792 individuals (aged 40-79 years) enrolled in 1988-1990, were followed until death, or when they moved away from the surveyed communities, or the end of 2003. Pneumonia death was defined following 480-486 (International Classification of Diseases, 9th Revision) or J12-J18 (10th Revision). Age-adjusted and multivariate hazard ratios were calculated along with 95% confidence intervals using the Cox proportional hazards model.

RESULTS

With 1,112,747 person-years of the study, a total of 1,246 persons died of pneumonia. We found history of blood transfusion (multivariate hazard ratio=2.0 [95% confidence interval: 1.7-2.4]) was a potent novel risk factor. Walking 0.5-1 hour/day (0.8 [0.6-1.0]), 1+ hour/day (0.7 [0.6-0.8]), and/or a history of pregnancy (0.6 [0.4-0.9]) were found to reduce pneumonia mortality. A large body mass index (BMI) (25+kg/m²) was a protective factor (0.7 [0.5-0.8]), while low BMI (<18) was confirmed as a risk one (2.1 [1.7-2.6]). Smoking was an important preventable risk factor (1.6 [1.3-1.9], population attributable risk proportion=14%), and its cessation reduced risk (0.7 [0.5-1.0]) to levels comparable to never-smokers (0.7 [0.5-1.0]).

CONCLUSIONS

The risk and protective factors ascertained here for pneumonia mortality among community residents, history of blood transfusion, large BMI, and walking habits, warrant further study. Smoking cessation may effectively reduce pneumonia mortality.

Mortality and risk factors for stroke and its subtypes in a cohort study in Japan

OBJECTIVE

To estimate stroke mortality and evaluate risk factors for total stroke deaths and its two principal subtypes in a cohort study in Japan.

METHODS

A total of 9651 subjects aged 40 or over and free of stroke were analyzed in a cohort study conducted in Fukuoka Prefecture, Japan. The follow-up period was from 1986 to 2003. Mortality rate per 100,000 person-years of stroke was estimated. The Cox proportional hazards model was used to estimate the hazard ratios and 95% confidence interval.

RESULTS

A total of 226 stroke deaths were recorded during 132,972 years of follow-up. Among these, 47 were intracerebral hemorrhage and 109 were cerebral infarction. Stroke mortality rates were 209.4 per 100,000 person-years in males, and 140.5 in females. The results showed that advanced age, male gender, low body mass index (BMI), history of diabetes, hypertension, and transfusion were associated with an increased risk of mortality from total stroke.

CONCLUSION

We confirmed that advanced age, male gender, low BMI, history of diabetes, history of hypertension and history of transfusion were associated with an increased risk of total stroke mortality. In addition, the magnitude of these associations differed between the two principal stroke subtypes.

Model-based linkage analyses confirm chromosome 19q13.3 as a susceptibility locus for intracranial aneurysm

BACKGROUND AND PURPOSE

In previous studies of familial intracranial aneurysm (IA), parametric linkage analyses have been undertaken for five unrelated families, four providing maximum logarithm of odds (LOD) scores with dominant models and one with a recessive model. Each family was linked to a distinct locus, indicating locus heterogeneity. This study aimed to examine whether Japanese IA families consistent with autosomal-dominant mode of inheritance support linkage to these loci.

METHODS

We performed genomewide linkage analysis using the GENEHUNTER program. Affected-only parametric linkage analysis was used for 41 affected members in nine unrelated IA families with dominant models, which were selected from 29 families used for a nonparametric (model-free) linkage analysis in our previous study.

RESULTS

We failed to support the linkage to previously reported autosomal-dominant loci. Instead, we found linkage to chromosome 19q13.3 with a maximum multipoint LOD score of 4.10. The LOD-1 interval (regions with LOD scores of >1) was 8.0 cM between D19S198 and D19S902.

CONCLUSIONS

A genomewide scan for IA families with dominant models in Japan confirmed the locus at chromosome 19q13.3, which has also been reported as a candidate locus in a Finnish population.

Body Mass Index and Risk of Hemorrhagic Stroke in Korean Adults: Case-control Study

OBJECTIVES

To evaluate the association between body mass index (BMI) and hemorrhagic stroke.

METHODS

A case-control study was conducted on 2,712 persons (904 cases, 904 hospital controls, and 904 community controls) participating in an Acute Brain Bleeding Analysis study from October 2002 to March 2004. Two controls for each case were matched according to age and gender. The information was obtained by trained interviewers using standardized questionnaire. A conditional logistic regression model was used to estimate the association between BMI and the frequency of having a hemorrhagic stroke.

RESULTS

Obese men (25.0 <or= BMI < 30.0 kg/m(2)) had an odds ratios (OR) of 1.39 (95% CI 1.03 to 1.87) a hemorrhagic stroke, compared to men with a normal BMI (18.5 to 24.9 kg/m(2)). Conversely, women with lower BMI had a higher risk of having hemorrhagic stroke. With respect to subtypes of hemorrhagic stroke, we observed about a three-fold increase in the risk of intracerebral hemorrhage (ICH) in the highly obese group. However, these trends were not significant in patients with subarachnoid hemorrhages.

CONCLUSIONS

Obesity was identified as one of the risk factors in hemorrhagic stroke, in particular ICH. Conversely, in women, a lean body weight increases the risk of hemorrhagic stroke. Consequently, managing one\s weight is essential to reduce the risks of hemorrhagic stroke.