Factor V leiden and ischemic stroke risk: the Genetics of Early Onset Stroke (GEOS) study

Thrombophilia Testing in Stroke: A Case Report and Review of Evidence

Thrombophilia is commonly associated with venous thromboembolism, but its relationship with arterial thrombosis, specifically stroke, is not as clearly established. Several large studies have failed to establish a significant connection between inherited thrombophilia and stroke. While tests for Factor V Leiden mutation, prothrombin mutation, protein C deficiency, protein S deficiency, antithrombin deficiency, and antiphospholipid antibodies are typically done for thrombophilia diagnosis, there appears to be little or no correlation between these markers and stroke. In this article, we discuss a case of a 26-year-old male admitted with right neck pain that developed after playing basketball; he was found to have a right cerebellar infarction. He underwent extensive tests for hypercoagulable disorders, which were negative. We also review current evidence and reassess the value of thrombophilia testing in stroke patients.

Genomic risk scores and oral contraceptive-associated ischemic stroke risk: a call for collaboration

Background

Oral contraceptives (OCs) are generally safe but vascular risk factors increase OC-associated ischemic stroke risk. We performed a case-control study to evaluate whether a genomic risk score for ischemic stroke modifies OC-associated ischemic stroke risk.

Methods

The Genetics of Early-Onset Stroke study includes 332 premenopausal women (136 arterial ischemic stroke cases and 196 controls) with data on estrogen-containing OC use within 30 days before the index event (for cases) or interview (for controls). Using a previously validated genetic risk score (metaGRS) for ischemic stroke based on 19 polygenic risk scores for stroke and stroke-associated risk factors, we stratified our combined case-control sample into tertiles of genomic risk. We evaluated the association between OC use and ischemic stroke within each tertile. We tested if the association between OC use and ischemic stroke depended on the genomic risk of stroke using logistic regression with an OC use × metaGRS interaction term. These analyses were performed with and without adjustment for smoking, hypertension, diabetes, coronary heart disease, and body mass index.

Results

After adjustment for vascular risk factors, the odds ratio of OC use was 3.2 (1.7-6.3) overall and increased from the lower, middle, and upper tertile of genomic risk from 1.6 (0.5-5.4) to 2.5 (0.08-8.2) to 13.7 (3.8-67.3) respectively, and a p-value for interaction of 0.001.

Conclusions

Our results suggest that genomic profile may modify the OC-associated ischemic stroke risk. Larger studies are warranted to determine whether a genomic risk score could be clinically useful in reducing OC-associated ischemic stroke.

Factor V Leiden, Factor II, Protein C, Protein S, and Antithrombin and Ischemic Strokes in Young Adults: A Meta-Analysis

Ischemic strokes are one of the leading causes of death worldwide. The aim of this meta-analysis is to elaborate on the role of inherited predisposition to thrombophilia in the etiology of ischemic strokes in young adults. The keywords factor V Leiden (FVL), factor II, prothrombin (PT), protein C (PC), protein S (PS), antithrombin (AT), ischemic stroke, and young were used to search different databases. We selected studies with participants who were between 18 and 65 years. A total of 104 studies were eligible for inclusion in the meta-analysis. All the studied genetic markers were risk factors for ischemic stroke according to our results (FVL OR = 1.74; PT OR = 1.95; PC OR = 10.20; PS OR = 1.74; AT OR = 3.47; p < 0.05). There was moderate heterogeneity for most of the results, and subgroup analyses were conducted by dividing the studies according to the geographic location, gender ratio, and selection criteria of the performed study. There were no significant differences between the groups, but different geographic location was a probable source of heterogeneity. All of the studied markers—FVL, prothrombin, PC, PS, and AT—were significantly associated with increased risk of ischemic stroke in young adults and, if tested, could improve the quality of care.

Contribution of Common Genetic Variants to Risk of Early-Onset Ischemic Stroke

BACKGROUND AND OBJECTIVES

Current genome-wide association studies of ischemic stroke have focused primarily on late-onset disease. As a complement to these studies, we sought to identify the contribution of common genetic variants to risk of early-onset ischemic stroke.

METHODS

We performed a meta-analysis of genome-wide association studies of early-onset stroke (EOS), ages 18-59 years, using individual-level data or summary statistics in 16,730 cases and 599,237 nonstroke controls obtained across 48 different studies. We further compared effect sizes at associated loci between EOS and late-onset stroke (LOS) and compared polygenic risk scores (PRS) for venous thromboembolism (VTE) between EOS and LOS.

RESULTS

We observed genome-wide significant associations of EOS with 2 variants in ABO, a known stroke locus. These variants tag blood subgroups O1 and A1, and the effect sizes of both variants were significantly larger in EOS compared with LOS. The odds ratio (OR) for rs529565, tagging O1, was 0.88 (95% confidence interval [CI]: 0.85-0.91) in EOS vs 0.96 (95% CI: 0.92-1.00) in LOS, and the OR for rs635634, tagging A1, was 1.16 (1.11-1.21) for EOS vs 1.05 (0.99-1.11) in LOS; p-values for interaction = 0.001 and 0.005, respectively. Using PRSs, we observed that greater genetic risk for VTE, another prothrombotic condition, was more strongly associated with EOS compared with LOS (p = 0.008).

DISCUSSION

The ABO locus, genetically predicted blood group A, and higher genetic propensity for venous thrombosis are more strongly associated with EOS than with LOS, supporting a stronger role of prothrombotic factors in EOS.

Differences in Multiple Risk Factors Between Black and White Individuals With Young-Onset Ischemic Stroke

BACKGROUND AND OBJECTIVES

Stroke in young adults constitutes 15%-18% of all ischemic stroke cases. Black individuals have an excess risk of ischemic stroke especially in young adults. Although it is known that Black patients have a higher prevalence of hypertension and diabetes, few studies have addressed the association of concurrent multiple vascular risk factors with the excess risk of early-onset stroke among Black individuals.

METHODS

A population-based case-control study of early-onset ischemic stroke, ages 15-49 years, was conducted in the Baltimore-Washington DC region between 1992 and 2007. Presence of the risk factors of obesity, hypertension, diabetes, and current smoking were obtained from both cases and controls by an in-person interview. Risk factor groups were defined as (1) 1 risk factor, (2) 2 risk factors, (3) 3 risk factors, and (4) 4 risk factors. Logistic regression analysis adjusting for age and sex was used to evaluate the association between each risk factor group and ischemic stroke compared with the reference group with no risk factors.

RESULTS

The study included 1,034 cases and 1,091 controls. Of the cases, 47% were Black, 54% were men, and the mean (±SD) age was 41.0 (±6.9) years. The odds of having a stroke increased exponentially as the number of risk factors increased, 2.1, 2.6, 7.6, 16.5, all p < 0.001, for groups 1-4, respectively. When stratified by race, Black individuals were approximately 6 times more likely to have all 4 risk factors.

DISCUSSION

The risk of stroke in young adults increased exponentially with the number of risk factors. Young Black patients with ischemic stroke were approximately 6 times more likely to have the co-occurrence of obesity, hypertension, diabetes, and smoking compared with their White counterparts. Targeting public health interventions to identify and improve care to Black young adults with multiple stroke risk factors may have substantial impact on lowering risk of stroke.

Black-white Differences in Left Ventricular Hypertrophy Rates Among Young Adults with Ischemic Stroke

OBJECTIVES

Few studies have addressed Black-White differences in left ventricular hypertrophy (LVH) in young stroke patients without a history of hypertension.

METHODS

A case-only cross-sectional analysis performed in 2019 of data from the Stroke Prevention in Young Adults Study, a population-based case-control study of ischemic stroke patients ages 15-49. The main outcomes were hypertension indicators at the time of stroke hospitalization: self-reported history of hypertension, LVH by echocardiography (Echo-LVH) and LVH by electrocardiogram (ECG-LVH). The prevalence of Echo-LVH was further determined in those with and without a history of hypertension. Adjusted odds ratios and 95% confidence intervals comparing blacks and whites were calculated by logistic regression.

RESULTS

The study population included 1028 early-onset ischemic stroke patients, 48% Black cases, 54% men, median age 43 years (interquartile range, 38-46 years). Overall, the prevalence of hypertension history, Echo-LVH and ECG-LVH were 41.3%, 34.1% and 17.5%, respectively. Each of the hypertension indicators were more frequent in men than in women and in Black cases than in White cases. Black patients without a history of hypertension had higher rates of Echo-LVH than their white counterparts, 40.3% vs 27.7% (age and obesity adjusted OR 1.8; 95% CI 1.02-3.4) among men and 20.9% vs 7.6% (adjusted OR 2.7; 95% CI 1.2-6.2) among women.

CONCLUSIONS

LVH was common in young patients with ischemic stroke, regardless of self-reported history of hypertension. These findings emphasize the need for earlier screening and more effective treatment of hypertension in young adults, particularly in the Black population.

Black-White Differences in Ischemic Stroke Risk Factor Burden in Young Adults

BACKGROUND AND PURPOSE

Although the US Black population has a higher incidence of stroke compared with the US White population, few studies have addressed Black-White differences in the contribution of vascular risk factors to the population burden of ischemic stroke in young adults.

METHODS

A population-based case-control study of early-onset ischemic stroke, ages 15 to 49 years, was conducted in the Baltimore-Washington DC region between 1992 and 2007. Risk factor data was obtained by in-person interview in both cases and controls. The prevalence, odds ratio, and population-attributable risk percent (PAR%) of smoking, diabetes, and hypertension was determined among Black patients and White patients, stratified by sex.

RESULTS

The study included 1044 cases and 1099 controls. Of the cases, 47% were Black patients, 54% were men, and the mean (±SD) age was 41.0 (±6.8) years. For smoking, the population-attributable risk percent were White men 19.7%, White women 32.5%, Black men 10.1%, and Black women 23.8%. For diabetes, the population-attributable risk percent were White men 10.5%, White women 7.4%, Black men 17.2%, and Black women 13.4%. For hypertension, the population-attributable risk percent were White men 17.2%, White women 19.3%, Black men 45.8%, and Black women 26.4%.

CONCLUSIONS

Modifiable vascular risk factors account for a large proportion of ischemic stroke in young adults. Cigarette smoking was the strongest contributor to stroke among White patients while hypertension was the strongest contributor to stroke among Black patients. These results support early primary prevention efforts focused on smoking cessation and hypertension detection and treatment.

Marijuana Use and the Risk of Early Ischemic Stroke: The Stroke Prevention in Young Adults Study

BACKGROUND AND PURPOSE

Few studies have examined the dose-response and temporal relationships between marijuana use and ischemic stroke while controlling for important confounders, including the amount of tobacco smoking. The purpose of our study was to address these knowledge gaps.

METHODS

A population-based case-control study with 1090 cases and 1152 controls was used to investigate the relationship of marijuana use and early-onset ischemic stroke. Cases were first-ever ischemic stroke between the ages of 15 and 49 identified from 59 hospitals in the Baltimore-Washington region. Controls obtained by random digit dialing from the same geographic region were frequency-matched to cases by age, sex, region of residence and, except for the initial study phase, race. After excluding subjects with cocaine and other vasoactive substance use, the final study sample consisted of 751 cases and 813 controls. All participants underwent standardized interviews to characterize stroke risk factors and marijuana use. Unconditional logistic regression analysis was used to assess the relationships between marijuana use and risk of ischemic stroke, adjusting for age, sex, race, study phase, the amount of current tobacco smoking, current alcohol use, hypertension, and diabetes.

RESULTS

After adjusting for other risk factors, including the amount of current tobacco smoking, marijuana use was not associated with ischemic stroke, regardless of the timing of use in relationship to the stroke, including ever use, use within 30 days, and use within 24 hours. There was a nonsignificant trend towards increased stroke risk among those who smoked marijuana at least once a week (odds ratio, 1.9 [95% CI, 0.8-4.9]).

CONCLUSIONS

These analyses do not demonstrate an association between marijuana use and an increased risk of early-onset ischemic stroke, although statistical power was limited for assessing the association among very heavy users.

Thrombophilia Testing After Ischemic Stroke: Why, When, and What?

Thrombophilia testing is frequently performed after an ischemic stroke, particularly when cryptogenic. However, there is minimal evidence supporting a significant association between most conditions assessed through thrombophilia testing and ischemic stroke, and the rationale for thrombophilia testing in many clinical situations remains uncertain. In this topical review, we review and contextualize the existing data on the risks, predictors, and outcomes of thrombophilic conditions in patients with ischemic stroke. We report that inherited thrombophilias have an uncertain relationship with ischemic stroke. Conversely, antiphospholipid syndrome, an acquired immune-mediated thrombophilia, seems to be a strong risk factor for arterial thromboembolic events, including ischemic stroke, and especially among young patients. Our findings suggest that certain circumstances may warrant targeted thrombophilia testing, such as stroke in the young, cryptogenic stroke, and high estrogen states. Future prospective studies should investigate the utility and cost effectiveness of thrombophilia testing in various stroke settings, including among patients with patent foramen ovale; as well as the optimal secondary stroke prevention regimen in patients with confirmed thrombophilia, particularly if no other potential stroke mechanism is identified.

Sickle Cell Trait and Risk of Ischemic Stroke in Young Adults

BACKGROUND AND PURPOSE

Approximately 8% of Blacks have sickle cell trait (SCT), and there are conflicting reports from recent cohort studies on the association of SCT with ischemic stroke (IS). Most prior studies focused on older populations, with few data available in young adults.

METHODS

A population-based case-control study of early-onset IS was conducted in the Baltimore-Washington region between 1992 and 2007. From this study, 342 Black IS cases, ages 15 to 49, and 333 controls without IS were used to examine the association between SCT and IS. Each participant's SCT status was established by genotyping and imputation. For analysis, χ² tests and logistic regression models were performed with adjustment for potential confounding variables.

RESULTS

Participants with SCT (n=55) did not differ from those without SCT (n=620) in prevalence of hypertension, previous myocardial infarction, diabetes mellitus, and current smoking status. Stroke cases had increased prevalence in these risk factors compared with controls. We did not find an association between SCT and early-onset IS in our overall population (odds ratio=0.9 [95% CI, 0.5-1.7]) or stratified by sex in males (odds ratio=1.26 [95% CI, 0.56-2.80]) and females (odds ratio=0.67 [95% CI, 0.28-1.69]).

CONCLUSIONS

Our data did not find evidence of increased risk of early-onset stroke with SCT.

[The association of hemostasis system genes with the development of ischemic stroke in patients under the age of 50 years]

AIM

To study an influence of polymorphic variants of hemostasis system genes on the risk of ischemic stroke (IS) in patients of the Slavic population under the age of 50 years.

MATERIAL AND METHODS

Ninety-two patients (19 women and 73 men), aged 18-50 years, were examined. The diagnosis of stroke was confirmed by neuroimaging (CT or MRI) in all patients. Polymorphic alleles of GP1BA, F2, F5 were studied by a real-time polymerase chain reaction using the TaqMan technology.

RESULTS AND CONCLUSION

An analysis of the GP1BA -5T/C polymorphism showed that it was associated with IS in young men, lacunar stroke and stroke due to thrombosis of the brachiocephalic arteries. This association was not found in young women. The F5 G1691A polymorphism was associated with lacunar stroke. The F2 G20210A polymorphism was associated with stroke due to thrombosis of the brachiocephalic arteries.

Genetics of the thrombomodulin-endothelial cell protein C receptor system and the risk of early-onset ischemic stroke

BACKGROUND AND PURPOSE

Polymorphisms in coagulation genes have been associated with early-onset ischemic stroke. Here we pursue an a priori hypothesis that genetic variation in the endothelial-based receptors of the thrombomodulin-protein C system (THBD and PROCR) may similarly be associated with early-onset ischemic stroke. We explored this hypothesis utilizing a multi-stage design of discovery and replication.

METHODS

Discovery was performed in the Genetics-of-Early-Onset Stroke (GEOS) Study, a biracial population-based case-control study of ischemic stroke among men and women aged 15-49 including 829 cases of first ischemic stroke (42.2% African-American) and 850 age-comparable stroke-free controls (38.1% African-American). Twenty-four single-nucleotide-polymorphisms (SNPs) in THBD and 22 SNPs in PROCR were evaluated. Following LD pruning (r2≥0.8), we advanced uncorrelated SNPs forward for association analyses. Associated SNPs were evaluated for replication in an early-onset ischemic stroke population (onset-age<60 years) consisting of 3676 cases and 21118 non-stroke controls from 6 case-control studies. Lastly, we determined if the replicated SNPs also associated with older-onset ischemic stroke in the METASTROKE data-base.

RESULTS

Among GEOS Caucasians, PROCR rs9574, which was in strong LD with 8 other SNPs, and one additional independent SNP rs2069951, were significantly associated with ischemic stroke (rs9574, OR = 1.33, p = 0.003; rs2069951, OR = 1.80, p = 0.006) using an additive-model adjusting for age, gender and population-structure. Adjusting for risk factors did not change the associations; however, associations were strengthened among those without risk factors. PROCR rs9574 also associated with early-onset ischemic stroke in the replication sample (OR = 1.08, p = 0.015), but not older-onset stroke. There were no PROCR associations in African-Americans, nor were there any THBD associations in either ethnicity.

CONCLUSION

PROCR polymorphisms are associated with early-onset ischemic stroke in Caucasians.

Prothrombotic factors do not increase the risk of recurrent ischemic events after cryptogenic stroke at young age: the FUTURE study

BACKGROUND

The role of hypercoagulable states and preceding infections in the etiology of young stroke and their role in developing recurrent ischemic events remains unclear. Our aim is to determine the prevalence of these conditions in patients with cryptogenic stroke at young age and to assess the long-term risk of recurrent ischemic events in patients with and without a hypercoagulable state or a recent pre-stroke infection with Borrelia or Syphilis.

PATIENTS AND METHODS

We prospectively included patients with a first-ever transient ischemic attack or ischemic stroke, aged 18-50, admitted to our hospital between 1995 and 2010. A retrospective analysis was conducted of prothrombotic factors and preceding infections. Outcome was recurrent ischemic events.

RESULTS

Prevalence of prothrombotic factors did not significantly differ between patients with a cryptogenic stroke and with an identified cause (24/120 (20.0%) and 32/174 (18.4%) respectively). In patients with a cryptogenic stroke the long-term risk [mean follow-up of 8.9 years (SD 4.6)] of any recurrent ischemic event or recurrent cerebral ischemia did not significantly differ between patients with and without a hypercoagulable state or a recent infection. In patients with a cryptogenic stroke 15-years cumulative risk of any recurrent ischemic event was 24 and 23% in patients with and without any prothrombotic factor respectively.

CONCLUSIONS

The prevalence of prothrombotic factors and preceding infections did not significantly differ between stroke patients with a cryptogenic versus an identified cause of stroke and neither is significantly associated with an increased risk of recurrent ischemic events after cryptogenic stroke.

A Diagnostic Approach to Stroke in Young Adults

OPINION STATEMENT

Optimal diagnosis and management of stroke in young adults benefit from a multidisciplinary team, including a vascular neurology specialist. In addition to the "standard" vascular risk factors including smoking, hypertension, diabetes, and hyperlipidemia, one needs to consider alternative etiologies including substance abuse, carotid/vertebral artery dissections, and rare genetic conditions among others. Once a young patient is determined to have had a stroke, the next question a clinician should ask is why did this patient have a stroke? A "heart to head" diagnostic approach is recommended. A thorough history is performed, including a detailed family history with specific annotations on each family member. A thorough physical examination is necessary including a careful evaluation of the patient's general appearance, noting any joint laxity, and/or abnormalities of the skin, eyes, and heart. Findings across multiple organ systems in the patient and/or their family may indicate a genetic etiology. After an initial head CT rules out hemorrhagic stroke, additional testing should include a brain MRI, neck and cerebral vascular imaging (e.g., CTA for head and neck), transthoracic echocardiogram with a bubble study, telemetry monitoring, basic risk factor blood work (e.g., lipid panel, hemoglobin A1c, TSH, ESR, CRP, RPR, HIV, and toxicology screen), and, when appropriate, sickle screen and pregnancy test. There should be a low threshold to obtain blood cultures or a lumbar puncture. The acute treatment of ischemic stroke in young adult patients does not differ from treatment of older adults, using intravenous alteplase within 4.5 h, assuming no contraindications. In suspected proximal large artery occlusive disease, interventional clot extraction procedures should be employed in patients deemed eligible. Long-term secondary prevention strategies aimed to reduce recurrent stroke risk by targeting and modifying vascular risk factors should be instituted. The mainstay of preventative therapy is aspirin for most etiologies; however, for atrial fibrillation, anticoagulation is recommended. Statin therapy is another pharmacologic intervention recommended in most stroke patients. Other measures employed are blood pressure reduction, smoking cessation, optimal glucose control in diabetic patients, the initiation of a healthy diet and regular exercise, and lastly, substance abuse counseling in appropriate patients.

Searching for Explanations for Cryptogenic Stroke in the Young: Revealing the Triggers, Causes, and Outcome (SECRETO): Rationale and design

BACKGROUND

Worldwide, about 1.3 million annual ischaemic strokes (IS) occur in adults aged <50 years. Of these early-onset strokes, up to 50% can be regarded as cryptogenic or associated with conditions with poorly documented causality like patent foramen ovale and coagulopathies.

KEY HYPOTHESES/AIMS

(1) Investigate transient triggers and clinical/sub-clinical chronic risk factors associated with cryptogenic IS in the young; (2) use cardiac imaging methods exceeding state-of-the-art to reveal novel sources for embolism; (3) search for covert thrombosis and haemostasis abnormalities; (4) discover new disease pathways using next-generation sequencing and RNA gene expression studies; (5) determine patient prognosis by use of phenotypic and genetic data; and (6) adapt systems medicine approach to investigate complex risk-factor interactions.

DESIGN

Searching for Explanations for Cryptogenic Stroke in the Young: Revealing the Etiology, Triggers, and Outcome (SECRETO; NCT01934725) is a prospective multi-centre case-control study enrolling patients aged 18-49 years hospitalised due to first-ever imaging-proven IS of undetermined etiology. Patients are examined according to a standardised protocol and followed up for 10 years. Patients are 1:1 age- and sex-matched to stroke-free controls. Key study elements include centralised reading of echocardiography, electrocardiography, and neurovascular imaging, as well as blood samples for genetic, gene-expression, thrombosis and haemostasis and biomarker analysis. We aim to have 600 patient-control pairs enrolled by the end of 2018.

SUMMARY

SECRETO is aiming to establish novel mechanisms and prognosis of cryptogenic IS in the young and will provide new directions for therapy development for these patients. First results are anticipated in 2019.

Activated Protein C Resistance Does Not Increase Risk for Recurrent Stroke or Death in Stroke Patients

Background

Activated protein C (APC) resistance is the most common inherited prothrombotic disorder. The role of APC resistance in ischemic stroke is controversially discussed.

Objectives

The aim of this single center follow up study was to investigate the effect of APC resistance on stroke recurrence and survival in stroke patients.

Patients/Methods

We retrospectively identified 966 patients who had had an ischemic stroke or transitory ischemic attack (TIA) and in whom laboratory tests for APC resistance had been conducted. These patients were contacted to determine the primary outcomes of recurrent ischemic stroke or death.

Results

A total of 858 patients with an average follow up time of 8.48 years were included. APC resistance did not influence cumulative incidence functions for stroke free and total survival. In multivariate analyses, crude and adjusted hazard ratios for recurrent stroke as well as for death where not significantly increased in patients with APC resistance. This also applies to the subgroups of young patients, patients with cryptogenic stroke and patients with atrial fibrillation.

Conclusion

APC-resistance is not a risk factor for subsequent stroke or death in patients with a first ischemic stroke or TIA. Testing for APC-resistance in stroke patients therefore cannot be routinely recommended.

Cocaine Use and Risk of Ischemic Stroke in Young Adults

BACKGROUND AND PURPOSE

Although case reports have long identified a temporal association between cocaine use and ischemic stroke (IS), few epidemiological studies have examined the association of cocaine use with IS in young adults, by timing, route, and frequency of use.

METHODS

A population-based case-control study design with 1090 cases and 1154 controls was used to investigate the relationship of cocaine use and young-onset IS. Stroke cases were between the ages of 15 and 49 years. Logistic regression analysis was used to evaluate the association between cocaine use and IS with and without adjustment for potential confounders.

RESULTS

Ever use of cocaine was not associated with stroke with 28% of cases and 26% of controls reporting ever use. In contrast, acute cocaine use in the previous 24 hours was strongly associated with increased risk of stroke (age-sex-race adjusted odds ratio, 6.4; 95% confidence interval, 2.2-18.6). Among acute users, the smoking route had an adjusted odds ratio of 7.9 (95% confidence interval, 1.8-35.0), whereas the inhalation route had an adjusted odds ratio of 3.5 (95% confidence interval, 0.7-16.9). After additional adjustment for current alcohol, smoking use, and hypertension, the odds ratio for acute cocaine use by any route was 5.7 (95% confidence interval, 1.7-19.7). Of the 26 patients with cocaine use within 24 hours of their stroke, 14 reported use within 6 hours of their event.

CONCLUSIONS

Our data are consistent with a causal association between acute cocaine use and risk of early-onset IS.

Ischemic stroke in the young: Current perspectives on incidence, risk factors, and cardiovascular prognosis

About one-fourth of ischemic strokes occur in working-aged individuals in the high-income countries, with worldwide increasing incidence in this age group from 1980s to present. Recent evidence suggests that traditional vascular risk factors are more prevalent than previously suggested in young adult stroke patients and they accumulate with age particularly in men. Accordingly, relatively high rates of atherosclerotic changes have been detected in these patients. The strength of association of vascular risk factors has gone poorly studied, however. Many young patients with ischemic stroke have, in turn, no traditional risk factors, while they may harbor other conditions with weak or uncertain association with the stroke alone. These individual conditions often represent a risk factor that may be strictly young-age specific, more prevalent in younger than older stroke patients (e.g. patent foramen ovale), or more prevalent among the young in the population. Despite high rates of vascular risk factors and atherosclerotic changes, these findings do not translate to higher frequencies of identified classical stroke mechanisms. In fact, cryptogenic causes are markedly common and even more frequent among the very young patients. Limited randomized trial evidence exists to support secondary prevention decision-making in patients, yet they face an increased risk of death and future vascular events for years to come-dependent on risk factor profile and cause of the stroke. This review provides an overview of recent data on epidemiology, risk factors, and their strength of association in ischemic stroke in the young. Furthermore, the relationship between with the risk factors and cardiovascular outcomes and key features on the evidence related to secondary prevention will be discussed.

Genome-Wide Association Analysis of Young-Onset Stroke Identifies a Locus on Chromosome 10q25 Near HABP2

BACKGROUND AND PURPOSE

Although a genetic contribution to ischemic stroke is well recognized, only a handful of stroke loci have been identified by large-scale genetic association studies to date. Hypothesizing that genetic effects might be stronger for early- versus late-onset stroke, we conducted a 2-stage meta-analysis of genome-wide association studies, focusing on stroke cases with an age of onset <60 years.

METHODS

The discovery stage of our genome-wide association studies included 4505 cases and 21 968 controls of European, South-Asian, and African ancestry, drawn from 6 studies. In Stage 2, we selected the lead genetic variants at loci with association P<5×10(-6) and performed in silico association analyses in an independent sample of ≤1003 cases and 7745 controls.

RESULTS

One stroke susceptibility locus at 10q25 reached genome-wide significance in the combined analysis of all samples from the discovery and follow-up stages (rs11196288; odds ratio =1.41; P=9.5×10(-9)). The associated locus is in an intergenic region between TCF7L2 and HABP2. In a further analysis in an independent sample, we found that 2 single nucleotide polymorphisms in high linkage disequilibrium with rs11196288 were significantly associated with total plasma factor VII-activating protease levels, a product of HABP2.

CONCLUSIONS

HABP2, which encodes an extracellular serine protease involved in coagulation, fibrinolysis, and inflammatory pathways, may be a genetic susceptibility locus for early-onset stroke.

Obesity increases risk of ischemic stroke in young adults

BACKGROUND AND PURPOSE

Body mass index has been associated with ischemic stroke in older populations, but its association with stroke in younger populations is not known. In light of the current obesity epidemic in the United States, the potential impact of obesity on stroke risk in young adults deserves attention.

METHODS

A population-based case-control study design with 1201 cases and 1154 controls was used to investigate the relationship of obesity and young onset ischemic stroke. Stroke cases were between the ages of 15 and 49 years. Logistic regression analysis was used to evaluate the association between body mass index and ischemic stroke with and without adjustment for comorbid conditions associated with stroke.

RESULTS

In analyses adjusted for age, sex, and ethnicity, obesity (body mass index >30 kg/m(2)) was associated with an increased stroke risk (odds ratio, 1.57; 95% confidence interval, 1.28-1.94) although this increased risk was highly attenuated and not statistically significant after adjustment for smoking, hypertension, and diabetes mellitus.

CONCLUSIONS

These results indicate that obesity is a risk factor for young onset ischemic stroke and suggest that this association may be partially mediated through hypertension, diabetes mellitus, or other variables associated with these conditions.

[Idiopathic intracranial hypertension and factor V Leiden mutation]

Activated proteinC resistance is a frequent prothrombotic abnormality. In most cases it is due to factorV Leiden mutation by nucleotide G1691A substitution. This recently described thrombophilic defect of activated proteinC resistance has been postulated to be implicated in the pathogenesis of idiopathic intracranial hypertension (IIH). We report a case of factorV Leiden mutation in association with IIH and their likely link and implication in the management of IIH.

The growing problem of stroke among young adults

Although overall stroke incidence has been declining in developed countries, there is evidence that stroke in the young is increasing. Increasing incidence may be particularly pronounced among minorities in whom historically a higher burden of stroke has been reported. Compared with older adults, time spent with disability is longer for those affected at younger ages, and new data suggests that among 30-day young adult stroke survivors, increased mortality persists for as long as 20 years. Stroke in young adults is often missed by less experienced clinicians due to its unexpectedness, leading to lost opportunities for intervention. The causes and risk factors for stroke in the young are often rare or undetermined, but young adults with stroke also have a high burden of traditional cardiovascular risk factors, including hypertension, diabetes, obesity, and substance abuse. Disseminating awareness and promoting research on young adult stroke are steps towards reducing the burden of stroke.

Ischaemic stroke in young adults: risk factors and long-term consequences

Contrary to trends in most other diseases, the average age of ischaemic stroke onset is decreasing, owing to a rise in the incidence of stroke among 'young' individuals (under 50 years of age). This Review provides a critical overview of the risk factors and aetiology of young ischaemic stroke and addresses its long-term prognosis, including cardiovascular risk, functional outcome and psychosocial consequences. We highlight the diminishing role of 'rare' risk factors in the pathophysiology of young stroke in light of the rising prevalence of 'traditional' vascular risk factors in younger age groups. Long-term prognosis is of particular interest to young patients, because of their long life expectancy and major responsibilities during a demanding phase of life. The prognosis of young stroke is not as favourable as previously thought, with respect either to mortality or cardiovascular disease or to psychosocial consequences. Therefore, secondary stroke prevention is probably a life-long endeavour in most young stroke survivors. Due to under-representation of young patients in past trials, new randomized trials focusing on this age group are needed to confirm the benefits of long-term secondary preventive medication. The high prevalence of poor functional outcome and psychosocial problems warrants further study to optimize treatment and rehabilitation for these young patients.

Prothrombin G20210A mutation is associated with young-onset stroke: the genetics of early-onset stroke study and meta-analysis

BACKGROUND AND PURPOSE

Although the prothrombin G20210A mutation has been implicated as a risk factor for venous thrombosis, its role in arterial ischemic stroke is unclear, particularly among young adults. To address this issue, we examined the association between prothrombin G20210A and ischemic stroke in a white case-control population and additionally performed a meta-analysis.

METHODS

From the population-based Genetics of Early Onset Stroke (GEOS) study, we identified 397 individuals of European ancestry aged 15 to 49 years with first-ever ischemic stroke and 426 matched controls. Logistic regression was used to calculate odds ratios (ORs) in the entire population and for subgroups stratified by sex, age, oral contraceptive use, migraine, and smoking status. A meta-analysis of 17 case-control studies (n=2305 cases <55 years) was also performed with and without GEOS data.

RESULTS

Within GEOS, the association of the prothrombin G20210A mutation with ischemic stroke did not achieve statistical significance (OR=2.5; 95% confidence interval [CI]=0.9-6.5; P=0.07). However, among adults aged 15 to 42 years (younger than median age), cases were significantly more likely than controls to have the mutation (OR=5.9; 95% CI=1.2-28.1; P=0.03), whereas adults aged 42 to 49 years were not (OR=1.4; 95% CI=0.4-5.1; P=0.94). In our meta-analysis, the mutation was associated with significantly increased stroke risk in adults ≤55 years (OR=1.4; 95% CI=1.1-1.9; P=0.02), with significance increasing with addition of the GEOS results (OR=1.5; 95% CI=1.1-2.0; P=0.005).

CONCLUSIONS

The prothrombin G20210A mutation is associated with ischemic stroke in young adults and may have an even stronger association among those with earlier onset strokes. Our finding of a stronger association in the younger young adult population requires replication.

The role of classic risk factors and prothrombotic factor gene mutations in ischemic stroke risk development in young and middle-aged individuals

BACKGROUND

In young individuals, a genetically predisposing hypercoagulability and classic modifying risk factors can act synergistically on the ischemic stroke risk development. The aim of the study was to compare the prevalence of classic vascular risk factors and polymorphisms of the G20210A coagulation factor II (prothrombin), Arg506Glu coagulation factor V Leiden, C677T methylenetetrahydrofolate reductase (MTHFR), and 4G/5G plasminogen activator inhibitor-1 (PAI-1) and the impact of these gene mutations and classic vascular risk factors on the overall stroke risk in individuals aged 55 years or younger.

METHODS

The study included 155 stroke patients aged 55 years or younger and 150 control subjects. Stroke prevalence and odds ratio (OR) were assessed for the following parameters: G20210A prothrombin, Arg506Glu factor V Leiden, C677T MTHFR, and 4G/5G PAI-1 polymorphisms; total number of study polymorphisms in a particular subject (genetic sum); and classic vascular risk factors of hypertension, obesity, diabetes mellitus, cigarette smoking, hypercholesterolemia, hypertriglyceridemia, and elevated levels of low-density lipoprotein (LDL) cholesterol and very low-density lipoprotein cholesterol.

RESULTS

The prevalence of hypertension (P < .001), smoking (P < .001), decreased HDL cholesterol levels (P < .001), obesity (P = .001), elevated LDL cholesterol (P = .036), C677T MTHFR polymorphism (P < .001), and genetic sum was significantly higher in the group of stroke patients. The following parameters were found to act as independent risk factors for ischemic stroke: decreased HDL cholesterol level (P < .001; OR 4.618; 95% confidence interval [CI] 2.381-8.957); hypertension (P = .001; OR 2.839; 95% CI 1.519-5.305); obesity (P = .040; OR 2.148; 95% CI 1.036-4.457); smoking (P = .001; OR 2.502; 95% CI 1.436-4.359); and genetic sum as a continuous variable (P < .01; OR 2.307; 95% CI 1.638-3.250).

CONCLUSIONS

Gene mutations of the procoagulable and proatherosclerotic factors investigated exerted a synergistic action in the development of overall risk of ischemic stroke in young and middle-aged individuals.

Polymorphisms in migraine-associated gene, atp1a2, and ischemic stroke risk in a biracial population: the genetics of early onset stroke study

In a recent meta-analysis migraine was associated with a two-fold increase in stroke risk. While the mechanism driving this association is unknown, one intriguing hypothesis is that migraineurs are genetically predisposed to developing ischemic stroke. Mutations in the ATP1A2 gene are implicated in familial hemiplegic migraine type II and increase the severity of ischemic brain injury in animal models. To further explore these observations, we assessed the association between ATP1A2 polymorphisms, migraine, and the risk of ischemic stroke in participants of the Genetics of Early-Onset Stroke Study, a population-based case-control study of ischemic stroke among men and women aged 15-49. Using responses to a headache symptoms questionnaire, subjects were classified as having no migraine, or migraine with or without visual aura. Evaluating a total of 134 ATP1A2 polymorphisms genotyped using a combination of Illumina platforms (Cardiovascular Gene-centric 50 K SNP Array and HumanOmni1-Quad_v1-0_B Bead Chip), only one polymorphism (rs2070704) demonstrated a nominally significant association with stroke in an age-, gender-, ethnicity-adjusted model (OR = 0.83, 95% CI = 0.71-0.98, p = 0.025) and in a vascular risk factor model adjusting for age, gender, ethnicity, hypertension, diabetes, smoking, and myocardial infarction (OR = 0.74, 95% CI = 0.63-0.89, p = 0.001). Ethnicity-stratified analyses demonstrated a significant association for rs2070704 among African-Americans (OR = 0.68, 95% CI = 0.53-0.90, p = 0.005) but not Caucasians (OR = 0.82, 95% CI = 0.64-1.04, p = 0.107). These associations were unchanged when migraine subtypes were included as co-variates. We did not observe an association between ATP1A2 polymorphisms and migraine. While our results do not demonstrate a strong relationship between ATP1A2 polymorphisms and migraine associated stroke risk, the results are hypothesis generating and indicate that an association between ATP1A2 polymorphisms and stroke risk may exist. Additional studies are required.