Racial and ethnic diversity in global neuroscience clinical trials.

Background: Despite efforts to increase diversity in neuroscience trials, racial and ethnic minority groups remain underrepresented. Disparities in clinical trial participation could reflect unequal opportunities to participate and may contribute to decreased generalizability of findings and failure to identify important differences in efficacy and safety outcomes. Methods: We retrospectively reviewed the F. Hoffmann-La Roche database for global, multicenter, neuroscience clinical trials from February 2016 to February 2021 and summarized and stratified race and ethnicity distributions by clinical trial therapeutic area and by country. These data were then compared to national population data for each study's targeted age group (available for studies conducted in the US, Canada, and the UK). The underrepresentation or overrepresentation of each racial and ethnic group was summarized. Results: The analysis population included 8015 participants from 47 countries. Globally, 85.6 % of participants were White, 7.1 % were Asian, 1.6 % were Black, 1.3 % were American Indian or Alaska Native, less than 0.1 % were Native Hawaiian or other Pacific Islander, 0.7 % were of multiple races, and 3.6 % were of other/unknown race. White individuals predominated in all but one trial. Black individuals were underrepresented in all trials but one. Asian individuals were overrepresented in approximately 20 % of trials. In the US, 7.3 % of participants were of Hispanic or Latino ethnicity vs 16.4 % of the US population. Conclusion: The findings and learnings from this summary and analysis demonstrate the need for continued awareness and new approaches in designing studies that reflect population diversity.

Real-world evidence on the dosing and safety of C.E.R.A. in pediatric dialysis patients: findings from the International Pediatric Dialysis Network registries.

BACKGROUND: This retrospective real-world study used data from two registries, International Pediatric Peritoneal Dialysis Network (IPPN) and International Pediatric Hemodialysis Network (IPHN), to characterize the efficacy and safety of continuous erythropoietin receptor activator (C.E.R.A.) in pediatric patients with chronic kidney disease (CKD) on peritoneal dialysis (PD) or hemodialysis (HD). METHODS: IPPN and IPHN collect prospective data (baseline and every 6 months) from pediatric PD and HD centers worldwide. Demographics, clinical characteristics, dialysis information, treatment, laboratory parameters, number and causes of hospitalization events, and deaths were extracted for patients on C.E.R.A. treatment (IPPN: 2007-2021; IPHN: 2013-2021). RESULTS: We analyzed 177 patients on PD (median age 10.6 years) and 52 patients on HD (median age 14.1 years) who had ≥ 1 observation while being treated with C.E.R.A. The median (interquartile range [IQR]) observation time under C.E.R.A. exposure was 6 (0-12.5) and 12 (0-18) months, respectively. Hemoglobin concentrations were stable over time; respective means (standard deviation) at last observation were 10.9 (1.7) g/dL and 10.4 (1.7) g/dL. Respective median (IQR) monthly C.E.R.A. doses at last observation were 3.5 (2.3-5.1) µg/kg, or 95 (62-145) µg/m2 and 2.1 (1.2-3.4) µg/kg, or 63 (40-98) µg/m2. Non-elective hospitalizations occurred in 102 (58%) PD and 32 (62%) HD patients. Seven deaths occurred (19.8 deaths per 1000 observation years). CONCLUSIONS: C.E.R.A. was associated with efficient maintenance of hemoglobin concentrations in pediatric patients with CKD on dialysis, and appeared to have a favorable safety profile. The current analysis revealed no safety signals.

Functional brain connectivity in young adults with post-stroke epilepsy.

Approximately 1 in 10 young stroke patients (18-50 years) will develop post-stroke epilepsy, which is associated with cognitive impairment. While previous studies have shown altered brain connectivity in patients with epilepsy, little is however known about the changes in functional brain connectivity in young stroke patients with post-stroke epilepsy and their relationship with cognitive impairment. Therefore, we aimed to investigate whether young ischaemic stroke patients have altered functional networks and whether this alteration is related to cognitive impairment. We included 164 participants with a first-ever cerebral infarction at young age (18-50 years), along with 77 age- and sex-matched controls, from the Follow-Up of Transient Ischemic Attack and Stroke patients and Unelucidated Risk Factor Evaluation study. All participants underwent neuropsychological testing and resting-state functional MRI to generate functional connectivity networks. At follow-up (10.5 years after the index event), 23 participants developed post-stroke epilepsy. Graph theoretical analysis revealed functional network reorganization in participants with post-stroke epilepsy, in whom a weaker (i.e. network strength), less-integrated (i.e. global efficiency) and less-segregated (i.e. clustering coefficient and local efficiency) functional network was observed compared with the participants without post-stroke epilepsy group and the controls (P < 0.05). Regional analysis showed a trend towards decreased clustering coefficient, local efficiency and nodal efficiency in contralesional brain regions, including the caudal anterior cingulate cortex, posterior cingulate cortex, precuneus, superior frontal gyrus and insula in participants with post-stroke epilepsy compared with those without post-stroke epilepsy. Furthermore, participants with post-stroke epilepsy more often had impairment in the processing speed domain than the group without post-stroke epilepsy, in whom the network properties of the precuneus were positively associated with processing speed performance. Our findings suggest that post-stroke epilepsy is associated with functional reorganization of the brain network after stroke that is characterized by a weaker, less-integrated and less-segregated brain network in young ischaemic stroke patients compared with patients without post-stroke epilepsy. The contralesional brain regions, which are mostly considered as hub regions, might be particularly involved in the altered functional network and may contribute to cognitive impairment in post-stroke epilepsy patients. Overall, our findings provide additional evidence for a potential role of disrupted functional network as underlying pathophysiological mechanism for cognitive impairment in patients with post-stroke epilepsy.

Long-term Risk of Bleeding and Ischemic Events After Ischemic Stroke or Transient Ischemic Attack in Young Adults.

BACKGROUND AND OBJECTIVES: Guidelines recommend antithrombotic medication as secondary prevention for patients with ischemic stroke or transient ischemic attack (TIA) at young age based on results from trials in older patients. We investigated the long-term risk of bleeding and ischemic events in young patients after ischemic stroke or TIA. METHODS: We included 30-day survivors of first-ever ischemic stroke or TIA aged 18-50 years from the Follow-Up of TIA and Stroke Patients and Unelucidated Risk Factor Evaluation (FUTURE) study, a prospective cohort study of stroke at young age. We obtained information on recurrent ischemia based on structured data collection from 1995 until 2014 as part of the FUTURE study follow-up, complemented with information on any bleeding and ischemic events by retrospective chart review from baseline until last medical consultation or June 2020. Primary outcome was any bleeding; secondary outcome any ischemic event during follow-up. Both were stratified for sex, age, etiology, and use of antithrombotic medication at discharge. Bleeding and ischemic events were classified according to location and bleeding events also by severity. RESULTS: We included 544 patients (56.1% women, median age of 42.2; interquartile range [IQR] 36.5-46.7 years) with a median follow-up of 9.6 (IQR 2.5-14.3) years. Ten-year cumulative risk of any bleeding event was 21.8% (95% CI 17.4-26.0) and 33.9% (95% CI 28.3-37.5) of any ischemic event. Risk of bleeding was higher in women with a cumulative risk of 28.2% (95% CI 21.6-34.3) vs 13.7% (95% CI 8.2-18.9) in men (p < 0.01), mainly because of gynecologic bleeds. Female sex (p < 0.001) and age between 40 and 49 years (p = 0.04) were independent predictors of bleeding. DISCUSSION: Young patients after ischemic stroke or TIA have a substantial long-term risk of both bleeding (especially women) and ischemic events. Future studies should investigate the effects of long-term antithrombotics in young patients, taking into account the risk of bleeding complications.

Natural history and burden of Huntington's disease in the UK: A population-based cohort study.

BACKGROUND: Huntington's disease (HD) is a rare neurodegenerative disease that presents with progressive psychological, cognitive and motor impairment. These diverse symptoms place a high burden on the patient, families and the healthcare systems they rely on. This study aimed to describe the epidemiology and clinical burden in individuals with HD compared with controls from the general population. METHODS: This cohort study utilised data from general practitioner medical records to estimate the prevalence and incidence of HD between January 2000 and December 2018. A cohort of incident HD cases were matched 1:3 to controls from the general population, in whom common clinical diagnoses, medications and healthcare interventions were compared at the time of first recorded diagnosis and at a time close to death. Incidence rates of common diagnoses and mortality were compared with matched controls in the time following HD diagnosis. RESULTS: Prevalence of HD increased between 2000 and 2018, whilst incidence remained stable. Prevalence of psychiatric diagnoses and symptomatic treatments were higher in HD cases than controls. A higher relative risk of psychotic disorders, depression, insomnia, dementia, weight loss, pneumonia and falls was observed in HD cases. Risk of death was >4 times higher in HD, with a median survival of ~12 years from first recorded diagnosis. CONCLUSIONS: This study demonstrates the significant and progressive clinical burden in individuals with HD up to 18 years after first recorded diagnosis.

Risk Prediction Using Polygenic Risk Scores for Prevention of Stroke and Other Cardiovascular Diseases.

Early prediction of risk of cardiovascular disease (CVD), including stroke, is a cornerstone of disease prevention. Clinical risk scores have been widely used for predicting CVD risk from known risk factors. Most CVDs have a substantial genetic component, which also has been confirmed for stroke in recent gene discovery efforts. However, the role of genetics in prediction of risk of CVD, including stroke, has been limited to testing for highly penetrant monogenic disorders. In contrast, the importance of polygenic variation, the aggregated effect of many common genetic variants across the genome with individually small effects, has become more apparent in the last 5 to 10 years, and powerful polygenic risk scores for CVD have been developed. Here we review the current state of the field of polygenic risk scores for CVD including stroke, and their potential to improve CVD risk prediction. We present findings and lessons from diseases such as coronary artery disease as these will likely be useful to inform future research in stroke polygenic risk prediction.

Health utility in preclinical and prodromal Alzheimer's disease for establishing the value of new disease-modifying treatments-EQ-5D data from the Swedish BioFINDER study.

Quality of life and health utility are important outcomes for patients with Alzheimer's disease (AD) and central for demonstrating the value of new treatments. Estimates in biomarker-confirmed AD populations are missing, potentially delaying payer approval of treatment. We examined whether health utility, assessed with the EuroQoL-5 3-level version (EQ-5D-3L), differed between individuals with a positive or negative amyloid beta (Aß) biomarker in patients with mild cognitive impairment (MCI) and cognitively unimpaired (CU) participants from the Swedish BioFINDER study (n = 578). Participants with prodromal AD (Aß-positive MCI) reported better health utility (n = 79, mean = 0.81, 95% confidence interval [CI] 0.77-0.85) than Aß-negative MCI (mean = 0.71, 95% CI 0.64-0.78), but worse than controls (Aß-negative CU, mean = 0.87, 95% CI 0.86-0.89). Health utility in preclinical AD (Aß-positive CU; mean = 0.86, 95% CI 0.83-0.89) was similar to controls. This relatively good health utility in prodromal AD suggests a larger value of delaying progression to dementia than previously anticipated and a great value of delaying clinical progression in preclinical AD.

Genetic basis of lacunar stroke: a pooled analysis of individual patient data and genome-wide association studies.

BACKGROUND: The genetic basis of lacunar stroke is poorly understood, with a single locus on 16q24 identified to date. We sought to identify novel associations and provide mechanistic insights into the disease. METHODS: We did a pooled analysis of data from newly recruited patients with an MRI-confirmed diagnosis of lacunar stroke and existing genome-wide association studies (GWAS). Patients were recruited from hospitals in the UK as part of the UK DNA Lacunar Stroke studies 1 and 2 and from collaborators within the International Stroke Genetics Consortium. Cases and controls were stratified by ancestry and two meta-analyses were done: a European ancestry analysis, and a transethnic analysis that included all ancestry groups. We also did a multi-trait analysis of GWAS, in a joint analysis with a study of cerebral white matter hyperintensities (an aetiologically related radiological trait), to find additional genetic associations. We did a transcriptome-wide association study (TWAS) to detect genes for which expression is associated with lacunar stroke; identified significantly enriched pathways using multi-marker analysis of genomic annotation; and evaluated cardiovascular risk factors causally associated with the disease using mendelian randomisation. FINDINGS: Our meta-analysis comprised studies from Europe, the USA, and Australia, including 7338 cases and 254 798 controls, of which 2987 cases (matched with 29 540 controls) were confirmed using MRI. Five loci (ICA1L-WDR12-CARF-NBEAL1, ULK4, SPI1-SLC39A13-PSMC3-RAPSN, ZCCHC14, ZBTB14-EPB41L3) were found to be associated with lacunar stroke in the European or transethnic meta-analyses. A further seven loci (SLC25A44-PMF1-BGLAP, LOX-ZNF474-LOC100505841, FOXF2-FOXQ1, VTA1-GPR126, SH3PXD2A, HTRA1-ARMS2, COL4A2) were found to be associated in the multi-trait analysis with cerebral white matter hyperintensities (n=42 310). Two of the identified loci contain genes (COL4A2 and HTRA1) that are involved in monogenic lacunar stroke. The TWAS identified associations between the expression of six genes (SCL25A44, ULK4, CARF, FAM117B, ICA1L, NBEAL1) and lacunar stroke. Pathway analyses implicated disruption of the extracellular matrix, phosphatidylinositol 5 phosphate binding, and roundabout binding (false discovery rate <0·05). Mendelian randomisation analyses identified positive associations of elevated blood pressure, history of smoking, and type 2 diabetes with lacunar stroke. INTERPRETATION: Lacunar stroke has a substantial heritable component, with 12 loci now identified that could represent future treatment targets. These loci provide insights into lacunar stroke pathogenesis, highlighting disruption of the vascular extracellular matrix (COL4A2, LOX, SH3PXD2A, GPR126, HTRA1), pericyte differentiation (FOXF2, GPR126), TGF-ß signalling (HTRA1), and myelination (ULK4, GPR126) in disease risk. FUNDING: British Heart Foundation.

Emerging insights from the genetics of cerebral small-vessel disease.

Cerebral small-vessel disease (cSVD) is a common cause of stroke, functional decline, vascular cognitive impairment, and dementia. Pathological processes in the brain's microcirculation are tightly interwoven with pathology in the brain parenchyma, and this interaction has been conceptualized as the neurovascular unit (NVU). Despite intensive research efforts to decipher the NVU's structure and function to date, molecular mechanisms underlying cSVD remain poorly understood, which hampers the development of cSVD-specific therapies. Important steps forward in understanding the disease mechanisms underlying cSVD have been made using genetic approaches in studies of both monogenic and sporadic SVD. We provide an overview of the NVU's structure and function, the implications for cSVD, and the underlying molecular mechanisms of dysfunction that have emerged from recent genetic studies of both monogenic and sporadic diseases of the small cerebral vasculature.

Subtype Specificity of Genetic Loci Associated With Stroke in 16 664 Cases and 32 792 Controls.

BACKGROUND: Genome-wide association studies have identified multiple loci associated with stroke. However, the specific stroke subtypes affected, and whether loci influence both ischemic and hemorrhagic stroke, remains unknown. For loci associated with stroke, we aimed to infer the combination of stroke subtypes likely to be affected, and in doing so assess the extent to which such loci have homogeneous effects across stroke subtypes. METHODS: We performed Bayesian multinomial regression in 16 664 stroke cases and 32 792 controls of European ancestry to determine the most likely combination of stroke subtypes affected for loci with published genome-wide stroke associations, using model selection. Cases were subtyped under 2 commonly used stroke classification systems, TOAST (Trial of Org 10172 Acute Stroke Treatment) and causative classification of stroke. All individuals had genotypes imputed to the Haplotype Reference Consortium 1.1 Panel. RESULTS: Sixteen loci were considered for analysis. Seven loci influenced both hemorrhagic and ischemic stroke, 3 of which influenced ischemic and hemorrhagic subtypes under both TOAST and causative classification of stroke. Under causative classification of stroke, 4 loci influenced both small vessel stroke and intracerebral hemorrhage. An EDNRA locus demonstrated opposing effects on ischemic and hemorrhagic stroke. No loci were predicted to influence all stroke subtypes in the same direction, and only one locus (12q24) was predicted to influence all ischemic stroke subtypes. CONCLUSIONS: Heterogeneity in the influence of stroke-associated loci on stroke subtypes is pervasive, reflecting differing causal pathways. However, overlap exists between hemorrhagic and ischemic stroke, which may reflect shared pathobiology predisposing to small vessel arteriopathy. Stroke is a complex, heterogeneous disorder requiring tailored analytic strategies to decipher genetic mechanisms.

Publisher Correction: Multiancestry genome-wide association study of 520,000 subjects identifies 32 loci associated with stroke and stroke subtypes.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Genetic variation in PLEKHG1 is associated with white matter hyperintensities (n = 11,226).

OBJECTIVE: To identify novel genetic associations with white matter hyperintensities (WMH). METHODS: We performed a genome-wide association meta-analysis of WMH volumes in 11,226 individuals, including 8,429 population-based individuals from UK Biobank and 2,797 stroke patients. Replication of novel loci was performed in an independent dataset of 1,202 individuals. In all studies, WMH were quantified using validated automated or semi-automated methods. Imputation was to either the Haplotype Reference Consortium or 1,000 Genomes Phase 3 panels. RESULTS: We identified a locus at genome-wide significance in an intron of PLEKHG1 (rs275350, ß [SE] = 0.071 [0.013]; p = 1.6 × 10-8), a Rho guanine nucleotide exchange factor that is involved in reorientation of cells in the vascular endothelium. This association was validated in an independent sample (overall p value, 2.4 × 10-9). The same single nucleotide polymorphism was associated with all ischemic stroke (odds ratio [OR] [95% confidence interval (CI)] 1.07 [1.03-1.12], p = 0.00051), most strongly with the small vessel subtype (OR [95% CI] 1.09 [1.00-1.19], p = 0.044). Previous associations at 17q25 and 2p16 reached genome-wide significance in this analysis (rs3744020; ß [SE] = 0.106 [0.016]; p = 1.2 × 10-11 and rs7596872; ß [SE] = 0.143 [0.021]; p = 3.4 × 10-12). All identified associations with WMH to date explained 1.16% of the trait variance in UK Biobank, equivalent to 6.4% of the narrow-sense heritability. CONCLUSIONS: Genetic variation in PLEKHG1 is associated with WMH and ischemic stroke, most strongly with the small vessel subtype, suggesting it acts by promoting small vessel arteriopathy.

Genetic risk, incident stroke, and the benefits of adhering to a healthy lifestyle: cohort study of 306 473 UK Biobank participants.

OBJECTIVE: To evaluate the associations of a polygenic risk score and healthy lifestyle with incident stroke. DESIGN: Prospective population based cohort study. SETTING: UK Biobank Study, UK. PARTICIPANTS: 306 473 men and women, aged 40-73 years, recruited between 2006 and 2010. MAIN OUTCOME MEASURE: Hazard ratios for a first stroke, estimated using Cox regression. A polygenic risk score of 90 single nucleotide polymorphisms previously associated with stroke was constructed at P<1×10-5 to test for an association with incident stroke. Adherence to a healthy lifestyle was determined on the basis of four factors: non-smoker, healthy diet, body mass index <30 kg/m2, and regular physical exercise. RESULTS: During a median follow-up of 7.1 years (2 138 443 person years), 2077 incident strokes (1541 ischaemic stroke, 287 intracerebral haemorrhage, and 249 subarachnoid haemorrhage) were ascertained. The risk of incident stroke was 35% higher among those at high genetic risk (top third of polygenic score) compared with those at low genetic risk (bottom third): hazard ratio 1.35 (95% confidence interval 1.21 to 1.50), P=3.9×10-8. Unfavourable lifestyle (0 or 1 healthy lifestyle factors) was associated with a 66% increased risk of stroke compared with a favourable lifestyle (3 or 4 healthy lifestyle factors): 1.66 (1.45 to 1.89), P=1.19×10-13. The association with lifestyle was independent of genetic risk stratums. CONCLUSION: In this cohort study, genetic and lifestyle factors were independently associated with incident stroke. These results emphasise the benefit of entire populations adhering to a healthy lifestyle, independent of genetic risk.

Genetic Study of White Matter Integrity in UK Biobank (N=8448) and the Overlap With Stroke, Depression, and Dementia.

BACKGROUND AND PURPOSE: Structural integrity of the white matter is a marker of cerebral small vessel disease, which is the major cause of vascular dementia and a quarter of all strokes. Genetic studies provide a way to obtain novel insights in the disease mechanism underlying cerebral small vessel disease. The aim was to identify common variants associated with microstructural integrity of the white matter and to elucidate the relationships of white matter structural integrity with stroke, major depressive disorder, and Alzheimer disease. METHODS: This genome-wide association analysis included 8448 individuals from UK Biobank-a population-based cohort study that recruited individuals from across the United Kingdom between 2006 and 2010, aged 40 to 69 years. Microstructural integrity was measured as fractional anisotropy- (FA) and mean diffusivity (MD)-derived parameters on diffusion tensor images. White matter hyperintensity volumes (WMHV) were assessed on T2-weighted fluid-attenuated inversion recovery images. RESULTS: We identified 1 novel locus at genome-wide significance (VCAN [versican]: rs13164785; P=3.7×10-18 for MD and rs67827860; P=1.3×10-14 for FA). LD score regression showed a significant genome-wide correlation between FA, MD, and WMHV (FA-WMHV rG 0.39 [SE, 0.15]; MD-WMHV rG 0.56 [SE, 0.19]). In polygenic risk score analysis, FA, MD, and WMHV were significantly associated with lacunar stroke, MD with major depressive disorder, and WMHV with Alzheimer disease. CONCLUSIONS: Genetic variants within the VCAN gene may play a role in the mechanisms underlying microstructural integrity of the white matter in the brain measured as FA and MD. Mechanisms underlying white matter alterations are shared with cerebrovascular disease, and inherited differences in white matter microstructure impact on Alzheimer disease and major depressive disorder.

Causal Impact of Type 2 Diabetes Mellitus on Cerebral Small Vessel Disease: A Mendelian Randomization Analysis.

BACKGROUND AND PURPOSE: The relationship between type 2 diabetes mellitus (T2D) and cerebral small vessel disease (CSVD) is unclear. We aimed to examine the causal effect of T2D, fasting glucose levels, and higher insulin resistance on CSVD using Mendelian randomization. METHODS: Five CSVD phenotypes were studied; 2 were clinical outcomes associated with CSVD (lacunar stroke: n=2191/27 297 and intracerebral hemorrhage [ICH]: n=2254/8195 [deep and lobar ICH]), whereas 3 were radiological markers of CSVD (white matter hyperintensities: n=8429; fractional anisotropy [FA]: n=8357; and mean diffusivity: n=8357). We applied 2 complementary analyses to evaluate the association of T2D with CSVD. First, we used summarized data from genome-wide association study to calculate the effects of T2D-related variants on CSVD with inverse-variance weighted and weighted median approaches. Second, we performed a genetic risk score approach to test the effects of T2D-associated variants on white matter hyperintensities, FA, and mean diffusivity using individual-level data in UK Biobank. RESULTS: T2D was associated with higher risk of lacunar stroke (odds ratio [OR], 1.15; 95% confidence interval [CI], 1.04-1.28; P=0.007) and lower mean FA (OR, 0.78; 95% CI, 0.66-0.92; P=0.004) but not white matter hyperintensities volume (OR, 1.01; 95% CI, 0.97-1.04; P=0.626), higher mean diffusivity (OR, 1.04; 95% CI, 0.89-1.23; P=0.612), ICH (OR, 1.07; 95% CI, 0.95-1.20; P=0.269), lobar ICH (OR, 1.07; 95% CI, 0.89-1.28; P=0.466), or deep ICH (OR, 1.16; 95% CI, 0.99-1.36; P=0.074). Weighted median and penalized median weighted analysis showed similar effect estimates of T2D on lacunar stroke and FA, but with wider CIs, meaning they were not significant. The genetic score on individual-level data was significantly associated with FA (OR, 0.63; 95% CI, 0.45-0.89; P=0.008) after adjusting for potential confounders. CONCLUSIONS: Our Mendelian randomization study provides evidence to suggest that T2D may be causally associated with CSVD, in particular with lacunar stroke and FA.

Multiancestry genome-wide association study of 520,000 subjects identifies 32 loci associated with stroke and stroke subtypes.

Stroke has multiple etiologies, but the underlying genes and pathways are largely unknown. We conducted a multiancestry genome-wide-association meta-analysis in 521,612 individuals (67,162 cases and 454,450 controls) and discovered 22 new stroke risk loci, bringing the total to 32. We further found shared genetic variation with related vascular traits, including blood pressure, cardiac traits, and venous thromboembolism, at individual loci (n = 18), and using genetic risk scores and linkage-disequilibrium-score regression. Several loci exhibited distinct association and pleiotropy patterns for etiological stroke subtypes. Eleven new susceptibility loci indicate mechanisms not previously implicated in stroke pathophysiology, with prioritization of risk variants and genes accomplished through bioinformatics analyses using extensive functional datasets. Stroke risk loci were significantly enriched in drug targets for antithrombotic therapy.

Increased Risk of Pregnancy Complications After Stroke: The FUTURE Study (Follow-Up of Transient Ischemic Attack and Stroke Patients and Unelucidated Risk Factor Evaluation).

BACKGROUND AND PURPOSE: The study goal was to investigate the prevalence of pregnancy complications and pregnancy loss in women before, during, and after young ischemic stroke/transient ischemic attack. METHODS: In the FUTURE study (Follow-Up of Transient Ischemic Attack and Stroke Patients and Unelucidated Risk Factor Evaluation), a prospective young stroke study, we assessed the occurrence of pregnancy, miscarriages, and pregnancy complications in 223 women aged 18 to 50 years with a first-ever ischemic stroke/transient ischemic attack. Pregnancy complications (gestational hypertension, diabetes mellitus, preeclampsia, and hemolysis, elevated liver enzymes, low platelet count syndrome) were assessed before, during, and after stroke using standardized questionnaires. Primary outcome was occurrence of pregnancy complications and the rate of pregnancy loss compared with the Dutch population. Secondary outcome was the risk of recurrent vascular events after stroke, stratified by a history of hypertensive disorder in pregnancy. RESULTS: Data were available for 213 patients. Mean age at event was 39.6 years (SD=7.8) and mean follow-up 9.5 years (SD=8.5). Miscarriages occurred in 35.2% and fetal death in 6.2% versus 13.5% and 0.9% in the Dutch population, respectively (P<0.05). In nulliparous women after stroke (n=22), in comparison with Dutch population, there was a high prevalence of hypertensive disorders in pregnancy (33.3 versus 12.2%; P<0.05), hemolysis, elevated liver enzymes, low platelet count syndrome (9.5 versus 0.5%; P<0.05), and early preterm delivery <32 weeks (9.0 versus 1.4%; P<0.05). In primi/multiparous women (n=141) after stroke, 29 events occurred (20-year cumulative risk 35.2%; 95% confidence interval, 21.3-49.0), none during subsequent pregnancies, and a history of a hypertensive disorder in pregnancy did not modify this risk (log-rank P=0.62). CONCLUSIONS: When compared with the general population, women with young stroke show higher rates of pregnancy loss throughout their lives. Also, after stroke, nulliparous women more frequently experienced serious pregnancy complications.

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.

Risk factors and mechanisms of stroke in young adults: The FUTURE study.

Incidence of ischemic stroke and transient ischemic attack in young adults is rising. However, etiology remains unknown in 30-40% of these patients when current classification systems designed for the elderly are used. Our aim was to identify risk factors according to a pediatric approach, which might lead to both better identification of risk factors and provide a stepping stone for the understanding of disease mechanism, particularly in patients currently classified as "unknown etiology". Risk factors of 656 young stroke patients (aged 18-50) of the FUTURE study were categorized according to the "International Pediatric Stroke Study" (IPSS), with stratification on gender, age and stroke of "unknown etiology". Categorization of risk factors into ≥1 IPSS category was possible in 94% of young stroke patients. Chronic systemic conditions were more present in patients aged <35 compared to patients ≥35 (32.6% vs. 15.6%, p < 0.05). Among 226 patients classified as "stroke of unknown etiology" using TOAST, we found risk factors in 199 patients (88%) with the IPSS approach. We identified multiple risk factors linked to other mechanisms of stroke in the young than in the elderly . This can be a valuable starting point to develop an etiologic classification system specifically designed for young stroke patients.

Nonlinear temporal dynamics of cerebral small vessel disease: The RUN DMC study.

OBJECTIVE: To investigate the temporal dynamics of cerebral small vessel disease (SVD) by 3 consecutive assessments over a period of 9 years, distinguishing progression from regression. METHODS: Changes in SVD markers of 276 participants of the Radboud University Nijmegen Diffusion Tensor and Magnetic Resonance Imaging Cohort (RUN DMC) cohort were assessed at 3 time points over 9 years. We assessed white matter hyperintensities (WMH) volume by semiautomatic segmentation and rated lacunes and microbleeds manually. We categorized baseline WMH severity as mild, moderate, or severe according to the modified Fazekas scale. We performed mixed-effects regression analysis including a quadratic term for increasing age. RESULTS: Mean WMH progression over 9 years was 4.7 mL (0.54 mL/y; interquartile range 0.95-5.5 mL), 20.3% of patients had incident lacunes (2.3%/y), and 18.9% had incident microbleeds (2.2%/y). WMH volume declined in 9.4% of the participants during the first follow-up interval, but only for 1 participant (0.4%) throughout the whole follow-up. Lacunes disappeared in 3.6% and microbleeds in 5.7% of the participants. WMH progression accelerated over time: including a quadratic term for increasing age during follow-up significantly improved the model (p < 0.001). SVD progression was predominantly seen in participants with moderate to severe WMH at baseline compared to those with mild WMH (odds ratio [OR] 35.5, 95% confidence interval [CI] 15.8-80.0, p < 0.001 for WMH progression; OR 5.7, 95% CI 2.8-11.2, p < 0.001 for incident lacunes; and OR 2.9, 95% CI 1.4-5.9, p = 0.003 for incident microbleeds). CONCLUSIONS: SVD progression is nonlinear, accelerating over time, and a highly dynamic process, with progression interrupted by reduction in some, in a population that on average shows progression.