BACKGROUND:People living in homelessness or precarious housing experience more health challenges and earlier mortality than the general population. We characterized longitudinal changes in magnetic resonance imaging (MRI) measures of brain atrophy among people living without stable housing, evaluated risk factors associated with longitudinal atrophy, and assessed whether atrophy was associated with mortality. METHODS:Data was collected as part of an ongoing longitudinal observational study of people living without stable housing in Vancouver, Canada. We included 307 participants with two-or-more brain MRI scans over an average of 7.0 years. We evaluated select risk factors for brain atrophy and assessed whether brain atrophy was associated with mortality during the study. RESULTS:Across 307 participants and 1,173 brain MRI scans, alcohol dependence (β = -0.053, 95% confidence interval [CI] -0.075 to -0.032, p < 0.0001) and higher cardiovascular risk scores (β = -0.021, 95% CI -0.029 to -0.012, p < 0.0001) were associated with more rapid brain atrophy over time, and history of moderate or severe traumatic brain injury was associated with more atrophy at baseline (β = -0.27, 95% CI -0.46 to -0.075, p = 0.0075). More brain atrophy at baseline was associated with mortality during the study, adjusting for age, sex, and other comorbidities (Hazard Ratio [HR]Quartile1 = reference; HRQ2 = 2.37, p = 0.035; HRQ3 = 4.01, p = 0.00032; HRQ4 = 4.91, p < 0.0001). CONCLUSIONS AND RELEVANCE:Alcohol dependence, cardiovascular risk, and traumatic brain injury may represent particularly important risk factors for brain atrophy, and brain atrophy is associated with mortality among people living without stable housing. Targeting these modifiable risk factors may improve brain health and functioning outcomes among people living without stable housing.

Background: People with congenital heart disease (CHD) face developmental and acquired risks to their neurocognitive health. Mechanisms and clinical-neuroimaging correlates are not well-defined. We report baseline neuroimaging findings, their associations with demographic/clinical factors, and cognitive performance, from a longitudinal study of brain health in adult CHD (ACHD). Methods: Participants (n=99) aged >18y with moderate-severe complexity CHD were recruited from the ACHD referral centre for Western Canada. They underwent clinical review and had bloodwork, Holter, echocardiography MRI brain, cognitive testing (MoCA, NIH Toolbox [NIHTB]). Forward stepwise linear and logistic regression models were used to identify demographic/clinical factors that predicted MRI findings. Relationships between demographic/clinical factors with MRI findings, and MRI findings with cognition, were then explored with multivariable linear and logistic regression as appropriate. Results: Median(IQR) age 35y (29-40); 42% female.(Figure 1) CHD complexity (21% severe) was independently associated with lower total brain volume (TBV). TBV independently predicted cognitive performance (B[95%CI] for MoCA change/100mm3: 2.73x10 -3 [3.0x10 -4 - 5.1 x 10 -3 ]; p=0.03; NIHTB 8.39x10 -3 [2.2x10 -3 - 1.46x10 -2 ]; p=0.009). History of dyslipidemia was independently associated with white matter hyperintensity (WMH) volume but not presence of WMH. Cerebral microbleeds (CMB, 60% of participants) and lacunes (16%) were independently associated with history and number of cardiopulmonary bypass surgeries. None of WMH, CMB or lacunes predicted cognitive performance. Conclusions: In this high-functioning cohort of mostly younger ACHD, neuroimaging abnormalities were common. TBV was independently associated with CHD severity. WMH were associated with dyslipidemia; CMB and lacunes with bypass. Only TBV predicted cognitive performance. Acknowledging our modest cohort size with heterogenous CHD types, our results suggest that the pathophysiology impacting brain health reflects a combination of early- and later-life factors. Longitudinal studies may identify optimal preventative interventions and their timing; dyslipidemia may be a modifiable target.

Previous research suggests that COVID-19 infection may be associated with brain changes that are similar to a decade of aging.1 It is unknown whether symptom duration influences brain structure. We compared participants with COVID-19 symptoms for more than 2 months (long-COVID) (n=43) to participants who recovered within 2 months (normal recovery) (n=56). We assessed white matter with diffusion tensor imaging, regional brain volumes using Freesurfer, and cognition using the NIH Toolbox. Although the effect of age on MRI indices and cognition was readily detectable, we found no differences between long-COVID and normal recovery on brain structure or cognitive performance.

Background The pathophysiology of protracted symptoms after COVID-19 is unclear. This study aimed to determine if long-COVID is associated with differences in baseline characteristics, markers of white matter diffusivity in the brain, and lower scores on objective cognitive testing. Methods Individuals who experienced COVID-19 symptoms for more than 60 days post-infection (long-COVID) (n=56) were compared to individuals who recovered from COVID-19 within 60 days of infection (normal recovery) (n=35). Information regarding physical and mental health, and COVID-19 illness was collected. The National Institute of Health Toolbox Cognition Battery was administered. Participants underwent magnetic resonance imaging (MRI) with diffusion tensor imaging (DTI). Tract-based spatial statistics were used to perform a whole-brain voxel-wise analysis on standard DTI metrics (fractional anisotropy, axial diffusivity, mean diffusivity, radial diffusivity), controlling for age and sex. NIH Toolbox Age-Adjusted Fluid Cognition Scores were used to compare long-COVID and normal recovery groups, covarying for Age-Adjusted Crystallized Cognition Scores and years of education. False discovery rate correction was applied for multiple comparisons. Results There were no significant differences in age, sex, or history of neurovascular risk factors between the groups. The long-COVID group had significantly (p<0.05) lower mean diffusivity than the normal recovery group across multiple white matter regions, including the internal capsule, anterior and superior corona radiata, corpus callosum, superior fronto-occiptal fasciculus, and posterior thalamic radiation. However, the effect sizes of these differences were small (all β<|0.3|) and no significant differences were found for the other DTI metrics. Fluid cognition composite scores did not differ significantly between the long-COVID and normal recovery groups (p>0.05). Conclusions Differences in diffusivity between long-COVID and normal recovery groups were found on only one DTI metric. This could represent subtle areas of pathology such as gliosis or edema, but the small effect sizes and non-specific nature of the diffusion indices make pathological inference difficult. Although long-COVID patients reported many neuropsychiatric symptoms, significant differences in objective cognitive performance were not found.

Background: Homeless and precariously housed persons exhibit significant memory impairment, but the component processes underlying memory dysfunction have not been explored. We examined the serial position profile (i.e., primacy and recency effects) of verbal memory and its neuroanatomical correlates to identify the nature of memory difficulties in a large cohort of homeless and precariously housed adults. Method: The sample included 227 community-dwelling homeless and precariously housed adults. Serial position scores (primacy, middle, recency) were computed using the Hopkins Verbal Learning Test-Revised. Paired sample t-tests were used to compare percent recall from each word list region. Age-adjusted correlations assessed associations between serial position scores and other cognitive domains (attention, processing speed, executive functioning). Regression analyses were conducted to examine regional brain volumes of interest (hippocampus, entorhinal cortex, dorsolateral prefrontal cortex [DLPFC]) and their differential associations with serial position scores. Results: The serial position profile was characterized by a diminished recency effect in relation to the primacy effect. Serial position scores positively correlated with sustained attention and cognitive control. Larger hippocampal volume was associated with better primacy item recall. DLPFC volume was not associated with serial position recall after adjustment for false discovery rate. There were no associations between regional brain volumes and recency item recall. Conclusion: Our results suggest that commonly reported memory difficulties in homeless and precariously housed adults are likely secondary to a core deficit in executive control due to compromised frontal lobe functioning. These findings have implications for cognitive rehabilitation in this complex and vulnerable group.

Background: VOD/SOS is a potentially life-threatening complication caused by damage to sinusoidal endothelial cells. It has historically been associated with toxicity from conditioning regimens preceding hematopoietic cell transplantation (HCT), but its epidemiology and characteristics outside the HCT setting are not well understood. We conducted a systematic review to examine the incidence, mortality, diagnosis, and the burden of illness of non-HCT VOD/SOS. Methods: We searchedMEDLINE and Embase (2002-2023), as well as recent congress proceedings (2019-2023) for studies reporting the following in the non-HCT VOD/SOS setting: incidence, diagnosis, relevant medical history, disease management, clinical burden, health-related quality of life, costs, and patients' (pts) unmet needs. All study designs were eligible except case series with <5 participants. Studies of pulmonary VOD or VOD/SOS resulting from ingestion of pyrrolizidine alkaloids were excluded. Two independent reviewers screened titles/abstracts and full-text articles and assessed the methodological quality of studies. Results: Of 3874 records screened, 92 studies were included; 57% were retrospective cohort studies and 70% were conducted in the United States or Europe. VOD/SOS was reported in 17 acute myeloid leukemia (AML) studies and 13 acute lymphoblastic leukemia (ALL) studies. The highest incidences of non-HCT VOD/SOS occurred in pts with colorectal liver metastases (CLM; median 35%) and Wilms tumor (median 14%; Table 1). The occurrences of severe non-HCT VOD/SOS and mortality are provided in Table 2. Clinical criteria (eg, McDonald, Seattle, or Baltimore) were widely used to diagnose both hematological (i.e., AML and ALL) and nonhematological disease (i.e., Wilms tumor), while Rubbia-Brandt histological criteria were used to diagnose VOD/SOS in pts with CLM. While most studies did not report how non-HCT VOD/SOS was managed, 26 studies reported defibrotide use: 80/112 pts (71%) with hematologic cancer and 223/309 pts (72%) in other disease settings. In 7/26 studies, all pts who received defibrotide recovered. Two of 26 studies reported high rates of recovery from VOD/SOS at 70 days following defibrotide initiation: one with 71% of patients alive at day 70 following the start of defibrotide (58/82 pts) and one with 83% of patients alive at day 70 (5/6 pts). Nine studies did not report any outcomes related to defibrotide and another did not distinguish between outcomes in pts treated with defibrotide compared with other treatments. No defibrotide use was reported in studies evaluating pts with CLM. Among non-defibrotide treatments, the most reported VOD/SOS treatment was supportive therapy (14%; 13/92 studies), followed by switching or pausing chemotherapy (11%; 10/92 studies). One study reported outcomes for 206 children who received supportive care for VOD/SOS during 6-thioguanine therapy for ALL; only three pts had acute hepatic failure and all pts recovered from VOD/SOS. Of the studies reporting switching or pausing chemotherapy to manage VOD/SOS, four studies reported 100% recovery from VOD/SOS, and five studies did not report treatment outcomes. The severity of VOD/SOS in these pts was unknown. Four studies reported any adverse events (AEs) in pts treated for VOD/SOS: two reported zero AEs (in four children with ALL treated with defibrotide and two children with Wilms tumor treated with N-acetylcsteine); one reported AEs in 27% (of 82 defibrotide-treated pts, mostly with hematologic cancers); and one reported ≥1 treatment-emergent serious AE of interest in 15% (of 46 pts with hematologic or nonhematologic cancers treated with defibrotide), including infection (9%) and hemorrhage (9%). Conclusions: Non-HCT VOD/SOS occurs in diverse disease areas, including hematologic and solid tumor cancers. A lack of consensus regarding VOD/SOS diagnosis in the non-HCT setting may lead to underdiagnosis; therefore, clinicians should be vigilant for VOD/SOS even in non-HCT pts. Though defibrotide is approved for post-HCT VOD/SOS, there is no approved therapy for non-HCT VOD/SOS; future trials should focus on diagnosis and treatment outside the HCT setting, which represents a significant unmet need. Limitations include a lack of population-based studies to estimate true incidence and that the evidence is based on studies whose main objective was not to investigate non-HCT VOD/SOS.

Background The SARS‐CoV‐2 virus has impacted life in many ways, one change being the use of face masks. Their effect on MRI‐based measurements of cerebral oxygen levels with quantitative susceptibility mapping (QSM) and cerebral blood flow (CBF) is not known. Purpose This study investigated whether wearing a face mask leads to changes in CBF and cerebral venous oxygen saturation measured with MRI. Study Type Repeated‐measures cohort study. Population A total of 16 healthy volunteers (eight male, eight female; 22–36 years) were recruited for the 3‐ply study. Ten of the 16 participants (five male, five female; 23–36 years) took part in the KN95 study. Field Strength/Sequence A 3 T, single‐delay 3D gradient‐and spin‐echo pseudo‐continuous arterial spin labeling (pCASL) scan for CBF quantification, and gradient‐echo for QSM and oxygenation quantification. Assessment Gray matter CBF and magnetic susceptibility were assessed by masking the pCASL CBF map and the QSM map to the T 1 ‐weighted gray matter tissue segmentation. Venous oxygenation was determined from venous segmentation of QSM maximum intensity projections. Statistical Tests Paired Student's t ‐tests and Cohen's d effect sizes were used to compare the face mask and no face mask scans for gray matter CBF, gray matter magnetic susceptibility, and cerebral venous oxygen saturation. Standard t ‐tests were used to assess whether the order of scanning with and without a mask had any impact. A statistical cut off of P < 0.05 was used. Results The 3‐ply masks increased gray matter CBF from an average of 43.99 mL/(100 g*min) to 46.81 mL/(100 g*min). There were no significant changes in gray matter magnetic susceptibility ( P = 0.07), or cerebral venous oxygen saturation ( P = 0.36) for the 3‐ply data set. The KN95 masks data set showed no statistically significant changes in gray matter CBF ( P = 0.52) and magnetic susceptibility ( P = 0.97), or cerebral venous oxygen saturation ( P = 0.93). Data Conclusion The changes in blood flow and oxygenation due to face masks are small. Only CBF increased significantly due to wearing a 3‐ply mask. Evidence Level 2 Technical Efficacy Stage 3

Background Homeless or precariously housed individuals live with poor health and experience premature mortality compared with the general population, yet little is known about age-related brain changes among these individuals. We evaluated whether MRI measures of brain structure are differentially associated with age and selected risk factors among individuals who are homeless or precariously housed compared with a general population sample. Methods We compared T1-weighted and diffusion tensor imaging measures of brain macrostructure and white matter microstructure in a well-characterised sample of 312 precariously housed participants with a publicly available dataset of 382 participants recruited from the general population. We used piecewise and multiple linear regression to examine differential associations between MRI measures and between the samples, and to explore associations with risk factors in the precariously housed sample. Results Compared with the general population sample, older age in the precariously housed sample was associated with more whole-brain atrophy (β=−0.20, p=0.0029), lower whole-brain fractional anisotropy (β=−0.32, p<0.0001) and higher whole-brain mean diffusivity (β=0.69, p<0.0001). Several MRI measures had non-linear associations with age, with further adverse changes after age 35–40 in the precariously housed sample. History of traumatic brain injury, stimulant dependence and heroin dependence was associated with more atrophy or alterations in white matter diffusivity in the precariously housed sample. Conclusions Older age is associated with adverse MRI measures of brain structure among homeless and precariously housed individuals compared with the general population. Education, improvements in care provision and policy may help to reduce the health disparities experienced by these individuals.

Cavities in the hippocampus are morphological variants of uncertain significance. Aberrant neurodevelopment along with vascular and inflammatory etiologies have been proposed. We sought to characterize these cavities and their potential risk factors in a marginally housed population, with high rates of viral infection, addiction, and mental illness. (1) The volume of hippocampal cavities (HCavs) is greater in this highly multimorbid population compared to the general population. (2) Conventional vascular risk factors such as greater age and systolic blood pressure are associated with higher HCav volume. (3) Nonprescribed substance-related risk factors such as stimulant use or dependence, and smoking are associated with increased HCav volume independent of vascular risk factors. This is a retrospective analysis of an ongoing prospective study. We analyzed baseline data, including medical history, physical exam, psychiatric diagnosis, and MRI from a total of 375 participants. Hippocampal cavities were defined as spaces isointense to CSF on T1 MRI sequences, bounded on all sides by hippocampal tissue, with a volume of at least 1 mm3 . Risk factors were evaluated using negative binomial multiple regression. Stimulant use was reported by 87.3% of participants, with stimulant dependence diagnosed in 83.3% of participants. Prevalence of cavities was 71.6%, with a mean total bilateral HCav volume of 13.89 mm3 . On average, a 1 mmHg greater systolic blood pressure was associated with a 2.17% greater total HCav volume (95% CI = [0.57%, 3.79%], p = .0076), while each cigarette smoked per day trended toward a 2.69% greater total HCav volume (95% CI = [-0.87%, 5.54%], p = .058). A diagnosis of stimulant dependence was associated with a 95.6% greater total HCav volume (95% CI = [5.39%, 263.19%], p = .0335). Hypertension and diagnosis of stimulant dependence were associated with a greater total volume of HCav.

Background Homeless and precarious housed persons are particularly prone to traumatic brain injuries (TBIs), but existent incidence rates are hampered by poor case acquisition. We rigorously documented TBIs in precariously housed persons transitioning in and out of homelessness. Methods Between December 2016 and May 2018, 326 precariously housed participants enrolled in a longitudinal study in Vancouver, Canada were assessed monthly for TBI occurrences after education on sequelae. Over one participant-year, 2433 TBI screenings were acquired for 326 person-years and variables associated with odds of incident TBI were evaluated. Findings One hundred participants acquired 175 TBIs, yielding an observed incidence proportion of 30.7% and event proportion of 53.7%. Of the injured, 61% reported one TBI and 39% reported multiple injuries. Acute intoxication was present for more than half of the TBI events assessed. Additionally, 9.7% of TBI events occurred in the context of a drug overdose. Common injury mechanisms were falls (45.1%), assaults (25.1%), and hitting one's head on an object (13.1%). In this community-based but non-randomly recruited sample, exploratory analyses identified factors associated with odds of an incident TBI over one year of follow-up, including: schizophrenia disorders (odds ratio (OR) = 0.43, 95% confidence interval (CI) 0.19, 0.94), role functioning (OR = 0.69, 95% CI 0.52, 0.91), opioid dependence (OR = 2.17, 95% CI 1.27, 3.72) and those reporting past TBIs (OR =1.99, 95% CI 1.13, 3.52). Interpretation Given the ubiquity of TBIs revealed in this precariously housed sample, we identify an underappreciated and urgent healthcare priority. Several factors modified the odds of incident TBI, which can facilitate investigations into targeted prevention efforts. Copyright (c) 2022 The Author(s). Published by Elsevier Ltd.

Individuals who are homeless or precariously housed experience poorer health and earlier mortality compared to the general population. We evaluated longitudinal changes in quantitative MRI measures of brain structure, and how these changes are related to mortality, and change in health and functioning.

Mindfulness-based interventions can enhance cognitive abilities among older adults, thereby effectively delaying cognitive decline. These cognitive enhancements are theorized to accompany neuroplastic changes in the brain. However, this mindfulness-associated neuroplasticity has yet to be documented adequately. A randomized controlled trial was carried out among participants with mild cognitive impairment (MCI) to examine the effects of a mindfulness-based intervention on various cognitive outcomes and cortical thickness (CT) in the context of age-related cognitive impairment. Participants were assigned to a mindfulness awareness program (MAP)(n = 27) and an active control condition - health education program (n = 27). In both, they attended weekly sessions for three months and subsequently, monthly sessions for six months. Cognitive assessments and structural scans were carried out across three time-points. Whole brain analyses on CT were carried out and were supplemented with region of interest-based analyses. ROI values and cognitive outcomes were analyzed with mixed MANOVAs and followed up with univariate ANOVAs. Nine-month MAP-associated gains in working memory span and divided attention, along with an increased CT in the right frontal pole and decreased CT in the left anterior cingulate were observed. Three-month MAP-associated CT increase was observed in the left inferior temporal gyrus but did not sustain thereafter. MAP led to significant cognitive gains and various CT changes. Most of these neurobehavioral changes, may require sustained effort across nine months, albeit at a reduced intensity. MAP can remediate certain cognitive impairments and engender neuroplastic effects even among those with MCI.

This study aims to identify the effects of cerebral small vessel disease (cSVD) on structural brain network characteristics of homeless or precariously housed adults.

OBJECTIVE:Individuals with early psychosis may have prefrontal-limbic cortical deficits, which are associated with symptom severity and cognitive impairment. This study investigated the impact of an exercise intervention on fronto-temporal cortical plasticity in female participants with early psychosis. METHODS:In a cohort of 51 female participants with early psychosis from Hong Kong, we investigated the effects of a 12-week, moderate intensity aerobic or Hatha yoga exercise trial (yoga (N = 21), aerobic (N = 18) or waitlist group (N = 12)) on cortical grey matter. Clinical assessments and structural MRI were completed pre- and post- a 12-week exercise intervention. RESULTS:Increases in cortical volume and thickness were observed in the medial temporal cortical regions, primarily in fusiform cortical thickness (F(2, 48) = 4.221, p = 0.020, η2 = 0.150) and volume (F(2, 48) = 3.521, p = 0.037, η2 = 0.128) for participants with early psychosis in the aerobic arm, but not in the yoga and waitlist arms. Increased fusiform cortical thickness (ß = 0.402, p = 0.003) was associated with increased hippocampal volume for all psychosis participants. For the aerobic group only, increases in the entorhinal and fusiform temporal gyri were associated with reduced symptom severity. CONCLUSIONS:These findings suggest exercise-induced neuroplasticity in medial temporal cortical regions occurs with aerobic exercise. These changes may be associated with improvements in psychosis symptom severity. People with early psychosis may benefit from exercise interventions, particularly aerobic exercise, as an adjunct treatment to address clinical, physical health, and neuroanatomic concerns. NIH National Library of Medicine ClinicalTrials.gov Registration #: NCT01207219https://clinicaltrials.gov/ct2/show/NCT01207219.

Objective: The amygdala is a brain region comprised of a group of functionally distinct nuclei that play a central role in social behavior. In homeless and precariously housed individuals, high rates of multimorbidity, and structural aspects of the environment may dysregulate social functioning. This study examined the neurobiological substrates of social connection in homeless and precariously housed persons by examining associations between amygdala nuclei volumes and social network size. Methods: Sixty participants (mean age 43.6 years; 73.3% male) were enrolled from an ongoing study of homeless and precariously housed adults in Vancouver, Canada. Social network size was assessed using the Arizona Social Support Interview Schedule. Amygdala nuclei volumes were extracted from anatomic T1-weighted MRI data. The central and basolateral amygdala nuclei were selected as they are implicated in anxiety-related and social behaviors. The hippocampus was included as a control brain region. Multivariable regression analysis investigated the relationship between amygdala nuclei volumes and social network size. Results: After controlling for age, sex, and total brain volume, individuals with the larger amygdala and central nucleus volumes had a larger network size. This association was not observed for the basolateral amygdala complex, though subsequent analysis found the basal and accessory basal nuclei of the basolateral amygdala were significantly associated with social network size. No association was found for the lateral amygdala nucleus or hippocampus. Conclusions: These findings suggest that select amygdala nuclei may be differentially involved in the social connections of persons with multimorbid illness and social marginalization.

Objective: It has been proposed that different stages of the bipolar disorder might have distinct neurobiological changes. However, the evidence for this has not been consistent, as the studies in early stages of the illness are limited by small sample sizes. The purpose of this study was to investigate the gray matter volume changes in bipolar patients who recently recovered from their first episode of mania (FEM). Methods: Using a whole-brain voxel-based analysis, we compared the regional gray matter volumes of 61 bipolar patients who have recovered from their FEM in the past 3 months with 43 age- and gender-matched healthy participants. We also performed a series of subgroup analyses to determine the effects of hospitalization during the FEM, history of depressive episodes, and exposure to lithium. Results: No statistically significant difference was found between gray matter volumes of FEM patients and healthy participants, even at a more liberal threshold ( P < 0.001, uncorrected for multiple comparisons). Voxel-based subgroup analyses did not reveal significant gray matter differences except for a trend toward decreased gray matter volume in left lateral occipital cortex ( P < 0.001, uncorrected) in patients with a previous history of depression. Conclusion: This study represents the largest structural neuroimaging investigation of FEM published to date. Early stage of bipolar disorder was not found to be associated with significant gray matter volume changes. Our findings suggest that there might be a window of opportunity for early intervention strategies to prevent or delay neuroprogression in bipolar disorder.

BACKGROUND AND PURPOSE:We aim to describe the burden, characteristics, and cognitive associations of cerebral small vessel disease in a Canadian sample living with multimorbidity in precarious housing. METHODS:Participants received T1, T2-fluid-attenuated inversion recovery, and susceptibility-weighted imaging 3T magnetic resonance imaging sequences and comprehensive clinical, laboratory, and cognitive assessments. Cerebral small vessel disease burden was characterized using a modified Small Vessel Disease (mSVD) score. One point each was given for moderate-severe white matter hyperintensities, ≥1 cerebral microbleeds, and ≥1 lacune. Multivariable regression explored associations between mSVD score, risk factors, and cognitive performance. RESULTS:Median age of the 228 participants (77% male) was 44.7 years (range, 23.3-63.2). In n=188 participants with consistent good quality magnetic resonance imaging sequences, mSVD scores were 0 (n=127, 68%), 1 (n=50, 27%), and 2 (n=11, 6%). Overall, one-third had an mSVD ≥1 n=61 (32%); this proportion was unchanged when adding participants with missing sequences n=72/228 (32%). The most prevalent feature was white matter hyperintensities 53/218 (24%) then cerebral microbleed 16/191 (8%) and lacunes 16/228 (7%). Older age (odds ratio, 1.10 [95% CI, 1.05-1.15], P<0.001), higher diastolic blood pressure (odds ratio, 1.05 [95% CI, 1.01-1.09], P=0.008), and a history of injection drug use (odds ratio, 3.13 [95% CI, 1.07-9.16], P=0.037) had significant independent associations with a mSVD score of ≥1 in multivariable analysis. mSVD ≥1 was associated with lower performance on tests of verbal memory, sustained attention, and decision-making, contributing 4% to 5% of the variance in each cognitive domain. CONCLUSIONS:The 32% prevalence of cerebral small vessel disease in this young, socially marginalized cohort was higher than expected for age and was associated with poorer cognitive performance.