The Aging Brain With HIV Infection: Effects of Alcoholism or Hepatitis C Comorbidity

Delirium among people aging with and without HIV: Role of alcohol and Neurocognitively active medications

BACKGROUND

People aging with and without HIV (PWH and PWoH) want to avoid neurocognitive dysfunction, especially delirium. Continued use of alcohol in conjunction with neurocognitively active medications (NCAMs) may be a largely underappreciated cause, especially for PWH who experience polypharmacy a decade earlier than PWoH. We compare absolute and relative risk of delirium among PWH and PWoH by age, level of alcohol use, and exposure to NCAMs.

METHODS

Using the VACS cohort, we compare absolute and relative risk of inpatient delirium among PWH and PWoH by age, level of alcohol use, and exposure to NCAMs between 2007 and 2019. We matched each case based on age, race/ethnicity, sex, HIV, baseline year, and observation time with up to 5 controls. The case/control date was defined as date of admission for cases and the date corresponding to the same length of time on study for controls. Level of alcohol use was defined using Alcohol Use Disorder Identification Test-Consumption (AUDIT-C). Medication exposure was measured from 45 to 3 days prior to index date; medications were classified as anticholinergic NCAM, non-anticholinergic NCAM, or non NCAM and counts generated. We used logistic regression to determine odds ratios (ORs) for delirium associated with medication counts stratified by HIV status and adjusted for demographics, severity of illness, and related diagnoses.

RESULTS

PWH experienced a higher incidence of delirium (5.6, [95% CI 5.3-5.9/1000 PY]) than PWoH (5.0, [95% CI 4.8-5.1/1000 PY]). In multivariable analysis, anticholinergic and non-anticholinergic NCAM counts and level of alcohol use demonstrated strong independent dose-response associations with delirium.

CONCLUSIONS

Decreasing alcohol use and limiting the use of neurocognitively active medications may help decrease excess rates of delirium, especially among PWH.

Alcohol Use Disorder and Its Comorbidity With HIV Infection Disrupts Anterior Cingulate Cortex Functional Connectivity

BACKGROUND

Individuals with alcohol use disorder (AUD) have a heightened risk of contracting HIV infection. The effects of these two diseases and their comorbidity on brain structure have been well described, but their effects on brain function have never been investigated at the scale of whole-brain connectomes.

METHODS

In contrast with prior studies that restricted analyses to specific brain networks or examined relatively small groups of participants, our analyses are based on whole-brain functional connectomes of 292 participants.

RESULTS

Relative to participants without AUD, the functional connectivity between the anterior cingulate cortex and orbitofrontal cortex was lower for participants with AUD. Compared with participants without AUD+HIV comorbidity, the functional connectivity between the anterior cingulate cortex and hippocampus was lower for the AUD+HIV participants. Compromised connectivity between these pairs was significantly correlated with greater total lifetime alcohol consumption; the effects of total lifetime alcohol consumption on executive functioning were significantly mediated by the functional connectivity between the pairs.

CONCLUSIONS

Taken together, our results suggest that the functional connectivity of the anterior cingulate cortex is disrupted in individuals with AUD alone and AUD with HIV infection comorbidity. Moreover, the affected connections are associated with deficits in executive functioning, including heightened impulsiveness.

Altered white matter integrity in the corpus callosum in adults with HIV: a systematic review of diffusion tensor imaging studies

We systematically reviewed studies comparing differences in the integrity of the corpus callosum in adults with HIV compared to healthy controls, using Diffusion Tensor Imaging (DTI), using search engines Science Direct, Web of Science and PubMed. The search terms used were "HIV", "corpus callosum", and a variation of either "DTI" or "Diffusion Tensor Imaging" with or without the term "adults". We specifically examined the corpus callosum as it is the largest white matter tract in the brain, plays a primary role in cognition, and has been shown to be morphologically altered in people living with HIV. Lower fractional anisotropy (FA) was consistently found in the corpus callosum in people with HIV compared to controls. As most studies used only FA as a measure of diffusion, it would be informative for future research if other DTI metrics, such as mean diffusivity (MD), were also investigated as these metrics may be more sensitive markers of HIV-related neuropathology.

Binge Drinking Relates to Worse Neurocognitive Functioning Among Adults Aging with HIV

OBJECTIVE

Given the aging population of people with HIV (PWH), along with increasing rates of binge drinking among both PWH and the general older adult population, this study examined the independent and interactive effects of HIV, binge drinking, and age on neurocognition.

METHOD

Participants were 146 drinkers stratified by HIV and binge drinking status (i.e., ≥4 drinks for women and ≥5 drinks for men within approximately 2 h): HIV+/Binge+ (n = 30), HIV-/Binge+ (n = 23), HIV+/Binge- (n = 55), HIV-/Binge- (n = 38). All participants completed a comprehensive neuropsychological battery measuring demographically-corrected global and domain-specific neurocognitive T scores. ANCOVA models examined independent and interactive effects of HIV and binge drinking on neurocognitive outcomes, adjusting for overall alcohol consumption, lifetime substance use, sex, and age. Subsequent multiple linear regressions examined whether HIV/Binge group moderated the relationship between age and neurocognition.

RESULTS

HIV+/Binge+ participants had worse global neurocognition, processing speed, delayed recall, and working memory than HIV-/Binge- participants (p's < .05). While there were significant main effects of HIV and binge drinking, their interaction did not predict any of those neurocognitive outcomes (p's > .05). Significant interactions between age and HIV/Binge group showed that HIV+/Binge+ participants demonstrated steeper negative relationships between age and neurocognitive outcomes of learning, delayed recall, and motor skills compared to HIV-/Binge- participants (p's < .05).

CONCLUSIONS

Results showed adverse additive effects of HIV and binge drinking on neurocognitive functioning, with older adults demonstrating the most vulnerability to these effects. Findings support the need for interventions to reduce binge drinking, especially among older PWH.

Pathophysiological Consequences of At-Risk Alcohol Use; Implications for Comorbidity Risk in Persons Living With Human Immunodeficiency Virus

At-risk alcohol use is a significant risk factor associated with multisystemic pathophysiological effects leading to multiorgan injury and contributing to 5.3% of all deaths worldwide. The alcohol-mediated cellular and molecular alterations are particularly salient in vulnerable populations, such as people living with HIV (PLWH), diminishing their physiological reserve, and accelerating the aging process. This review presents salient alcohol-associated mechanisms involved in exacerbation of cardiometabolic and neuropathological comorbidities and their implications in the context of HIV disease. The review integrates consideration of environmental factors, such as consumption of a Western diet and its interactions with alcohol-induced metabolic and neurocognitive dyshomeostasis. Major alcohol-mediated mechanisms that contribute to cardiometabolic comorbidity include impaired substrate utilization and storage, endothelial dysfunction, dysregulation of the renin-angiotensin-aldosterone system, and hypertension. Neuroinflammation and loss of neurotrophic support in vulnerable brain regions significantly contribute to alcohol-associated development of neurological deficits and alcohol use disorder risk. Collectively, evidence suggests that at-risk alcohol use exacerbates cardiometabolic and neurocognitive pathologies and accelerates biological aging leading to the development of geriatric comorbidities manifested as frailty in PLWH.

A sobering addition to the literature on COVID-19 and the brain

Several coronavirus disease 2019 (COVID-19) studies have focused on neuropathology. In this issue of the JCI, Qin, Wu, and Chen et al. focused specifically on people whose acute infection lacked obvious neurological involvement. Severely infected patients showed abnormal gray matter volumes, white matter diffusion, and cerebral blood flow compared with healthy controls and those with mild infection. The data remain associative rather than mechanistic, but correlations with systemic immune markers suggest effects of inflammation, hypercoagulation, or other aspects of disease severity. Mechanistic research is warranted. Given the lack of obvious neurological symptoms, neurocognitive assessments were not performed, but the findings suggest that such assessments may be warranted in severely affected patients, even without obvious symptoms. Further, studying CNS involvement of other disorders with overlapping pathophysiologies such as inflammation, coagulation, hypoxia, or direct viral infection may reveal the causes for COVID-19-related neuropathology.

Comparison of dementia risk after age 50 between individuals with and without HIV infection

OBJECTIVE

To compare risk of dementia after age 50 by HIV status among individuals in a primary care setting.

DESIGN

Observational cohort study; participants were identified from 2013 to 2017 and followed through 2019.

METHODS

Participants were people with HIV (PWH) on antiretroviral therapy (ART) and demographically similar people without HIV (PWOH), all at least 50 years old and with no prior diagnosis of dementia. The study setting was Kaiser Permanente Northern California, an integrated healthcare delivery system in the United States. Incident dementia diagnoses and baseline data on sociodemographics, smoking, alcohol use, other substance use, and clinical factors were gathered from the electronic health record. Cumulative proportion of incident dementia by HIV status was assessed using Kaplan--Meier curves. Unadjusted and adjusted hazard ratios for incident dementia by HIV status were generated using Cox proportional hazards models with age as the time scale.

RESULTS

The study included 5381 PWH and 119 022 PWOH (average age at baseline: 57 and 58 years, respectively). Incident dementia was diagnosed in 117 PWH and 2427 PWOH. By age 80, 25.8% of PWH and 13.8% of PWOH had been diagnosed with dementia, corresponding with an unadjusted hazard ratio of 1.98 (95% CI 1.64-2.39). After adjustment for sociodemographic, substance use, and clinical factors, including frequency of outpatient visits, the risk of dementia among PWH remained elevated (vs. PWOH, adjusted hazard ratio = 1.58, 95% CI 1.31-1.92).

CONCLUSION

Compared with PWOH, PWH were at 58% higher risk for dementia despite HIV treatment with ART. Research is needed to investigate the potential benefits of targeted risk factor management or earlier cognitive screening in this population.

Neuroimaging the Neuropathogenesis of HIV

PURPOSE OF REVIEW

This review highlights neuroimaging studies of HIV conducted over the last 2 years and discusses how relevant findings further our knowledge of the neuropathology of HIV. Three major avenues of neuroimaging research are covered with a particular emphasis on inflammation, aging, and substance use in persons living with HIV (PLWH).

RECENT FINDINGS

Neuroimaging has been a critical tool for understanding the neuropathological underpinnings observed in HIV. Recent studies comparing levels of neuroinflammation in PLWH and HIV-negative controls show inconsistent results but report an association between elevated neuroinflammation and poorer cognition in PLWH. Other recent neuroimaging studies suggest that older PLWH are at increased risk for brain and cognitive compromise compared to their younger counterparts. Finally, recent findings also suggest that the effects of HIV may be exacerbated by alcohol and drug abuse. These neuroimaging studies provide insight into the structural, functional, and molecular changes occurring in the brain due to HIV. HIV triggers a strong neuroimmune response and may lead to a cascade of events including increased chronic inflammation and cognitive decline. These outcomes are further exacerbated by age and age-related comorbidities, as well as lifestyle factors such as drug use/abuse.

Neuroimaging and Cognitive Evidence for Combined HIV-Alcohol Effects on the Central Nervous System: A Review

Alcohol use disorder (AUD) among people living with HIV (PLWH) is a significant public health concern. Despite the advent of effective antiretroviral therapy, up to 50% of PLWH still experience worsened neurocognition, which comorbid AUD exacerbates. We report converging lines of neuroimaging and neuropsychological evidence linking comorbid HIV/AUD to dysfunction in brain regions linked to executive function, learning and memory, processing speed, and motor control, and consequently to impairment in daily life. The brain shrinkage, functional network alterations, and brain metabolite disruption seen in individuals with HIV/AUD have been attributed to several interacting pathways: viral proteins and EtOH are directly neurotoxic and exacerbate each other's neurotoxic effects; EtOH reduces antiretroviral adherence and increases viral replication; AUD and HIV both increase gut microbial translocation, promoting systemic inflammation and HIV transport into the brain by immune cells; and HIV may compound alcohol's damaging effects on the liver, further increasing inflammation. We additionally review the neurocognitive effects of aging, Hepatitis C coinfection, obesity, and cardiovascular disease, tobacco use, and nutritional deficiencies, all of which have been shown to compound cognitive changes in HIV, AUD, and in their comorbidity. Finally, we examine emerging questions in HIV/AUD research, including genetic and cognitive protective factors, the role of binge drinking in HIV/AUD-linked cognitive decline, and whether neurocognitive and brain functions normalize after drinking cessation.

Predicting brain age with complex networks: From adolescence to adulthood

In recent years, several studies have demonstrated that machine learning and deep learning systems can be very useful to accurately predict brain age. In this work, we propose a novel approach based on complex networks using 1016 T1-weighted MRI brain scans (in the age range 7-64years). We introduce a structural connectivity model of the human brain: MRI scans are divided in rectangular boxes and Pearson's correlation is measured among them in order to obtain a complex network model. Brain connectivity is then characterized through few and easy-to-interpret centrality measures; finally, brain age is predicted by feeding a compact deep neural network. The proposed approach is accurate, robust and computationally efficient, despite the large and heterogeneous dataset used. Age prediction accuracy, in terms of correlation between predicted and actual age r=0.89and Mean Absolute Error MAE =2.19years, compares favorably with results from state-of-the-art approaches. On an independent test set including 262 subjects, whose scans were acquired with different scanners and protocols we found MAE =2.52. The only imaging analysis steps required in the proposed framework are brain extraction and linear registration, hence robust results are obtained with a low computational cost. In addition, the network model provides a novel insight on aging patterns within the brain and specific information about anatomical districts displaying relevant changes with aging.

Regional brain volumetric changes despite 2 years of treatment initiated during acute HIV infection

OBJECTIVE

To assess changes in regional brain volumes after 24 months among individuals who initiated combination antiretroviral therapy (cART) within weeks of HIV exposure.

DESIGN

Prospective cohort study of Thai participants in the earliest stages of HIV-1infection.

METHODS

Thirty-four acutely HIV-infected individuals (AHI; Fiebig I-V) underwent brain magnetic resonance (MR) imaging and MR spectroscopy at 1.5 T and immediately initiated cART. Imaging was repeated at 24 months. Regional brain volumes were quantified using FreeSurfer's longitudinal pipeline. Voxel-wise analyses using tensor-based morphometry (TBM) were conducted to verify regional assessments. Baseline brain metabolite levels, blood and cerebrospinal fluid biomarkers assessed by ELISA, and peripheral blood monocyte phenotypes measured by flow cytometry were examined as predictors of significant volumetric change.

RESULTS

Participants were 31 ± 8 years old. The estimated mean duration of infection at cART initiation was 15 days. Longitudinal analyses revealed reductions in volumes of putamen (P < 0.001) and caudate (P = 0.006). TBM confirmed significant atrophy in the putamen and caudate, and also in thalamic and hippocampal regions. In exploratory post-hoc analyses, higher baseline frequency of P-selectin glycoprotein ligand-1 (PSGL-1)-expressing total monocytes correlated with greater caudate volumetric decrease (ρ = 0.67, P = 0.017), whereas the baseline density of PSGL-1-expressing inflammatory (CD14CD16) monocytes correlated with putamen atrophy (ρ = 0.65, P = 0.022).

CONCLUSION

Suppressive cART initiated during AHI may not prevent brain atrophy. Volumetric decrease appears greater than expected age-related decline, although examination of longitudinal change in demographically similar HIV-uninfected Thai individuals is needed. Mechanisms underlying progressive HIV-related atrophy may include early activation and enhanced adhesive and migratory capacity of circulating monocyte populations.

Cognitive impairment severity in relation to signs of subclinical Wernicke's encephalopathy in HIV and alcoholism comorbidity

OBJECTIVES

The comorbidity of HIV infection and alcoholism (ALC) is prevalent. Wernicke's encephalopathy, a neurological disorder resulting from thiamine depletion, has been generally associated with alcoholism but has also been reported in HIV infection. This study examined whether subclinical Wernicke's encephalopathy signs could contribute to the heterogeneity of cognitive and motor deficits observed in individuals with both disease conditions (HIV+ALC).

DESIGN

Sixty-one HIV+ALC individuals and 59 controls were assessed on attention and working memory, production, immediate and delayed episodic memory, visuospatial abilities, and upper limb motor function.

METHODS

Using Caine criteria (dietary deficiency, oculomotor abnormality, cerebellar dysfunction, and altered mental state), HIV+ALC individuals were classified by subclinical Wernicke's encephalopathy risk factors.

RESULTS

Signs of subclinical Wernicke's encephalopathy were present in 20% of the HIV+ALC participants. For attention/working memory, delayed memory, and upper limb motor function, HIV+ALC Caine 2+ (i.e. meeting two or three criteria) demonstrated the most severe deficits, scoring lower than HIV+ALC Caine 1 (i.e. meeting one criterion), HIV+ALC Caine 0 (i.e. meeting no criteria), and controls.

CONCLUSION

The high prevalence of subclinical signs of Wernicke's encephalopathy and relevance to performance indicate that this condition should be considered in assessment of HIV-infected individuals, especially when alcoholism comorbidity is known or suspected. Above and beyond clinical factors, such as depression, alcoholism and HIV disease-related variables, AIDS, hepatitis C and drug history known to mediate neuropsychological performance, subclinical Wernicke's encephalopathy signs could partly explain the heterogeneity in patterns and severity of cognitive and motor impairments in HIV-infected individuals with alcoholism comorbidity.

Cognitive and Motor Impairment Severity Related to Signs of Subclinical Wernicke's Encephalopathy in HIV Infection

BACKGROUND

Wernicke's encephalopathy (WE) is a neurological condition resulting from thiamine deficiency. Although commonly associated with alcoholism, nonalcoholic WE has been described in individuals with HIV infection, but subclinical WE may be underdiagnosed. The current study questioned whether the presence of subclinical WE signs underlies cognitive and motor deficits in HIV individuals as observed in alcoholism.

SETTING

Fifty-six HIV-positive individuals (HIV+) and 53 HIV-negative controls (HIV-) were assessed on 6 cognitive and motor domains: attention/working memory, production, immediate and delayed episodic memory, visuospatial abilities, and upper-limb motor function.

METHODS

Based on a rating scheme by Caine et al, HIV+ individuals were categorized by subclinical WE risk factors (dietary deficiency, oculomotor abnormality, cerebellar dysfunction, and altered mental state). Performance was expressed as age- and education-corrected Z-scores standardized on controls.

RESULTS

Sorting by Caine criteria yielded 20 HIV+ as Caine 0 (ie, meeting no criteria), 22 as Caine 1 (ie, meeting one criterion), and 14 as Caine 2 (ie, meeting 2 criteria). Comparison among HIV+ Caine subgroups revealed a graded effect: Caine 0 performed at control levels, Caine 1 showed mild to moderate deficits on some domains, and Caine 2 showed the most severe deficits on each domain.

CONCLUSION

This graded severity pattern of performance among Caine subgroups suggests that signs of subclinical WE can partly explain the heterogeneity in HIV-related cognitive and motor impairment. This study highlights the utility of Caine criteria in identifying potential causes of HIV-related neurocognitive disorders and has implications for disease management.

Pathogenesis of age-related HIV neurodegeneration

People over the age of 50 are the fastest growing segment of the HIV-infected population in the USA. Although antiretroviral therapy has remarkable success controlling the systemic HIV infection, HIV-associated neurocognitive disorder (HAND) prevalence has increased or remained the same among this group, and cognitive deficits appear more severe in aged patients with HIV. The mechanisms of HAND in the aged population are not completely understood; a leading hypothesis is that aged individuals with HIV might be at higher risk of developing Alzheimer's disease (AD) or one of the AD-related dementias (ADRD). There are a number of mechanisms through which chronic HIV disease alone or in combination with antiretroviral therapy and other comorbidities (e.g., drug use, hepatitis C virus (HCV)) might be contributing to HAND in individuals over the age of 50 years, including (1) overlapping pathogenic mechanisms between HIV and aging (e.g., decreased proteostasis, DNA damage, chronic inflammation, epigenetics, vascular), which could lead to accelerated cellular aging and neurodegeneration and/or (2) by promoting pathways involved in AD/ADRD neuropathogenesis (e.g., triggering amyloid β, Tau, or α-synuclein accumulation). In this manuscript, we will review some of the potential common mechanisms involved and evidence in favor and against a role of AD/ADRD in HAND.

Brain-behavior relations and effects of aging and common comorbidities in alcohol use disorder: A review

OBJECTIVE

Alcohol use disorder (AUD) is a complex, dynamic condition that waxes and wanes with unhealthy drinking episodes and varies in drinking patterns and effects on brain structure and function with age. Its excessive use renders chronically heavy drinkers vulnerable to direct alcohol toxicity and a variety of comorbidities attributable to nonalcohol drug misuse, viral infections, and accelerated or premature aging. AUD affects widespread brain systems, commonly, frontolimbic, frontostriatal, and frontocerebellar networks.

METHOD AND RESULTS

Multimodal assessment using selective neuropsychological testing and whole-brain neuroimaging provides evidence for AUD-related specific brain structure-function relations established with double dissociations. Longitudinal study using noninvasive imaging provides evidence for brain structural and functional improvement with sustained sobriety and further decline with relapse. Functional imaging suggests the possibility that some alcoholics in recovery can compensate for impairment by invoking brain systems typically not used for a target task but that can enable normal-level performance.

CONCLUSIONS

Evidence for AUD-aging interactions, indicative of accelerated aging, together with increasing alcohol consumption in middle-age and older adults, put aging drinkers at special risk for developing cognitive decline and possibly dementia. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Is treated HIV infection still toxic to the brain?

Clinically apparent HIV infection, accompanied by CNS opportunistic infections and HIV encephalopathy, was often associated with profound structural and functional brain effects prior to the introduction of anti-retroviral therapy (ART). With treatment, HIV structural and functional brain effects are smaller and have not been as easily detected. With near complete elimination of CNS opportunistic infections, the HIV neuroimaging research community now grapples with the problem of detecting subtler structural and functional changes against a background of persisting confounds, such as comorbidities and clinical features common in the HIV infected population. This situation also raises the question of whether imaging measure changes that are reported as HIV brain effects are purely related to viral infection, rather than originating from confounding effects that might include age, substance use, hepatitis C coinfection, cerebrovascular risk factors, ART, premorbid cognitive skills and illness duration. In addition to cohort characteristics, variation in image acquisition and analysis techniques may also contribute to study outcome heterogeneity. We review the potential effects of these confounds on detection of HIV infection effects and discuss strategies to avoid or mitigate the effects of these confounds. We then present a systematic approach to measurement, design and analysis in HIV neuroimaging studies, combining both experimental and statistical control techniques to determine if HIV infection effects persist, fluctuate or worsen in groups achieving viral suppression from ART.

Understanding the Role of Antiviral Cytokines and Chemokines on Neural Stem/Progenitor Cell Activity and Survival

Viral infections of the central nervous system are accompanied by the expression of cytokines and chemokines that can be critical for the control of viral replication in the brain. The outcomes of cytokine/chemokine signaling in neural cells vary widely, with cell-specific effects on cellular activity, proliferation, and survival. Neural stem/progenitor cells (NSPCs) are often altered during viral infections, through direct infection by the virus or by the influence of immune cell activity or cytokine/chemokine signaling. However, it has been challenging to dissect the contribution of the virus and specific inflammatory mediators during an infection. In addition to initiating an antiviral program in infected NSPCs, cytokines/chemokines can induce multiple changes in NSPC behavior that can perturb NSPC numbers, differentiation into other neural cells, and migration to sites of injury, and ultimately brain development and repair. The focus of this review was to dissect the effects of common antiviral cytokines and chemokines on NSPC activity, and to consider the subsequent pathological consequences for the host from changes in NSPC function.

Accelerated and Premature Aging Characterizing Regional Cortical Volume Loss in Human Immunodeficiency Virus Infection: Contributions From Alcohol, Substance Use, and Hepatitis C Coinfection

BACKGROUND

Life expectancy of successfully treated human immunodeficiency virus (HIV)-infected individuals is approaching normal longevity. The growing HIV population ≥50 years of age is now at risk of developing HIV-associated neurocognitive disorder, acquiring coinfection with the hepatitis C virus (HCV), and engaging in hazardous drinking or drug consumption that can adversely affect trajectories of the healthy aging of brain structures.

METHODS

This cross-sectional/longitudinal study quantified regional brain volumes from 1101 magnetic resonance imaging scans collected over 14 years in 549 participants (25 to 75 years of age): 68 HIV-infected individuals without alcohol dependence, 60 HIV-infected individuals with alcohol dependence, 222 alcohol-dependent individuals, and 199 control subjects. We tested 1) whether localized brain regions in HIV-infected individuals exhibited accelerated aging, or alternatively, nonaccelerated premature aging deficits; and 2) the extent to which alcohol or substance dependence or HCV coinfection altered brain aging trajectories.

RESULTS

The HIV-infected cohort exhibited steeper declining volume trajectories than control subjects, consistently in the frontal cortex. Nonaccelerated volume deficits occurred in the temporal, parietal, insular, and cingulate regions of all three diagnostic groups. Alcohol and drug dependence comorbidities and HCV coinfection exacerbated HIV-related volume deficits. Accelerated age interactions in frontal and posterior parietal volumes endured in HIV-infected individuals free of alcohol or substance dependence and HCV infection comorbidities. Functionally, poorer HIV-associated neurocognitive disorder scores and Veterans Aging Cohort Study indices correlated with smaller regional brain volumes in the HIV-infected individuals without alcohol dependence and alcohol-dependent groups.

CONCLUSIONS

HIV infection itself may confer a heightened risk of accelerated brain aging, potentially exacerbated by HCV coinfection and substance dependency. Confirmation would require a prospective study with a preinfection baseline.