John D Fisk's research while affiliated with Dalhousie University and other places
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Publications (283)
Reports of cognitive impairment in inflammatory bowel disease (IBD) have been mixed. IBD and cardiovascular disease are often co-morbid, yet it remains unknown whether vascular comorbidity confers a risk for decreased cognitive functioning, as observed in other populations. Participants with IBD were recruited from a longitudinal study of immune-me...
Background:
Fatigue is highly prevalent in people with inflammatory bowel disease (IBD). Fatigue scales are important for studies testing fatigue interventions, but information about psychometric properties of many scales is insufficient in IBD. We compared the psychometric properties of multiple generic fatigue scales in participants with IBD.
M...
Background and objectives
Little is known of the potential sex and age differences in the MS prodrome. We investigated sex and age differences in healthcare utilization during the MS prodrome.
Methods
This was a population-based matched cohort study linking administrative and clinical data from British Columbia, Canada (population = 5 million). MS...
Introduction:
We estimated the incidence and prevalence of benzodiazepine and Z-drug (separately and jointly as BZD) use in the inflammatory bowel disease (IBD) population compared with matched controls without IBD and examined the association of mood/anxiety disorders (M/ADs) with the use of BZD from 1997 to 2017.
Methods:
Using administrative...
Background
The relationship between socioeconomic status (SES) and mortality among persons with multiple sclerosis (PwMS) is poorly understood.
Objective
To investigate the association between SES and mortality risk in PwMS.
Methods
From health-administrative data, we identified 12,126 incident MS cases with a first demyelinating event (MS ‘onset...
Background: Reports of cognitive impairment in inflammatory bowel disease (IBD) have been mixed. IBD and cardiovascular disease are often co-morbid, yet it remains unknown whether vascular comorbidity confers a risk for decreased cognitive functioning, as observed in other populations.
Methods: Participants with IBD were recruited from a longitudin...
Background and Objectives
We examined the association between the disease-modifying drugs (DMDs) for multiple sclerosis (MS) and survival in a multiregion population-based study.
Methods
We accessed multiple administrative health databases from 4 Canadian provinces. Persons with MS were identified and followed from the most recent of the first MS...
The Comorbidity and Cognition in Multiple Sclerosis (CCOMS) study represents a coordinated effort by a team of clinicians, neuropsychologists, and neuroimaging experts to investigate the neural basis of cognitive changes and their association with comorbidities among persons with multiple sclerosis (MS). The objectives are to determine the relation...
Objective
Extensive blood-brain barrier (BBB) leakage has been linked to cognitive impairment (CI) in systemic lupus erythematosus (SLE). This study aimed to examine the associations of brain functional connectivity (FC) with CI and BBB dysfunction among patients with SLE.
Methods
Cognitive function was assessed by neuropsychological testing (n =...
Objective:
Cognitive impairment is common in patients with SLE but the cause is unknown. The current cross-sectional study examined the association between select SLE-related autoantibodies, other serological biomarkers and extensive blood-brain barrier (BBB) leakage in patients with SLE with and without cognitive impairment. In addition, we deter...
Objective
Vascular comorbidities are associated with reduced cognitive performance and with changes in brain structure in people with multiple sclerosis (MS). Understanding causal pathways is necessary to support the design of interventions to mitigate the impacts of comorbidities, and to monitor their effectiveness. We assessed the inter-relations...
Objective
Use of benzodiazepines and Z-drugs (non-benzodiazepine sedative hypnotics) is controversial due to adverse health outcomes in the general population. However, little is known about their use in people with multiple sclerosis (MS). We estimated the incidence and prevalence of benzodiazepine and Z-drug use (jointly BZD) in the MS population...
We described emergency department (ED) visits (all visits and infection-related) by persons with multiple sclerosis (MS) in British Columbia, Canada (1 April 2012 to 31 December 2017). We identified 15,350 MS cases using health administrative data; 73.4% were women, averaging 51.4 years at study entry. Over 4.9 years of follow-up (mean), 56.0% of M...
Background
Evidence regarding the efficacy or effectiveness of the disease-modifying drugs (DMDs) in the older multiple sclerosis (MS) population is scarce. This has contributed to a lack of evidence-based treatment recommendations for the ageing MS population in practice guidelines. We examined the relationship between age (<55 and ≥55 years), DMD...
Objective
We assessed the relationship between the multiple sclerosis (MS) disease-modifying drugs (DMDs) and healthcare use.
Methods
Persons with MS (aged ⩾18 years) were identified using linked population-based health administrative data in four Canadian provinces and were followed from the most recent of their first MS/demyelinating event or 1...
The IVS10+14 microtubule‐associated protein tau gene (MAPT) mutation causes dysregulated protein splicing of MAPT, resulting in abnormal 4‐repeat isoform tau accumulation and associated with neurodegeneration. Three families expressing the IVS10+14 MAPT mutation have been reported who express the IVS10+14 MAPT mutation displaying a high degree of i...
Parkinson's disease (PD) is a neurodegenerative disorder that is typified by motor signs and symptoms but can also lead to significant cognitive impairment and dementia Parkinson's Disease Dementia (PDD). While dementia is considered a nonmotor feature of PD that typically occurs later, individuals with PD may experience mild cognitive impairment (...
Background: The IVS10+14 mutation in the microtubule-associated protein tau gene, MAPT , is a rare point mutation that dysregulates tau splicing resulting in pathological aggregation. This mutation has been identified in three families with severe neurodegenerative disease. We characterized the clinicopathological features of a fourth, Canadian fam...
Objective:
To determine whether childhood maltreatment is associated with immune-mediated inflammatory disorders (IMIDs; multiple sclerosis [MS], inflammatory bowel disease [IBD], and rheumatoid arthritis [RA]). We further aimed to determine the relationship between maltreatment and psychiatric comorbidity in IMIDs and whether these relationships...
Background
: Multiple sclerosis (MS) is a chronic demyelinating disease which leads to sensory, motor, autonomic, and cognitive symptoms. Cannabis is a common way for persons with MS (pwMS) to seek symptomatic therapy. Given the capacity for both cannabis and MS to cause cognitive impairment, it is important to determine whether there is any negati...
Background
Comorbidity decreases the likelihood of initiating disease-modifying therapy (DMT) for multiple sclerosis (MS). Our objective was to characterize the relationship between comorbidity and initial DMT persistence along with reasons for DMT discontinuation.
Methods
We identified individuals with relapsing remitting MS or clinically isolate...
We aimed to examine rates of breast and cervical cancer screening in women with immune-mediated inflammatory diseases (IMID), including inflammatory bowel disease (IBD), multiple sclerosis (MS) and rheumatoid arthritis (RA) versus a matched cohort with IMID; and examine the association of psychiatric comorbidity with screening in these populations....
Background
: Few studies have evaluated the association between comorbidities associated with increased vascular risk and brain volume changes in multiple sclerosis (MS). To date, findings have not been consistent with respect to which comorbidities are associated with lower brain volumes or whether comorbidities associated with increased vascular...
Background:
Individuals with immune-mediated inflammatory diseases, such as inflammatory bowel disease, multiple sclerosis and rheumatoid arthritis, are at increased risk for influenza and related complications. We examined and compared the uptake of influenza vaccination among people with and without these diseases, as well as the influence of ps...
In sporadic Alzheimer's disease (SpAD), acetylcholinesterase and butyrylcholinesterase, co-regulators of acetylcholine, are associated with β-amyloid plaques and tau neurofibrillary tangles in patterns suggesting a contribution to neurotoxicity. This association has not been explored in early-onset familial Alzheimer's disease (FAD). We investigate...
Objective
Childhood maltreatment is associated with pain catastrophizing. Both childhood maltreatment and pain catastrophizing are prevalent in certain immune-mediated inflammatory disease (IMID) populations. However, it is unknown whether childhood maltreatment contributes to the high rates of pain catastrophizing in IMID cohorts. We assessed the...
Mutations in the microtubule-associated protein tau (MAPT) gene are known to cause progressive neurodegenerative disorders with variable clinical and neuropathological phenotypes, including the intronic 10 +14 (IVS10+14) splice site mutation. Three families have been reported with the IVS10+14 MAPT mutation. Here, we describe the clinical and neuro...
Background: Cognitive impairment is common in multiple sclerosis (MS). Interpretation of neuropsychological tests requires the use of normative data. Traditionally, normative data have been reported for discrete categories such as age. More recently continuous norms have been developed using multivariable regression equations that account for multi...
Brackground
We aimed to examine associations between elevated symptoms of depression and anxiety and disease activity in inflammatory bowel disease (IBD). Previous findings have been inconsistent and have not accounted for variability in the courses of these conditions over time.
Methods
We followed 247 participants with IBD (153 Crohn’s disease [...
A diverse spectrum of nervous system events occurs frequently in patients with systemic lupus erythematosus (SLE). These have a negative impact on health-related quality of life and are associated with a higher overall mortality rate. Of these neuropsychiatric (NP) events, approximately one-third are attributable to lupus. They include both focal N...
Background
Inflammatory bowel disease (IBD) is associated with an increase in psychiatric comorbidity (PC) compared with the general population. We aimed to determine the impact of PC on health care utilization in persons with IBD.
Methods
We applied a validated administrative definition of IBD to identify all Manitobans with IBD from April 1, 200...
Background: Relatively little is known about the use of disease-modifying drugs (DMDs) for multiple sclerosis (MS) in the population-based universal healthcare setting. This study aimed to describe the characteristics of a population-based cohort with MS and their DMD exposure in four Canadian provinces.
Methods: We identified all adults (aged ≥18...
Background
Little is known about the effects of changes in the presence or absence of psychiatric disorders on health care utilization in multiple sclerosis (MS).
Objective
To evaluate the association between “active” mood and anxiety disorders (MAD) and health care utilization in MS.
Methods
Using administrative data from Manitoba, Canada, we id...
Objectives:
To examine the association between blood-brain barrier (BBB) integrity, brain volume and cognitive dysfunction in adult patients with systemic lupus erythematosus (SLE).
Methods:
A total of 65 ambulatory patients with SLE and 9 healthy controls underwent dynamic contrast-enhanced MRI scanning, for quantitative assessment of BBB perme...
Objective:
To test the hypothesis that degree of frailty and neuropathologic burden independently contribute to global cognition and odds of dementia.
Methods:
This was a secondary analysis of a prospective cohort study of older adults living in Illinois, USA. Participants underwent an annual neuropsychological and clinical evaluation. We includ...
Background:
Longitudinal studies assessing depression and anxiety effects on cognition in multiple sclerosis (MS) are limited.
Objective:
We tested whether within-person fluctuations in symptoms of depression or anxiety over time affect cognition in persons with MS, inflammatory bowel disease (IBD), rheumatoid arthritis (RA), and a lifetime hist...
Introduction:
Despite the urgent need for remote neurobehavioral assessment of individuals with cognitive impairment, guidance is lacking. Our goal is to provide a multi-dimensional framework for remotely assessing cognitive, functional, behavioral, and physical aspects of people with cognitive impairment, along with ethical and technical consider...
Hospitals and intensive care units are straining to provide care for a large surge of patients with coronavirus disease 19 (Covid-19). Contingency plans are being made for the possibility that resources for lifesaving care, including mechanical ventilators, will be in short supply. Covid-19 is more severe and more likely to be fatal in older person...
Objectives
Psychiatric comorbidity is frequent in rheumatoid arthritis (RA) and complicates treatment. We describe the impact of psychiatric comorbidity on health care use (utilization) in RA.
Methods
We accessed administrative health data (1984‐2016) and identified a prevalent cohort with diagnosed RA. RA cases (N=12984) were matched on age, sex...
Background
There is increasing evidence of prodromal multiple sclerosis (MS).
Objective
The aim of this study was to determine whether fatigue, sleep disorders, anaemia or pain form part of the MS prodrome.
Methods
This population-based matched cohort study used linked administrative and clinical databases in British Columbia, Canada. The odds of...
Background:
Spatially normalizing brain MRI data to a template is commonly performed to facilitate comparisons between individuals or groups. However, the presence of multiple sclerosis (MS) lesions and other MS-related brain pathologies may compromise the performance of automated spatial normalization procedures. We therefore aimed to systematica...
Background:
There is growing evidence of a prodromal period in multiple sclerosis (MS). A better understanding of the prodrome may facilitate prompt recognition and treatment of MS as well as narrowing of the etiologically relevant -period when searching for MS risk factors.
Objectives:
To explore and further delineate the MS prodrome, we used s...
Aims
Although immune-mediated inflammatory diseases (IMID) are associated with multiple mental health conditions, there is a paucity of literature assessing personality disorders (PDs) in these populations. We aimed to estimate and compare the incidence of any PD in IMID and matched cohorts over time, and identify sociodemographic characteristics a...
We conducted a systematic review and a fixed-effects meta-analysis to determine whether incident adverse psychiatric events (APE) including depression, anxiety, psychosis, or suicide were associated with biologic therapy in IBD. Six randomized controlled trials and a cohort study met criteria, reporting an incidence of APE in 4,882 patients. The ri...
Objective:
Immune-mediated inflammatory diseases (IMID) such as multiple sclerosis (MS), inflammatory bowel disease (IBD) and rheumatoid arthritis (RA) are associated with a high prevalence of psychiatric comorbidity but little is known about the prevalence of social phobia in IMID, or the factors associated with social phobia. We aimed to determi...
Background:
To establish whether a unique multiple sclerosis (MS) prodrome exists by comparing health care utilization in the five-year period before initial presentation with optic neuritis (ON) or transverse myelitis (TM) among those who were and were not subsequently diagnosed with MS.
Methods:
Using population-based administrative health dat...
Importance
Cognitive impairment in multiple sclerosis (MS) can lead to reduced quality of life, social functioning, and employment. Few studies have investigated cognitive outcomes among patients with pediatric-onset MS (POMS) over the long term.
Objective
To compare long-term information-processing efficiency between patients with POMS and adult-...
Background: Primary Progressive Aphasia (PPA) involves an isolated impairment of language function at disease onset. The cholinergic system is implicated in language and cholinergic deficits are seen in brains of individuals with PPA. One major source of cholinergic innervation is the nucleus basalis of Meynert (NBM) within which lies the nucleus s...
Objective
To test the validity and reliability of screening instruments for depression and anxiety in rheumatoid arthritis (RA).
Methods
Participants with RA completed the Patient Health Questionnaire (PHQ‐2, PHQ‐9), Patient Reported Outcomes Measurement Information System Depression Short Form‐8a (PROMIS Depression) and Anxiety Short Form‐8a (PRO...
RÉSUMÉ
Les facteurs de protection retrouvés chez des octogénaires atteints de sclérose en plaques (SP) vivant à domicile ont été comparés à ceux d’individus sans SP du même groupe d’âge et de personnes moins âgées atteintes de SP. Les données provenant des octogénaires atteints de SP ( n = 23) et d’un groupe de répondants plus jeunes avec cette mal...
In epidemiological studies of secondary data sources, lack of accurate disease classifications often requires investigators to rely on diagnostic codes generated by physicians or hospital systems to identify case and control groups, resulting in a less‐than‐perfect assessment of the disease under investigation. Moreover, because of differences in c...
Background
In healthy (non-psychotic) controls, caffeine intake is associated with better performance in attention, memory, and processing speed. These domains typically are those impaired in schizophrenia patients. Despite the fact that schizophrenia patients consume three times more caffeine than the general population, only one study has looked...
Functional MRI (fMRI) has emerged as a safe alternative to invasive procedures for determining hemispheric language dominance prior to neurosurgery. Despite this, there are currently no standardized fMRI protocols that have been explored in healthy controls to determine the influence of individual patient variables on the results, which poses chall...
Objective:
We assessed the information needs of persons with any of three immune-mediated inflammatory diseases (multiple sclerosis [MS], inflammatory bowel disease [IBD] and rheumatoid arthritis [RA]) regarding depression, as a first step toward developing patient-relevant information resources, ultimately to facilitate self-management and approp...
Background
Inflammatory bowel disease (IBD) is associated with a high prevalence of comorbid depressive and anxiety disorders. A significant proportion of IBD patients with comorbid psychiatric disorders remain undiagnosed and untreated, but factors associated with diagnosis are unknown. We evaluated the prevalence of undiagnosed depression and anx...
Background:
Primary Progressive Aphasia (PPA) is a syndrome characterized by an isolated impairment of language function at disease onset. The cholinergic system is implicated in language function and cholinergic deficits are seen in the brains of individuals with PPA. One major source of cholinergic innervation of the cerebral cortex is the nucle...
We examined the existence of a prodrome in relapsing‐onset multiple sclerosis (RMS) and primary progressive MS (PPMS) by comparing the number of physician encounters (via International Classification of Diseases diagnoses and physician speciality) in the five years before symptom onset in 1,887 RMS, 171 PPMS cases, and 9,837 matched population cont...
Objective: To determine whether anxiety and depression are associated with cognition in multiple sclerosis (MS), and whether these associations are similar in other immune-mediated inflammatory diseases (IMID; including inflammatory bowel disease [IBD] and rheumatoid arthritis [RA]) and in anxious/depressed individuals (ANX/DEP) without an IMID.
M...
Introduction: Alzheimer’s disease (AD) is a neurodegenerative disorder with a clinical presentation characterized by memory impairment and executive dysfunction. Our group previously demonstrated significant alterations in white matter microstructural metrics in AD compared to healthy older adults. We aimed to further investigate the relationship b...
Background
Magnetic resonance imaging (MRI) plays an important role in the diagnosis and monitoring of people with multiple sclerosis (MS). MRI rates in MS populations are poorly understood. Although Canada has universal health care, socioeconomic status (SES) is associated with MRI use. It is unknown if such disparities persist for specific condit...
Background:
Psychiatric comorbidity is prevalent in persons with multiple sclerosis (MS). Few studies have assessed whether second-generation disease-modifying therapies (DMT) are associated with adverse psychiatric effects.
Objective:
We aimed to systematically review the literature regarding the APEs associated with natalizumab, fingolimod, di...
Objective:
We aimed to validate administrative case definitions to identify individuals with optic neuritis (ON) or transverse myelitis (TM), and to distinguish which of these individuals had a monophasic presentation versus multiple sclerosis (MS).
Methods:
Using population-based administrative (health claims) data from Manitoba, Canada, we dev...
Background:
Previous studies suggest the existence of a prodromal period in multiple sclerosis, but little is known about the phenotypic characteristics. This study aims to characterize the multiple sclerosis (MS) prodrome using data mining analytics in the healthcare setting.
Methods:
We identified people with MS and matched general population...
Background
Psychiatric comorbidity in inflammatory bowel disease (IBD) is well known; however, data from a truly representative sample are sparse. We aimed to estimate the incidence and prevalence of psychiatric disorders in an IBD cohort compared with a matched cohort without IBD.
Methods
Using population-based administrative health data from Man...
Background:
The multiple sclerosis (MS) prodrome is poorly characterized.
Objective:
To phenotype the MS prodrome via health care encounters.
Methods:
Using data from a population-based cohort study linking administrative and clinical data in four Canadian provinces, we compared physician and hospital encounters and prescriptions filled (via I...
Background:
Within the multiple sclerosis (MS) population, depression and anxiety are highly prevalent comorbidities that are associated with adverse outcomes such as diminished quality of life and disability progression. In the general population, many people who do not meet formal diagnostic criteria for depression or anxiety disorders still ide...
Impairment in work function is a frequent outcome in patients with chronic conditions such as immune-mediated inflammatory diseases (IMID), depression and anxiety disorders. The personal and economic costs of work impairment in these disorders are immense. Symptoms of pain, fatigue, depression and anxiety are potentially remediable forms of distres...
Objective:
We determined the association between any common mental disorder (CMD: depression, anxiety disorder, bipolar disorder) and mortality and suicide in three immune-mediated inflammatory diseases (IMID), inflammatory bowel disease (IBD), multiple sclerosis (MS) and rheumatoid arthritis (RA), versus age-, sex- and geographically-matched cont...
Background:
Persons with multiple sclerosis (MS) use health resources with greater frequency than the general population. However, little is known regarding which patient characteristics might contribute.
Objective:
The study aimed to evaluate characteristics associated with healthcare use in MS patients.
Methods:
Consecutive MS clinic attende...
Background
We evaluated the validity and reliability of multiple symptom scales for depression and anxiety for persons with inflammatory bowel disease (IBD).
Methods
IBD participants in a cohort study completed a Structured Clinical Interview for DSM-IV-TR Axis I Disorders (SCID) and completed the Patient Health Questionnaire (PHQ-9), Hospital Anx...
Objective
Little is known about disease-modifying treatments (DMTs) for multiple sclerosis (MS) and infection risk in clinical practice. We examined the association between DMTs and infection-related medical encounters.
Methods
Using population-based administrative data from British Columbia, Canada, we identified MS cases and followed them from t...
Objective:
Emerging evidence suggests that comorbidity may influence disability outcomes in multiple sclerosis (MS); we investigated the association between psychiatric comorbidity and MS disability progression in a large multiclinic population.
Methods:
This retrospective cohort study accessed prospectively collected information from linked cli...
Background
Suicide is a leading cause of death worldwide. Transition from suicidal ideation (SI) to suicide attempt is high within a year of SI onset. The risk of suicide and SI is elevated in persons with inflammatory bowel disease (IBD) versus the general population. We aimed to validate the Patient Heath Questionnaire (PHQ)-9 as a screening tool...
Background:
Studies assessing the prevalence of depression and anxiety in multiple sclerosis (MS) have used various ascertainment methods that capture different constructs. The relationships between these methods are incompletely understood. Psychiatric comorbidity is associated with lower health-related quality of life (HRQOL) in MS, but the effe...
Background: Alzheimer’s disease (AD) is a neurodegenerative disorder that may benefit from early diagnosis and intervention. Therefore, there is a need to identify early biomarkers of AD using non-invasive techniques such as functional magnetic resonance imaging (fMRI). Recently, novel approaches to the analysis of resting-state fMRI data have been...