Melbourne School of Psychological Sciences - Research Publications
Permanent URI for this collection
Search Results
1 - 5 of 5
-
ItemNo Preview AvailableThe risk of secondary progressive multiple sclerosis is geographically determined but modifiable(OXFORD UNIV PRESS, 2023-11-02)Geographical variations in the incidence and prevalence of multiple sclerosis have been reported globally. Latitude as a surrogate for exposure to ultraviolet radiation but also other lifestyle and environmental factors are regarded as drivers of this variation. No previous studies evaluated geographical variation in the risk of secondary progressive multiple sclerosis, an advanced form of multiple sclerosis that is characterized by steady accrual of irreversible disability. We evaluated differences in the risk of secondary progressive multiple sclerosis in relation to latitude and country of residence, modified by high-to-moderate efficacy immunotherapy in a geographically diverse cohort of patients with relapsing-remitting multiple sclerosis. The study included relapsing-remitting multiple sclerosis patients from the global MSBase registry with at least one recorded assessment of disability. Secondary progressive multiple sclerosis was identified as per clinician diagnosis. Sensitivity analyses used the operationalized definition of secondary progressive multiple sclerosis and the Swedish decision tree algorithm. A proportional hazards model was used to estimate the cumulative risk of secondary progressive multiple sclerosis by country of residence (latitude), adjusted for sex, age at disease onset, time from onset to relapsing-remitting phase, disability (Multiple Sclerosis Severity Score) and relapse activity at study inclusion, national multiple sclerosis prevalence, government health expenditure, and proportion of time treated with high-to-moderate efficacy disease-modifying therapy. Geographical variation in time from relapsing-remitting phase to secondary progressive phase of multiple sclerosis was modelled through a proportional hazards model with spatially correlated frailties. We included 51 126 patients (72% female) from 27 countries. The median survival time from relapsing-remitting phase to secondary progressive multiple sclerosis among all patients was 39 (95% confidence interval: 37 to 43) years. Higher latitude [median hazard ratio = 1.21, 95% credible interval (1.16, 1.26)], higher national multiple sclerosis prevalence [1.07 (1.03, 1.11)], male sex [1.30 (1.22, 1.39)], older age at onset [1.35 (1.30, 1.39)], higher disability [2.40 (2.34, 2.47)] and frequent relapses [1.18 (1.15, 1.21)] at inclusion were associated with increased hazard of secondary progressive multiple sclerosis. Higher proportion of time on high-to-moderate efficacy therapy substantially reduced the hazard of secondary progressive multiple sclerosis [0.76 (0.73, 0.79)] and reduced the effect of latitude [interaction: 0.95 (0.92, 0.99)]. At the country-level, patients in Oman, Tunisia, Iran and Canada had higher risks of secondary progressive multiple sclerosis relative to the other studied regions. Higher latitude of residence is associated with a higher probability of developing secondary progressive multiple sclerosis. High-to-moderate efficacy immunotherapy can mitigate some of this geographically co-determined risk.
-
ItemVariability of the response to immunotherapy among subgroups of patients with multiple sclerosis(WILEY, 2023-04)BACKGROUND AND PURPOSE: This study assessed the effect of patient characteristics on the response to disease-modifying therapy (DMT) in multiple sclerosis (MS). METHODS: We extracted data from 61,810 patients from 135 centers across 35 countries from the MSBase registry. The selection criteria were: clinically isolated syndrome or definite MS, follow-up ≥ 1 year, and Expanded Disability Status Scale (EDSS) score ≥ 3, with ≥1 score recorded per year. Marginal structural models with interaction terms were used to compare the hazards of 12-month confirmed worsening and improvement of disability, and the incidence of relapses between treated and untreated patients stratified by their characteristics. RESULTS: Among 24,344 patients with relapsing MS, those on DMTs experienced 48% reduction in relapse incidence (hazard ratio [HR] = 0.52, 95% confidence interval [CI] = 0.45-0.60), 46% lower risk of disability worsening (HR = 0.54, 95% CI = 0.41-0.71), and 32% greater chance of disability improvement (HR = 1.32, 95% CI = 1.09-1.59). The effect of DMTs on EDSS worsening and improvement and the risk of relapses was attenuated with more severe disability. The magnitude of the effect of DMT on suppressing relapses declined with higher prior relapse rate and prior cerebral magnetic resonance imaging activity. We did not find any evidence for the effect of age on the effectiveness of DMT. After inclusion of 1985 participants with progressive MS, the effect of DMT on disability mostly depended on MS phenotype, whereas its effect on relapses was driven mainly by prior relapse activity. CONCLUSIONS: DMT is generally most effective among patients with lower disability and in relapsing MS phenotypes. There is no evidence of attenuation of the effect of DMT with age.
-
ItemNo Preview AvailableIllness perceptions and coping in the relationship between personality, depression, anxiety and illness acceptance in multiple sclerosis(Sage Publications, 2021-10-01)Background: Clinical levels of depression and anxiety are highly prevalent among individuals with multiple sclerosis (MS) and have deleterious biopsychological outcomes. Despite this, the mechanisms that contribute to the development and maintenance of depression, anxiety and positive adjustment outcomes are largely unknown. Objectives: Assess the utility of Leventhal’s Common-Sense Model in predicting psychological adjustment outcomes depression, anxiety and illness acceptance in individuals with MS. This study focuses on the relations between personality traits neuroticism and optimism, illness perceptions, coping strategies and adjustment outcomes utilising a cross-sectional design. Methods: Individuals with MS (n= 428) completed online questionnaires and were mostly female (86.7%), located in Australia (45%) or the United States (32%) and reported a relapsing remitting course of MS (83.4%). Measures included the NEO-Five Factor Inventory-3; Life Orientation Test Revised; Depression Anxiety and Stress Scale; Acceptance of Chronic Health Conditions Scale; Revised Illness Perceptions Questionnaire; and the BRIEF COPE. Mediation analyses were analysed through PROCESS macro for SPSS. Results: Perceptions of illness coherence, control, timeline, identity, emotional representations and avoidant coping and approach coping were significant simple and parallel mediators in the relationships between personality traits and depression, anxiety and illness acceptance. The serial effects of negative emotional representations on high avoidant coping partially mediated the relationships between neuroticism and depression[β=.05, BCa 95% CI (.02, .11)] and anxiety [β=.04, BCa 95% CI (.02, .09)], whereas the serial effects of less negative emotional representations on lower avoidant coping mediated the relationship between high optimism and low depressive levels [β=.-.06, BCa 95% CI (-.13, -.04)]. Conclusion: Illness perceptions and coping styles, particularly emotional representations and avoidant coping, are significant mechanisms involved in depression, anxiety and illness acceptance and may represent effectual targets for psychological intervention in individuals with MS.
-
ItemTobacco product use and smoking frequency among US adults with intellectual and developmental disabilities(WILEY, 2018-08)BACKGROUND: People with intellectual and developmental disabilities (IDD) have been overlooked in tobacco use research although they are likely to experience tobacco-related health disparities. This study examined tobacco product use and smoking frequency and amount among a sample of US Special Olympics athletes with IDD. METHODS: Multiple regression analysis was used to test whether age, gender, body mass index, blood pressure, bone density, eating fruits and vegetables and family member tobacco use were correlated with the number of cigarettes smoked per day. RESULTS: The sample of people with IDD who used tobacco (n = 501) were aged 18-75 (M = 33.37) and 76.4% were male. About 73.6% reported cigarette use only, 10.6% reported dual or poly use of cigarettes and other tobacco products (cigars, pipe, and chewing tobacco) and 15.8% reported using only tobacco products other than cigarettes. Men were more likely than women to use tobacco products other than cigarettes. Of the cigarette smokers, 79.6% were daily smokers, and their mean cigarettes per day was 10.08 (SD = 9.50). Special Olympics athletes who did not have low bone density and those who consumed fruits and vegetables less than daily reported higher numbers of cigarettes per day. CONCLUSIONS: Although people with IDD are less likely to use tobacco than the general population, study results suggest that people with IDD who smoke cigarettes are just as likely as smokers in the general US population to smoke daily. Improving overall health behaviours may be important in helping smokers with IDD to reduce their tobacco use. Research is needed to understand longitudinal patterns of tobacco use and how to prevent tobacco use among people with IDD.
-
ItemGenioglossus reflex responses to negative upper airway pressure are altered in people with tetraplegia and obstructive sleep apnoea(WILEY, 2018-07-15)KEY POINTS: Protective reflexes in the throat area (upper airway) are crucial for breathing. Impairment of these reflexes can cause breathing problems during sleep such as obstructive sleep apnoea (OSA). OSA is very common in people with spinal cord injury for unknown reasons. This study shows major changes in protective reflexes that serve to keep the upper airway open in response to suction pressures in people with tetraplegia and OSA. These results help us understand why OSA is so common in people with tetraplegia and provide new insight into how protective upper airway reflexes work more broadly. ABSTRACT: More than 60% of people with tetraplegia have obstructive sleep apnoea (OSA). However, the specific causes are unknown. Genioglossus, the largest upper-airway dilator muscle, is important in maintaining upper-airway patency. Impaired genioglossus muscle function following spinal cord injury may contribute to OSA. This study aimed to determine if genioglossus reflex responses to negative upper-airway pressure are altered in people with OSA and tetraplegia compared to non-neurologically impaired able-bodied individuals with OSA. Genioglossus reflex responses measured via intramuscular electrodes to ∼60 brief (250 ms) pulses of negative upper-airway pressure (∼-15 cmH2 O at the mask) were compared between 13 participants (2 females) with tetraplegia plus OSA and 9 able-bodied controls (2 females) matched for age and OSA severity. The initial short-latency excitatory reflex response was absent in 6/13 people with tetraplegia and 1/9 controls. Genioglossus reflex inhibition in the absence of excitation was observed in three people with tetraplegia and none of the controls. When the excitatory response was present, it was significantly delayed in the tetraplegia group compared to able-bodied controls: excitation onset latency (mean ± SD) was 32 ± 16 vs. 18 ± 9 ms, P = 0.045; peak excitation latency was 48 ± 17 vs. 33 ± 8 ms, P = 0.038. However, when present, amplitude of the excitation response was not different between groups, 195 ± 26 vs. 219 ± 98% at baseline, P = 0.55. There are major differences in genioglossus reflex morphology and timing in response to rapid changes in airway pressure in people with tetraplegia and OSA. Altered genioglossus function may contribute to the increased risk of OSA in people with tetraplegia. The precise mechanisms mediating these differences are unknown.