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Neurological Sciences : Official... Jan 2022Prevalence of multiple sclerosis (MS) is increasing world-wide. Iran is not exception. As the prevalence reported differently in various provinces, we designed this... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Prevalence of multiple sclerosis (MS) is increasing world-wide. Iran is not exception. As the prevalence reported differently in various provinces, we designed this systematic review and meta-analysis to estimate pooled prevalence of MS in Iran.
METHODS
Two researchers systematically searched Scientific Information Database (SID), PubMed, Scopus, EMBASE, Web of Science, and google scholar. They also searched references of the included studies, and conference abstracts which were published up to April 2021. The search strategy included the MeSH and text words as ((((Multiple Sclerosis OR Sclerosis, Multiple) OR Sclerosis, Disseminated) OR Dis-seminated Sclerosis) OR MS (Multiple Sclerosis)) OR Multiple Sclerosis, Acute Fulminating)) AND (prevalence OR prevalences OR period prevalence OR prevalence, period OR point prevalence OR point prevalences OR prevalence, point) AND (Iran OR Islamic Republic of Iran)))).
RESULTS
The literature search revealed 2817 articles, after deleting duplicates 2184 remained. For the systematic review, 34 studies were included. The prevalence is highest in Tehran and lowest in Khuzestan and Sistan-Baluchestan provinces. The pooled prevalence was 0.001 (95% CI: 0.000-0.001) (I=0, P<0.001).
CONCLUSION
The results of this study show that the pooled prevalence of MS in Iran is 100 in 100,000 which is high. The prevalence in provinces increases dramatically.
Topics: Databases, Factual; Humans; Iran; Multiple Sclerosis; Prevalence
PubMed: 34787755
DOI: 10.1007/s10072-021-05750-w -
European Journal of Neurology Dec 2021According to the hygiene hypothesis, infections by agents such as parasites have a protective role against the risk of developing multiple sclerosis (MS). Among... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND AND PURPOSE
According to the hygiene hypothesis, infections by agents such as parasites have a protective role against the risk of developing multiple sclerosis (MS). Among parasites, Toxoplasma gondii, an intracellular parasite, showed evidence of a protective effect. This study was undertaken to summarize the available evidence on the association between T. gondii infection and MS.
METHODS
A systematic review of all the available articles published up to November 2020 has been conducted independently by two investigators in the following databases: PubMed, Scopus, Lissa, and SciELO. The association between T. gondii infection and MS has been pooled with a random effects model.
RESULTS
From 562 articles, seven were included in the systematic review and meta-analysis for a global population of 752 MS cases and 1282 controls. T. gondii infection was associated with MS with a pooled odds ratio of 0.68 (95% confidence interval = 0.50-0.93).
CONCLUSIONS
The available evidence supports the hypothesis that T. gondii infection represents a protective factor against the development of MS.
Topics: Antibodies, Protozoan; Humans; Multiple Sclerosis; Risk Factors; Seroepidemiologic Studies; Toxoplasma; Toxoplasmosis
PubMed: 34374174
DOI: 10.1111/ene.15055 -
Multiple Sclerosis and Related Disorders Dec 2023Persons with multiple sclerosis (MS) engage in less physical activity than the general population, and the disease manifestations and comorbidity conditions might... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Persons with multiple sclerosis (MS) engage in less physical activity than the general population, and the disease manifestations and comorbidity conditions might further predispose them toward sedentary behavior (SB) among this population. We performed a systematic review with meta-analysis of studies that compared SB in persons with MS and non-MS controls, and examined factors that may moderate the difference in SB between the two groups.
METHODS
We conducted a systematic search using PubMed, PsycINFO, Scopus, and CINAHL from inception up to August 2022, and identified studies that involved group comparison of SB outcomes between MS and non-MS controls. Effect sizes were calculated as standardized mean differences (SMDs) using Hedge's g. We generated a multilevel random-effects model for estimating an overall effect, and performed moderator analyses. Methodological quality was assessed using the Appraisal Tool for Cross-Sectional Studies (AXIS tool).
RESULTS
Eleven studies were included (1403 MS vs. 449 controls) and yielded 17 effects for meta-analysis. Results indicated an overall small, but significant effect (SMD [95% CI] = 0.27 [0.02, 0.53], p = 0.03) with significant heterogeneity (Q = 72.2, p < 0.01; I = 75.8%). There were larger effects when the MS sample had a higher proportion of females, or when SB was reported as percent sedentary time per day compared with other SB outcomes (p = 0.03 and 0.05, respectively). The included studies achieved fairly good quality (91.4%) using the AXIS tool.
CONCLUSIONS
The cumulative evidence supports that persons with MS engage in more SB than non-MS controls. Our findings may support the design of targeted behavioral change interventions for reducing SB and improving health and function in the MS population.
Topics: Female; Humans; Sedentary Behavior; Multiple Sclerosis; Cross-Sectional Studies; Exercise
PubMed: 37956522
DOI: 10.1016/j.msard.2023.105124 -
Environmental Research May 2021Air pollution is a major public health threat. The present study is the first systematic review (SR) to determine the association of exposure to air pollution and... (Review)
Review
Air pollution is a major public health threat. The present study is the first systematic review (SR) to determine the association of exposure to air pollution and Multiple Sclerosis (MS) Progression. A Literature search was carried out using relevant keywords within several international databases. A comprehensive literature search was carried out systematically and yielded 24 eligible studies concerning the relationship of exposure to air pollution including criteria air pollutants such as particulate matter, NOx and SOx, CO, traffic noise, etc. and MS disease. The results of the included studies reveal that there was a significant relationship between exposure to air pollution and MS development and progression. Although the effect of air pollution in the pathogenesis of MS is notfully known, according to the results of the included studies exposure to polluted air can stimulate several mechanisms that act as risk factors for developing MS and for having disease relapses or neurological disability. The major potential mechanism is Dysimmune inflammatory responses subsequent oxidative stress (OS), which leads to neuroinflammation and breakdown of the normal balance between immunity and self-tolerance. Air pollutants induce and sustain chemical reactions that produce reactive oxygen species (ROSs) and nitrogen reactive species (RNSs) which can initiate inflammatory cascades via the redox-sensitive mitogen-activated protein kinase (MAPK) and NF-κB that recruit and activate neutrophils, monocytes, and dendritic cells that stimulate the adaptive immune responses such as Th1 and Th17 inflammatory responses. The uncontrolled inflammatory responses following these events cause cell death and the release of self-antigens capable of stimulating the production of auto-aggressive T-cells via enhancing antigen presentation and facilitate entry of these cells to the central nervous system. Thus, oxidative stress is the culprit in the systemic inflammation and immune imbalance development and progression, powerful risk factors in MS.
Topics: Air Pollutants; Air Pollution; Central Nervous System; Environmental Exposure; Humans; Multiple Sclerosis; Particulate Matter
PubMed: 33129851
DOI: 10.1016/j.envres.2020.110386 -
Multiple Sclerosis and Related Disorders Nov 2022According to Leventhal's self-regulation model, ill people construct personal representations of their disease, namely illness perceptions, which impact their coping... (Review)
Review
According to Leventhal's self-regulation model, ill people construct personal representations of their disease, namely illness perceptions, which impact their coping strategies and the emotional response to their condition. Since these representations develop in the social environment, the individuals' perceptions may also be related to the opinions of their caregivers. This systematic review aims at synthesising and critically appraising literature pertaining the relationship between illness perceptions and outcome in persons with multiple sclerosis and their caregivers. A literature search was conducted in MEDLINE, PsycINFO, and CINAHL. Only papers with the following characteristics were included: quantitative studies; written in English or Italian; published from 1992; investigating the relationship between illness perceptions and any outcome in persons with multiple sclerosis and/or their caregivers; using validated scales assessing illness perceptions. Twenty papers were included and appraised through the 16-item Quality Assessment Tool for Studies with Diverse Designs. The quality of the papers was acceptable. Eighteen out of 20 papers reported the existence of a moderate effect size when analysing the relationship between illness perceptions and outcome, whereby "positive" perceptions (e.g. stronger beliefs of control) related to better outcomes, while "negative" ones (e.g. attribution of negative consequences to the disease) related to worse outcome.
Topics: Humans; Multiple Sclerosis; Adaptation, Psychological; Caregivers; Emotions
PubMed: 36130458
DOI: 10.1016/j.msard.2022.104180 -
Multiple Sclerosis and Related Disorders Sep 2020Multiple sclerosis (MS) is a debilitating immune disease leading to demyelination, neurodegeneration, and chronic inflammation of the central nervous system. Pediatric... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Multiple sclerosis (MS) is a debilitating immune disease leading to demyelination, neurodegeneration, and chronic inflammation of the central nervous system. Pediatric MS is a rare form of the disease and effects approximately 2-10% of individuals with MS. Diagnostic criteria and therapies are continuously evolving, thus it is imperative to further understand the epidemiology and subsequently global and regional disease burden of pediatric MS. Our objective was to conduct a systematic literature review and meta-analysis to assess the incidence and prevalence of pediatric MS globally. Subgroup analyses were also conducted by region and diagnostic criteria used to ascertain cases.
METHODS
A systematic literature review was conducted using searches run in EMBASE and MEDLINE. A hand search was also conducted, and the bibliographies of any relevant articles were reviewed for any studies potentially not captured by the databases. A random effects model was used to combine epidemiological estimates across studies. Subgroup analyses by region and diagnostic criteria were performed in instances when three or more studies were available for analyses.
RESULTS
A total of 2,965 publications were identified, of which 187 were eligible for full-text screening. A total of 21 full-text articles met the eligibility criteria and were included for data extraction, with 18 studies included for meta-analysis. Regional epidemiologic estimates were obtained for North America, Europe, Middle East, and Asia. Country specific data was available for Canada, United States, Germany, Iceland, Netherlands, Sardinia, Slovenia, UAE/Abu Dhabi, Iran, Israel, Jordan, Kuwait, Tunisia, Taiwan, and Japan. Thirteen studies representing 12 countries reported incidence of pediatric MS. Overall incidence ranged from 0.05 to 2.85 and pooled global incidence was calculated to be 0.87 (95% CI: 0.35-1.40) per 100,000 individuals annually. Ten studies representing 10 countries reported on the prevalence of pediatric MS. Overall prevalence ranged from 0.69 to 26.92 per 100,000 individuals and pooled global prevalence was calculated to be 8.11 (95% CI: 2.28-13.93) per 100,000 people.
CONCLUSION
To our knowledge, this is the first meta-analysis conducted to provide pooled estimates of incidence and prevalence estimates of pediatric MS globally. In general, incidence estimates were similar across regions; however, prevalence was found to be more variable. Noticeable gaps in evidence include a lack of pediatric MS estimates from other large regions of the world such as Africa, South America, Russia, and Australia. Moreover, there is a need for more population-based studies using the most up to date diagnostic criteria.
Topics: Australia; Canada; Child; Europe; Germany; Humans; Iran; Italy; Japan; Kuwait; Middle East; Multiple Sclerosis; North America; Prevalence; Slovenia; Tunisia; United Arab Emirates
PubMed: 32540746
DOI: 10.1016/j.msard.2020.102260 -
Frontiers in Public Health 2023We decided to conduct the first systematic review with meta-analysis to provide the highest level of up-to-date evidence on the occupational risk factors for Multiple... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
We decided to conduct the first systematic review with meta-analysis to provide the highest level of up-to-date evidence on the occupational risk factors for Multiple Sclerosis.
METHODS
A systematic, comprehensive literature search was performed in four electronic academic databases. We included any case-control study that enrolled working-age subjects and compared the proportion of MS cases with controls who were not exposed to an occupational risk factor. The primary outcome was the occurrence of MS. The quality assessment was performed with the Critical Appraisal Checklist for Case Control Studies, developed, and validated by the Joanna Briggs Institute. All the selection process was also carried out by two independent and previously trained researchers.
RESULTS
Overall, the total sample included 19,004 people with MS and 4,164,162 controls. Agricultural workers (OR = 1.44, 95% CI 1.13-1.83), offshore workers (OR = 3.56, 95% CI 2.74-4.61), and hairdressers (OR = 8.25, 95% CI 1.02-66.52) were associated with a higher probability of being diagnosed with MS. In parallel, workers exposed to toxic fumes from oil wells (OR = 16.80, 95% CI 8.33-33.90), low-frequency magnetic fields (OR = 1.71, 95% CI 1.03-2.72), and pesticides (OR = 3.17, 95% CI = 2.53-3.99) also had an increased likelihood of having MS.
CONCLUSION
Our study has the potential to influence more assertive public policies. Nevertheless, future studies on how the occupational setting may contribute to the incidence of MS are highly recommended.
SYSTEMATIC REVIEW REGISTRATION
The protocol was registered in the international prospective register of systematic reviews (PROSPERO- CRD42023443257).
Topics: Humans; Occupational Diseases; Multiple Sclerosis; Case-Control Studies; Occupational Exposure; World Health Organization; Cost of Illness; Risk Factors
PubMed: 38054069
DOI: 10.3389/fpubh.2023.1285103 -
Multiple Sclerosis and Related Disorders Aug 2021Many studies have been conducted investigating a range of environmental factors which have been implicated in the pathogenesis of multiple sclerosis (MS). We collated... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Many studies have been conducted investigating a range of environmental factors which have been implicated in the pathogenesis of multiple sclerosis (MS). We collated available data about exposure to domestic animals before symptom onset in MS to perform a systematic review and meta-analysis.
METHODS
Medline, Embase and Cinahl were searched for relevant articles, based on pre-defined inclusion and exclusion criteria and reference lists were hand-searched. Data were extracted and critical analysis was conducted using the Newcastle-Ottawa criteria. Meta-analysis used random effects.
RESULTS
Study heterogeneity was high and study quality was variable. Random effects meta-analysis showed no associations with any pet ownership and development of MS.
CONCLUSION
It is not possible to draw definitive conclusions from this work. The studies included had a high level of heterogeneity. There are many variables involved in pet ownership and exposure and the nature of the way these have been studied makes the analysis challenging.
Topics: Animals; Child; Humans; Multiple Sclerosis; Ownership
PubMed: 34090130
DOI: 10.1016/j.msard.2021.103046 -
Multiple Sclerosis and Related Disorders Sep 2021Multiple sclerosis (MS) is an inflammatory demyelinating CNS disease and the most common neurological immune-mediated disorder. Due to its progressive format, it affects... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Multiple sclerosis (MS) is an inflammatory demyelinating CNS disease and the most common neurological immune-mediated disorder. Due to its progressive format, it affects patients' quality of life (QoL) significantly. This study aimed to evaluate epidemiologic parameters of MS in the Asia and Oceania continents.
METHODS
A comprehensive literature search on October 1st, 2020, was performed in PubMed, Scopus, and Web of Science to retrieve original population-based studies on MS epidemiology in the Asian and Oceanian countries, published between January 1st, 1985 and October 1st, 2020. The designed search strategy was repeated for each country, and the relevant referenced articles were added to our database. A random-effect model was used to combine the epidemiological estimates, and subgroup analysis was also performed by continent, region, and country, when possible. Meta-regression analysis was done to evaluate the effects of Human Developmental Index (HDI), latitude, and study period on the epidemiologic parameters.
RESULTS
A total of 3,109 publications were found, of which 89 articles met the eligibility criteria and were included for data extraction. These articles provided data on prevalence, incidence, and mean age at disease onset in 18 countries in Asia and Oceania, including Iran, Turkey, Cyprus, Kuwait, Saudi Arabia, Qatar, UAE, Jordan, Israel, India, Malaysia, China, Hong Kong, Taiwan, Republic of Korea, Japan, Australia, and New Zealand. The pooled total prevalence, incidence, and mean age of onset in Asia and Oceania were 37.89/100000 (95% CI: 35.65 - 40.142), 2.40/100000 (95% CI: 2.22 - 2.58), and 28.21 (95% CI: 27.55 - 28.88), respectively. MS prevalence and incidence in the female gender (68.7/100000 and 4.42/100000, respectively) were infinitely higher than in the male gender (24.52/100000 and 2.06/100000, respectively). Our subgroup analysis showed that MS was much more prevalent in Australia and West Asia among the studied area. The meta-regression showed that the total incidence decreased with an increase in the HDI, and the total prevalence in Asia increased with increasing latitude gradients. Also, the study period had a positive effect on the total prevalence and incidence in Asia and Oceania.
CONCLUSION
MS prevalence and incidence have increased in recent decades. This study highlights the need for further studies to elucidate MS's geographical and temporal variations' exact etiologies.
Topics: Asia; Female; Humans; Incidence; Male; Multiple Sclerosis; Oceania; Quality of Life
PubMed: 34247103
DOI: 10.1016/j.msard.2021.103119 -
Neurorehabilitation and Neural Repair Sep 2019. Cognitive impairments are common in people with multiple sclerosis (MS). Systematic reviews reported promising evidence for various cognitive interventions in this... (Review)
Review Meta-Analysis
. Cognitive impairments are common in people with multiple sclerosis (MS). Systematic reviews reported promising evidence for various cognitive interventions in this population. Computerized cognitive training (CCT) has strong evidence for safety and efficacy in several populations, but its effects in MS have yet to be specified. . We aimed to synthesize the evidence from randomized controlled trials (RCTs) investigating the effects of CCT on cognitive, psychosocial, and functional outcomes in adults with MS. . We searched MEDLINE, EMBASE, PsycINFO, CINAHL, and CENTRAL from inception to March 2019. We calculated standardized mean difference (Hedges' ) of change from baseline in untrained measures of cognition, individual domains, psychosocial functioning, and daily function between CCT and control groups using a random-effects model. . A total of 20 RCTs encompassing 982 participants (78% with relapsing-remitting MS) were included. The overall cognitive effect size was moderate ( = 0.30; 95% CI = 0.18-0.43), with no evidence of small-study effect or between-study heterogeneity (prediction interval = 0.17-0.44). Small to moderate effect sizes were found for attention/processing speed, executive functions, and verbal and visuospatial memory. Evidence for working memory, fatigue, and psychosocial and daily functioning were inconclusive. Cognitive effects waned without further training. . CCT is efficacious for overall and key cognitive domains in adults with MS, but efficacy on other outcomes and in progressive subtypes remains unclear. Long-term and well-powered trials with diverse cohorts are needed to optimize and maintain the efficacy of CCT, investigate transfer to daily living, and determine who can benefit and whether CCT is a cost-effective strategy to attenuate cognitive decline in MS.
Topics: Cognition Disorders; Humans; Learning; Multiple Sclerosis
PubMed: 31328637
DOI: 10.1177/1545968319860490