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Objective: The objective of this study was to investigate occupational and hobby exposures to silica, solvents, and heavy metals and the odds of having the idiopathic inflammatory myopathy (IIM) phenotypes dermatomyositis (DM) and polymyositis (PM) versus inclusion body myositis (IBM), lung disease plus fever or arthritis (LD+), and systemic autoimmune rheumatic disease-associated overlap myositis (OM)., Methods: The sample included 1,390 patients (598 with DM, 409 with PM, and 383 with IBM) aged ≥18 years from a national registry. Of these, 218 (16%) were identified with LD+, and 166 (12%) with OM. Of these, 218 (16%) were identified with LD+, and 166 (12%) with OM. We calculated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) and explored joint effects with smoking., Results: High silica exposure was associated with increased odds of having DM (OR 2.02, 95% CI 1.18-3.46, compared to no exposure; P trend = 0.004), LD+ (OR 1.75, 95% CI 1.10-2.78, vs no LD; P trend = 0.005), and OM (OR 2.07, 95% CI 1.19-3.61, P trend = 0.020). Moderate to high heavy metals exposure was associated with greater odds of having LD+ (OR 1.49, 95% CI 1.00-2.14, P trend = 0.026) and OM (OR 1.59, 95% CI 0.99-2.55, P trend = 0.051). Greater odds of having LD+ were seen among smokers with moderate to high silica exposure versus nonsmokers with low or no exposure (high-certainty assessment OR 2.53, 95% CI 1.31-4.90, P interaction = 0.061)., Conclusion: These findings, based on a systematic exposure assessment, suggest that occupational and hobby exposures to silica and heavy metals contribute to adult IIM phenotypes, including DM, OM, and LD+, a possible marker for antisynthetase syndrome or other autoantibody-associated lung diseases., (© 2024 The Myositis Association. DLH Holdings Corp and The Author(s). Arthritis Care & Research published by Wiley Periodicals LLC on behalf of American College of Rheumatology. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

Purpose of Review: To review recent advances in our understanding of the epidemiology, pathophysiology, and management of inclusion body myositis (IBM)., Recent Findings: Recent epidemiologic studies have highlighted the morbidity and mortality associated with IBM, including the impact of dysphagia. Multiomic analyses of IBM tissues have identified new pathogenic pathways and biomarkers for use in clinical trials. New diagnostic criteria and outcome measures have been proposed to improve clinical trial design. Ongoing clinical trials are targeting T cells and autophagy., Summary: Improvements in our understanding of IBM pathogenesis are identifying new pathways and biomarkers that need validation in larger cohorts. Exercise remains the primary therapeutic modality available, and new treatment targets are needed., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: Inclusion body myositis (IBM), an inflammatory myopathy with progressive weakness without efficient treatment, typically presents after 45 years of age and younger patients are sparsely studied., Methods: In a population-based study during a 33-year period, 142 patients with IBM were identified in western Sweden. Six patients fell outside the European Neuromuscular Centre 2011 criteria for IBM due to young age at symptom onset, verified by a muscle biopsy < 50 years of age. These were defined as early-onset IBM and included in this study. Medical records, muscle strength, comorbidities, muscle biopsies, and nuclear- and mitochondrial DNA were examined and compared with patients with IBM and age matched controls from the same population., Results: The median age at symptom onset was 36 (range 34-45) years and at diagnosis 43 (range 38-58) years. Four patients were deceased at a median age of 59 (range 50-75) years. The median survival from diagnosis was 14 (range 10-18) years. The prevalence December 31 2017 was 1.2 per million inhabitants and the mean incidence 0.12 patients per million inhabitants and year. The mean decline in quadriceps strength ± 1 standard deviation was 1.21 ± 0.2 Newton or 0.91 ± 0.2% per month and correlated to time from diagnosis (p < 0.001). Five patients had swallowing difficulties. All patients displayed mitochondrial changes in muscle including cytochrome c oxidase deficiency and the mitochondrial DNA mutation load was high., Conclusions: Early-onset IBM is a severe disease, causing progressive muscle weakness, high muscle mitochondrial DNA mutation load and a reduced cumulative survival in young and middle-aged individuals., (© 2023. The Author(s).)

Background: Inclusion body myositis (IBM) is the most frequent type of myositis in elder patients with a slow chronic progression and refractory to treatment. Previous cost of illness (COI) studies in IBM used claims data to estimate direct costs in the US. No evidence exists globally on both direct and indirect costs in IBM from a societal perspective. We conducted a survey in patients registered in the German IBM patient registry. Self-developed items were used to assess the utilized healthcare resources and estimate the cost. The German Self-Administered Comorbidity Questionnaire (SCQ-D), the sIBM Physical Functioning Assessment (sIFA) and patient-reported measures for satisfaction and improvements in healthcare were applied for an explorative analysis., Results: In total, 82 patients completed the survey. We estimated the mean total annual per capita COI of US$102,682 (95% CI US$82,763-US$123,090) in 2021. 92.7% of the total COI were direct costs. Medical costs were similar to nonmedical costs, with substantial costs for pharmacotherapy and informal care. Depending on the prevalence estimate, the total national COI per year were US$42.7 million-US$213.7 million. Significant differences in total COI were identified for the degree of disability, marital and employment status (p < 0.05)., Conclusions: We identified remarkable and heterogenous cost in IBM. As informal care costs represented the most relevant cost driver, caregiver burden is a major factor in the patient journey. For the first time, comprehensive economic potentials were identified as a basis to improve the actual care situations and prioritizing future activities for research, pharmaceutical and digital product development as well as health politics., (© 2023. Institut National de la Santé et de la Recherche Médicale (INSERM).)

Purpose of Review: To discuss recent developments in our understanding of epidemiology, diagnostics, biomarkers, pathology, pathogenesis, outcome measures, and therapeutics in inclusion body myositis (IBM)., Recent Findings: Recent epidemiology data confirms a relatively higher prevalence in the population aged above 50 years and the reduced life expectancy. Association with cancer and other systemic disorders is better defined. The role of magnetic resonance imaging (MRI) and ultrasound in diagnosis as well as in following disease progression has been elucidated. There are new blood and imaging biomarkers that show tremendous promise for diagnosis and as outcome measures in therapeutic trials. Improved understanding of the pathogenesis of the disease will lead to better therapeutic interventions, but also highlights the importance to have sensitive and responsive outcome measures that accurately quantitate change., Summary: There are exciting new developments in our understanding of IBM which should lead to improved management and therapeutic options., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: We performed a population-based study on inclusion body myositis with the primary aims to define the prevalence, survival rate, and incidence, and to investigate the symptom profiles associated with disease duration and sex over a 33-year period., Methods: Patients diagnosed between 1985 and 2017 in Region Västra Götaland, Sweden, were identified according to the European Neuromuscular Centre diagnostic criteria from 2011., Results: We identified 128 patients, 89 men and 39 women, with the strict clinicopathological definition of inclusion body myositis. The prevalence was 32 per million inhabitants, 19 per million women and 45 per million men, by December 31, 2017. Mean incidence was 2.5 per million inhabitants and year. Mean age at symptom onset was 64.4 years with quadriceps weakness being the most common presenting symptom followed by finger flexor weakness. Dysphagia was a common presenting symptom being more frequent in women (23%) than men (10%) and was during the disease course reported in 74% of men and 84% of women. Seventy-three patients were deceased, with a mean survival of 14 years from symptom onset. Survival rates from both diagnosis date and symptom onset were decreased compared to the matched population. Twenty-one percent of the patients had an additional autoimmune disease. A cross-sectional analysis of autoantibodies in 50 patients and 28 matched controls showed autoantibodies to cytosolic 5'-nucleotidase 1A in 40% of the patients and 3.6% of controls., Interpretation: Inclusion body myositis is an autoimmune disease with decreased survival rate and with marked sex differences in both prevalence and clinical manifestations. ANN NEUROL 2022;92:201-212., (© 2022 The Authors. Annals of Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Objective: To evaluate survival and associated comorbidities in inclusion body myositis (IBM) in a population-based, case-control study., Methods: We utilized the expanded Rochester Epidemiology Project medical records-linkage system, including 27 counties in Minnesota and Wisconsin, to identify patients with IBM, other inflammatory myopathies (IIM), and age/sex-matched population-controls. We compared the frequency of various comorbidities and survival among groups., Results: We identified 50 IBM patients, 65 IIM controls and 294 population controls. Dysphagia was most common in IBM (64%) patients. The frequency of neurodegenerative disorders (dementia/parkinsonism) and solid cancers was not different between groups. Rheumatoid arthritis was the most common rheumatic disease in all groups. A total of 36% of IBM patients had a peripheral neuropathy, 6% had Sjögren's syndrome and 10% had a haematologic malignancy. T-cell large granular lymphocytic leukaemia was only observed in the IBM group. None of the IBM patients had hepatitis B or C, or HIV. IBM patients were 2.7 times more likely to have peripheral neuropathy, 6.2 times more likely to have Sjögren's syndrome and 3.9 times more likely to have a haematologic malignancy than population controls. IBM was associated with increased mortality, with a 10-year survival of 36% from index, compared with 67% in IIM and 59% in population controls. Respiratory failure or pneumonia (44%) was the most common cause of death., Conclusions: IBM is associated with lower survival, and higher frequency of peripheral neuropathy, Sjögren's syndrome and haematologic malignancies than the general population. Close monitoring of IBM-related complications is warranted., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Rheumatology.)

Objectives: To determine the prevalence and natural history of sporadic inclusion body myositis (sIBM) and to test the hypothesis that patients with sIBM have higher cancer or mortality rates than the general population., Methods: We sought patients with sIBM defined by the 2011 European Neuromuscular Centre (ENMC) diagnostic criteria among Olmsted County, Minnesota, residents in 40-year time period., Results: We identified 20 patients (10 clinicopathologically defined, 9 clinically defined, and 1 probable) according to the ENMC criteria and 1 patient with all features of clinicopathologically defined sIBM except for symptom onset at <45 years of age. The prevalence of sIBM in 2010 was 18.20 per 100,000 people ≥50 years old. Ten patients developed cancers. The incidence of cancers in sIBM did not differ from that observed in the general population (odds ratio 1.89, 95% confidence interval [CI] 0.639-5.613, p = 0.24). Two-thirds of patients developed dysphagia, and half required a feeding tube. Nine patients required a wheelchair. The median time from symptom onset to wheelchair dependence was 10.5 (range 1-29) years. Overall life expectancy was shorter in the sIBM group compared to the general population (84.1 [95% CI 78-88.4] vs 87.5 [95% CI 85.2-89.5] years, p = 0.03). Thirteen patients died; 9 deaths were sIBM related (7 respiratory and 2 unspecified sIBM complications). Female sex ( p = 0.03) and dysphagia ( p = 0.05) were independent predictors of death., Conclusion: Olmsted County has the highest prevalence of sIBM reported to date. Patients with sIBM have similar risk of cancer, but slightly shorter life expectancy compared to matched patients without sIBM., Classification of Evidence: This study provides Class II evidence that patients with sIBM have similar risks of cancers and slightly shorter life expectancy compared to controls., (© 2021 American Academy of Neurology.)

Objective: Dermatomyositis (DM) has been associated with geospatial differences in ultraviolet (UV) radiation, but the role of individual determinants of UV exposure prior to diagnosis is unknown. The objective was to examine the role of those individual determinants., Methods: We analyzed questionnaire data from 1,350 adults in a US national myositis registry (638 with DM, 422 with polymyositis [PM], and 290 with inclusion body myositis [IBM] diagnosed at ages 18-65 years), examining the likelihood of DM compared with PM and IBM diagnosis, in relation to self-reported sunburn history and job- and hobby-related sun exposures in the year prior to diagnosis. We estimated odds ratios (ORs) and 95% confidence intervals (95% CIs) using logistic regression adjusted for age, skin tone, and sex, to determine the association of individual UV exposures with DM diagnosis. We also evaluated the proportion of DM by maximum daily ambient UV exposure, based on UVB erythemal irradiances for participant residence in the year prior to diagnosis., Results: DM was associated with sunburn in the year before diagnosis (2 or more sunburns OR 1.77 [95% CI 1.28-2.43] versus PM/IBM; 1 sunburn OR 1.44 [95% CI 1.06-1.95]) and with having elevated job- or hobby-related sun exposure (high exposure OR 1.64 [95% CI 1.08-2.49] or moderate exposure OR 1.35 [95% CI 1.02-1.78] versus low or no exposure). Ambient UV intensity was associated with DM in females (β = 3.97, P = 0.046), but not overall., Conclusion: Our findings suggest that high or moderate personal exposure to intense sunlight is associated with developing DM compared with other types of myositis. Prospective research on UV exposure as a modifiable risk factor for DM is warranted., (© 2019, American College of Rheumatology. This article has been contributed to by US Government employees and their work is in the public domain in the USA.)

Inclusion body myositis is a rare sporadic inflammatory-degenerative myopathy of the elderly. Despite being the commonest type of acquired myopathy after the age of 50, misdiagnosis is extremely common. The most frequent hurdle in identifying new cases is the wrong diagnosis of polymyositis or motor neuron disease. Novel insights into pathogenic mechanisms have heralded the quest for newer therapeutics as well as drug repurposing in this otherwise progressive disorder., (© 2020 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.)

Objective: This study identifies the health care costs and utilization, as well as comorbidities, in a Medicare population of inclusion body myositis (IBM) patients., Methods: Medicare patients aged ≥65 years with a diagnosis claim for IBM were identified and matched to a cohort of non-IBM patients based on age, sex, race, calendar year and census region. Generalized linear models were used to estimate health care costs and utilization during the follow-up period., Results: The prevalence of IBM in this population, aged ≥65 years, was 83.7 cases per 1 million patients. Mean 1 year costs for the IBM cohort (N = 361) were $44,838 compared to $10,182 for the matched non-IBM cohort (N = 1805), an excess of $34,656. IBM was significantly associated with multiple unsuspected comorbidities, including hypertension (66% vs. 22%), hyperlipidemia (47% vs. 18%) and myocardial infarction (13% vs. 2%) (all p < .0001)., Conclusions: IBM patients utilize more health care resources and incur higher health care costs than patients without IBM. Furthermore, IBM patients were more likely to have multiple comorbidities, including cardiovascular risk factors and events, muscle and joint pain, and pulmonary complications compared to those without IBM., Limitations: The presence of a diagnosis code for a condition on a medical claim does not necessarily indicate the presence of the disease condition because the diagnosis code could be incorrectly entered in the database. Clinical and disease-specific parameters were not available in the claims data. Additionally, due to the observational study design, the analysis may be affected by unobserved differences between patients.

Introduction: We analyzed the burden of illness of sporadic inclusion body myositis (sIBM) patients and the costs to the healthcare system., Methods: A retrospective cohort analysis of 333 sIBM patients aged ≥ 50 years was performed using United States (U.S.) claims data. sIBM patients were matched in a 1:5 ratio to randomly selected individuals with ≥1 healthcare encounter within the year of index date., Results: sIBM patients presented with higher rates of disease- and muscle-related conditions, such as myalgia, myositis, muscle weakness, dysphagia, pneumonia, and falls. Use of healthcare resources, including physical therapy, office visits, emergency room (ER) visits, and hospitalizations, was greater in sIBM patients. This was also reflected in significantly higher overall healthcare costs in the sIBM population driven mainly by more all-cause office visits, all-cause ER visits and hospitalizations., Conclusions: sIBM imposes a substantial burden on U.S. patients in terms of additional healthcare usage and associated costs. Muscle Nerve 56: 861-867, 2017., (© 2017 Wiley Periodicals, Inc.)

Objective: To analyze clinical characteristics, survival and causes of death of patients diagnosed with autoimmune inflammatory myositis in the REMICAM registry from the Society of Rheumatology in the Community of Madrid (SORCOM)., Methods: Multicenter cohort of patients diagnosed with autoimmune inflammatory myopathy with follow-up between January 1980 and December 2014. A total of 313 variables concerning demographic, clinical and morbidity data were collected, and a comparison was performed between clinical subgroups., Results: A total of 479 patients were recruited from 12 centers, with 14% of patients lost to follow-up. Seventy-four percent of cases were women, age at diagnosis of 44±23 years and a mean follow-up period of 10±8 years. The most frequent clinical subgroups were primary myositis (PM 29%, DM 22%), followed by overlap myositis (20.5%), juvenile myositis (18%), myositis associated with cancer (8%), immune-mediated necrotizing myositis (1%) and inclusion body myositis (1%). During the follow-up period, a total of 114 deaths (28%) were registered, the main causes being cancer (24%), infections (23%) and cardiovascular events (21%)., Conclusions: A total of 479 patients were recruited in the REMICAM registry of inflammatory myopathies. Including sociodemographic, clinical and prognostic information, it represents the largest Spanish multicenter registry to date in rheumatology, and constitutes an important source for conducting further substudies., (Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.)

Background: Sporadic Inclusion Body Myositis (sIBM) is a rare and slowly progressive debilitating muscle disease with symptoms generally developing≥50 years of age., Objective: To conduct a systematic review and meta-analysis of the prevalence of sIBM literature, including a methodological quality assessment of the selected papers., Methods: A systematic search of Medline, Embase, Cochrane Database of Systematic Reviews and major Myositis and Neurological conferences was conducted. Articles reporting prevalence and published in English up to March 2017 were assessed for methodology quality using the Loney quality assessment, Downs & Black score, and the Methodological Evaluation of Observational Research checklists. Meta-analyses using random effects were completed on both general population and≥50 years prevalence estimates., Results: 315 articles were retrieved and data were extracted from 10 relevant studies. One study was subsequently excluded due to methodological issues. The meta-prevalence estimate from 9 papers was 24.8/1,000,000 (95% CI: 20.0-29.6). The methodological quality results were consistent across assessment tools with four articles scoring 4 or 5 out of 8 in the Loney assessment. The meta-prevalence of these four articles was 45.6/ 1,000,000 (95% CI: 35.9-55.2)., Conclusion: There was high variability in reported sIBM prevalence estimates and the quality of the studies conducted. Existing evidence suggests an increase of prevalence estimates over time, which may be explained by growing disease awareness, improvements in diagnostic criteria and study methodologies. Further high quality studies are needed to understand if prevalence varies across geographies or ethnicities.

Background: Sporadic inclusion body myositis (sIBM) is the most prevalent acquired muscle disease in the elderly. sIBM is an intractable and progressive disease of unknown cause and without effective treatment. The etiology of sIBM is still unknown; however, genetic factors, aging, lifestyles, and environmental factors may be involved. The purpose of this study is to elucidate the cross-sectional profile of patients affected by sIBM in Japan., Methods: We surveyed patient data for 146 cases diagnosed at a number of centers across Japan. We also issued a questionnaire for 67 patients and direct caregivers to further elucidate the natural history of the disease., Results: The mean age at the onset was 63.4 ± 9.2 years. The mean length of time from the onset to diagnosis was 55.52 ± 49.72 months, suggesting that there is a difficulty in diagnosing this disease with long-term consequences because of late treatment. 73 % described the psychological/mental aspect of the disease. The most popular primary caregiver was the patient's spouse and 57 % patients mentioned that they were having problems managing the finances., Conclusions: Through these surveys, we described the cross-sectional profiles of sIBM in Japan. Many patients described psychological/mental and financial anxiety because of the aged profile of sIBM patients. The profiles of sIBM patients are similar to those in Western countries.

Purpose of Review: In this review, we describe recent progress in the clinical epidemiology of sporadic inclusion body myositis (IBM)., Recent Findings: In a population-based, retrospective study from Norway, performed with a denominator population of 2.6 million; and with cases defined by the 1997 and/or 2011 European Neuro-Muscular Centre Research Diagnostic criteria, the estimated point prevalence of IBM was 3.3/100 000. Mean time from symptom onset to diagnosis was 5.6 years, longer than in earlier studies. The male to female ratio was 3 : 2, and the mean age at diagnosis 67 years, very similar to figures reported this year from a nationwide, Dutch myopathy registry. Coexisting rheumatic diseases were recorded in 25% of Norwegian IBM cases, with Sjøgren's syndrome as the most commonly encountered. Mortality was increased in IBM, with a standardized mortality rate of 1.7, but there was no indication of increased cancer risk., Summary: Population-based data indicate that the prevalence of IBM in Europe is higher than expected from previous studies. Diagnostic delay appears to be a persisting problem in IBM; a major challenge with promising new therapies on the horizon.

Objective: To clarify whether there is any association between inclusion body myositis (IBM) and hepatitis C virus (HCV) infection., Methods: We assessed the prevalence of HCV infection in 114 patients with IBM whose muscle biopsies were analyzed pathologically for diagnostic purpose from 2002 to 2012 and in 44 age-matched patients with polymyositis diagnosed in the same period as a control by administering a questionnaire survey to the physicians in charge. We also compared clinicopathologic features including the duration from onset to development of representative symptoms of IBM and the extent of representative pathologic changes between patients with IBM with and without HCV infection., Results: A significantly higher number of patients with IBM (28%) had anti-HCV antibodies as compared with patients with polymyositis (4.5%; odds ratio 8.2, 95% confidence interval 1.9-36) and the general Japanese population in their 60s (3.4%). Furthermore, between patients with IBM with and without HCV infection, we did not find any significant difference in the clinicopathologic features, indicating that the 2 groups have essentially the same disease regardless of HCV infection., Conclusion: Our results provide the statistical evidence for an association between IBM and HCV infection, suggesting a possible pathomechanistic link between the 2 conditions., (© 2015 American Academy of Neurology.)

Introduction: Few studies of the demographics, natural history, and clinical management of inclusion body myositis (IBM) have been performed in a large patient population. To more accurately define these characteristics, we developed and distributed a questionnaire to patients with IBM., Methods: A cross-sectional, self-reporting survey was conducted., Results: The mean age of the 916 participants was 70.4 years, the male-to-female ratio was 2:1, and the majority reported difficulty with ambulation and activities of daily living. The earliest symptoms included impaired use and weakness of arms and legs. The mean time from first symptoms to diagnosis was 4.7 years. Half reported that IBM was their initial diagnosis. A composite functional index negatively associated with age and disease duration, and positively associated with participation in exercise., Conclusions: These data are valuable for informing patients how IBM manifestations are expected to impair daily living and indicate that self-reporting could be used to establish outcome measures in clinical trials., (© 2014 Wiley Periodicals, Inc.)

The objective of this study was to investigate if patients with endomysial mononuclear cell infiltrates invading non-necrotic fibers have a disease course consistent with inclusion body myositis (IBM), irrespective of other histopathological and clinical characteristics. All patients with a muscle biopsy showing endomysial inflammation with invasion of non-necrotic muscle fibers during the period 1979-2006 in two tertiary neuromuscular referral centers were classified into three groups: 1) patients whose biopsies also showed rimmed vacuoles; 2) patients whose biopsies showed no vacuoles but fulfilled clinical criteria for IBM, and 3) patients whose biopsies showed no vacuoles, and also did not fulfill clinical criteria for IBM (unclassified patients). These groups were compared with regard to age, gender, clinical features, and disease course including response to immunosuppressive treatment. Eighty-one individuals (41 men) were included. Rimmed vacuoles were found in 49 patients (60.5%). Fourteen patients (17.3%) fulfilled clinical criteria for IBM and 18 patients (22.2%) were unclassified at presentation. At follow up (mean duration 9 years) three women remained unclassified (4%). There were no differences in disease course or effect of treatment between the three groups. Men had more often rimmed vacuoles than women (73% vs 48%; p = 0.018), and women more often than men were unclassified. Women tended to show more often temporary improvement if treated (p = 0.07), but none had sustained improvement. In conclusion, patients with a muscle biopsy showing endomysial cell infiltration with invasion of non-necrotic muscle fibers most probably have IBM, regardless of clinical and other pathological features. Women lack typical features more often than men., (Copyright © 2015 Elsevier B.V. All rights reserved.)

A previous study showed that, in carriers of the apolipoprotein E (APOE) genotype ε3/ε3 or ε3/ε4, the presence of a very long (VL) polyT repeat allele in "translocase of outer mitochondrial membrane 40" (TOMM40) was less frequent in patients with sporadic inclusion body myositis (sIBM) compared with controls and associated with a later age of sIBM symptom onset, suggesting a protective effect of this haplotype. To further investigate the influence of these genetic factors in sIBM, we analyzed a large sIBM cohort of 158 cases as part of an International sIBM Genetics Study. No significant association was found between APOE or TOMM40 genotypes and the risk of developing sIBM. We found that the presence of at least 1 VL polyT repeat allele in TOMM40 was significantly associated with about 4 years later onset of sIBM symptoms. The age of onset was delayed by 5 years when the patients were also carriers of the APOE genotype ε3/ε3. In addition, males were likely to have a later age of onset than females. Therefore, the TOMM40 VL polyT repeat, although not influencing disease susceptibility, has a disease-modifying effect on sIBM, which can be enhanced by the APOE genotype ε3/ε3., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

Background and Purpose: Knowledge about the occurrence of sporadic inclusion body myositis (sIBM) in the general population is limited. Here, our aim was to identify and characterize every sIBM patient living in southeast Norway (population 2.64 million) from 2003 to 2012., Method: Two sIBM case finding strategies were applied. First, all hospital databases in southeast Norway were screened to identify cases with sIBM-compatible International Classification of Diseases 10 (ICD-10) codes. These cases were then manually chart reviewed. Secondly, all muscle histology reports encoded with inflammation were independently reviewed. Finally, cases were classified according to the 1997 and the 2011 European Neuro-Muscular Centre (ENMC) Research Diagnostic Criteria for sIBM., Results: The combined case finding strategy identified 3160 patients with sIBM compatible ICD-10 codes, and a largely overlapping cohort of 500 patients having muscle biopsies encoded with inflammation. Detailed retrospective review of chart and histology data showed that 95 patients met the 2011 ENMC sIBM criteria and 92 met the 1997 criteria. Estimated point prevalence of sIBM was 33/1 000 000, equal with both criteria sets. Mean age at diagnosis was 66.9 years and mean diagnostic delay was 5.6 years. Chart review revealed higher frequencies of dysphagia (94% vs. 65%) and anti-Sjøgren syndrome A antibodies (39% vs. 12%) in female sIBM patients (n = 40) than in males. Coexisting rheumatic diseases were present in 25% of sIBM cases, with Sjøgren's syndrome in 10%., Conclusion: An estimated point prevalence of sIBM seven times higher than previously observed in Europe is reported. Our data show considerable diagnostic delay, a major challenge with new sIBM treatments in the pipeline., (© 2014 EAN.)

The idiopathic inflammatory myopathies are systemic, chronic autoimmune diseases characterized by proximal symmetrical muscle weakness. One of the main diseases in this group is inclusion body myositis (IBM), an underdiagnosed, progressive muscle disease characteristically affecting the middle-aged and older population. It has a slow, relentlessly progressive course. The precise pathogenesis of the disease remains unknown. In most of the cases it is diagnosed a few years after the appearance of the first symptoms. The muscle biopsy typically shows endomysial inflammation, with invasion of mononuclear cells into the non-necrotic fibers, and also rimmed vacuoles. It appers, that both inflammation and degeneration are present at the onset of the disease. Our aim is to raise awareness about this disease which leads to severe disability, with clinicopathological case presentations and literature overview, emphasizing the importance of collaboration between the clinician and the neuropathologist. No effective therapy is currently available but the rapid diagnosis is essential to slow disease progression. Although this is a relatively rare disease, patients are presenting not only in immunology outpatient clinics; our reports aims to raise awareness and facilitate accurate early diagnosis of IBM.

This study is to investigate the clinical and pathologic features of sporadic inclusion body myositis (sIBM) in China. We retrospectively evaluated the clinical and pathological features of consecutive patients in our department between January 1986 to May 2012. Total 28 cases of sIBM (20 males, 8 females, mean age was 56.93±8.79) were obtained by review of all 4099 muscle biopsy reports. The proportion of sIBM was 0.68% (28/4099) in China. Muscle weakness of quadriceps appeared 100% in 28 cases, while conspicuous atrophy of quadriceps appeared only in five cases (17.86%). Creatase values of 28 patients with sIBM were normal or mildly elevated. Muscle biopsies showed that atrophic fibers resembled more frequent in small angular and irregular shape (82.14%), less common in small round shape (17.86%). Rimmed vacuoles resembled crack (67.86%) and round (32.14%) shape. Mononuclear cell invasion into necrotic muscle fibers (35.71%) was more frequent than non-necrotic muscle fibers (7.14%). sIBM was still a rare disease in China compared to other countries. There were some certain specific pathological characteristics existed in Chinese sIBM patients., (Copyright © 2015 Polish Neurological Society. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.)

Introduction: Idiopathic inflammatory myopathy (called also myositis) is a systemic autoimmune disease mainly characterised with proximal muscle weakness. The most frequent subsets are polymyositis and dermatomyositis. The epidemiology of these diseases is not entirely explored. There is a need to build national and international registries which may help to obtain more data. The Myositis Team at the Department of Clinical Immunology, University of Debrecen, has been established in 1975., Aim: The aim of the authors was to obtain epidemiological data on this disease., Method: The authors analysed the database of the National Health Insurance Fund Administration of Hungary which included 1119 patients with myositis, of which 289 patients were followed up by the authors., Results: The average incidence of the disease was found to be 0.95/100.000/year. The male/female ratio was 1/2. Dermatomyositis occurred both in children and adult, but polymyositis was found mainly in adults. These epidemiological data partly correlate with those published in the international literature., Conclusions: The authors propose to establish a National Myositis Registry in the frame of multicentric collaboration in order to have more information about the disease.

The idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of rare disorders that share many similarities. In addition to sporadic inclusion body myositis (IBM), these include dermatomyositis, polymyositis, and autoimmune necrotizing myopathy. IBM is the most common IIM after age 50 years. Muscle histopathology shows endomysial inflammatory exudates surrounding and invading nonnecrotic muscle fibers often accompanied by rimmed vacuoles and protein deposits. It is likely that IBM is has a prominent degenerative component. This article reviews the evolution of knowledge in IBM, with emphasis on recent developments in the field, and discusses ongoing clinical trials., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Objective: To use patient data to evaluate and construct diagnostic criteria for inclusion body myositis (IBM), a progressive disease of skeletal muscle., Methods: The literature was reviewed to identify all previously proposed IBM diagnostic criteria. These criteria were applied through medical records review to 200 patients diagnosed as having IBM and 171 patients diagnosed as having a muscle disease other than IBM by neuromuscular specialists at 2 institutions, and to a validating set of 66 additional patients with IBM from 2 other institutions. Machine learning techniques were used for unbiased construction of diagnostic criteria., Results: Twenty-four previously proposed IBM diagnostic categories were identified. Twelve categories all performed with high (≥97%) specificity but varied substantially in their sensitivities (11%-84%). The best performing category was European Neuromuscular Centre 2013 probable (sensitivity of 84%). Specialized pathologic features and newly introduced strength criteria (comparative knee extension/hip flexion strength) performed poorly. Unbiased data-directed analysis of 20 features in 371 patients resulted in construction of higher-performing data-derived diagnostic criteria (90% sensitivity and 96% specificity)., Conclusions: Published expert consensus-derived IBM diagnostic categories have uniformly high specificity but wide-ranging sensitivities. High-performing IBM diagnostic category criteria can be developed directly from principled unbiased analysis of patient data., Classification of Evidence: This study provides Class II evidence that published expert consensus-derived IBM diagnostic categories accurately distinguish IBM from other muscle disease with high specificity but wide-ranging sensitivities., (© 2014 American Academy of Neurology.)

Sporadic inclusion body myositis (sIBM) is an intractable and progressive skeletal muscle disease of unknown etiology and without effective treatment. While the etiology is still unknown, however, genetic factors, aging, life style, and environmental factors may be involved. Muscle biopsy typically reveals endomysial inflammation, invasion of mononuclear cells into non-necrotic fibers and rimmed vacuoles, suggesting inflammation and degeneration co-exist as part of the pathomechanism. Recent studies implicate amyloid beta accumulation, defects of proteolysis, and immune system abnormalities. The clinical course is slow with chronic worsening. Diagnosis of sIBM is usually made 5 years after onset. Muscle weakness and atrophy in the quadriceps, wrist flexor and finger flexors are the typical neurological findings of sIBM. Dysphagia and asymmetric weakness are often found. Serum creatine kinase is usually below 2,000 IU/L. sIBM is generally refractory to current therapy, such as steroids or immunosuppressants. Elucidation of the pathomechanism of sIBM is the most important to therapy.

Introduction: The hallmark clinical presentation of inclusion-body myositis (IBM) is slowly progressive weakness that characteristically affects the quadriceps and finger and wrist finger flexor muscles. Facial weakness can also occur, but it is typically mild and not a prominent finding., Methods: We describe the clinical features, laboratory investigations, and muscle biopsy findings in a 58-year old man who presented with a 6-year history of marked progressive symmetrical facial weakness. Examination also showed shoulder abduction and hip extensor weakness., Results: The patient's serum creatine kinase level was 655 U/L, and electromyography showed fibrillation potentials and myopathic motor unit potentials. A biopsy specimen of the left biceps muscle was pathognomonic for IBM., Conclusions: This patient did not have a typical presentation for IBM but rather fulfilled the pathological criteria for IBM. To our knowledge, facial diplegia has not been reported previously as a presenting manifestation of IBM., (Copyright © 2013 Wiley Periodicals, Inc.)

Inclusion body myositis (IBM) belongs to the group of idiopathic inflammatory myopathies. It is a poorly understood disease, which affects skeletal muscles. IBM usually occurs as an isolated condition, but in some cases, it may be associated with another autoimmune disorder, Sjögren's syndrome. We report a case of a 47-year-old woman with headaches, symptoms of trigeminal neuralgia, progressive weakness in muscles of the upper and lower extremities and symptoms of dry eyes and mouth. On admission, creatine kinase level was increased to 6,956 IU/mL and lactate dehydrogenase (LDH) to 1,011 U/L in the serum. The increase in inflammatory factor (CRP, ESR) levels was not found. The diagnosis of inclusion body myositis associated with Sjögren's syndrome was established on the basis of clinical picture and diagnostic tests. In this therapy, methotrexate and methylprednisolone were administered. The considerable improved muscle strength in the upper and lower extremities, improved speech and swallowing, disappearance of headache and reduction in CPK and LDH levels were found 8 months after establishing the diagnosis. Treatment with methotrexate and methylprednisolone improved the clinical symptoms and quality of life of this patient and may offer a therapeutic option for some patients with IBM and concomitant Sjögren's syndrome.

Objective: The aims of the study were: (1) to evaluate subjective sleep quality and daytime sleepiness in patients affected by sporadic inclusion-body myositis (IBM); (2) to define the sleep and sleep-related respiratory pattern in IBM patients., Methods: Thirteen consecutive adult patients affected by definite IBM were enrolled, six women and seven men, mean age 66.2 ± 11.1 years (range: 50-80). Diagnosis was based on clinical and muscle biopsy studies. All patients underwent subjective sleep evaluation (Pittsburgh Sleep Quality Index, PSQI and Epworth Sleepiness Scale, ESS), oro-pharingo-esophageal scintigraphy, pulmonary function tests, psychometric measures, anatomic evaluation of upper airways, and laboratory-based polysomnography. Findings in IBM patients were compared to those obtained from a control group of 25 healthy subjects (13 men and 12 women, mean age 61.9 ± 8.6 years)., Results: Disease duration was >10 years in all. Mean IBM severity score was 28.8 ± 5.4 (range 18-36). Dysphagia was present in 10 patients. Nine patients had PSQI scores ≥ 5; patients had higher mean PSQI score (IBM: 7.2 ± 4.7, CONTROLS: 2.76 ± 1.45, p=0.005); one patient (and no controls) had EES>9. Polysomnography showed that IBM patients, compared to controls, had lower sleep efficiency (IBM: 78.8 ± 12.0%,, Controls: 94.0 ± 4.5%, p<0.001), more awakenings (IBM: 11.9 ± 11.0, CONTROLS: 5.2 ± 7.5, p=0.009) and increased nocturnal time awake (IBM: 121.2 ± 82.0 min.,, Controls: 46.12 ± 28.8 min., p=0.001). Seven Patients (and no controls) had polysomnographic findings consistent with sleep disordered breathing (SDB)., Conclusion: Data suggest that sleep disruption, and in particular SDB, might be highly prevalent in IBM., Significance: Data indicate that IBM patients have poor sleep and high prevalence of SDB., (Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Objectives: To evaluate serum levels of 25(OH) vitamin D in patients with idiopathic inflammatory myopathies (IIM) (polymyositis (PM), dermatomyosistis (DM), inclusion body myositis (IBM) and juvenile DM (JDM)) and to compare these with healthy controls., Methods: Serum samples from 149 patients with IIM and 290 healthy controls matched for gender and the month of blood sampling were analysed for 25(OH) vitamin D. ORs for vitamin D classes with 95% CI were calculated using a matched (conditional) logistic regression model. Groups were compared by the Kruskal-Wallis test and p values <0.05 were considered significant., Results: Patients with IIM had significantly lower serum levels of 25(OH) vitamin D than healthy controls (median 39 (10-168) nmol/l vs 68 (19-197) nmol/l; p=0.0001). There was no significant difference in vitamin D levels between the myositis subgroups. When vitamin D levels were subclassified into deficient (<50 nmol/l), insufficient (50-74 nmol/l) and normal (≥75 nmol/l), most of the patients with PM (68%), DM (65%) and IBM (53%) had deficient levels compared with only 60 (21%) healthy individuals. In patients with IIM the OR for deficient versus normal was 17.7 (95% CI 8.1 to 38.6) and the OR for insufficient versus normal was 2.4 (95% CI 1.2 to 4.7)., Conclusions: Low serum levels of vitamin D were found in most patients with IIM and may confer a risk factor for developing adult myositis, similar to some other autoimmune diseases.

Inclusion body myositis is the most common disabling inflammatory myopathy in the elderly. It is more frequent in men and after the age of 50 years. Inflammatory and degenerative features coexist. There is a T-cell mediated autoimmunity driven by in situ clonally expanded cytotoxic CD8-positive T-cells invading non-necrotic muscle fibres expressing MHC-I antigen. The hallmarks of degeneration are the deposition of protein aggregates and the formation of vesicles. The course of the disease is slow and the diagnosis is usually set after several years. The muscle weakness and wasting is assymetric, affecting predominantly distal muscles of the upper extremity and proximal muscles of the legs. The signs and clinical course can be characteristic, but the diagnosis is established by muscle biopsy. There is currently no evidence based effective treatment for sIBM. Prednisone, azathioprine, methotrexate, cyclosporine and IFN-beta failed. Oxandrolon did not improve symptoms. Treatment with intravenous immunglobuline (IVIG) induced in some patients a transient improvement of swallowing and of muscle strenght, but the overall study results were negative. A T-cell depleting monoclonal antibody (alemtuzumab), in a small uncontrolled study slowed down disease progression for a six-month period. Repeated muscle biopsies showed the reduction of T-cells in the muscle and the suppression of some degeneration associated molecules. An effective therapeutic mean should act on both aspects of the pathomechanism, on the inflammatory and the degenerative processes as well.

Objective: The incidence of sporadic inclusion body myositis (sIBM) in the Japanese population has increased, and some researchers have suggested that race and genetic background may influence the clinical features of the disease. The aim of this study was to clarify the demographic features of Japanese patients with sIBM., Methods: We retrospectively evaluated the demographic features of consecutive patients who were referred to our institution between 1995 and 2011 for diagnostic muscle biopsies and who subsequently were diagnosed to have sIBM., Results: Seventy-three patients comprising 54 men and 19 women received a diagnosis of sIBM during the study period. The patients were divided into two groups based on the date of diagnosis (before and including 2002, and after 2002). The annual number of patients who received a diagnosis of sIBM increased significantly from 3.6±1.6 (mean ± SD) before and including 2002 to 4.9±3.1 (mean ± SD) after 2002 (p<0.05), whereas the annual number of patients who received a diagnosis of polymyositis (PM) or dermatomyositis (DM) remained consistent from 1995 to 2011. The ratio of PM and DM to sIBM was 7.6 during the period from 1995 to 2002 and 5.5 during the period from 2003 to 2011. However, the age-adjusted annual number of patients newly diagnosed with sIBM did not increase significantly after 2002., Conclusion: The number of Japanese patients with sIBM appears to have increased in recent years; however, the characteristics of the patients have not changed. Considering the increased size of the elderly population, prolonged lifespans could explain the demographic movement of sIBM in Japan.

Purpose of Review: Inclusion body myositis (IBM) is a poorly understood progressive muscle disease of middle and later life. Its dual pathologies of autoimmunity and unexplained myofiber degeneration and loss have been enigmatic since its earliest descriptions over 40 years ago. No reliable effective therapy currently exists for IBM. This review provides an update of current issues in the pathogenesis and therapy of IBM., Recent Findings: Recent studies have further defined the clinical features of IBM, including natural history, pattern of muscle involvement, and role of MRI imaging. Further potential immune mediators have been identified. An autoantibody directed against a muscle antigen appears to have high specificity for IBM among muscle diseases. Further evidence for myonuclear degeneration has been reported., Summary: IBM remains a poorly understood muscle disease, although understanding of the pathophysiological mechanisms continues to expand and is supporting new therapeutic approaches.

Inclusion body myositis is an inflammatory myopathy characterized pathologically by rimmed vacuoles and the accumulation of amyloid-related proteins. Autopsy studies in these patients, including histochemical examinations of multiple skeletal muscles, have not yet been published. In this paper, we describe the autopsy findings of a patient with inclusion body myositis and hypertrophic cardiomyopathy. A 69-year-old man, who was a human T lymphotropic virus type 1 carrier, exhibited slowly progressive muscle weakness and atrophy, predominantly affecting the scapular, quadriceps femoris, and forearm flexor muscles. His disease course was more rapidly progressive than that typically observed; the patient died suddenly of arrhythmia 5 years after diagnosis. Autopsy findings revealed that multiple muscles, including the respiratory muscles, were involved. Longitudinal studies revealed an increased frequency of rimmed vacuoles and p62/sequestosome 1- and/or TAR DNA-binding protein 43-positive deposits in autopsied muscles, although the amount of inflammatory infiltrate appeared to be decreased. We speculated that muscle degeneration may be more closely involved in disease progression compared with autoimmunity. Genetic analysis revealed a myosin binding protein C3 mutation, which is reportedly responsible for familial hypertrophic cardiomyopathy. This mutation and human T lymphotropic virus type 1 infection may have affected the skeletal muscles of this patient., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Sporadic inclusion body myositis (sIBM), the most common form of myopathy with inflammation in those over the age of 50 in Western countries, is an intractable and progressive skeletal muscle disease of unknown cause and without effective treatment. Muscle biopsy typically reveals endomysial inflammation, invasion of mononuclear cells into non-necrotic fibers and rimmed vacuoles, suggesting inflammation and degeneration are co-existed in the pathogenesis. We estimated the prevalence of sIBM in Japan is 9.83 per million in 2003 and an increase in the number of sIBM in Japan in the decade. In this review, we discuss the diagnostic criteria sIBM in Japan, and describe available treatments and promising new therapeutic strategies. We also provide an update on the current understanding of sIBM pathogenesis.

Sporadic inclusion body myositis (sIBM) is an intractable and progressive skeletal muscle disease of unknown cause and without effective treatment. The etiology of sIBM is still unknown, however genetic factors, aging, life styles, environmental factors may be involved. sIBM is generally refractory to current therapy, such as steroid or immunosuppressants. To elucidate the pathomechanism of sIBM is the most important way to make therapeutic approach. In this review we estimated the prevalence of sIBM in Japan and discuss the pathomechanism of sIBM.

Sporadic inclusion body myositis is considered to be a slowly progressive myopathy. Long-term follow-up data are, however, not yet available. Follow-up data are important with a view to informing patients about their prognosis and selecting appropriate outcome measures for clinical trials. We performed a follow-up study of 64 patients with sporadic inclusion body myositis who participated in a national epidemiological study in the Netherlands. Case histories were recorded, and manual and quantitative muscle tests as well as laboratory tests were performed at baseline and 12 years (median) after the first out-patient visit. Date and cause of death were recorded for all deceased patients. Forty-six patients died during the follow-up period, two patients chose not to participate and one patient was lost to follow-up. The remaining 15 surviving patients had a mean disease duration of 20 years and were clinically evaluated at the second time point. The mean decline in strength was 3.5 and 5.4% per year according to the manual muscle testing and quantitative muscle testing, respectively. This decline was most pronounced in the lower legs, which were also the weakest extremities. Life expectancy was normal at 81 years, but activities of daily life were clearly restricted. At follow-up, all patients were found to be using a wheelchair, seven of them (47%) being completely wheelchair-bound. Disorders of the respiratory system were the most common cause of death. In three patients, euthanasia was requested and in another three, continuous deep sedation was applied. The fact that end-of-life care interventions were used in six patients (13%) reflects the severe disability and loss of quality of life at the end stage of this disease. Sporadic inclusion body myositis is a chronic progressive disorder, leading to major disabilities at the end stage of the disease due to extensive muscle weakness.

Susceptibility to sporadic inclusion body myositis (sIBM) in Caucasians has been consistently associated with alleles of the major histocompatibility complex (MHC) 8.1 ancestral haplotype (AH) (defined by HLA-B*0801 and HLA-DRB1*0301). In this study recombination mapping was utilised to further refine the known 8.1AH susceptibility region near HLA-DRB1*0301. Caucasian sIBM patients carrying part of the 8.1AH were genotyped for a selection of 8.1AH-haplotypic polymorphisms. A common 8.1AH-specific susceptibility region was defined, spanning 172 kb and encompassing three genes--HLA-DRB3, HLA-DRA and BTNL2. It is thus likely that 8.1AH-derived susceptibility to sIBM originates from at least one of these genes., (Copyright © 2011. Published by Elsevier B.V.)

In a muscle biopsy based study, only 9 out of 5450 biopsy samples, received from all parts of greater Istanbul area, had typical clinical and most suggestive light microscopic sporadic-inclusion body myositis (s-IBM) findings. Two other patients with and ten further patients without characteristic light microscopic findings had referring diagnosis of s-IBM. As the general and the age-adjusted populations of Istanbul in 2010 were 13.255.685 and 2.347.300 respectively, the calculated corresponding 'estimated prevalences' of most suggestive s-IBM in the Istanbul area were 0.679 X 10(-6) and 3.834 X 10(-6). Since Istanbul receives heavy migration from all regions of Turkey and ours is the only muscle pathology laboratory in Istanbul, projection of these figures to the Turkish population was considered to be reasonable and an estimate of the prevalence of s-IBM in Turkey was obtained. The calculated 'estimated prevalence' of s-IBM in Turkey is lower than the previously reported rates from other countries. The wide variation in the prevalence rates of s-IBM may reflect different genetic, immunogenetic or environmental factors in different populations.

Aims: The long-terms complications of immunosuppressive and anti-inflammatory treatment in idiopathic inflammatory myositis (IIM) are unknown. We sought to determine the complications of these treatments in a large cohort of patients with biopsy-proven IIM., Methods: A South Australian database for patients with biopsy-proven IIM was established. Clinical details of patients including treatment received were recorded., Results: Forty-three patients with dermatomyositis (DM), 184 with polymyositis (PM) and 117 with inclusion body myositis (IBM) were registered on the database. The prevalence of hypertension and diabetes in this population was 62% and 29%, respectively, considerably higher than the background prevalence of 9.4% and 4%, making detection of treatment-related adverse effects difficult. Hypertension and ischemic heart disease were more likely to be present prior to the diagnosis of IIM rather than following it. Hypertension and diabetes occurred more frequently following the diagnosis of myositis, in patients with DM compared with PM or IBM., Conclusions: We report a novel association of IIM with hypertension, diabetes and ischemic heart disease, indicating that a comprehensive assessment of vascular risk factors is essential in IIM.

Dermatomyositis (DM), polymyositis (PM), and sporadic inclusion-body myositis (sIBM) constitute a heterogeneous group of subacute or chronic acquired skeletal muscle diseases. Known as idiopathic inflammatory myopathies (IIM), they all share the presence of considerable weakness due to muscle inflammation and necrosis. Diagnosis is based on clinical findings, confirmed by laboratory examinations (serum muscle enzyme concentrations, autoantibodies against nuclear or cytoplasmatic antigens, electromyography, and muscle biopsy). Environmental exposures leading to immune activation in genetically susceptible individuals seem to be a probable pathogenic mechanism. Infectious agents, drugs, and ultraviolet radiation have been identified as a cause of the onset, exacerbation, or acceleration of these myopathies. Several case reports and population studies have been reported to support the relationship between inflammatory myopathy and the environment. Moreover, seasonal patterns of the onset of IIM have frequently been reported., (2009 Elsevier B.V. All rights reserved.)

The purpose of this study was to explore the prevalence and nature of cardiac abnormalities in sporadic inclusion body myositis (sIBM). Fifty-one sIBM patients were cross-sectionally studied using history-taking, physical examination, measurements of serum creatine kinase activity, the MB fraction (CK-MB), cardiac troponin T (cTnT) and I (cTnI), a 12-lead electrocardiogram (ECG) and 2-dimensional echocardiography. Present cardiac history was abnormal in 12 (24%) out of 51 patients, 12 (24%) patients had abnormalities on ECG, mostly aspecific, and in 12 (24%) patients the echocardiograph showed abnormalities. Elevated CK-MB was present in 42 (82%) patients and 40 (78%) had an elevated cTnT in the absence of acute cardiac pathology. In contrast, in one patient (2%) cTnI was elevated. There was no apparent association between elevated biomarkers, ECG or echocardiographic abnormalities. The prevalence of cardiac abnormalities in sIBM does not seem to be higher than would be expected in these elderly patients. Elevated CK-MB and cTnT levels are common, in contrast to cTnI, but do not reflect cardiac pathology.

Sporadic inclusion body myositis (sIBM) is the most common myopathy presenting over the age of 40 years but its prevalence varies considerably in different populations. Genetic factors play a part in the pathogenesis of sIBM and in Caucasians susceptibility has been linked to the HLA-DR3 allele and the 8.1 MHC ancestral haplotype (AH) which is also associated with other autoimmune diseases. The variable prevalence of sIBM in different populations may be related to differences in the population frequency of this haplotype. Our recent observations indicate that the clinical phenotype at presentation is also quite variable and that the influence of the MHC is more complex than previously appreciated with HLA alleles also having modifying effects on the age-at-onset, severity and rate of progression of the disease. Recent recombinant mapping studies of polymorphisms in the Class II/III regions of the MHC by our group have further refined the susceptibility region and have identified a number of candidate genes warranting further investigation. The significance of these findings for the pathogenesis of the disease is discussed.

Sporadic inclusion body myositis (sIBM) is considered to be the most common acquired muscle disease associated with aging. It is a disabling disorder still without effective treatment. sIBM causes weakness and atrophy of the distal and proximal muscles. Involvement of quadriceps and deep finger flexors are clues to early diagnosis. Dysphagia in the course of the disease is common. Muscle biopsy shows chronic myopathic features, lymphocytic infiltration invading non-necrotic fibbers, rimmed vacuoles and accumulation of amyloid-related proteins. It remains uncertain whether sIBM is primarily an immune-mediated inflammatory myopathy or a degenerative myopathy with an associated inflammatory component. This review describes the epidemiology and clinical features of the disease as well as the current genetic and pathogenic concepts and therapeutic approaches. Despite recent clues, in many respects sIBM remains an unsolved mystery.