Sleep is an emerging risk factor for dementia but its association with brain health remains unclear. This study included UK Biobank (n = 29,545; mean age = 54.65) participants at imaging visit with sleep measures and brain scans, and a subset (n = 14,206) with cognitive measures. Multiple linear regression analyses were conducted to study the associations between sleep and brain health. Every additional hour of sleep above 7 h/day was associated with 0.10–0.25% lower brain volumes. In contrast, a negative non-linear association was observed between sleep duration, grey matter, and hippocampal volume. Both longer (> 9 h/day) and shorter sleep (< 6 h/day) durations were associated with lower brain volumes and cognitive measures (memory, reaction time, fluid intelligence). Additionally, daytime dozing was associated with lower brain volumes (grey matter and left hippocampus volume) and lower cognitive measures (reaction time and fluid intelligence). Poor sleep (< 6 h/day, > 9 h/day, daytime dozing) at midlife was associated with lower brain health. Sleep may be an important target to improve brain health into old age and delay the onset of dementia.

IntroductionIdiopathic inflammatory myopathies (IIM). described as ‘inflammatory myositis’, are a heterogeneous group of rare muscular autoimmune diseases characterised by skeletal muscle inflammation. Its complex characteristics with lack of accurate diagnostic tests, unified classification system and comprehensive widely used diagnostic criteria could lead to diagnostic delay. This study will review diagnostic delay in myositis and provide an overview and clearer insight of patients’ experiences, causes and consequences of diagnostic delay in myositis.Methods and analysisThe literature source will be a systematic search of PubMed/MEDLINE, Scopus, ProQuest and sources of grey literature, conducted from database inception to December 2021 without restrictions on publication date. All study types (qualitative and quantitative) except review articles, examining diagnostic delay, incorrect diagnosis, missed diagnosis or slow diagnosis of all types of myositis in all ages will be included. Evidence of patients’ experiences associated with diagnostic delay will also be examined. Studies in languages other than English, German and Indonesian will be excluded. Outcomes will be diagnostic delay time, patients’ experiences, and causes and consequences associated with diagnostic delay in myositis. Two review authors will independently screen the titles and abstracts of search results against the inclusion criteria. The Mixed Methods Appraisal Tool (MMAT) will be used to appraise selected studies. Two independent authors will extract data using a prepiloted data extraction tool. If sufficient quantitative data is available, a meta-analysis will be conducted along with subgroup analysis including pooled diagnostic delay in each type of myositis. Qualitative data will be analysed in line with meta-aggregation methods. If data is insufficient, a narrative synthesis will be conducted.Ethics and disseminationAs this work is a systematic review, ethical approval was not required. Findings of the study will be disseminated through publications in peer-reviewed journals, conferences and symposia.PROSPERO registration numberCRD42022289830.

Background Idiopathic inflammatory myopathies (IIM) are a heterogenous group of rare muscular autoimmune diseases characterised by skeletal muscle inflammation with possible diagnostic delay. Our aim was to review the existing evidence to identify overall diagnostic delay for IIM, factors associated with diagnostic delay, and people’s experiences of diagnostic delay. Methods Three databases and grey literature sources were searched. Diagnostic delay was defined as the period between the onset of symptoms and the year of first diagnosis of IIM. We pooled the mean delay using random effects inverse variance meta-analysis and performed subgroup analyses. Results 328 titles were identified from which 27 studies were included. Overall mean diagnostic delay was 27.91 months (95% CI 15.03–40.79, I2 = 99%). Subgroup analyses revealed a difference in diagnostic delay between non-inclusion body myositis (IBM) and IBM types. There was no difference in diagnostic delay between studies in which myositis specific autoantibodies (MSA) were tested or not tested. In countries with gatekeeper health systems, where primary care clinicians authorize access to specialty care, people experienced longer periods of diagnostic delay than people with IIM in countries with non-gatekeeper systems. While studies discussed factors that may influence diagnostic delay, significant associations were not identified. No qualitative studies examining people’s experiences of diagnostic delay were identified. Conclusion Diagnostic delay of IIM has extensive impacts on the quality of life of people living with this disease. Understanding the experiences of people with IIM, from symptom onset to diagnosis, and factors that influence diagnostic delay is critical to inform clinical practice and training activities aimed at increasing awareness of this rare disease and expediting diagnosis. Trial registration: PROSPERO Registration number: CRD42022307236 URL of the PROSPERO registration: https://www.crd.york.ac.uk/PROSPEROFILES/307236_PROTOCOL_20220127.pdf

Sarcoidosis is a rare systemic inflammatory granulomatous disease with broad manifestation ranging from acute epileptic seizures to fatigue and pain syndromes that are subject to the organ involved. Delays in the diagnosis of sarcoidosis are attributed to the lack of a single diagnostic test or unified commonly used diagnostic criteria, and diagnosis based on exclusion of possible alternative diagnoses. We aim to systematically review the evidence about diagnostic delay in sarcoidosis to elucidate the causes and consequences of diagnostic delay, including people with sarcoidosis’ experiences. This will inform the development of interventions, tools, and health policies aiming to improve diagnostic efficiency and patients’ experiences of sarcoidosis.

Introduction Sarcoidosis is a rare systemic inflammatory granulomatous disease of unknown cause. It can manifest in any organ. The incidence of sarcoidosis varies across countries, and by ethnicity and gender. Delays in the diagnosis of sarcoidosis can lead to extension of the disease and organ impairment. Diagnosis delay is attributed in part to the lack of a single diagnostic test or unified commonly used diagnostic criteria, and to the diversity of disease manifestations and symptom load. There is a paucity of evidence examining the determinants of diagnostic delay in sarcoidosis and the experiences of people with sarcoidosis related to delayed diagnosis. We aim to systematically review available evidence about diagnostic delay in sarcoidosis to elucidate the factors associated with diagnostic delay for this disease in different contexts and settings, and the consequences for people with sarcoidosis. Methods and analysis A systematic search of the literature will be conducted using PubMed/Medline, Scopus, and ProQuest databases, and sources of grey literature, up to 25th of May 2022, with no limitations on publication date. We will include all study types (qualitative, quantitative, and mixed methods) except review articles, examining diagnostic delay, incorrect diagnosis, missed diagnosis or slow diagnosis of all types of sarcoidosis across all age groups. We will also examine evidence of patients’ experiences associated with diagnostic delay. Only studies in English, German and Indonesian will be included. The outcomes we examine will be diagnostic delay time, patients’ experiences, and factors associated with diagnostic delay in sarcoidosis. Two people will independently screen the titles and abstracts of search results, and then the remaining full-text documents against the inclusion criteria. Disagreements will be resolved with a third reviewer until consensus is reached. Selected studies will be appraised using the Mixed Methods Appraisal Tool (MMAT). A meta-analysis and subgroup analyses of quantitative data will be conducted. Meta-aggregation methods will be used to analyse qualitative data. If there is insufficient data for these analyses, a narrative synthesis will be conducted. Discussion This review will provide systematic and integrated evidence on the diagnostic delay, associated factors, and experiences of diagnosis delay among people with all types of sarcoidosis. This knowledge may shed light on ways to improve diagnosis delays in diagnosis across different subpopulations, and with different disease presentations. Ethics and dissemination Ethical approval will not be required as no human recruitment or participation will be involved. Findings of the study will be disseminated through publications in peer-reviewed journals, conferences, and symposia. Trial registration PROSPERO Registration number: CRD42022307236. URL of the PROSPERO registration: https://www.crd.york.ac.uk/PROSPEROFILES/307236_PROTOCOL_20220127.pdf.