Objectives To outline which infectious diseases in the pre-covid-19 era persist in children and adolescents in China and to describe recent trends and variations by age, sex, season, and province. Design National surveillance studies, 2008-17. Setting 31 provinces in mainland China. Participants 4 959 790 Chinese students aged 6 to 22 years with a diagnosis of any of 44 notifiable infectious diseases

Objective To determine the relative effectiveness of dietary macronutrient patterns and popular named diet programmes for weight loss and cardiovascular risk factor improvement among adults who are overweight or obese. Design Systematic review and network meta-analysis of randomised trials. Data sources Medline, Embase, CINAHL, AMED, and CENTRAL from database inception until September 2018, reference

Objective To compare the risk of mortality among people with opioid use disorder on and off opioid agonist treatment (OAT) in a setting with a high prevalence of illicitly manufactured fentanyl and other potent synthetic opioids in the illicit drug supply. Design Population based retrospective cohort study. Setting Individual level linkage of five health administrative datasets capturing drug dispensations

Objective To use data from the Global Burden of Disease Study between 1990 and 2017 to report the rates and trends of point prevalence, annual incidence, and years lived with disability for neck pain in the general population of 195 countries. Design Systematic analysis. Data source Global Burden of Diseases, Injuries, and Risk Factors Study 2017. Main outcome measures Numbers and age standardised

Objective To delineate the clinical characteristics of patients with coronavirus disease 2019 (covid-19) who died. Design Retrospective case series. Setting Tongji Hospital in Wuhan, China. Participants Among a cohort of 799 patients, 113 who died and 161 who recovered with a diagnosis of covid-19 were analysed. Data were collected until 28 February 2020. Main outcome measures Clinical characteristics

Objective To assess the efficacy of manual acupuncture as prophylactic treatment for acupuncture naive patients with episodic migraine without aura. Design Multicentre, randomised, controlled clinical trial with blinded participants, outcome assessment, and statistician. Setting Seven hospitals in China, 5 June 2016 to 15 November 2018. Participants 150 acupuncture naive patients with episodic migraine

Objective To systematically examine the design, reporting standards, risk of bias, and claims of studies comparing the performance of diagnostic deep learning algorithms for medical imaging with that of expert clinicians. Design Systematic review. Data sources Medline, Embase, Cochrane Central Register of Controlled Trials, and the World Health Organization trial registry from 2010 to June 2019. Eligibility

Objective To examine the association between reporting on suicides, especially deaths of celebrities by suicide, and subsequent suicides in the general population. Design Systematic review and meta-analysis. Data sources PubMed/Medline, PsychInfo, Scopus, Web of Science, Embase, and Google Scholar, searched up to September 2019. Review methods Studies were included if they compared at least one time

Objective To investigate the association of macronutrient intake with all cause mortality and cardiovascular disease (CVD), and the implications for dietary advice. Design Prospective population based study. Setting UK Biobank. Participants 195 658 of the 502 536 participants in UK Biobank completed at least one dietary questionnaire and were included in the analyses. Diet was assessed using Oxford

Clinical prediction models aim to predict outcomes in individuals, to inform diagnosis or prognosis in healthcare. Hundreds of prediction models are published in the medical literature each year, yet many are developed using a dataset that is too small for the total number of participants or outcome events. This leads to inaccurate predictions and consequently incorrect healthcare decisions for some

Objective To determine whether bicycle commuting is associated with risk of injury. Design Prospective population based study. Setting UK Biobank. Participants 230 390 commuters (52.1% women; mean age 52.4 years) recruited from 22 sites across the UK compared by mode of transport used (walking, cycling, mixed mode versus non-active (car or public transport)) to commute to and from work on a typical

Objective To identify, appraise, and synthesise the best available evidence on the efficacy of perioperative interventions to reduce postoperative pulmonary complications (PPCs) in adult patients undergoing non-cardiac surgery. Design Systematic review and meta-analysis of randomised controlled trials. Data sources Medline, Embase, CINHAL, and CENTRAL from January 1990 to December 2017. Eligibility

Objective To determine the annual rate of tuberculosis development after a positive tuberculin skin test (TST) or interferon-gamma release assay result (IGRA), or both, among untreated populations with characteristics believed to increase the risk of tuberculosis (at risk populations). Design Systematic review and meta-analysis. Data sources Embase, Medline, and Cochrane Controlled Register of Trials

Objective To evaluate the association between egg intake and cardiovascular disease risk among women and men in the United States, and to conduct a meta-analysis of prospective cohort studies. Design Prospective cohort study, and a systematic review and meta-analysis of prospective cohort studies. Setting Nurses’ Health Study (NHS, 1980-2012), NHS II (1991-2013), Health Professionals’ Follow-Up Study

Objectives To evaluate the associations of habitual fish oil supplementation with cardiovascular disease (CVD) and mortality in a large prospective cohort. Design Population based, prospective cohort study. Setting UK Biobank. Participants A total of 427 678 men and women aged between 40 and 69 who had no CVD or cancer at baseline were enrolled between 2006 and 2010 and followed up to the end of 2018

Objective To examine the associations between stopping treatment with opioids, length of treatment, and death from overdose or suicide in the Veterans Health Administration. Design Observational evaluation. Setting Veterans Health Administration. Participants 1 394 102 patients in the Veterans Health Administration with an outpatient prescription for an opioid analgesic from fiscal year 2013 to the

OBJECTIVE To evaluate the effectiveness and cost effectiveness of a complex intervention in primary care that aims to increase uptake of hepatitis C virus (HCV) case finding and treatment. DESIGN Pragmatic, two armed, practice level, cluster randomised controlled trial and economic evaluation. SETTING AND PARTICIPANTS 45 general practices in South West England (22 randomised to intervention and 23

OBJECTIVE To examine the dose-response relation between reduction in dietary sodium and blood pressure change and to explore the impact of intervention duration. DESIGN Systematic review and meta-analysis following PRISMA guidelines. DATA SOURCES Ovid MEDLINE(R), EMBASE, and Cochrane Central Register of Controlled Trials (Wiley) and reference lists of relevant articles up to 21 January 2019. INCLUSION

OBJECTIVE To describe the temporal and spatial trends of mortality and disability adjusted life years (DALYs) due to chronic respiratory diseases, by age and sex, across the world during 1990-2017 using data from the Global Burden of Disease Study 2017. DESIGN Systematic analysis. DATA SOURCE The Global Burden of Diseases, Injuries, and Risk Factors Study 2017. METHODS Mortality and DALYs from chronic

OBJECTIVE To assess the association between macrolide antibiotics prescribing during pregnancy and major malformations, cerebral palsy, epilepsy, attention deficit hyperactivity disorder, and autism spectrum disorder in children. DESIGN Population based cohort study. SETTING The UK Clinical Practice Research Datalink. PARTICIPANTS The study cohort included 104 605 children born from 1990 to 2016 whose

OBJECTIVE To evaluate the risk of adverse maternal and infant outcomes following in utero exposure to duloxetine. DESIGN Cohort study nested in the Medicaid Analytic eXtract for 2004-13. SETTING Publicly insured pregnancies in the United States. PARTICIPANTS Pregnant women 18 to 55 years of age and their liveborn infants. INTERVENTIONS Duloxetine exposure during the etiologically relevant time window

OBJECTIVE To study the clinical characteristics of patients in Zhejiang province, China, infected with the 2019 severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) responsible for coronavirus disease 2019 (covid-2019). DESIGN Retrospective case series. SETTING Seven hospitals in Zhejiang province, China. PARTICIPANTS 62 patients admitted to hospital with laboratory confirmed SARS-Cov-2 infection

OBJECTIVES To identify and summarise existing indices for measuring multimorbidity beyond disease counts, to establish which indices include mental health comorbidities or outcomes, and to develop recommendations based on applicability, performance, and usage. DESIGN Systematic review. DATA SOURCES Seven medical research databases (Medline, Web of Science Core Collection, Cochrane Library, Embase,

OBJECTIVE To compare established associations between risk factors and mortality in UK Biobank, a study with an exceptionally low rate of response to its baseline survey, against those from representative studies that have conventional response rates. DESIGN Prospective cohort study alongside individual participant meta-analysis of other cohort studies. SETTING United Kingdom. PARTICIPANTS Analytical

OBJECTIVE To examine the validity and findings of studies that examine the accuracy of algorithm based smartphone applications ("apps") to assess risk of skin cancer in suspicious skin lesions. DESIGN Systematic review of diagnostic accuracy studies. DATA SOURCES Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL, CPCI, Zetoc, Science Citation Index, and online trial registers

OBJECTIVE To assess short term mortality risks and excess mortality associated with exposure to ozone in several cities worldwide. DESIGN Two stage time series analysis. SETTING 406 cities in 20 countries, with overlapping periods between 1985 and 2015, collected from the database of Multi-City Multi-Country Collaborative Research Network. POPULATION Deaths for all causes or for external causes only

Objectives To conduct a systematic review and meta-analysis of the effects of rosiglitazone treatment on cardiovascular risk and mortality using multiple data sources and varying analytical approaches with three aims in mind: to clarify uncertainties about the cardiovascular risk of rosiglitazone; to determine whether different analytical approaches are likely to alter the conclusions of adverse event

Objective To examine the association between expansion of the Medicaid program under the Affordable Care Act and changes in healthcare spending among low income adults during the first four years of the policy implementation (2014-17). Design Quasi-experimental difference-in-difference analysis to examine out-of-pocket spending and financial burden among low income adults after Medicaid expansions

Objective To assess whether an association exists between financial links to the indoor tanning industry and conclusions of indoor tanning literature. Design Systematic review. Data sources PubMed, Embase, and Web of Science, up to 15 February 2019. Study selection criteria Articles discussing indoor tanning and health were eligible for inclusion, with no article type restrictions (original research

OBJECTIVE To examine the distribution and patterns of opioid prescribing in the United States. DESIGN Retrospective, observational study. SETTING National private insurer covering all 50 US states and Washington DC. PARTICIPANTS An annual average of 669 495 providers prescribing 8.9 million opioid prescriptions to 3.9 million patients from 2003 through 2017. MAIN OUTCOME MEASURES Standardized doses

OBJECTIVE To investigate the association between several types of soy products and all cause and cause specific mortality. DESIGN Population based cohort study. SETTING Japan Public Health Centre-based Prospective Study, which includes 11 public health centre areas in Japan. PARTICIPANTS 92 915 participants (42 750 men and 50 165 women) aged 45 to 74 years. EXPOSURES Intake of total soy products, fermented

OBJECTIVE To study the impact of maternal smoking during pregnancy on fractures in offspring during different developmental stages of life. DESIGN National register based birth cohort study with a sibling comparison design. SETTING Sweden. PARTICIPANTS 1 680 307 people born in Sweden between 1983 and 2000 to women who smoked (n=377 367, 22.5%) and did not smoke (n=1 302 940) in early pregnancy. Follow-up

OBJECTIVE To assess the magnitude and duration of any hypothesised protective effect of household exposure to a child with varicella on the relative incidence of herpes zoster in adults. DESIGN Self controlled case series. SETTING UK general practices contributing to Clinical Practice Research Datalink. PARTICIPANTS 9604 adults (≥18 years) with a diagnosis of herpes zoster (in primary care or hospital

OBJECTIVE To investigate pharmaceutical or medical device industry funding of patient groups. DESIGN Systematic review with meta-analysis. DATA SOURCES Ovid Medline, Embase, Web of Science, Scopus, and Google Scholar from inception to January 2018; reference lists of eligible studies and experts in the field. ELIGIBILITY CRITERIA FOR SELECTING STUDIES Observational studies including cross sectional

OBJECTIVES To study the impact of blinding on estimated treatment effects, and their variation between trials; differentiating between blinding of patients, healthcare providers, and observers; detection bias and performance bias; and types of outcome (the MetaBLIND study). DESIGN Meta-epidemiological study. DATA SOURCE Cochrane Database of Systematic Reviews (2013-14). ELIGIBILITY CRITERIA FOR SELECTING

OBJECTIVE To investigate the impact of modifications to contemporary cancer protocols, which minimize exposures to cardiotoxic treatments and preserve long term health, on serious cardiac outcomes among adult survivors of childhood cancer. DESIGN Retrospective cohort study. SETTING 27 institutions participating in the Childhood Cancer Survivor Study. PARTICIPANTS 23 462 five year survivors (6193 (26

In systematic reviews that lack data amenable to meta-analysis, alternative synthesis methods are commonly used, but these methods are rarely reported. This lack of transparency in the methods can cast doubt on the validity of the review findings. The Synthesis Without Meta-analysis (SWiM) guideline has been developed to guide clear reporting in reviews of interventions in which alternative synthesis

OBJECTIVES To determine whether patients discharged after hospital admissions for conditions covered by national readmission programs who received care in emergency departments or observation units but were not readmitted within 30 days had an increased risk of death and to evaluate temporal trends in post-discharge acute care utilization in inpatient units, emergency departments, and observation units

OBJECTIVE To examine how a healthy lifestyle is related to life expectancy that is free from major chronic diseases. DESIGN Prospective cohort study. SETTING AND PARTICIPANTS The Nurses' Health Study (1980-2014; n=73 196) and the Health Professionals Follow-Up Study (1986-2014; n=38 366). MAIN EXPOSURES Five low risk lifestyle factors: never smoking, body mass index 18.5-24.9, moderate to vigorous

OBJECTIVE To determine, in critically ill patients, the relative impact of proton pump inhibitors (PPIs), histamine-2 receptor antagonists (H2RAs), sucralfate, or no gastrointestinal bleeding prophylaxis (or stress ulcer prophylaxis) on outcomes important to patients. DESIGN Systematic review and network meta-analysis. DATA SOURCES Medline, PubMed, Embase, Cochrane Central Register of Controlled Trials

OBJECTIVE To study the effect of long term exposure to ambient fine particulate matter of diameter ≤2.5 μm (PM2.5) on the incidence of total, ischemic, and hemorrhagic stroke among Chinese adults. DESIGN Population based prospective cohort study. SETTING Prediction for Atherosclerotic Cardiovascular Disease Risk in China (China-PAR) project carried out in 15 provinces across China. PARTICIPANTS 117 575

OBJECTIVE To estimate the risks of daily hospital admissions for cause specific major cardiovascular diseases associated with short term exposure to ambient fine particulate matter (aerodynamic diameter ≤2.5 μm; PM2.5) pollution in China. DESIGN National time series study. SETTING 184 major cities in China. POPULATION 8 834 533 hospital admissions for cardiovascular causes in 184 Chinese cities recorded

OBJECTIVE To determine whether researchers are submitting manuscripts and peer reviews to BMJ journals out of hours and whether this has changed over time. DESIGN Observational study of research manuscripts and peer reviews submitted between 2012 and 2019 for which an author's address could be geocoded. SETTING Online BMJ submission systems for two large general medical journals. MAIN OUTCOME MEASURES

OBJECTIVE To determine whether fast driving, luxury car ownership, and leniency by police officers differ across medical specialties. DESIGN Observational study. SETTING Florida, USA. PARTICIPANTS 5372 physicians and a sample of 19 639 non-physicians issued a ticket for speeding during 2004-17. MAIN OUTCOME MEASURES Observed rates of extreme speeding (defined as driving >20 mph above the speed limit)

OBJECTIVES To compare the proportional representation of healthcare workers in receipt of New Year honours (NYHs) with workers in other industries and to determine whether the NYH system has gender or geographical biases. DESIGN Observational study of the UK honours system with a comparative analysis of proportional representation of the UK workforce and subgroup analyses of gender and geographical

OBJECTIVE To explore associations between different frequencies of arts engagement and mortality over a 14 year follow-up period. DESIGN Prospective cohort study. PARTICIPANTS English Longitudinal Study of Ageing cohort of 6710 community dwelling adults aged 50 years and older (53.6% women, average age 65.9 years, standard deviation 9.4) who provided baseline data in 2004-05. INTERVENTION Self reported

OBJECTIVES To evaluate the associations between birth month, birth season, and overall and cardiovascular disease mortality, and to examine the role of familial and socioeconomic factors in these associations. DESIGN Prospective cohort study. SETTING Nurses' Health Study, established in 1976, an ongoing prospective cohort study in the United States. PARTICIPANTS Female registered nurses who reported

OBJECTIVE To determine the validity of the superstition that utterance of the word "quiet" in a clinical setting increases workload. DESIGN Prospective randomised controlled non-inferiority study. SETTING Microbiology department of a large teaching hospital in Lancashire, UK. PARTICIPANTS Two members of the medical microbiology team carried out the duty work on any given week day and an on-call team

OBJECTIVES To identify and calculate the prevalence of spin in studies of spin. DESIGN Meta-research analysis (research on research). SETTING 35 studies of spin in the scientific literature. MAIN OUTCOME MEASURES Spin, categorised as: reporting practices that distort the presentation and interpretation of results, creating misleading conclusions; discordance between results and their interpretation

OBJECTIVE To determine the implications of car ownership for physical activity and weight in a global city. DESIGN Quasi-experimental cross sectional study. SETTING Beijing, China, 2011-15. PARTICIPANTS People aged 18 and older from a random sample of households who had entered a permit lottery to purchase a vehicle between January 2011 and November 2015. INTERVENTIONS Permit allowing purchase of a

OBJECTIVES Women remain underrepresented on faculties of medicine and the life sciences more broadly. Whether gender differences in self presentation of clinical research exist and may contribute to this gender gap has been challenging to explore empirically. The objective of this study was to analyze whether men and women differ in how positively they frame their research findings and to analyze whether

OBJECTIVE To understand and report on the nature of patient group interactions with the pharmaceutical industry from the perspective of patient group representatives by exploring the range of attitudes towards pharmaceutical industry sponsorship and how, why, and when interactions occur. DESIGN Empirical qualitative interview study informed by ethics theory. SETTING Australian patient groups. PARTICIPANTS

OBJECTIVES To identify the frequency with which antibiotics are prescribed in the absence of a documented indication in the ambulatory care setting, to quantify the potential effect on assessments of appropriateness of antibiotics, and to understand patient, provider, and visit level characteristics associated with antibiotic prescribing without a documented indication. DESIGN Cross sectional study

OBJECTIVE To evaluate the impact of the US government's Feed the Future initiative on nutrition outcomes in children younger than 5 years in sub-Saharan Africa. DESIGN Difference-in-differences quasi-experimental approach. SETTING Households in 33 low and lower middle income countries in sub-Saharan Africa. POPULATION 883 309 children aged less than 5 years with weight, height, and age recorded in

OBJECTIVE To determine the effectiveness of management strategies for uninvestigated dyspepsia. DESIGN Systematic review and network meta-analysis. DATA SOURCES Medline, Embase, Embase Classic, the Cochrane Central Register of Controlled Trials, and clinicaltrials.gov from inception to September 2019, with no language restrictions. Conference proceedings between 2001 and 2019. ELIGIBILITY CRITERIA

OBJECTIVE To evaluate the associations between maternal diabetes diagnosed before or during pregnancy and early onset cardiovascular disease (CVD) in offspring during their first four decades of life. DESIGN Population based cohort study. SETTING Danish national health registries. PARTICIPANTS All 2 432 000 liveborn children without congenital heart disease in Denmark during 1977-2016. Follow-up began

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OBJECTIVE To determine associations between important pre-arrest and intra-arrest prognostic factors and survival after in-hospital cardiac arrest. DESIGN Systematic review and meta-analysis. DATA SOURCES Medline, PubMed, Embase, Scopus, Web of Science, and the Cochrane Database of Systematic Reviews from inception to 4 February 2019. Primary, unpublished data from the United Kingdom National Cardiac

OBJECTIVE To investigate whether remote ischaemic preconditioning (RIPC) prevents myocardial injury in patients undergoing hip fracture surgery. DESIGN Phase II, multicentre, randomised, observer blinded, clinical trial. SETTING Three Danish university hospitals, 2015-17. PARTICIPANTS 648 patients with cardiovascular risk factors undergoing hip fracture surgery. 286 patients were assigned to RIPC and

OBJECTIVE To determine how the UK National Health Service (NHS) is performing relative to health systems of other high income countries, given that it is facing sustained financial pressure, increasing levels of demand, and cuts to social care. DESIGN Observational study using secondary data from key international organisations such as Eurostat and the Organization for Economic Cooperation and Development