Objective To comprehensively examine the associations between changes in carbohydrate intake and weight change at four year intervals. Design Prospective cohort study. Setting Nurses’ Health Study (1986-2010), Nurses’ Health Study II (1991-2015), and Health Professionals Follow-Up Study (1986-2014). Participants 136 432 men and women aged 65 years or younger and free of diabetes, cancer, cardiovascular

Objective To evaluate the association between recently raised anticholinergic burden and risk of acute cardiovascular events in older adults. Design Case-case-time-control study (ie, incorporating a case crossover design and a control crossover design consisting of future cases). Setting Taiwan’s National Health Insurance Research Database. Participants 317 446 adults aged ≥65 who were admitted to

This article outlines the issues of exposure time trends in the case crossover design and the implementation of the case-case-time-control design, a control crossover analysis using “future cases” to adjust the exposure time trends. The future-case control crossover analysis minimises the influence of constant time confounders, as well as the protopathic bias arising from exposure time trends. The

Objective To report the efficacy, safety, and exploratory immunogenicity findings of two 5 µg doses of the BIV1-CovIran vaccine. Design Randomised, placebo controlled, double blind, multicentre, phase 3 clinical trial. Setting In six cities of Iran, including Bushehr, Isfahan, Karaj, Mashhad, Shiraz, and Tehran. The first vaccine or placebo injection of the first participant was on 16 May 2021 in Tehran

Objective To estimate the associations between gestational weight gain (GWG) during pregnancy and neonatal outcomes in low and middle income countries. Design Individual participant data meta-analysis. Setting Prospective pregnancy studies from 24 low and middle income countries. Main outcome measures Nine neonatal outcomes related to timing (preterm birth) and anthropometry (weight, length, and head

Objective To explore attendance at organised mammographic screening among immigrant groups that received an invitation letter and information leaflet (invitation) in their language of origin and Norwegian compared with Norwegian only. Design Randomised controlled trial. Setting Population based screening programme for breast cancer in Norway (BreastScreen Norway), which invites women aged 50-69 to

Objective To examine the proportion of healthcare visits are delivered by nurse practitioners and physician assistants versus physicians and how this has changed over time and by clinical setting, diagnosis, and patient demographics. Design Cross-sectional time series study. Setting National data from the traditional Medicare insurance program in the USA. Participants Of people using Medicare (ie,

Objective To assess the incidence rate of oesophageal adenocarcinoma among patients with non-erosive gastro-oesophageal reflux disease compared with the general population. Design Population based cohort study. Setting All patients in hospital and specialised outpatient healthcare in Denmark, Finland, and Sweden from 1 January 1987 to 31 December 2019. Participants 486 556 adults (>18 years) who underwent

Objective To assess the associations between exposure to food additive emulsifiers and risk of cardiovascular disease (CVD). Design Prospective cohort study. Setting French NutriNet-Santé study, 2009-21. Participants 95 442 adults (>18 years) without prevalent CVD who completed at least three 24 hour dietary records during the first two years of follow-up. Main outcome measures Associations between

Objective To study the influence of concomitant use of hormonal contraception and non-steroidal anti-inflammatory drugs (NSAIDs) on the risk of venous thromboembolism. Design Nationwide cohort study. Setting Denmark through national registries. Participants All 15-49 year old women living in Denmark between 1996 and 2017 with no medical history of any venous or arterial thrombotic event, cancer, thrombophilia

Objective To systematically assess credibility and certainty of associations between cannabis, cannabinoids, and cannabis based medicines and human health, from observational studies and randomised controlled trials (RCTs). Design Umbrella review. Data sources PubMed, PsychInfo, Embase, up to 9 February 2022. Eligibility criteria for selecting studies Systematic reviews with meta-analyses of observational

Objective To determine the effectiveness of an exercise and functional activity therapy intervention in adults with early dementia or mild cognitive impairment compared with usual care. Design Randomised controlled trial. Setting Participants’ homes and communities at five sites in the United Kingdom. Participants 365 adults with early dementia or mild cognitive impairment who were living at home,

Objective To determine the effects of salt reduction interventions designed for home cooks and family members. Design Cluster randomised controlled trial. Setting Six provinces in northern, central, and southern China from 15 October 2018 to 30 December 2019. Participants 60 communities from six provinces (10 communities from each province) were randomised; each community comprised 26 people (two people

Objective To estimate the effects of providing access to an alcohol intervention based on a smartphone. Design Randomised controlled trial.. Setting Four higher education institutions in Switzerland. Participants 1770 students (≥18 years) who screened positive for unhealthy alcohol use (ie, a score on the alcohol use disorders identification test-consumption (AUDIT-C) of ≥4 for men and ≥3 for women)

Objective To evaluate the effect of protracted low dose, low dose rate exposure to ionising radiation on the risk of cancer. Design Multinational cohort study. Setting Cohorts of workers in the nuclear industry in France, the UK, and the US included in a major update to the International Nuclear Workers Study (INWORKS). Participants 309 932 workers with individual monitoring data for external exposure

Objectives To characterize the long term risk of death and hospital readmission after an index admission with covid-19 among Medicare fee-for-service beneficiaries, and to compare these outcomes with historical control patients admitted to hospital with influenza. Design Retrospective cohort study. Setting United States. Participants 883 394 Medicare fee-for-service beneficiaries age ≥65 years discharged

Objective To systematically review the proportions of infants with early exposure to antenatal corticosteroids but born at term or late preterm, and short term and long term outcomes. Design Systematic review and meta-analyses. Data sources Eight databases searched from 1 January 2000 to 1 February 2023, reflecting recent perinatal care, and references of screened articles. Eligibility criteria for

Objectives To quantify mortality rates for patients successfully treated for hepatitis C in the era of interferon-free, direct acting antivirals and compare these rates with those of the general population. Design Population based cohort study. Setting British Columbia, Scotland, and England (England cohort consists of patients with cirrhosis only). Participants 21 790 people who were successfully

Objective To investigate the associations between exposure to antenatal corticosteroids and serious infection in children during the first three, six, and 12 months of life. Design Nationwide cohort study. Setting National Health Insurance Research Database, Birth Reporting Database, and Maternal and Child Health Database, 1 January 2008 to 31 December 2019, to identify all pregnant individuals and

Objective To estimate the effectiveness of the bivalent mRNA booster vaccines containing the original SARS-CoV-2 and omicron BA.4-5 or BA.1 subvariants as the fourth dose against severe covid-19. Design Nationwide cohort analyses, using target trial emulation. Setting Denmark, Finland, Norway, and Sweden, from 1 July 2022 to 10 April 2023. Participants People aged ≥50 years who had received at least

Objective To examine the association between the omicron adapted bivalent mRNA covid-19 booster vaccines received as a fourth dose and risk of adverse events. Design Nationwide cohort study. Setting Denmark. Participants 2 225 567 adults aged ≥50 years who received three covid-19 vaccine doses during the study period, 1 January 2021 to 10 December 2022. Main outcome measures The main outcome measure

Objective To investigate the comparative vaccine effectiveness of heterologous booster schedules (ie, three vaccine doses) compared with primary schedules (two vaccine doses) and with homologous mRNA vaccine booster schedules (three vaccine doses) during a period of omicron predominance. Design Population based cohort analyses. Setting Denmark, Finland, Norway, and Sweden, 27 December 2020 to 31 December

Objectives To examine whether there is an association between people who experienced disrupted access to healthcare during the covid-19 pandemic and risk of an avoidable hospital admission. Design Observational analysis using evidence from seven linked longitudinal cohort studies for England. Setting Studies linked to electronic health records from NHS Digital from 1 March 2020 to 25 August 2022. Data

Objective To review the evidence on trends and impacts of private equity (PE) ownership of healthcare operators. Design Systematic review. Data sources PubMed, Web of Science, Embase, Scopus, and SSRN. Eligibility criteria for study selection Empirical research studies of any design that evaluated PE owned healthcare operators. Main outcome measures The main outcome measures were impact of PE ownership

Objectives To assess the different educational inequalities in mortality among generations born between 1940 and 1979 in China, and to investigate the role of socioeconomic, behavioural, and metabolic factors as potential contributors to the reduction of educational inequalities. Design Nationwide, population based, prospective cohort study. Setting The ChinaHEART (China Health Evaluation And risk

Objective To determine whether health systems in the United States modify treatment or discharge decisions for otherwise similar patients based on health insurance coverage. Design Regression discontinuity approach. Setting American College of Surgeons’ National Trauma Data Bank, 2007-17. Participants Adults aged between 50 and 79 years with a total of 1 586 577 trauma encounters at level I and level

Objectives To synthesise research investigating data and code sharing in medicine and health to establish an accurate representation of the prevalence of sharing, how this frequency has changed over time, and what factors influence availability. Design Systematic review with meta-analysis of individual participant data. Data sources Ovid Medline, Ovid Embase, and the preprint servers medRxiv, bioRxiv

Objective To analyze the therapeutic value of supplemental indications compared with first indications for drugs approved in the US and Europe. Design Retrospective cohort study. Setting New and supplemental indications approved by the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) between 2011 and 2020. Main outcome measures Proportion of first and supplemental indications

Objective To describe hospital admissions associated with SARS-CoV-2 infection in children and adolescents. Design Cohort study of 3.2 million first ascertained SARS-CoV-2 infections using electronic health care record data. Setting England, July 2020 to February 2022. Participants About 12 million children and adolescents (age <18 years) who were resident in England. Main outcome measures Ascertainment

Objectives To assess the association between use of menopausal hormone therapy and development of dementia according to type of hormone treatment, duration of use, and age at usage. Design Nationwide, nested case-control study. Setting Denmark through national registries. Participants 5589 incident cases of dementia and 55 890 age matched controls were identified between 2000 and 2018 from a population

Objective To investigate whether supplementing older adults with monthly doses of vitamin D alters the incidence of major cardiovascular events. Design Randomised, double blind, placebo controlled trial of monthly vitamin D (the D-Health Trial). Computer generated permuted block randomisation was used to allocate treatments. Setting Australia from 2014 to 2020. Participants 21 315 participants aged

Abstract Objective To study age specific associations of modest reductions in estimated glomerular filtration rate (eGFR) with adverse outcomes. Design Retrospective, population based cohort study. Setting Linked healthcare administrative datasets in Ontario, Canada. Participants Adult residents (18-65 years) with at least one outpatient eGFR value (categorized in 10 unit increments from 50 mL/min/1

Objective To investigate the association between surgeon volume and patient outcomes after elective shoulder replacement surgery to improve patient outcomes and inform future resource planning for joint replacement surgery. Design Prospective cohort study. Setting Public and private hospitals in the United Kingdom, 2012-20. Participants Adults aged 18 years or older who had shoulder replacement surgery

Objectives To derive and validate risk prediction algorithms (QCOVID4) to estimate the risk of covid-19 related death and hospital admission in people with a positive SARS-CoV-2 test result during the period when the omicron variant of the virus was predominant in England, and to evaluate performance compared with a high risk cohort from NHS Digital. Design Cohort study. Setting QResearch database

Objective To determine the effectiveness of risk stratification using the Global Registry of Acute Coronary Events (GRACE) risk score (GRS) for patients presenting to hospital with suspected non-ST elevation acute coronary syndrome. Design Parallel group cluster randomised controlled trial. Setting Patients presenting with suspected non-ST elevation acute coronary syndrome to 42 hospitals in England

Objectives To describe long term breast cancer mortality among women with a diagnosis of breast cancer in the past and estimate absolute breast cancer mortality risks for groups of patients with a recent diagnosis. Design Population based observational cohort study. Setting Routinely collected data from the National Cancer Registration and Analysis Service. Participants All 512 447 women registered

Objectives To describe gender and geographical inequalities in invitations to review and the response to these invitations and to assess whether inequalities increased during the covid-19 pandemic. Design Retrospective cohort study. Setting 19 specialist medical journals and two large general medical journals from BMJ Publishing Group. Population Reviewers invited to review manuscripts submitted between

Objective To test for potential non-specific effects of an additional, early measles, mumps, and rubella (MMR) vaccine at age 5-7 months on risk of infection related hospitalisation before age 12 months. Design Randomised, double blinded, placebo controlled trial. Setting Denmark, a high income setting with low exposure to MMR. Participants 6540 Danish infants aged 5 to 7 months. Interventions Infants

Objective To compare the performance of a newly developed race-free kidney recipient specific glomerular filtration rate (GFR) equation with the three current main equations for measuring GFR in kidney transplant recipients. Design Development and validation study Setting 17 cohorts in Europe, the United States, and Australia (14 transplant centres, three clinical trials). Participants 15 489 adults

Objective To evaluate longer term symptoms and health outcomes associated with post-covid-19 condition within a cohort of individuals with a SARS-CoV-2 infection. Design Population based, longitudinal cohort. Setting General population of canton of Zurich, Switzerland. Participants 1106 adults with a confirmed SARS-CoV-2 infection who were not vaccinated before infection and 628 adults who did not

Objective To develop and validate a prognostic model to inform risk stratified decisions on frequency of monitoring blood tests during long term methotrexate treatment. Design Retrospective cohort study. Setting Electronic health records within the UK’s Clinical Practice Research Datalink (CPRD) Gold and CPRD Aurum. Participants Adults (≥18 years) with a diagnosis of an immune mediated inflammatory

Control interventions (often called “sham,” “placebo,” or “attention controls”) are essential for studying the efficacy or mechanism of physical, psychological, and self-management interventions in clinical trials. This article presents core recommendations for designing, conducting, and reporting control interventions to establish a quality standard in non-pharmacological intervention research. A

Objective To study the effects of a primary care medication review intervention centred around an electronic clinical decision support system (eCDSS) on appropriateness of medication and the number of prescribing omissions in older adults with multimorbidity and polypharmacy compared with a discussion about medication in line with usual care. Design Cluster randomised clinical trial. Setting Swiss

Objectives To determine the association between covid-19 vaccination types and doses with adverse outcomes of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection during the periods of delta (B.1.617.2) and omicron (B.1.1.529) variant predominance. Design Retrospective cohort. Setting US Veterans Affairs healthcare system. Participants Adults (≥18 years) who are affiliated to Veterans

Objective To determine whether gender and racial inequities exist among Lasker Award recipients. Design Observational, cross sectional analysis. Setting Population based study. Participants Recipients of four Lasker Awards from 1946 to 2022. Main outcome measures Gender and race (non-white categorized as racialized v white categorized as non-racialized) of all Lasker Award recipients. Personal characteristics

Objective To assess the effectiveness of oral spironolactone for acne vulgaris in adult women. Design Pragmatic, multicentre, phase 3, double blind, randomised controlled trial. Setting Primary and secondary healthcare, and advertising in the community and on social media in England and Wales. Participants Women (≥18 years) with facial acne for at least six months, judged to warrant oral antibiotics

Objective To explore inequalities in human resources for health (HRH) in relation to all cause and cause specific mortality globally in 1990-2019. Design Observational study. Setting 172 countries and territories. Data sources Databases of the Global Burden of Disease Study 2019, United Nations Statistics, and Our World in Data. Main outcome measures The main outcome was age standardized all cause

Objective To develop a clinically useful model that estimates the 10 year risk of breast cancer related mortality in women (self-reported female sex) with breast cancer of any stage, comparing results from regression and machine learning approaches. Design Population based cohort study. Setting QResearch primary care database in England, with individual level linkage to the national cancer registry

Objective To analyze the US Food and Drug Administration (FDA) approval, trials, unmet needs, benefit, and pricing of ultra-rare (<6600 affected US citizens), rare (6600-200 000 citizens), and common (>200 000 citizens) orphan cancer drug indications and non-orphan cancer drug indications. Design Cross sectional analysis. Setting Data from Drugs@FDA, FDA labels, Global Burden of Disease study, and

Objectives To evaluate the risks of any menstrual disturbance and bleeding following SARS-CoV-2 vaccination in women who are premenopausal or postmenopausal. Design A nationwide, register based cohort study. Setting All inpatient and specialised outpatient care in Sweden from 27 December 2020 to 28 February 2022. A subset covering primary care for 40% of the Swedish female population was also included

Objective To explore associations between early life physical and sexual abuse and subsequent risk of premature mortality (death before age 70 years). Design Prospective cohort study. Setting The Nurses’ Health Study II (2001-19). Participants 67 726 female nurses aged 37-54 years when completing a violence victimization questionnaire in 2001. Main outcome measures Hazard ratios and 95% confidence

Most clinical specialties have a plethora of studies that develop or validate one or more prediction models, for example, to inform diagnosis or prognosis. Having many prediction model studies in a particular clinical field motivates the need for systematic reviews and meta-analyses, to evaluate and summarise the overall evidence available from prediction model studies, in particular about the predictive

Objective To review the comparative effectiveness of osteoporosis treatments, including the bone anabolic agents, abaloparatide and romosozumab, on reducing the risk of fractures in postmenopausal women, and to characterise the effect of antiosteoporosis drug treatments on the risk of fractures according to baseline risk factors. Design Systematic review, network meta-analysis, and meta-regression

Objective To assess whether an easy-to-use multifaceted intervention for children presenting to primary care with respiratory tract infections would reduce antibiotic dispensing, without increasing hospital admissions for respiratory tract infection. Design Two arm randomised controlled trial clustered by general practice, using routine outcome data, with qualitative and economic evaluations. Setting

Objective To examine whether treatment with the antiviral agent molnupiravir during the first five days of SARS-CoV-2 infection is associated with reduced risk of post-acute adverse health outcomes. Design Cohort study. Setting US Department of Veterans Affairs. Participants 229 286 participants who tested positive for SARS-CoV-2 between 5 January 2022 and 15 January 2023, had at least one risk factor

Randomised controlled trials remain the reference standard for healthcare research on effects of interventions, and the need to report both benefits and harms is essential. The Consolidated Standards of Reporting Trials (the main CONSORT) statement includes one item on reporting harms (ie, all important harms or unintended effects in each group). In 2004, the CONSORT group developed the CONSORT Harms

Objective To investigate the effectiveness and safety of surgery compared with non-surgical treatment for sciatica. Design Systematic review and meta-analysis. Data sources Medline, Embase, CINAHL, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and the World Health Organisation International Clinical Trials Registry Platform from database inception to June 2022. Eligibility criteria

Objective To investigate the intake of specific types of beverages in relation to mortality and cardiovascular disease (CVD) outcomes among adults with type 2 diabetes. Design Prospective cohort study. Setting Health professionals in the United States. Participants 15 486 men and women with a diagnosis of type 2 diabetes at baseline and during follow-up (Nurses’ Health Study: 1980-2018; and Health

Objective To estimate the effect of denosumab compared with oral bisphosphonates on reducing the risk of type 2 diabetes in adults with osteoporosis. Design Population based study involving emulation of a randomized target trial using electronic health records. Setting IQVIA Medical Research Data primary care database in the United Kingdom, 1995-2021. Participants Adults aged 45 years or older who

Objective To estimate the effectiveness of nirmatrelvir, compared with no treatment, in reducing admission to hospital or death at 30 days in people infected with the SARS-CoV-2 virus and at risk of developing severe disease, according to vaccination status and history of previous SARS-CoV-2 infection. Design Emulation of a randomized target trial with electronic health records. Setting Healthcare