Background and Aims: Critical appraisal or risk of bias assessment is a fundamental part of systematic reviews that clarifies the degree to which included research articles are qualified and reliable. Version 2 of the Cochrane tool for assessing the risk of bias in randomized trials (RoB 2), the updated version of the first tool, was released in 2019. Here, we have compared these two versions of Cochrane risk of bias assessment tools and highlighted the pros and cons of RoB 2.Methods: Statistical analysis and methodology is not applicable to this article as no new data were created or analyzed in this study.Results: The overall approach in RoB 2 is that by answering some signaling questions after the specification of results, effects of interest, and sources of information, an overall judgment for the quality of each study is reached. Accordingly, in the original version of the Cochrane RoB tool, the judgment can be in three different conclusions, including low, unclear, and high risk of bias. The most prominent difference in bias domains is the removal of “other bias” domain being replaced by “overall bias” judgment. Also, the most common presentation types of Cochrane risk of bias assessments are the “summary” and “graph” which are generated by Review Manager, web‐based applications, or packages in R software.Conclusion: The RoB 2 tool, compared to the original RoB, has improved and is the recommended version by the Cochrane Collaboration for quality assessment of randomized controlled trials. It is recommended to consider funding source, duration of follow‐up, declaration of data availability, the status of baseline characteristics between groups, and sample size calculation methods in further revisions of the Cochrane risk of bias assessment tools.

There have been several local and systemic adverse events associated with mRNA COVID‐19 vaccines. Pericarditis, myocarditis and myocardial infarction are examples of cardiac complications related to these vaccines. In this article, we conducted a systematic review of case reports and case series to identify the clinical profile, investigations, and management of reported cardiac complications post‐mRNA COVID‐19 vaccines. We systematically searched PubMed, Scopus, Web of Science, and Google Scholar, as well as the medRxiv preprint server, with terms including: ‘SARS‐CoV‐2’, ‘COVID‐19’, ‘messenger RNA vaccine*’, ‘mRNA‐1273 vaccine’, ‘BNT162 vaccine’, ‘myocarditis’, ‘pericarditis’, ‘stroke’ and ‘Myocardial Ischemia’ up to 25 September 2021. Studies were excluded if they were not case reports or case series, or reported cases from non‐mRNA vaccines. Case reports and case series were included that investigated the potential cardiac complications associated with mRNA COVID‐19 vaccines. The JBI checklist was used to assess quality and data synthesis was conducted using a qualitative methodology called narrative synthesis. Sixty‐nine studies, including 43 case reports and 26 case series, were included. Myocarditis/myopericarditis and pericarditis were the most common adverse events among the 243 reported cardiac complications, post mRNA COVID‐19 vaccination. Males with a median age of 21 years had the highest frequency of myocarditis. Almost three quarters (74.4%) of cases with myocarditis had received the BNT162b2 vaccine and 87.7% had received the second dose of the vaccine. Chest pain (96.1%) and fever (38.2%) were the most common presentations. CK‐MB, troponin, and NT‐proBNP were elevated in 100%, 99.5% and 78.3% of subjects, respectively. ST‐segment abnormality was the most common electrocardiogram feature. Cardiac magnetic resonance imaging, which is the gold‐standard approach for diagnosing myocarditis, was abnormal in all patients diagnosed with myocarditis. Non‐steroidal anti‐inflammatory drugs were the most prescribed medication for the management of myocarditis. Apart from inflammatory conditions, some rare cases of Takotsubo cardiomyopathy, myocardial infarction, myocardial infarction with non‐obstructive coronary arteries, and isolated tachycardia were also reported following immunisation with mRNA COVID‐19 vaccines. We acknowledge that only reviewing case reports and case series studies is one potential limitation of our study. We found that myocarditis was the most commonly reported adverse cardiac event associated with mRNA COVID‐19 vaccines, which presented as chest pain with a rise in cardiac biomarkers. Further large‐scale observational studies are recommended.

Background: Cancers are leading causes of mortality and morbidity, with smoking being recognized as a significant risk factor for many types of cancer. We aimed to report the cancer burden attributable to tobacco smoking by sex, age, socio‐demographic index (SDI), and cancer type in 204 countries and territories from 1990 to 2019.Methods: The burden of cancers attributable to smoking was reported between 1990 and 2019, based upon the Comparative Risk Assessment approach used in the Global Burden of Disease (GBD) study 2019.Results: Globally, in 2019 there were an estimated 2.5 million cancer‐related deaths (95% UI: 2.3 to 2.7) and 56.4 million DALYs (51.3 to 61.7) attributable to smoking. The global age‐standardized death and DALY rates of cancers attributable to smoking per 100,000 decreased by 23.0% (−29.5 to −15.8) and 28.6% (−35.1 to −21.5), respectively, over the period 1990–2019. Central Europe (50.4 [44.4 to 57.6]) and Western Sub‐Saharan Africa (6.7 [5.7 to 8.0]) had the highest and lowest age‐standardized death rates, respectively, for cancers attributable to smoking. In 2019, the age‐standardized DALY rate of cancers attributable to smoking was highest in Greenland (2224.0 [1804.5 to 2678.8]) and lowest in Ethiopia (72.2 [51.2 to 98.0]). Also in 2019, the global number of DALYs was highest in the 65–69 age group and there was a positive association between SDI and the age‐standardized DALY rate.Conclusions: The results of this study clearly illustrate that renewed efforts are required to increase utilization of evidence‐based smoking cessation support in order to reduce the burden of smoking‐related diseases.

Summary: BNT162b2 and mRNA‐1273 are two types of mRNA‐based vaccine platforms that have received emergency use authorization. The emergence of novel severe acute respiratory syndrome (SARS‐CoV‐2) variants has raised concerns of reduced sensitivity to neutralization by their elicited antibodies. We aimed to systematically review the most recent in vitro studies evaluating the effectiveness of BNT162b2 and mRNA‐1273 induced neutralizing antibodies against SARS‐CoV‐2 variants of concern. We searched PubMed, Scopus, and Web of Science in addition to bioRxiv and medRxiv with terms including ‘SARS‐CoV‐2’, ‘BNT162b2’, ‘mRNA‐1273’, and ‘neutralizing antibody’ up to June 29, 2021. A modified version of the Consolidated Standards of Reporting Trials (CONSORT) checklist was used for assessing included study quality. A total 36 in vitro studies meeting the eligibility criteria were included in this systematic review. B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), and B.1.617.2 (Delta) are four SARS‐CoV‐2 variants that have recently been identified as variants of concern. Included studies implemented different methods regarding pseudovirus or live virus neutralization assays for measuring neutralization titres against utilized viruses. After two dose vaccination by BNT162b2 or mRNA‐1273, the B.1.351 variant had the least sensitivity to neutralizing antibodies, while B.1.1.7 variant had the most sensitivity; that is, it was better neutralized relative to the comparator strain. P.1 and B.1.617.2 variants had an intermediate level of impaired naturalization activity of antibodies elicited by prior vaccination. Our review suggests that immune sera derived from vaccinated individuals might show reduced protection of individuals immunized with mRNA vaccines against more recent SARS‐CoV‐2 variants of concern.

Background and Aims: Low back pain (LBP) is one of the most debilitating and prevalent disorders. The prevalence of LBP ranges from 30% to 80%, depending on the population, and increases with age. Causes of LBP are typically classified as spinal and non‐spinal. The main goal of this study was to investigate the non‐spinal causes of LBP, since neglecting these factors leads to increases in the financial, psychological, and physical burden of LBP on individuals as well as on society.Methods: The data were extracted after searching the PubMed database and Google Scholar search engine up to October 27, 2021. We included all studies that were conducted on a human population and assessed the effects of epidemiological, biological, psychological, and sociodemographic factors on the incidence or progression of LBP.Results: The most common causes of non‐spinal LBP were diseases such as nephrolithiasis, endometriosis, tumors, fibromyalgia, and conditions like psychological disorders and pregnancy. Nevertheless, the perceived intensity of the pain can be affected by factors such as socioeconomic level, genetics, age, habits, diet, and psychological status.Conclusion: The epidemiology, etiologies, and risk factors associated with LBP should be more clearly recognized to better prevent, diagnose, and treat the underlying disease and to reduce the burden of LBP.

Gastric cancer represents a major public health burden globally, with a disproportionately high incidence and mortality observed in Asian countries. To analyze the epidemiology of gastric cancer across Asia using data from the GLOBOCAN 2020 database and explore the potential correlations with socioeconomic indicators. The study reported numbers of cases, 5-year prevalence, crude and age-standardized rates of incidence (ASIR) and mortality (ASMR), mortality-to-incidence ratio (MIR), and cumulative risk percentages. Asia had the highest ASIR and ASMR of gastric cancer in the world in 2020, with 14.30 and 10.00 per 100,000 population, respectively. The ASIRs were 20.40 and 8.70 in Asian males and females, respectively. The ASMRs were also 14.20 and 6.20 in males and females, respectively. The incidence and mortality rates increased with age and peaked in the > 70-year age group. There was a moderate inverse correlation between MIR and human development index (HDI). The incident cases of gastric cancer and its mortality numbers in Asia are estimated to increase by 72.20% and 75.90% by 2040, respectively. Gastric cancer burden varies across Asia, with high incidence and mortality rates in Eastern Asia. Lower MIRs in socioeconomically developed nations suggest the impact of early detection and treatment access to improve patients’ outcomes.