BackgroundLow back pain may be having a significant impact on emergency departments around the world. Research suggests low back pain is one of the leading causes of emergency department visits. However, in the peer-reviewed literature, there has been limited focus on the prevalence and management of back pain in the emergency department setting. The aim of the systematic review was to synthesize evidence about the prevalence of low back pain in emergency settings and explore the impact of study characteristics including type of emergency setting and how the study defined low back pain.MethodsStudies were identified from PubMed and EMBASE, grey literature search, and other sources. We selected studies that presented prevalence data for adults presenting to an emergency setting with low back pain. Critical appraisal was conducted using a modified tool developed to assess prevalence studies. Meta-analyses and a meta-regression explored the influence of study-level characteristics on prevalence.ResultsWe screened 1187 citations and included 21 studies, reported between 2000 and 2016 presenting prevalence data from 12 countries. The pooled prevalence estimate from studies of standard emergency settings was 4.39% (95% CI: 3.67-5.18). Prevalence estimates of the included studies ranged from 0.9% to 17.1% and varied with study definition of low back pain and the type of emergency setting. The overall quality of the evidence was judged to be moderate as there was limited generalizability and high heterogeneity in the results.ConclusionThis is the first systematic review to examine the prevalence of low back pain in emergency settings. Our results indicate that low back pain is consistently a top presenting complaint and that the prevalence of low back pain varies with definition of low back pain and emergency setting. Clinicians and policy decisions makers should be aware of the potential impact of low back pain in their emergency settings.Electronic supplementary materialThe online version of this article (doi:10.1186/s12891-017-1511-7) contains supplementary material, which is available to authorized users.

Background:Research has shown that living in a smoke-free home has a positive effect on adolescents' perceived acceptance of smoking. However, the relationship between smoke-free homes and adolescent smoking behaviours remains unclear. The aim of this study was to examine the association between smoke-free homes and smoking susceptibility among high school students, and to determine whether these associations persist when analyses are stratified by familial smoking status. Methods:We conducted a random cross-sectional survey (2012/2013 Youth Smoking Survey) of primary, junior and high school students in Canada (n = 47 203). Multivariable logistic regression analyses were used to examine the associations between smoke-free homes and susceptibility to smoking among never-smoking high school students, with and without stratification by familial smoking.Results: Analyses showed that adolescents living in a smoke-free home had reduced odds of being susceptible to smoking (odds ratio [OR] 0.582, 95% confidence interval [CI] 0.428-0.791) compared with their peers living in households where smoking was permitted. When adolescents had other family members who were smokers, having a smoke-free home was not significantly associated with reduced smoking susceptibility (OR 0.878, 95% CI 0.721-1.071). Interpretation:Our results suggest that smoke-free homes may influence future smoking initiation. Optimal success in preventing youth smoking uptake necessitates having a coherent antismoking message between the home smoking environment and familial smoking behaviour. AbstractResearch Research CMAJ OPEN CMAJ OPEN, 4(2) E299This study looks to bridge the gap in the scientific literature with answers to the following questions: Are smoke-free homes associated with reduced smoking susceptibility among never-smoking adolescents; does this association persist after adjusting for familial smoking status; and does the association between smoke-free homes and reduced smoking susceptibility remain after stratification based on familial smoking status? Methods DesignThe Youth Smoking Survey is a nationally representative cross-sectional, biannual classroom-based survey that endeavours to provide estimates of tobacco use rates at national and provincial levels and capture issues influencing tobacco use (knowledge, social influences and attitudes). The 2012-2013 iteration was administered in 9 Canadian provinces (Manitoba declined to participate). Comparative estimates of 2010-2011 Youth Smoking Survey with and without Manitoba found no significant differences in smoking outcomes. 26 ParticipantsThe Youth Smoking Survey was administered to 47 203 students enrolled in grades 6-12. The cohort was drawn from a random sample of private, public and Catholic schools. Students attending special schools (special needs, visuallyimpaired, military), or attending a school with no eligible grades or no classes with at least 20 students were excluded. The University of Waterloo (the principal coordinator of the Youth Smoking Survey), Health Canada ...