Swiss chiropractic cohort (Swiss ChiCo) pilot study: feasibility for a musculoskeletal cohort study conducted within a nationwide practice-based research network.

PURPOSE: Practice-based research networks are collaborations between clinicians and researchers to advance primary care research. This study aims to assess the feasibility for longitudinal data collection within a newly established chiropractic PBRN in Switzerland. METHODS: A prospective observational cohort feasibility study was performed. PBRN participating chiropractors were asked to recruit patients seeking new conservative health care for musculoskeletal pain from March 28, 2022, to September 28, 2022. Participants completed clinically oriented survey questions and patient-reported outcome measures before the initial chiropractic assessment as well as 1 h, 2 weeks, 6 weeks, and 12 weeks thereafter. Feasibility was assessed through a variety of process, resource, and management metrics. Patient clinical outcomes were also assessed. RESULTS: A total of 76 clinicians from 35 unique primary care chiropractic clinics across Switzerland participated. A total of 1431 patients were invited to participate, of which 573 (mean age 47 years, 51% female) were enrolled. Patient survey response proportions were 76%, 64%, 61%, and 56%, at the 1-h, 2-, 6-, and 12-week survey follow-ups, respectively. Evidence of an association was found between increased patient age (OR = 1.03, 95%CI 1.01-1.04), patient from a German-speaking region (OR = 1.81, 95%CI 1.17-2.86), non-smokers (OR = 1.89, 95%CI 1.13-3.17), and increased pain impact score at baseline (OR = 1.18, 95%CI 1.01-1.38) and response to all surveys. CONCLUSION: The Swiss ChiCo pilot study exceeded its prespecified feasibility objectives. Nationwide longitudinal data capture was highly feasible. Similar to other practice-based cohorts, participant retention remains a challenge. Trial registration Swiss chiropractic cohort (Swiss ChiCo) pilot study (ClinicalTrials.gov identifier: NCT05116020).

Burden of infectious disease studies in Europe and the United Kingdom: a review of methodological design choices.

This systematic literature review aimed to provide an overview of the characteristics and methods used in studies applying the disability-adjusted life years (DALY) concept for infectious diseases within European Union (EU)/European Economic Area (EEA)/European Free Trade Association (EFTA) countries and the United Kingdom. Electronic databases and grey literature were searched for articles reporting the assessment of DALY and its components. We considered studies in which researchers performed DALY calculations using primary epidemiological data input sources. We screened 3053 studies of which 2948 were excluded and 105 studies met our inclusion criteria. Of these studies, 22 were multi-country and 83 were single-country studies, of which 46 were from the Netherlands. Food- and water-borne diseases were the most frequently studied infectious diseases. Between 2015 and 2022, the number of burden of infectious disease studies was 1.6 times higher compared to that published between 2000 and 2014. Almost all studies (97%) estimated DALYs based on the incidence- and pathogen-based approach and without social weighting functions; however, there was less methodological consensus with regards to the disability weights and life tables that were applied. The number of burden of infectious disease studies undertaken across Europe has increased over time. Development and use of guidelines will promote performing burden of infectious disease studies and facilitate comparability of the results.

Association Between First Attempt Buffalo Concussion Treadmill Test and Days to Recovery in 855 Children With Sport-Related Concussion: A Historical Cohort Study and Prognostic Factors Analysis.

OBJECTIVE: Little is known about the prognostic value of the Buffalo Concussion Treadmill Test (BCTT) after the acute phase of sport-related concussion (SRC). We examined the added prognostic value of the BCTT performed 10 to 21 days after SRC in children, in addition to participant, injury, and clinical process characteristics on days to recovery. DESIGN: Historical clinical cohort study. SETTING: Network of approximately 150 Canadian multidisciplinary primary-care clinics. PARTICIPANTS: 855 children (mean age 14 years, range 6-17 years, 44% female) who presented between January 2016, and April 2019 with SRC. ASSESSMENT OF RISK FACTORS: Participant, injury, and clinical process characteristics, with focus on BCTT exercise intolerance assessed 10 to 21 days after injury. OUTCOME: Days to clinical recovery. RESULTS: Children who were exercise intolerant experienced an increase of 13 days to recovery (95% CI, 9-18 days). Each additional day between SRC and first BCTT was associated with a recovery delay of 1 day (95% CI, 1-2 days), and prior history of concussion was associated with a recovery delay of 3 days (95% CI, 1-5 days). Participant, injury, and clinical process characteristics, and the first attempt BCTT result explained 11% of the variation in recovery time, with 4% accounted for by the BCTT. CONCLUSION: Exercise-intolerance assessed 10 to 21 days after SRC was associated with delayed recovery. However, this was not a strong prognostic factor for days to recovery.

Systematic Review Procedures for the World Health Organization (WHO) Evidence Syntheses on Benefits and Harms of Structured and Standardized Education/Advice, Structured Exercise Programs, Transcutaneous Electrical Nerve Stimulation (TENS), and Needling Therapies for the Management of Chronic Low Back Pain in Adults.

As commissioned by the WHO, we updated and expanded the scope of four systematic reviews to inform its (in development) clinical practice guideline for the management of CPLBP in adults, including older adults. Methodological details and results of each review are described in the respective articles in this series. In the last article of this series, we discuss methodological considerations, clinical implications and recommendations for future research.

Systematic Review to Inform a World Health Organization (WHO) Clinical Practice Guideline: Benefits and Harms of Structured Exercise Programs for Chronic Primary Low Back Pain in Adults.

PURPOSE: Evaluate benefits and harms of structured exercise programs for chronic primary low back pain (CPLBP) in adults to inform a World Health Organization (WHO) standard clinical guideline. METHODS: We searched for randomized controlled trials (RCTs) in electronic databases (inception to 17 May 2022). Eligible RCTs targeted structured exercise programs compared to placebo/sham, usual care, or no intervention (including comparison interventions where the attributable effect of exercise could be isolated). We extracted outcomes, appraised risk of bias, conducted meta-analyses where appropriate, and assessed certainty of evidence using GRADE. RESULTS: We screened 2503 records (after initial screening through Cochrane RCT Classifier and Cochrane Crowd) and 398 full text RCTs. Thirteen RCTs rated with overall low or unclear risk of bias were synthesized. Assessing individual exercise types (predominantly very low certainty evidence), pain reduction was associated with aerobic exercise and Pilates vs. no intervention, and motor control exercise vs. sham. Improved function was associated with mixed exercise vs. usual care, and Pilates vs. no intervention. Temporary increased minor pain was associated with mixed exercise vs. no intervention, and yoga vs. usual care. Little to no difference was found for other comparisons and outcomes. When pooling exercise types, exercise vs. no intervention probably reduces pain in adults (8 RCTs, SMD = - 0.33, 95% CI - 0.58 to - 0.08) and functional limitations in adults and older adults (8 RCTs, SMD = - 0.31, 95% CI - 0.57 to - 0.05) (moderate certainty evidence). CONCLUSIONS: With moderate certainty, structured exercise programs probably reduce pain and functional limitations in adults and older people with CPLBP.

Improving Rehabilitation Research to Optimize Care and Outcomes for People with Chronic Primary Low Back Pain: Methodological and Reporting Recommendations from a WHO Systematic Review Series.

Chronic primary low back pain (CPLBP) is a prevalent and disabling condition that often requires rehabilitation interventions to improve function and alleviate pain. This paper aims to advance future research, including systematic reviews and randomized controlled trials (RCTs), on CPLBP management. We provide methodological and reporting recommendations derived from our conducted systematic reviews, offering practical guidance for conducting robust research on the effectiveness of rehabilitation interventions for CPLBP. Our systematic reviews contributed to the development of a WHO clinical guideline for CPLBP. Based on our experience, we have identified methodological issues and recommendations, which are compiled in a comprehensive table and discussed systematically within established frameworks for reporting and critically appraising RCTs. In conclusion, embracing the complexity of CPLBP involves recognizing its multifactorial nature and diverse contexts and planning for varying treatment responses. By embracing this complexity and emphasizing methodological rigor, research in the field can be improved, potentially leading to better care and outcomes for individuals with CPLBP.

Systematic Review to Inform a World Health Organization (WHO) Clinical Practice Guideline: Benefits and Harms of Transcutaneous Electrical Nerve Stimulation (TENS) for Chronic Primary Low Back Pain in Adults.

PURPOSE: To evaluate benefits and harms of transcutaneous electrical nerve stimulation (TENS) for chronic primary low back pain (CPLBP) in adults to inform a World Health Organization (WHO) standard clinical guideline. METHODS: We searched for randomized controlled trials (RCTs) from various electronic databases from July 1, 2007 to March 9, 2022. Eligible RCTs targeted TENS compared to placebo/sham, usual care, no intervention, or interventions with isolated TENS effects (i.e., combined TENS with treatment B versus treatment B alone) in adults with CPLBP. We extracted outcomes requested by the WHO Guideline Development Group, appraised the risk of bias, conducted meta-analyses where appropriate, and graded the certainty of evidence using GRADE. RESULTS: Seventeen RCTs (adults, n = 1027; adults ≥ 60 years, n = 28) out of 2010 records and 89 full text RCTs screened were included. The evidence suggested that TENS resulted in a marginal reduction in pain compared to sham (9 RCTs) in the immediate term (2 weeks) (mean difference (MD) = -0.90, 95% confidence interval -1.54 to -0.26), and a reduction in pain catastrophizing in the short term (3 months) with TENS versus no intervention or interventions with TENS specific effects (1 RCT) (MD = -11.20, 95% CI -17.88 to -3.52). For other outcomes, little or no difference was found between TENS and the comparison interventions. The certainty of the evidence for all outcomes was very low. CONCLUSIONS: Based on very low certainty evidence, TENS resulted in brief and marginal reductions in pain (not deemed clinically important) and a short-term reduction in pain catastrophizing in adults with CPLBP, while little to no differences were found for other outcomes.

Systematic Review to Inform a World Health Organization (WHO) Clinical Practice Guideline: Benefits and Harms of Needling Therapies for Chronic Primary Low Back Pain in Adults.

PURPOSE: Evaluate benefits and harms of needling therapies (NT) for chronic primary low back pain (CPLBP) in adults to inform a World Health Organization (WHO) standard clinical guideline. METHODS: Electronic databases were searched for randomized controlled trials (RCTs) assessing NT compared with placebo/sham, usual care, or no intervention (comparing interventions where the attributable effect could be isolated). We conducted meta-analyses where indicated and graded the certainty of evidence. RESULTS: We screened 1831 citations and 109 full text RCTs, yeilding 37 RCTs. The certainty of evidence was low or very low across all included outcomes. There was little or no difference between NT and comparisons across most outcomes; there may be some benefits for certain outcomes. Compared with sham, NT improved health-related quality of life (HRQoL) (physical) (2 RCTs; SMD = 0.20, 95%CI 0.07; 0.32) at 6 months. Compared with no intervention, NT reduced pain at 2 weeks (21 RCTs; MD = - 1.21, 95%CI - 1.50; - 0.92) and 3 months (9 RCTs; MD = - 1.56, 95%CI - 2.80; - 0.95); and reduced functional limitations at 2 weeks (19 RCTs; SMD = - 1.39, 95%CI - 2.00; - 0.77) and 3 months (8 RCTs; SMD = - 0.57, 95%CI - 0.92; - 0.22). In older adults, NT reduced functional limitations at 2 weeks (SMD = - 1.10, 95%CI - 1.71; - 0.48) and 3 months (SMD = - 1.04, 95%CI - 1.66; - 0.43). Compared with usual care, NT reduced pain (MD = - 1.35, 95%CI - 1.86; - 0.84) and functional limitations (MD = - 2.55, 95%CI - 3.70; - 1.40) at 3 months. CONCLUSION: Based on low to very low certainty evidence, adults with CPLBP experienced some benefits in pain, functioning, or HRQoL with NT; however, evidence showed little to no differences for other outcomes.

Systematic Review to Inform a World Health Organization (WHO) Clinical Practice Guideline: Benefits and Harms of Structured and Standardized Education or Advice for Chronic Primary low back pain in Adults.

PURPOSE: Evaluate benefits and harms of education/advice for chronic primary low back pain (CPLBP) in adults to inform a World Health Organization (WHO) standard clinical guideline. METHODS: Electronic databases were searched for randomized controlled trials (RCTs) assessing education/advice compared with placebo/sham, usual care, or no intervention (including comparison interventions where the attributable effect of education/advice could be isolated). We conducted meta-analyses and graded the certainty of evidence. RESULTS: We screened 2514 citations and 86 full text RCTs and included 15 RCTs. Most outcomes were assessed 3 to 6 months post-intervention. Compared with no intervention, education/advice improved pain (10 RCTs, MD = -1.1, 95% CI -1.63 to -0.56), function (10 RCTs, SMD = -0.51, 95% CI -0.89 to -0.12), physical health-related quality of life (HRQoL) (2 RCTs, MD = 24.27, 95% CI 12.93 to 35.61), fear avoidance (5 RCTs, SMD = -1.4, 95% CI -2.51 to -0.29), depression (1 RCT; MD = 2.10, 95% CI 1.05 to 3.15), and self-efficacy (1 RCT; MD = 4.4, 95% CI 2.77 to 6.03). Education/advice conferred less benefit than sham Kinesio taping for improving fear avoidance regarding physical activity (1 RCT, MD = 5.41, 95% CI 0.28 to 10.54). Compared with usual care, education/advice improved pain (1 RCT, MD = -2.10, 95% CI -3.13 to -1.07) and function (1 RCT, MD = -7.80, 95% CI -14.28 to -1.32). There was little or no difference between education/advice and comparisons for other outcomes. For all outcomes, the certainty of evidence was very low. CONCLUSION: Education/advice in adults with CPLBP was associated with improvements in pain, function, HRQoL, and psychological outcomes, but with very low certainty.

Functional Movement Screen Task Scores and Joint Range-of-motion: A Construct Validity Study.

Little is known about the construct validity of the Functional Movement Screen (FMS). We aimed to assess associations between FMS task scores and measures of maximum joint range-of-motion (ROM) among university varsity student-athletes from 4 sports (volleyball, basketball, ice hockey, and soccer). Athletes performed FMS tasks and had their maximum ankle, hip and shoulder ROM measured. Multivariable linear regression was used to estimate associations between FMS task scores and ROM measurements. 101 university student-athletes were recruited (52 W/49 M; mean age 20.4±1.9 years). In general, athletes with higher FMS task scores had greater ROM compared to those with lower task scores. For example, athletes who scored 2 on the FMS squat task had 4° (95% CI, 1° to 7°) more uni-articular ankle dorsiflexion ROM compared with those who scored 1, while those who scored 3 on the FMS squat task had 10° (4° to 17°) more uni-articular ankle dorsiflexion ROM compared with those who scored 1. Large variation in ROM measurements was observed. In sum, substantial overlap in joint ROM between groups of athletes with different FMS task scores weakens the construct validity of the FMS as an indicator of specific joint ROM.

Most published meta-regression analyses based on aggregate data suffer from methodological pitfalls: a meta-epidemiological study.

BACKGROUND: Due to clinical and methodological diversity, clinical studies included in meta-analyses often differ in ways that lead to differences in treatment effects across studies. Meta-regression analysis is generally recommended to explore associations between study-level characteristics and treatment effect, however, three key pitfalls of meta-regression may lead to invalid conclusions. Our aims were to determine the frequency of these three pitfalls of meta-regression analyses, examine characteristics associated with the occurrence of these pitfalls, and explore changes between 2002 and 2012. METHODS: A meta-epidemiological study of studies including aggregate data meta-regression analysis in the years 2002 and 2012. We assessed the prevalence of meta-regression analyses with at least 1 of 3 pitfalls: ecological fallacy, overfitting, and inappropriate methods to regress treatment effects against the risk of the analysed outcome. We used logistic regression to investigate study characteristics associated with pitfalls and examined differences between 2002 and 2012. RESULTS: Our search yielded 580 studies with meta-analyses, of which 81 included meta-regression analyses with aggregated data. 57 meta-regression analyses were found to contain at least one pitfall (70%): 53 were susceptible to ecological fallacy (65%), 14 had a risk of overfitting (17%), and 5 inappropriately regressed treatment effects against the risk of the analysed outcome (6%). We found no difference in the prevalence of meta-regression analyses with methodological pitfalls between 2002 and 2012, nor any study-level characteristic that was clearly associated with the occurrence of any of the pitfalls. CONCLUSION: The majority of meta-regression analyses based on aggregate data contain methodological pitfalls that may result in misleading findings.

Lack of Conclusive Evidence of the Benefit of Biologic Augmentation in Core Decompression for Nontraumatic Osteonecrosis of the Femoral Head: A Systematic Review.

PURPOSE: To assess whether biologic augmentation in addition to core decompression (CD), compared with CD alone, improves clinical and radiographic outcomes in the treatment of nontraumatic osteonecrosis of the femoral head (ONFH). Our hypothesis was that biologic augmentation would reduce the progression of osteonecrosis and therefore also the rate of conversion to total hip arthroplasty (THA). METHODS: A systematic review was performed in accordance with the Preferred Reporting Items of Systematic Reviews and Meta-analysis (PRISMA) statement. Six databases were searched: Central, MEDLINE, Embase, Scopus, AMED, and Web of Science. Studies comparing outcomes of CD versus CD plus biologic augmentation (with or without structural augmentation), with a reported minimum level of evidence of III and ≥24 months of follow-up, were eligible. Procedural success was conceptualized as (1) avoidance of conversion to THA and (2) absence of radiographic disease progression. Risk of bias was assessed using the Joanna Briggs Institute critical appraisal checklists. A quantitative analysis of heterogeneity was undertaken. RESULTS: We included studies reporting on 560 hips in 484 patients. Biologic augmentation consisted of bone marrow stem cells in 10 studies, bone morphogenic protein in 2, and platelet-rich plasma in 1. Three studies used additional structural augmentation. The median maximum follow-up time was 45 months. Only 4 studies reported improvement in all clinical scores in the augmentation group. Seven studies observed a reduction in the rate of radiographic progression, and only 5 found reduced rates of conversion to THA when using augmentation. A high risk of bias and marked heterogeneity was found, with uncertainty about the study designs implemented, analytical approaches, and quality of reporting. CONCLUSION: Current evidence is inconclusive regarding the benefit of biologic augmentation in CD for nontraumatic ONFH, because of inconsistent results with substantial heterogeneity and high risk of bias. LEVEL OF EVIDENCE: III, systematic review of level I, II, and III studies.

Effect of Biomechanical Footwear on Knee Pain in People With Knee Osteoarthritis: The BIOTOK Randomized Clinical Trial.

IMPORTANCE: Individually calibrated biomechanical footwear therapy may improve pain and physical function in people with symptomatic knee osteoarthritis, but the benefits of this therapy are unclear. OBJECTIVE: To assess the effect of a biomechanical footwear therapy vs control footwear over 24 weeks of follow-up. DESIGN, SETTING, AND PARTICIPANTS: Randomized clinical trial conducted at a Swiss university hospital. Participants (N = 220) with symptomatic, radiologically confirmed knee osteoarthritis were recruited between April 20, 2015, and January 10, 2017. The last participant visit occurred on August 15, 2017. INTERVENTIONS: Participants were randomized to biomechanical footwear involving shoes with individually adjustable external convex pods attached to the outsole (n = 111) or to control footwear (n = 109) that had visible outsole pods that were not adjustable and did not create a convex walking surface. MAIN OUTCOMES AND MEASURES: The primary outcome was knee pain at 24 weeks of follow-up assessed with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscore standardized to range from 0 (no symptoms) to 10 (extreme symptoms). The secondary outcomes included WOMAC physical function and stiffness subscores and the WOMAC global score, all ranging from 0 (no symptoms) to 10 (extreme symptoms) at 24 weeks of follow-up, and serious adverse events. RESULTS: Among the 220 randomized participants (mean age, 65.2 years [SD, 9.3 years]; 104 women [47.3%]), 219 received the allocated treatment and 213 (96.8%) completed follow-up. At 24 weeks of follow-up, the mean standardized WOMAC pain subscore improved from 4.3 to 1.3 in the biomechanical footwear group and from 4.0 to 2.6 in the control footwear group (between-group difference in scores at 24 weeks of follow-up, -1.3 [95% CI, -1.8 to -0.9]; P < .001). The results were consistent for WOMAC physical function subscore (between-group difference, -1.1 [95% CI, -1.5 to -0.7]), WOMAC stiffness subscore (between-group difference, -1.4 [95% CI, -1.9 to -0.9]), and WOMAC global score (between-group difference, -1.2 [95% CI, -1.6 to -0.8]) at 24 weeks of follow-up. Three serious adverse events occurred in the biomechanical footwear group compared with 9 in the control footwear group (2.7% vs 8.3%, respectively); none were related to treatment. CONCLUSIONS AND RELEVANCE: Among participants with knee pain from osteoarthritis, use of biomechanical footwear compared with control footwear resulted in an improvement in pain at 24 weeks of follow-up that was statistically significant but of uncertain clinical importance. Further research would be needed to assess long-term efficacy and safety, as well as replication, before reaching conclusions about the clinical value of this device. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02363712.

Chiropractic care and risk for acute lumbar disc herniation: a population-based self-controlled case series study.

PURPOSE: Chiropractic care is popular for low back pain, but may increase the risk for acute lumbar disc herniation (LDH). Low back pain is a common early (prodromal) symptom of LDH and commonly precedes LDH diagnosis. Our objective was to investigate the association between chiropractic care and acute LDH with early surgical intervention, and contrast this with the association between primary care physician (PCP) care and acute LDH with early surgery. METHODS: Using a self-controlled case series design and population-based healthcare databases in Ontario, Canada, we investigated all adults with acute LDH requiring emergency department (ED) visit and early surgical intervention from April 1994 to December 2004. The relative incidence of acute LDH with early surgery in exposed periods after chiropractic visits relative to unexposed periods was estimated within individuals, and compared with the relative incidence of acute LDH with early surgery following PCP visits. RESULTS: 195 cases of acute LDH with early surgery (within 8 weeks) were identified in a population of more than 100 million person-years. Strong positive associations were found between acute LDH and both chiropractic and PCP visits. The risk for acute LDH with early surgery associated with chiropractic visits was no higher than the risk associated with PCP visits. CONCLUSIONS: Both chiropractic and primary medical care were associated with an increased risk for acute LDH requiring ED visit and early surgery. Our analysis suggests that patients with prodromal back pain from a developing disc herniation likely seek healthcare from both chiropractors and PCPs before full clinical expression of acute LDH. We found no evidence of excess risk for acute LDH with early surgery associated with chiropractic compared with primary medical care.

Chiropractic spinal manipulation and the risk for acute lumbar disc herniation: a belief elicitation study.

PURPOSE: Chiropractic spinal manipulation treatment (SMT) is common for back pain and has been reported to increase the risk for lumbar disc herniation (LDH), but there is no high quality evidence about this. In the absence of good evidence, clinicians can have knowledge and beliefs about the risk. Our purpose was to determine clinicians' beliefs regarding the risk for acute LDH associated with chiropractic SMT. METHODS: Using a belief elicitation design, 47 clinicians (16 chiropractors, 15 family physicians and 16 spine surgeons) that treat patients with back pain from primary and tertiary care practices were interviewed. Participants' elicited incidence estimates of acute LDH among a hypothetical group of patients with acute low back pain treated with and without chiropractic SMT, were used to derive the probability distribution for the relative risk (RR) for acute LDH associated with chiropractic SMT. RESULTS: Chiropractors expressed the most optimistic belief (median RR 0.56; IQR 0.39-1.03); family physicians expressed a neutral belief (median RR 0.97; IQR 0.64-1.21); and spine surgeons expressed a slightly more pessimistic belief (median RR 1.07; IQR 0.95-1.29). Clinicians with the most optimistic views believed that chiropractic SMT reduces the incidence of acute LDH by about 60% (median RR 0.42; IQR 0.29-0.53). Those with the most pessimistic views believed that chiropractic SMT increases the incidence of acute LDH by about 30% (median RR 1.29; IQR 1.11-1.59). CONCLUSIONS: Clinicians' beliefs about the risk for acute LDH associated with chiropractic SMT varied systematically across professions, in spite of a lack of scientific evidence to inform these beliefs. These probability distributions can serve as prior probabilities in future Bayesian analyses of this relationship.

The association between a lifetime history of work-related low back injury and future low back pain: a population-based cohort study.

PURPOSE: This population-based cohort study investigated the association between a lifetime history of a work-related low back injury, in those who had recovered to have no or mild low back pain, and the development of troublesome low back pain (LBP). A secondary analysis explored the possible effects of misclassification of the exposure by examining the association between a lifetime history of having taken time off work or performed light duties at work because of a work-related low back injury. Current evidence from cross-sectional studies suggests that individuals with a history of a work-related low back injury are more likely to experience future LBP. However, there is a need to examine this association prospectively in a large population-based cohort with adequate control of known confounders. METHODS: We formed a cohort of 810 randomly sampled Saskatchewan adults with no or mild LBP in September 1995. At baseline, participants were asked if they had ever injured their low back at work. The secondary analysis asked if they had ever had to take time off work or perform light duties at work because of a work-related low back injury. Prospective follow-up 6 and 12 months later, asked about the presence of troublesome LBP (grade II-IV) on the Chronic Pain Grade Questionnaire. Multivariable Cox proportional hazards regression analysis was used to estimate these associations while controlling for known confounders. RESULTS: The proportion followed up at 6 and 12 months was 76 and 65%, respectively. We found an association between a history of work-related low back injury and the onset of troublesome LBP after controlling for gender (adjusted HRR = 2.24; 95% CI 1.41-3.56). When covariates that may also be mediators of the association were added to the model, the effect estimate was attenuated (adjusted HRR = 1.37; 95% CI 1.41-3.56). We found a similar association between a lifetime history of having taken time off work or had to work light duties at work because of a work-related low back injury, adjusted for gender (adjusted HRR = 2.31; 95% CI 1.39-3.85) which was also diluted by the further adjustment for covariates that may also be mediators of the association (adjusted HRR = 1.80; 95% CI 1.08-3.01). CONCLUSION: Our study suggests that a history of work-related low back injury or taking time off work or having to perform light duties at work due to a work-related low back injury may be a risk factor for the development of troublesome LBP. Residual confounding may account for some of the observed associations, but this was less in the group who took time off work or had to work light duties due to a work-related low back injury.

Systematic search and review procedures: results of the International Collaboration on Mild Traumatic Brain Injury Prognosis.

OBJECTIVES: To update the last best-evidence synthesis conducted by the World Health Organization Collaborating Centre for Neurotrauma, Prevention, Management and Rehabilitation in 2002; and to describe the course, identify prognostic factors, determine long-term sequelae, identify effects of interventions for mild traumatic brain injury (MTBI), identify knowledge gaps in the literature, and make recommendations for future research. DATA SOURCES: MEDLINE, Embase, PsycINFO, Cumulative Index to Nursing and Allied Health, and SPORTDiscus were searched between 2001 and 2012. Inclusion criteria included published peer-reviewed articles in English and 5 other languages. References were also identified from relevant reviews and meta-analyses and the bibliographies of eligible articles. STUDY SELECTION: Controlled trials and cohort and case-control studies were selected according to predefined inclusion/exclusion criteria. Studies had to have at least 30 MTBI cases and assess outcomes relevant to prognosis after MTBI. DATA EXTRACTION: Eligible studies were critically appraised using modified Scottish Intercollegiate Guidelines Network (SIGN) criteria. Two reviewers independently reviewed each study and extracted data from accepted articles (ie, with a low risk of bias) into evidence tables. DATA SYNTHESIS: The evidence was synthesized qualitatively according to modified SIGN criteria and prioritized according to design as exploratory or confirmatory. The evidence was organized into separate articles according to population (eg, adults, children, and athletes) and outcomes (eg, risk of dementia after MTBI). CONCLUSIONS: After 77,914 records were screened, 299 articles were eligible and reviewed. Of these, 101 (34%) were accepted as scientifically admissible and form the basis of our findings, which are organized into 10 articles in this supplement. These reviews present the best available evidence on MTBI prognosis, but more research is needed.

Systematic review of the risk of Parkinson's disease after mild traumatic brain injury: results of the International Collaboration on Mild Traumatic Brain Injury Prognosis.

OBJECTIVE: To synthesize the best available evidence on the risk of Parkinson's disease (PD) after mild traumatic brain injury (MTBI). DATA SOURCES: MEDLINE and other databases were searched (1990-2012) with terms including "craniocerebral trauma" and "parkinsonian disorders." Reference lists of eligible articles and relevant systematic reviews and meta-analyses were also searched. STUDY SELECTION: Controlled clinical trials, cohort studies, and case-control studies were selected according to predefined criteria. Studies had to have a minimum of 30 concussion cases. DATA EXTRACTION: Eligible studies were critically appraised using a modification of the Scottish Intercollegiate Guidelines Network criteria. Two reviewers independently reviewed and extracted data from accepted studies into evidence tables. DATA SYNTHESIS: Evidence was synthesized qualitatively according to modified Scottish Intercollegiate Guidelines Network criteria. Sixty-five studies were eligible and reviewed, and 5 of these with a low risk of bias were accepted as scientifically admissible and form the basis of our findings. Among these admissible studies, the definitions of MTBI were highly heterogeneous. One study found a significant positive association between MTBI and PD (odds ratio, 1.5; 95% confidence interval, 1.4-1.7). The estimated odds ratio decreased with increasing latency between MTBI and PD diagnosis, which suggests reverse causality. The other 4 studies did not find a significant association. CONCLUSIONS: The best available evidence argues against an important causal association between MTBI and PD. There are few high-quality studies on this topic. Prospective studies of long duration would address the limitations of recall of head injury and the possibility of reverse causation.