Examining later-in-life health risks associated with sport-related concussion and repetitive head impacts: a systematic review of case-control and cohort studies.

OBJECTIVE: Concern exists about possible problems with later-in-life brain health, such as cognitive impairment, mental health problems and neurological diseases, in former athletes. We examined the future risk for adverse health effects associated with sport-related concussion, or exposure to repetitive head impacts, in former athletes. DESIGN: Systematic review. DATA SOURCES: Search of MEDLINE, Embase, Cochrane, CINAHL Plus and SPORTDiscus in October 2019 and updated in March 2022. ELIGIBILITY CRITERIA: Studies measuring future risk (cohort studies) or approximating that risk (case-control studies). RESULTS: Ten studies of former amateur athletes and 18 studies of former professional athletes were included. No postmortem neuropathology studies or neuroimaging studies met criteria for inclusion. Depression was examined in five studies in former amateur athletes, none identifying an increased risk. Nine studies examined suicidality or suicide as a manner of death, and none found an association with increased risk. Some studies comparing professional athletes with the general population reported associations between sports participation and dementia or amyotrophic lateral sclerosis (ALS) as a cause of death. Most did not control for potential confounding factors (eg, genetic, demographic, health-related or environmental), were ecological in design and had high risk of bias. CONCLUSION: Evidence does not support an increased risk of mental health or neurological diseases in former amateur athletes with exposure to repetitive head impacts. Some studies in former professional athletes suggest an increased risk of neurological disorders such as ALS and dementia; these findings need to be confirmed in higher quality studies with better control of confounding factors. PROSPERO REGISTRATION NUMBER: CRD42022159486.

Amsterdam 2022 process: A summary of the methodology for the Amsterdam International Consensus on Concussion in Sport.

The purpose of this paper is to summarise the consensus methodology that was used to inform the International Consensus Statement on Concussion in Sport (Amsterdam 2022). Building on a Delphi process to inform the questions and outcomes from the 5th International Conference on Concussion in Sport, the Scientific Committee identified key questions, the answers to which would help encapsulate the current science in sport-related concussion and help guide clinical practice. Over 3½ years, delayed by 2 years due to the pandemic, author groups conducted systematic reviews on each selected topic. The 6th International Conference on Concussion in Sport was held in Amsterdam (27-30 October 2022) and consisted of 2 days of systematic review presentations, panel discussions, question and answer engagement with the 600 attendees, and abstract presentations. This was followed by a closed third day of consensus deliberations by an expert panel of 29 with observers in attendance. The fourth day, also closed, was dedicated to a workshop to discuss and refine the sports concussion tools (Concussion Recognition Tool 6 (CRT6), Sport Concussion Assessment Tool 6 (SCAT6), Child SCAT6, Sport Concussion Office Assessment Tool 6 (SCOAT6) and Child SCOAT6). We include a summary of recommendations for methodological improvements for future research that grew out of the systematic reviews.

A conceptual framework for prognostic research.

BACKGROUND: Prognostic research has many important purposes, including (i) describing the natural history and clinical course of health conditions, (ii) investigating variables associated with health outcomes of interest, (iii) estimating an individual's probability of developing different outcomes, (iv) investigating the clinical application of prediction models, and (v) investigating determinants of recovery that can inform the development of interventions to improve patient outcomes. But much prognostic research has been poorly conducted and interpreted, indicating that a number of conceptual areas are often misunderstood. Recent initiatives to improve this include the Prognosis Research Strategy (PROGRESS) and the Transparent Reporting of a multivariable prediction model for Individual Prognosis or Diagnosis (TRIPOD) Statement. In this paper, we aim to show how different categories of prognostic research relate to each other, to differentiate exploratory and confirmatory studies, discuss moderators and mediators, and to show how important it is to understand study designs and the differences between prediction and causation. MAIN TEXT: We propose that there are four main objectives of prognostic studies - description, association, prediction and causation. By causation, we mean the effect of prediction and decision rules on outcomes as determined by intervention studies and the investigation of whether a prognostic factor is a determinant of outcome (on the causal pathway). These either fall under the umbrella of exploratory (description, association, and prediction model development) or confirmatory (prediction model external validation and investigation of causation). Including considerations of causation within a prognostic framework provides a more comprehensive roadmap of how different types of studies conceptually relate to each other, and better clarity about appropriate model performance measures and the inferences that can be drawn from different types of prognostic studies. We also propose definitions of 'candidate prognostic factors', 'prognostic factors', 'prognostic determinants (causal)' and 'prognostic markers (non-causal)'. Furthermore, we address common conceptual misunderstandings related to study design, analysis, and interpretation of multivariable models from the perspectives of association, prediction and causation. CONCLUSION: This paper uses a framework to clarify some concepts in prognostic research that remain poorly understood and implemented, to stimulate discussion about how prognostic studies can be strengthened and appropriately interpreted.

The association between a lifetime history of low back injury in a motor vehicle collision 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 low back injury in a motor vehicle collision (MVC) and future troublesome low back pain. Participants with a history of a low back injury in a motor vehicle collision who had recovered (no or mild low back pain) were compared to those without a history of injury. Current evidence from two cross-sectional and one prospective study suggests that individuals with a history of a low back injury in a MVC are more likely to experience future LBP. There is a need to test this association prospectively in population-based cohorts with adequate control of known confounders. METHODS: We formed a cohort of 789 randomly sampled Saskatchewan adults with no or mild LBP. At baseline, participants were asked if they had ever injured their low back in a MVC. Six and 12 months later, participants were 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 the association while controlling for known confounders. RESULTS: The follow-up rate was 74.8% (590/789) at 6 months and 64.5% (509/789) at 12 months. There was a positive crude association between a history of low back injury in a MVC and the development of troublesome LBP over a 12-month period (HRR = 2.76; 95% CI 1.42-5.39). Controlling for arthritis reduced this association (HRR = 2.25; 95% CI 1.11-4.56). Adding confounders that may be on the casual pathway (baseline LBP, depression and HRQoL) to the multivariable model further reduced the association (HRR = 2.20; 95% CI 1.04-4.68). CONCLUSION: Our analysis suggests that a history of low back injury in a MVC is a risk factor for developing future troublesome LBP. The consequences of a low back injury in a MVC can predispose individuals to experience recurrent episodes of low back pain.

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.

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.

What is the definition of sports-related concussion: a systematic review.

OBJECTIVES: Various definitions for concussion have been proposed, each having its strengths and weaknesses. We reviewed and compared current definitions and identified criteria necessary for an operational definition of sports-related concussion (SRC) in preparation of the 5th Concussion Consensus Conference (Berlin, Germany). We also assessed the role of biomechanical studies in informing an operational definition of SRC. DESIGN: This is a systematic literature review. DATA SOURCES: Data sources include MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Register of Clinical Trials and SPORT Discus (accessed 14 September 2016). ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Eligibility criteria were studies reporting (clinical) criteria for diagnosing SRC and studies containing SRC impact data. RESULTS: Out of 1601 articles screened, 36 studies were included (2.2%), 14 reported on criteria for SRC definitions and 22 on biomechanical aspects of concussions. Six different operational definitions focusing on clinical findings and their dynamics were identified. Biomechanical studies were obtained almost exclusively on American football players. Angular and linear head accelerations linked to clinically confirmed concussions demonstrated considerable individual variation. SUMMARY/CONCLUSIONS: SRC is a traumatic brain injury that is defined as a complex pathophysiological process affecting the brain, induced by biomechanical forces with several common features that help define its nature. Limitations identified include that the current criteria for diagnosing SRC are clinically oriented and that there is no gold/standard to assess their diagnostic properties. A future, more valid definition of SRC would better identify concussed players by demonstrating high predictive positive/negative values. Currently, the use of helmet-based systems to study the biomechanics of SRC is limited to few collision sports. New approaches need to be developed to provide objective markers for SRC.

Musculoskeletal Injury in Professional Dancers: Prevalence and Associated Factors: An International Cross-Sectional Study.

OBJECTIVE: The purpose of the study was to determine the prevalence and factors associated with injury in professional ballet and modern dancers, and assess if dancers are reporting their injuries and explore reasons for not reporting injuries. DESIGN: Cross-sectional study. SETTING: Participants were recruited from nine professional ballet and modern dance companies in Canada, Denmark, Israel, and Sweden. PARTICIPANTS: Professional ballet and modern dancers. INDEPENDENT VARIABLES: Sociodemographic variables included age, sex, height, weight, and before-tax yearly or monthly income. Dance specific characteristics included number of years in present dance company, number of years dancing professionally, number of years dancing total, and rank in the company. MAIN OUTCOME MEASURES: Self-reported injury and Self-Estimated Functional Inability because of Pain. RESULTS: A total of 260 dancers participated in the study with an overall response rate of 81%. The point prevalence of self-reported injury in professional ballet and modern dancers was 54.8% (95% CI, 47.7-62.1) and 46.3% (95% CI, 35.5-57.1), respectively. Number of years dancing professionally (OR = 4.4, 95% CI, 1.6-12.3) and rank (OR = 2.4, 95% CI, 1.2-4.8) were associated with injury in ballet dancers. More than 15% of all injured dancers had not reported their injury and their reasons for not reporting injury varied. CONCLUSIONS: The prevalence of injury is high in professional dancers with a significant percentage not reporting their injuries for a variety of reasons. Number of years dancing and rank are associated with injury in professional ballet dancers.

Risk of Carotid Stroke after Chiropractic Care: A Population-Based Case-Crossover Study.

BACKGROUND: Chiropractic manipulation is a popular treatment for neck pain and headache, but may increase the risk of cervical artery dissection and stroke. Patients with carotid artery dissection can present with neck pain and/or headache before experiencing a stroke. These are common symptoms seen by both chiropractors and primary care physicians (PCPs). We aimed to assess the risk of carotid artery stroke after chiropractic care by comparing association between chiropractic and PCP visits and subsequent stroke. METHODS: A population-based, case-crossover study was undertaken in Ontario, Canada. All incident cases of carotid artery stroke admitted to hospitals over a 9-year period were identified. Cases served as their own controls. Exposures to chiropractic and PCP services were determined from health billing records. RESULTS: We compared 15,523 cases to 62,092 control periods using exposure windows of 1, 3, 7, and 14 days prior to the stroke. Positive associations were found for both chiropractic and PCP visits and subsequent stroke in patients less than 45 years of age. These associations tended to increase when analyses were limited to visits for neck pain and headache-related diagnoses. There was no significant difference between chiropractic and PCP risk estimates. We found no association between chiropractic visits and stroke in those 45 years of age or older. CONCLUSIONS: We found no excess risk of carotid artery stroke after chiropractic care. Associations between chiropractic and PCP visits and stroke were similar and likely due to patients with early dissection-related symptoms seeking care prior to developing their strokes.

Is Sex an Indicator of Prognosis After Mild Traumatic Brain Injury: A Systematic Analysis of the Findings of the World Health Organization Collaborating Centre Task Force on Mild Traumatic Brain Injury and the International Collaboration on Mild Traumatic Brain Injury Prognosis.

OBJECTIVE: To determine sex differences in the recovery and prognosis after mild traumatic brain injury (MTBI) in adults and children. DATA SOURCES: We analyzed all scientifically admissible primary studies in the World Health Organization (WHO) (n=120) and International Collaboration on Mild Traumatic Brain Injury Prognosis (ICoMP) (n=101) systematic reviews regarding prognosis of MTBI for sex-stratified findings. They searched MEDLINE and other databases from 1980 through 2000 (WHO) and 2001 through 2012 (ICoMP) for published, peer-reviewed reports in English and other languages. STUDY SELECTION: We selected controlled trials and cohort and case-control studies that assessed the effect of sex on outcomes after MTBI. DATA EXTRACTION: Data from the eligible studies from both systematic reviews combined (n=14, 7%) were extracted into evidence tables. DATA SYNTHESIS: Prognostic information relating to sex was prioritized according to design as exploratory or confirmatory, and a best-evidence synthesis was conducted. After MTBI, females may have a higher risk of epilepsy (children, young adults) and suicide, and use more health care services; males may be at higher risk for schizophrenia. Most studies did not find a sex difference for postconcussion symptoms in children and adults. No sex difference was found for risk of dementia and primary brain tumor, return to work, or posttraumatic stress syndrome. CONCLUSIONS: Sex is not a well-studied prognostic indicator for recovery after MTBI, but small sex differences were found for some outcomes. More well-designed studies are needed that report outcomes according to sex and control for potential confounders.

Effect of Early Intensive Care on Recovery From Whiplash-Associated Disorders: Results of a Population-Based Cohort Study.

OBJECTIVE: To determine whether the results from previous research suggesting that early intensive health care delays recovery from whiplash-associated disorders (WADs) were confounded by expectations of recovery and whether the association between early health care intensity and time to recovery varies across patterns of health care. DESIGN: Population-based inception cohort. SETTING: All adults (≥18y) injured in motor vehicle collisions who received treatment from a regulated health professional or reported their injuries to the single provincially administered motor vehicle insurer. PARTICIPANTS: Participants with WAD (N=5204). Self-report visits to physicians, chiropractors, physiotherapists, massage therapists, and other professionals during the first 42 days postcollision were used to define health care intensity. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Self-perceived recovery. RESULTS: Individuals with high utilization health care had slower recovery independent of expectation of recovery and other confounders. Compared with individuals who reported low utilization of physician services, recovery was slower for those with high health care utilization, regardless of the type of profession. For instance, those with high physician (hazard rate ratio [HRR]=.56; 95% confidence interval [CI], .42-.75), physician and high physiotherapy utilization (HRR=.68; 95% CI, .61-.77), physician and high chiropractor utilization (HRR=.74; 95% CI, .64-.85), and physician and high massage therapy utilization (HRR=.78; 95% CI, .68-.90) had significantly slower recovery. CONCLUSIONS: Our study adds to the existing evidence that early intensive care is associated with slower recovery from WAD, independent of expectation of recovery. The results have policy implications and suggest that the optimal management of WADs focuses on reassurance and education instead of intensive care.

Healthy and productive workers: using intervention mapping to design a workplace health promotion and wellness program to improve presenteeism.

BACKGROUND: Presenteeism is a growing problem in developed countries mostly due to an aging workforce. The economic costs related to presenteeism exceed those of absenteeism and employer health costs. Employers are implementing workplace health promotion and wellness programs to improve health among workers and reduce presenteeism. How best to design, integrate and deliver these programs are unknown. The main purpose of this study was to use an intervention mapping approach to develop a workplace health promotion and wellness program aimed at reducing presenteeism. METHODS: We partnered with a large international financial services company and used a qualitative synthesis based on an intervention mapping methodology. Evidence from systematic reviews and key articles on reducing presenteeism and implementing health promotion programs was combined with theoretical models for changing behavior and stakeholder experience. This was then systematically operationalized into a program using discussion groups and consensus among experts and stakeholders. RESULTS: The top health problem impacting our workplace partner was mental health. Depression and stress were the first and second highest cause of productivity loss respectively. A multi-pronged program with detailed action steps was developed and directed at key stakeholders and health conditions. For mental health, regular sharing focus groups, social networking, monthly personal stories from leadership using webinars and multi-media communications, expert-led workshops, lunch and learn sessions and manager and employee training were part of a comprehensive program. Comprehensive, specific and multi-pronged strategies were developed and aimed at encouraging healthy behaviours that impact presenteeism such as regular exercise, proper nutrition, adequate sleep, smoking cessation, socialization and work-life balance. Limitations of the intervention mapping process included high resource and time requirements, the lack of external input and viewpoints skewed towards middle and upper management, and using secondary workplace data of unknown validity and reliability. CONCLUSIONS: In general, intervention mapping was a useful method to develop a workplace health promotion and wellness program aimed at reducing presenteeism. The methodology provided a step-by-step process to unravel a complex problem. The process compelled participants to think critically, collaboratively and in nontraditional ways.

Update and Overview of Spinal Injuries in Canadian Ice Hockey, 1943 to 2011: The Continuing Need for Injury Prevention and Education.

OBJECTIVE: To identify spinal injuries in Canadian ice hockey from 2006 to 2011 and to discuss data from 1943 to 2011 and impact of injury prevention programs. DESIGN: Data about spinal injuries with and without spinal cord injury in ice hockey have been collected by ThinkFirst's (now Parachute Canada) Canadian Ice Hockey Spinal Injuries Registry since 1981 through questionnaires from practitioners, ice hockey organizations, and media. SETTING: All Canadian provinces and territories. PARTICIPANTS: All registered Canadian ice hockey players. ASSESSMENT OF RISK FACTORS: Age, gender, level of play, location, mechanism of injury. MAIN OUTCOME MEASURES: Incidence, incidence rate, prevalence, and nature (morbidity) of the injuries. RESULTS: Between 2006 and 2011, 44 cases occurred, 4 (9.1%) of which were severe. The incidence in the recent years continues to be lower than the peak years. From 1943 to 2011, 355 cases have been documented, primarily males (97.7%) and cervical spine injuries (78.9%), resulting from impact with the boards (64.2%). Check or push from behind (36.0%) was still the most common cause of injury, although slightly lower during 2006 to 2011. From 1943 to 2011, Prince Edward Island, New Brunswick, and British Columbia/Yukon had the highest injury rates. Ontario and Quebec continued to show markedly different injury rates, with Ontario more than twice that of Quebec. CONCLUSIONS: Current data for 2006 to 2011 indicate that spinal injuries in ice hockey continue to occur, although still at lower rates than the peak years 1982 to 1995. It is imperative to continue educating players and team officials about spinal injury prevention and to reinforce the rules against checking or pushing from behind to reduce the incidence of these serious injuries.

Modeling community integration in workers with delayed recovery from mild traumatic brain injury.

BACKGROUND: Delayed recovery in persons after mild traumatic brain injury (mTBI) is poorly understood. Community integration (CI) is endorsed by persons with neurological disorders as an important outcome. We aimed to describe CI and its associated factors in insured Ontario workers with delayed recovery following mTBI. METHODS: A cross-sectional study of insured workers in the chronic phase following mTBI was performed at a rehabilitation hospital in Ontario, Canada. Sociodemographic, occupational, injury-related, clinical, and claim-related data were collected from self-reports, medical assessments, and insurers' referral files. Community Integration Questionnaire (CIQ) scores were compared using analysis of variance or Spearman's correlation tests. Stepwise multivariable linear regression models were used to evaluate the associations with CI. RESULTS: Ninety-four workers with mTBI (45.2 ± 9.9 years old, 61.2% male) at 197 days post-injury (interquartile range, 139-416 days) were included. The CIQ total and subscale scores were similar to those reported in more severe TBI samples. The CIQ scores were moderately to strongly correlated with various sociodemographic, claim-related, and clinical variables. In the multivariable regression analysis, several covariates accounted for 36.4% of the CIQ variance in the final fully adjusted model. DISCUSSION: This study evaluated CI in workers with mTBI, and analyzed its associated variables. Analysis revealed insomnia, head or neck pain, being married or in a relationship, time since injury, and a diagnosis of possible/probable malingering were independently associated with limited CI. CONCLUSIONS: Workers with delayed recovery from mTBI experience difficulty with CI. Insomnia is a particularly relevant covariate, explaining the greater part of its variance. To enhance participation, care should focus on clinical and non-clinical covariates.

Is low back pain associated with worse health-related quality of life 6 months later?

PURPOSE: The purpose of this study was to investigate the impact of low back pain (LBP) on future health-related quality of life (HRQoL). Current evidence suggests that individuals with LBP have poorer HRQoL than those without LBP. However, most of the evidence comes from cross-sectional studies where LBP and HRQoL are determined at the same time. One prospective study examined the association between days with LBP and HRQoL but did not account for the intensity of LBP. Therefore, this association needs to be tested in a large prospective population-based sample with a valid measure of LBP and adequate control of known confounders. METHODS: We formed a cohort of 1,110 randomly sampled Saskatchewan adults in September 1995. LBP at baseline was measured with the chronic pain questionnaire. The SF-36 questionnaire was used to measure physical and mental HRQoL at 6 months follow-up. Multivariable linear regression was used to estimate the association between graded LBP at baseline and HRQoL at 6 months while controlling for the effects of confounding. RESULTS: The 6-month follow-up rate was 70.7 % (785/1,110). LBP had a dose-response relationship with worsening physical HRQoL at 6 months, after controlling for age, income, arthritis, neck pain, and kidney disorders: grade III-IV LBP (ß = -10.23; 95 % CI -12.46, -7.99), grade II LBP (ß = -6.72, 95 % CI -8.79, -4.65), and grade I LBP (ß = -1.77; 95 % CI -3.18, -0.36). There was no dose-response relationship between LBP and mental HRQoL at 6 months. CONCLUSIONS: Low back pain has an impact on future physical HRQoL. Strategies for reducing the effects of LBP on HRQoL should be an important focus for clinicians, researchers, and health policy makers.

Chiropractors' characteristics associated with physician referrals: results from a survey of Canadian doctors of chiropractic.

OBJECTIVE: The purpose of this study was to identify characteristics of Canadian doctors of chiropractic (DCs) associated with the number of patients referred by medical doctors (MDs). METHODS: Secondary data analyses were performed on the 2011 cross-sectional survey of the Canadian Chiropractic Resources Databank. The Canadian Chiropractic Resources Databank survey included 81 questions about the practice of DCs. Of the 6533 mailed questionnaires, 2529 (38.7%) were returned and 489 did not meet our inclusion criteria. Our analyzed sample included 2040 respondents. Bivariate analyses were conducted between predetermined potential predictors and the annual number of patients referred by MDs, and negative binomial multivariate regression was performed. RESULTS: On average, DCs reported receiving 15.6 (standard deviation, 31.3) patient referrals from MDs per year and nearly one-third did not receive any. The type of clinic (multidisciplinary with MD), the province of practice (Atlantic provinces), the number of treatments provided per week, the number of practicing hours, rehabilitation and sports injuries as the main sector of activity, prescription of exercises, use of heat packs and ultrasound, and the percentage of patients referred to other health care providers were associated with a higher number of MD referrals to DCs. The percentage of patients with somatovisceral conditions, using a particular chiropractic technique (hole in one and Thompson), taking his/her own radiographs, being the client of a chiropractic management service, and considering maintenance/wellness care as a main sector of activity were associated with fewer MD referrals. CONCLUSION: Canadian DCs who interacted with other health care workers and who focus their practice on musculoskeletal conditions reported more referrals from MDs.

A Test-Retest Reliability Study of the Whiplash Disability Questionnaire in Patients With Acute Whiplash-Associated Disorders.

OBJECTIVE: The purpose of this study was to determine the test-retest reliability and the Minimal Detectable Change (MDC) of the Whiplash Disability Questionnaire (WDQ) in individuals with acute whiplash-associated disorders (WADs). METHODS: We performed a test-retest reliability study. We included insurance claimants from Ontario who were at least 18 years of age, within 21 days of their motor vehicle collision and diagnosed as having acute WAD grades I to III. The WDQ, a 13-item questionnaire scored from 0 (no disability) to 130 (complete disability), was administered to all participants at baseline and by telephone 3 days later. We computed the intraclass correlation coefficient (model 2,1) and the MDC with 95% confidence intervals (CIs; MDC95). RESULTS: The mean (SD) age of the 66 participants was 41.6 (12.7) years and 71.2% were female. Twenty-nine percent had WAD I and 71.2% had WAD II. Time since injury ranged from 0 to 19 days. The mean (SD) baseline WDQ score was 49.3 (28.8) and 46.5 (29.8) 3 days later. The intraclass correlation coefficient for the WDQ total score was 0.89 (95% CI, 0.85-0.92) in the entire sample and 0.83 (95% CI, 0.69-0.93) for the 15 participants reporting no change in neck pain. The MDC95 of the WDQ was 21.4 (SD = 14.9) for participants reporting no change. CONCLUSION: The WDQ was reliable in individuals with acute WAD. There is 95% confidence that a change of approximately one-sixth of the total score is beyond the daily variation of a stable condition. This level of measurement error must be taken into consideration when interpreting change in WDQ scores.

Population-based, inception cohort study of the incidence, course, and prognosis of mild traumatic brain injury after motor vehicle collisions.

OBJECTIVE: To determine the incidence, course, and prognosis of adult mild traumatic brain injury (MTBI) caused by motor vehicle collisions. DESIGN: Prospective, population-based, inception cohort study. SETTING: The province of Saskatchewan, Canada, with a population of about 1,000,000 inhabitants. PARTICIPANTS: All adults (N=1716) incurring an MTBI in a motor vehicle collision between November 1997 and December 1999 in Saskatchewan. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Age- and sex-stratified incidence rates, time to self-reported recovery, and prognostic factors over a 1-year follow-up. RESULTS: Of 7170 adults injured in a motor vehicle collision over the 2-year inception period, 1716 (24%) met our cohort definition of MTBI. There were more women affected (53%), and MTBI was most common in the 18- to 23-year-old group. Most were not hospitalized (73%), but 28% reported loss of consciousness and 23% reported posttraumatic amnesia. The annual incidence of MTBI per 100,000 adults was 106.1 (95% confidence interval [CI], 98.9-113.6) in the first year and 118.3 (95% CI, 110.8-126.3) in the second year of the study. The 1-year follow-up rate was 84%. The median time to recovery was 100 days (95% CI, 97-103), and about 23% reported not having recovered by 1 year. Factors associated with delayed recovery included being older than 50 years, having less than a high school education, having poor expectations for recovery, having depressive symptoms, having arm numbness, having hearing problems, having headaches, having low back pain, and having thoracic back pain. Loss of consciousness and posttraumatic amnesia were not associated with recovery. CONCLUSIONS: MTBI affects almost a quarter of persons reporting an injury after a traffic collision. The median time to recovery is 100 days, but 23% have still not recovered by 1 year. A mix of biopsychosocial factors is associated with recovery, including a strong effect of poor expectations for recovery.

Mild traumatic brain injury after motor vehicle collisions: what are the symptoms and who treats them? A population-based 1-year inception cohort study.

OBJECTIVE: To describe the 1-year course of symptoms following mild traumatic brain injury (MTBI) sustained in a motor vehicle collision as well as patterns of care-seeking. DESIGN: One-year follow-up of a population-based inception cohort. SETTING: The province of Saskatchewan, Canada, with a population of about 1,000,000 inhabitants. PARTICIPANTS: Persons (N=1716) sustaining an MTBI during a car collision between November 1997 and December 1999. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: We report the prevalence of sleep disturbances, tiredness, dizziness, forgetfulness, vision problems, hearing problems, headache, neck pain, mid back pain, and low back pain at 6 weeks and 3, 6, 9, and 12 months postcollision. At the same time points, we report self-reported care-seeking from registered health care professionals. RESULTS: A total of 1716 adults suffered MTBI after a motor vehicle collision over the 2-year inception period. Six weeks after the collision, 75% reported having more than 3 symptoms and 30% had clinically significant pain in more than 3 body sites. Over time, the prevalence of symptoms and pain decreased but they were still common after 1 year. Almost all participants sought care for their symptoms at all time points, most commonly from a physician. Care-seeking from physiotherapists, chiropractors, and massage therapists was also very common, and most participants sought care from 2 or 3 providers at all follow-up points. CONCLUSIONS: Up to 1 year after sustaining an MTBI during a motor vehicle collision, multiple symptoms and pain in several anatomical sites are common. Care-seeking from multiple providers continues throughout the first year postinjury.

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.