Causal assessment of occupational sitting and low back pain: results of a systematic review

Background contextLow back pain (LBP) is a common and disabling musculoskeletal disorder that often occurs in a working-age population. Determining the precise causation of LBP remains difficult. Any attempt to implicate a specific occupational activity in the genesis of LBP requires a methodologically rigorous approach.PurposeTo conduct a systematic review of the scientific literature focused on evaluating the causal relationship between occupational sitting and LBP.Study designSystematic review of the literature using Medline, EMBASE, CINAHL, Cochrane Library, Occupational Safety and Health database, grey literature, hand-searching occupational health journals, reference lists of included studies, and content experts. Evaluation of study quality using a modified version of the Newcastle-Ottawa Scale. Summary levels of evidence supporting Bradford-Hill criteria for different categories of sitting and types of LBP.SamplesStudies reporting an association between occupational sitting and LBP.Outcome measuresNumerical association between different levels of exposure to occupational sitting and the presence or severity of LBP.MethodsA systematic review was performed to identify, evaluate, and summarize the literature related to establishing a causal relationship, according to Bradford-Hill criteria, between occupational sitting and LBP.ResultsThis search yielded 2,766 citations. Twenty-four studies met the inclusion/exclusion criteria and five were high-quality studies, including two case-controls and three prospective cohorts. Strong, consistent evidence was found for no association between occupational sitting and LBP. A moderate level of evidence was found for the absence of any dose-response trend. Risk estimates evaluating temporality were not statistically significant. Biological plausibility was not discussed in these studies. No evidence was available to assess the experiment criterion.ConclusionsThis review failed to uncover high-quality studies to support any of the Bradford-Hill criteria to establish causality between occupational sitting and LBP. Strong and consistent evidence did not support criteria for association, temporality, and dose response. Based on these results, it is unlikely that occupational sitting is independently causative of LBP in the populations of workers studied.     

Causal assessment of occupational lifting and low back pain: results of a systematic review

Background ContextLow back pain (LBP) is a disorder that commonly affects the working population, resulting in disability, health-care utilization, and a heavy socioeconomic burden. Although the etiology of LBP remains uncertain, occupational activities have been implicated. Evaluating these potentially causal relationships requires a methodologically rigorous approach. Occupational repetitive and/or heavy lifting is widely thought to be a risk factor for the development of LBP.PurposeTo conduct a systematic review of the scientific literature to evaluate the causal relationship between occupational lifting and LBP.Study DesignSystematic review of the literature.SampleStudies reporting an association between occupational lifting and LBP.Outcome MeasuresNumerical association between different levels of exposure to occupational lifting and the presence or severity of LBP.MethodsA search was conducted using Medline, EMBASE, CINAHL, Cochrane Library, OSH-ROM, gray literature (eg, reports not published in scientific journals), hand-searching occupational health journals, reference lists of included studies, and content experts. Evaluation of study quality was performed using a modified version of the Newcastle-Ottawa Scale. Levels of evidence were evaluated for specific Bradford-Hill criteria (association, dose-response, temporality, experiment, and biological plausibility).ResultsThis search yielded 2,766 citations, of which 35 studies met eligibility criteria and 9 were considered high methodological quality studies, including four case-controls and five prospective cohorts. Among the high-quality studies, there was conflicting evidence for association with four studies reporting significant associations and five studies reporting nonsignificant results. Two of the three studies that assessed dose-response demonstrated a nonsignificant trend. There were no significant risk estimates that demonstrated temporality. No studies were identified that satisfied the experiment criterion. Subgroup analyses identified certain types of lifting and LBP that had statistically significant results, but there were none that satisfied more than two of the Bradford-Hill criteria.ConclusionsThis review uncovered several high-quality studies examining a relationship between occupational lifting and LBP, but these studies did not consistently support any of the Bradford-Hill criteria for causality. There was moderate evidence of an association for specific types of lifting and LBP. Based on these results, it is unlikely that occupational lifting is independently causative of LBP in the populations of workers studied. Further research in specific subcategories of lifting would further clarify the presence or absence of a causal relationship.     

Causal assessment of awkward occupational postures and low back pain: results of a systematic review

Background contextLow back pain (LBP) is a prevalent and costly musculoskeletal disorder that often occurs in the working-age population. Although numerous physical activities have been implicated in its complex etiology, determining causation remains challenging and requires a methodologically rigorous approach.PurposeTo conduct a systematic review of the scientific literature focused on establishing a causal relationship between awkward occupational postures and LBP.Study designSystematic review of the literature using MEDLINE, EMBASE, CINAHL, Cochrane Library, and Occupational Safety and Health database, gray literature, hand-searching occupational health journals, reference lists of included studies, and experts. Evaluation of methodological quality using a modified Newcastle-Ottawa Scale for observational studies. Summary levels of evidence for each of the Bradford Hill criteria for causality for each category of awkward occupational posture and type of LBP.SampleStudies reporting an association between awkward occupational postures and LBP.Outcome measuresNumerical association between different levels of exposure to awkward occupational postures and the presence or severity of LBP.MethodsA systematic review was performed to identify, evaluate, and summarize the literature related to establishing a causal relationship, according to Bradford Hill criteria, between awkward occupational postures and LBP.ResultsThis search yielded 2,766 citations. Eight high-quality studies reported on awkward occupational postures and LBP. Three were case-control studies, one was cross-sectional, and four were prospective cohort studies. There was strong evidence for consistency of no association between awkward occupational postures and LBP, with only two studies demonstrating significant associations in most of their risk estimates compared with six studies reported mainly nonsignificant associations. Two studies assessed dose response, with one study demonstrating a nonsignificant dose-response trend. Three studies were able to assess temporality, but all demonstrated nonsignificant risk estimates. Biological plausibility was discussed by two studies. There was no available evidence to assess the experiment criterion for causality.ConclusionsThere was strong evidence from six high-quality studies that there was no association between awkward postures and LBP. Similarly, there was strong evidence from three high-quality studies that there was no temporal relationship. Moreover, subgroup analyses identified only a handful of studies that demonstrated only weak associations and no evidence for other aspects of causality in certain specific subcategories. It is therefore unlikely that awkward occupational postures are independently causative of LBP in the populations of workers studied.     

Causal assessment of occupational bending or twisting and low back pain: results of a systematic review

Background contextLow back pain (LBP) is a common musculoskeletal disorder that often occurs in the working-age population. Although numerous physical activities have been implicated in its etiology, determining causation remains challenging and requires a methodologically rigorous approach.PurposeTo conduct a systematic review focused on establishing a causal relationship between occupational bending or twisting and LBP.Study designA systematic review of the literature using Medline, Embase, CINAHL, Cochrane Library, and Occupational Safety and Health database, gray literature, hand-searching occupational health journals, reference lists of included studies, and experts. Evaluation of methodological quality using a modified Newcastle-Ottawa Scale for observational studies. Summary levels of evidence for each of the Bradford-Hill criteria for causality for each category of bending or twisting and type of LBP.SampleStudies reporting an association between occupational bending or twisting and LBP.Outcome measuresNumerical association between different levels of exposure to bending or twisting and the presence or severity of LBP.MethodsA systematic review was performed to identify, evaluate, and summarize the literature related to establishing a causal relationship, according to Bradford-Hill criteria, between occupational bending or twisting and LBP.ResultsThis search yielded 2,766 citations. Ten high-quality studies reported on bending and LBP. Five were case-control studies and five were prospective cohort studies. There was conflicting evidence for association, with five studies demonstrating significant associations in the majority of their risk estimates, but no evidence for consistency. Seven studies assessed dose response, with four studies demonstrating a nonsignificant dose-response trend. Four studies were able to assess temporality, but only one demonstrated significant risk estimates. Biological plausibility was discussed by two studies. There was no available evidence for experiment. Seven high-quality studies reported on twisting and LBP. Two were case-control studies and five were prospective cohort studies. Three studies reported significant associations in the majority of their risk estimates, with no evidence for consistency. Three studies demonstrated a nonsignificant dose-response trend. Two studies were able to assess temporality, but only one study was able to demonstrate significant risk estimates. Two studies discussed biological plausibility. There was no available evidence for experiment.ConclusionsA summary of existing studies was not able to find high-quality studies that satisfied more than three of the Bradford-Hill criteria for causation for either occupational bending or twisting and LBP. Conflicting evidence in multiple criteria was identified. This suggests that specific subcategories could contribute to LBP. However, the evidence suggests that occupational bending or twisting in general is unlikely to be independently causative of LBP.     

Causal assessment of occupational standing or walking and low back pain: results of a systematic review

Background contextLow back pain (LBP) is a widespread musculoskeletal condition that frequently occurs in the working-age population. Numerous occupational physical activities have been implicated in its etiology.PurposeTo conduct a systematic review establishing a causal relationship between occupational standing or walking and LBP.Study designSystematic review of the literature.SampleStudies reporting an association between occupational standing or walking and LBP.Outcome measuresNumerical association between exposure to standing or walking and the presence of LBP.MethodsA systematic review was performed to identify, evaluate, and summarize the literature related to establishing a causal relationship, according to Bradford-Hill criteria for causality, between occupational standing or walking and LBP. A search was conducted using MEDLINE, Embase, CINAHL, Cochrane Library, and Occupational Safety and Health database, gray literature, hand-searching occupational health journals, reference lists of included studies, and expert knowledge. Evaluation of methodological quality was performed using a modified Newcastle-Ottawa Scale.ResultsThis search yielded 2,766 citations. Eighteen studies met the inclusion criteria. Five were high-quality studies related to standing, and two were high-quality studies related to walking. For occupational standing and LBP, there was moderate to strong evidence against the association criterion, the only study examining dose response did not support this criterion, four studies examining temporality failed to support this criterion, and only one study discussed the biological plausibility criterion. For occupational walking and LBP, there was moderate evidence against a causal relationship with respect to the association, temporality, dose response, and biological plausibility criteria. No studies assessed the experiment criterion for these activities.ConclusionsA summary of existing studies was not able to find any high-quality studies that satisfied more than two of the Bradford-Hill causation criteria for occupational standing or walking and LBP. Based on the evidence reviewed, it is unlikely that occupational standing or walking is independently causative of LBP in the populations of workers studied.     

Causal assessment of occupational pushing or pulling and low back pain: results of a systematic review

Background ContextLow back pain (LBP) is a prevalent and expensive musculoskeletal condition that predominantly occurs in working-age individuals of industrialized nations. Although numerous occupational physical activities have been implicated in its etiology, determining the causation of occupational LBP still remains a challenge.PurposeTo conduct a systematic review evaluating the causal relationship between occupational pushing or pulling and LBP.Study DesignSystematic review of the literature.SampleStudies reporting an association between occupational pushing or pulling and LBP.Outcome MeasuresNumerical association between exposure to pushing or pulling and the presence of LBP.MethodsA systematic review was performed to identify, evaluate, and summarize the literature related to establishing a causal relationship, according to Bradford-Hill criteria for causation for occupational pushing or pulling and LBP. A search was conducted using Medline, EMBASE, CINAHL, Cochrane Library, and OSH-ROM, gray literature, hand-searching occupational health journals, reference lists of included studies, and expert knowledge. Methodological quality was assessed using a modified Newcastle-Ottawa Scale.ResultsThis search yielded 2,766 citations. Thirteen studies met the inclusion criteria. Eight were high-quality studies and five were low-quality studies. There was conflicting evidence with one high-quality study demonstrating a positive association between occupational pushing or pulling and LBP and five studies showing no relationship. One study reported a nonstatistically significant dose-response trend, four studies discussed temporality of which one indicated a positive finding, two studies discussed the biological plausibility of a causal link between occupational pushing or pulling and LBP, and no evidence was uncovered to assess the experiment criterion.ConclusionsA qualitative summary of existing studies was not able to find any high-quality studies that fully satisfied any of the Bradford-Hill causation criteria for occupational pushing or pulling and LBP. Based on the evidence reviewed, it is unlikely that occupational pushing or pulling is independently causative of LBP in the populations of workers studied.     

Causal assessment of workplace manual handling or assisting patients and low back pain: results of a systematic review

Background ContextLow back pain (LBP) is a common musculoskeletal disorder associated with a considerable social and economic burden within the working-age population. Despite an unclear etiology, numerous physical activities are suspected of leading to LBP. Declaring a causal relationship between occupational activities and LBP remains challenging and requires a methodologically rigorous approach.PurposeTo conduct a systematic review focused on assessing the potentially causal relationship between workplace manual handling or assisting patients and LBP.Study DesignSystematic review of the literature.SamplesStudies reporting an association between workplace manual handling or assisting patients and LBP.Outcome MeasuresNumerical association between different levels of exposure to manual handling or assisting patients, and the presence or severity of LBP.MethodsA systematic review was conducted using Medline, EMBASE, CINAHL, Cochrane Library, and Occupational Safety and Health database, gray literature, hand-searching occupational health journals, reference lists of included studies, and content experts. The methodological quality of each study was assessed using a modified Newcastle-Ottawa Scale (NOS) for observational studies. The overall level of evidence supporting various Bradford-Hill criteria for causality for each category of manual handling or assisting patients and type of LBP was then evaluated. Studies were deemed of higher quality if they received a score of five or more on the modified NOS and used appropriate statistical analysis methods.ResultsThis search yielded 2,766 citations, and 32 studies met the eligibility criteria. Three high-quality studies reported on manual handling and LBP, including two prospective cohorts and one cross-sectional design. None demonstrated a significant association in most of their multivariate risk estimates. One study was able to assess dose-response and temporality, but its results did not support these criteria. Only one study discussed the biological plausibility of this association. Four high-quality studies evaluated assisting patients and LBP, including two case-controls, one cross-sectional, and one prospective cohort design. These studies were consistent in reporting no significant association. Two studies demonstrated a nonsignificant dose-response trend, and two studies discussed the biological plausibility of this association. No studies were able to demonstrate the temporality or experiment criteria.ConclusionsThe studies reviewed did not support a causal association between workplace manual handling or assisting patients and LBP in a Bradford-Hill framework. Conflicting evidence in specific subcategories of assisting patients was identified, suggesting that tasks such as assisting patients with ambulation may possibly contribute to LBP. It appears unlikely that workplace manual handling or assisting patients is independently causative of LBP in the populations of workers studied.     

The Prevalence of low back pain in Africa: a systematic review

Background  

Low back pain (LBP) is the most prevalent musculoskeletal condition and one the most common causes of disability in the developed nations. Anecdotally, there is a general assumption that LBP prevalence in Africa is comparatively lower than in developed countries. The aim of this review was to systematically appraise the published prevalence studies conducted on the African continent to establish the prevalence of LBP in Africa.     

Cost-effectiveness of guideline-endorsed treatments for low back pain: a systematic review

Healthcare costs for low back pain (LBP) are increasing rapidly. Hence, it is important to provide treatments that are effective and cost-effective. The purpose of this systematic review was to investigate the cost-effectiveness of guideline-endorsed treatments for LBP. We searched nine clinical and economic electronic databases and the reference list of relevant systematic reviews and included studies for eligible studies. Economic evaluations conducted alongside randomised controlled trials investigating treatments for LBP endorsed by the guideline of the American College of Physicians and the American Pain Society were included. Two independent reviewers screened search results and extracted data. Data extracted included the type and perspective of the economic evaluation, the treatment comparators, and the relative cost-effectiveness of the treatment comparators. Twenty-six studies were included. Most studies found that interdisciplinary rehabilitation, exercise, acupuncture, spinal manipulation or cognitive-behavioural therapy were cost-effective in people with sub-acute or chronic LBP. Massage alone was unlikely to be cost-effective. There were inconsistent results on the cost-effectiveness of advice, insufficient evidence on spinal manipulation for people with acute LBP, and no evidence on the cost-effectiveness of medications, yoga or relaxation. This review found evidence supporting the cost-effectiveness of the guideline-endorsed treatments of interdisciplinary rehabilitation, exercise, acupuncture, spinal manipulation and cognitive-behavioural therapy for sub-acute or chronic LBP. There is little or inconsistent evidence for other treatments endorsed in the guideline.     

Physical activity and low back pain: a systematic review of recent literature

The objective of the study is to systematically evaluate the available evidence on the association between physical activity (i.e. occupational load and non-occupational physical activities) and low back pain (LBP). A systematic approach was used to explore the literature between 1999 and 2009. Studies were selected for inclusion following a comprehensive search of Medline, Embase and CINAHL. The methodological quality of each study was assessed. Studies were considered to be of ‘high quality’ if they met the cut-off criterion of 60% of the maximum available quality score. Thirty-six cohort or case–control studies were retrieved. Heavy workload and the accumulation of loads or frequency of lifts were moderate to strong risk factors for LBP. Strong associations were found for flexed, rotated and the awkward positions of the lumbar spine. Inconsistent results were found for leisure time physical activities, sports and physical exercise. Studies focusing on daily habitual physical activities (e.g. domestic activities and commuting) in association with LBP are lacking. In conclusion, the occurrence of LBP is related to the nature and intensity of the physical activities undertaken. However, physical activities can be subdivided into separate types and intensities and the ultimate physical load is the sum of all these activities. This makes it difficult to designate one particular activity as the cause of LBP.     

Screening for malignancy in low back pain patients: a systematic review

To describe the accuracy of clinical features and tests used to screen for malignancy in patients with low back pain. A systematic review was performed on all available records on MEDLINE, EMBASE, and CINAHL electronic databases. Studies were considered eligible if they investigated a cohort of low back pain patients, used an appropriate reference standard, and reported sufficient data on the diagnostic accuracy of tests. Two authors independently assessed methodological quality and extracted data to calculate positive (LR+) and negative (LR−) likelihood ratios. Six studies evaluating 22 different clinical features and tests were identified. The prevalence of malignancy ranged from 0.1 to 3.5%. A previous history of cancer (LR+ = 23.7), elevated ESR (LR+ = 18.0), reduced hematocrit (LR+ = 18.2), and overall clinician judgement (LR+ = 12.1) increased the probability of malignancy when present. A combination of age ≥50 years, a previous history of cancer, unexplained weight loss, and failure to improve after 1 month had a reported sensitivity of 100%. Overall, there was poor reporting of methodological quality items, and very few studies were performed in community primary care settings. Malignancy is rare as a cause of low back pain. The most useful features and tests are a previous history of cancer, elevated ESR, reduced hematocrit, and clinician judgement.     

Cost-effectiveness of general practice care for low back pain: a systematic review

Care from a general practitioner (GP) is one of the most frequently utilised healthcare services for people with low back pain and only a small proportion of those with low back pain who seek care from a GP are referred to other services. The aim of this systematic review was to evaluate the evidence on cost-effectiveness of GP care in non-specific low back pain. We searched clinical and economic electronic databases, and the reference list of relevant systematic reviews and included studies to June 2010. Economic evaluations conducted alongside randomised controlled trials with at least one GP care arm were eligible for inclusion. Two reviewers independently screened search results and extracted data. Eleven studies were included; the majority of which conducted a cost-effectiveness or cost-utility analysis. Most studies investigated the cost-effectiveness of usual GP care. Adding advice, education and exercise, or exercise and behavioural counselling, to usual GP care was more cost-effective than usual GP care alone. Clinical rehabilitation and/or occupational intervention, and acupuncture were more cost-effective than usual GP care. One study investigated the cost-effectiveness of guideline-based GP care, and found that adding exercise and/or spinal manipulation was more cost-effective than guideline-based GP care alone. In conclusion, GP care alone did not appear to be the most cost-effective treatment option for low back pain. GPs can improve the cost-effectiveness of their treatment by referring their patients for additional services, such as advice and exercise, or by providing the services themselves.     

The association between pro-inflammatory biomarkers and nonspecific low back pain: a systematic review

BACKGROUND CONTEXT

About 85% of the patients with low back pain seeking medical care have nonspecific low back pain (NsLBP), implying that no definitive cause can be identified. Nonspecific low back pain is defined as low back pain and disability which cannot be linked to an underlying pathology, such as cancer, spinal osteomyelitis, fracture, spinal stenosis, cauda equine, ankylosing spondylitis, and visceral-referred pain. Many pain conditions are linked with elevated serum levels of pro-inflammatory biomarkers. Outcomes of interest are NsLBP and the level of pro-inflammatory biomarkers.

A systematic review of paracetamol for non-specific low back pain

The objective of this study was to assess the efficacy of paracetamol (acetaminophen) in the treatment of pain and disability in patients with non-specific low back pain. We conducted a systematic review of randomized controlled trials to assess the efficacy of paracetamol in the treatment of pain and disability in patients with non-specific low back pain. A search for randomized controlled trials was conducted using the Medline, Embase and CINAHL databases. Trials were eligible if they were randomized controlled trials comparing paracetamol to no treatment, placebo or another treatment in patients with non-specific low back pain. Two of the authors independently assessed trials for methodological quality on the PEDro Scale and extracted data. Continuous pain and disability data were converted to a common 0–10 scale; ordinal data were dichotomized (e.g., no pain, pain). The data was analyzed using the MIX version 1.61 meta-analysis software. Out of 205 unique articles found in the searches, 7 eligible trials were identified. The trials enrolled a total of 676 participants with 5 investigating acute low back pain, 1 investigating chronic low back pain and 1 investigating both. No trial provided data comparing paracetamol to placebo and only one trial compared paracetamol to no treatment. In general the trials were small (only 1 trial had >25 subjects per group) and of low methodological quality (only 2 had a score above 6 on the quality scale). All but one of the trials provided imprecise estimates of the effects of treatment with confidence intervals spanning clinically important beneficial and also harmful effects of paracetamol. No trial reported a statistically significant difference in favor of paracetamol. There is insufficient evidence to assess the efficacy of paracetamol in patients with low back pain. There is a clear need for large, high quality randomized controlled trials evaluating paracetamol, to provide reliable evidence of paracetamol’s effectiveness in patients with low back pain and to establish the validity of the recommendations in clinical guidelines.     

The association between physical activity and neck and low back pain: a systematic review

The effect of physical activity on neck and low back pain is still controversial. No systematic review has been conducted on the association between daily physical activity and neck and low back pain. The objective of this study was to evaluate the association between physical activity and the incidence/prevalence of neck and low back pain. Publications were systematically searched from 1980 to June 2009 in several databases. The following key words were used: neck pain, back pain, physical activity, leisure time activity, daily activity, everyday activity, lifestyle activity, sedentary, and physical inactivity. A hand search of relevant journals was also carried out. Relevant studies were retrieved and assessed for methodological quality by two independent reviewers. The strength of the evidence was based on methodological quality and consistency of the results. Seventeen studies were included in this review, of which 13 were rated as high-quality studies. Of high-quality studies, there was limited evidence for no association between physical activity and neck pain in workers and strong evidence for no association in school children. Conflicting evidence was found for the association between physical activity and low back pain in both general population and school children. Literature with respect to the effect of physical activity on neck and low back pain was too heterogeneous and more research is needed before any final conclusion can be reached.     

Manipulation and mobilization for treating chronic low back pain: a systematic review and meta-analysis

Background Context

Mobilization and manipulation therapies are widely used to benefit patients with chronic low back pain. However, questions remain about their efficacy, dosing, safety, and how these approaches compare with other therapies.