Associations of sickness absence for pain in the low back, neck and shoulders with wider propensity to pain.

OBJECTIVES: To explore the association of sickness absence ascribed to pain at specific anatomical sites with wider propensity to musculoskeletal pain. METHODS: As part of the CUPID (Cultural and Psychosocial Influences on Disability) study, potential risk factors for sickness absence from musculoskeletal pain were determined for 11 922 participants from 45 occupational groups in 18 countries. After approximately 14 months, 9119 (78%) provided follow-up information about sickness in the past month because of musculoskeletal pain, including 8610 who were still in the same job. Associations with absence for pain at specific anatomical sites were assessed by logistic regression and summarised by ORs with 95% CIs. RESULTS: 861 participants (10%) reported absence from work because of musculoskeletal pain during the month before follow-up. After allowance for potential confounders, risk of absence ascribed entirely to low back pain (n=235) increased with the number of anatomical sites other than low back that had been reported as painful in the year before baseline (ORs 1.6 to 1.7 for ≥4 vs 0 painful sites). Similarly, associations with wider propensity to pain were observed for absence attributed entirely to pain in the neck (ORs up to 2.0) and shoulders (ORs up to 3.4). CONCLUSIONS: Sickness absence for pain at specific anatomical sites is importantly associated with wider propensity to pain, the determinants of which extend beyond established risk factors such as somatising tendency and low mood. Better understanding of why some individuals are generally more prone to musculoskeletal pain might point to useful opportunities for prevention.

Whole-body vibration and back pain-related work absence among heavy equipment vehicle mining operators.

OBJECTIVE: To determine the association between several whole-body vibration (WBV) exposure estimates and back pain-related work absence. METHODS: Exposures (based on the weighted daily root mean square acceleration, A(8); the daily vibration dose value, VDV(8); and the daily equivalent static compression dose, Sed(8)) of 2302 workers during 4 years were estimated using each worker's monthly vehicle operation records and WBV measurements from 11 different types of heavy equipment vehicles in a large coal mine. Company payroll data provided work absence during the concurrent 4 years of exposure. Cox regression models estimated the associations between the different WBV metrics and time to first work absence related to back pain. An adjusted R2 statistic provided a measure of model fit. RESULTS: All estimated metrics of WBV exposures were positively and significantly associated with back pain-related absence. HRs varied from 2.03 to 12.39 for every 0.21 m/s2 increase in the A(8)-based exposures; from 1.03 to 1.18 for every 1.72 m/s1.75 increase in VDV(8)-based exposures; and from 1.04 to 1.07 for every 0.06 MPa increase in Sed(8)-based exposures. Models using the estimated VDV(8) metric for the z axis fit the data best as measured by the R2 statistic. CONCLUSION: Higher WBV exposures were associated with back pain-related absences in this population, which appears after a few years of follow-up. Introducing controls to lower exposure levels may help reduce back pain-related work absences.

Determinants of international variation in the prevalence of disabling wrist and hand pain.

BACKGROUND: Previous research has indicated that wide international variation in the prevalence of disabling low back pain among working populations is largely driven by factors predisposing to musculoskeletal pain more generally. This paper explores whether the same applies to disabling wrist/hand pain (WHP). METHODS: Using data from the Cultural and Psychosocial Influences on Disability (CUPID) study, we focused on workers from 45 occupational groups (office workers, nurses and other workers) in 18 countries. Among 11,740 participants who completed a baseline questionnaire about musculoskeletal pain and potential risk factors, 9082 (77%) answered a further questionnaire after a mean interval of 14 months, including 1373 (15%) who reported disabling WHP in the month before follow-up. Poisson regression was used to assess associations of this outcome with baseline risk factors, including the number of anatomical sites other than wrist/hand that had been painful in the 12 months before baseline (taken as an index of general propensity to pain). RESULTS: After allowance for other risk factors, the strongest associations were with general pain propensity (prevalence rate ratio for an index ≥6 vs. 0: 3.6, 95% confidence interval 2.9-4.4), and risk rose progressively as the index increased. The population attributable fraction for a pain propensity index > 0 was 49.4%. The prevalence of disabling WHP by occupational group ranged from 0.3 to 36.2%, and correlated strongly with mean pain propensity index (correlation coefficient 0.86). CONCLUSION: Strategies to prevent disability from WHP among working populations should explore ways of reducing general propensity to pain, as well as improving the ergonomics of occupational tasks.

Burden of musculoskeletal disorders in the Eastern Mediterranean Region, 1990-2013: findings from the Global Burden of Disease Study 2013.

OBJECTIVES: We used findings from the Global Burden of Disease Study 2013 to report the burden of musculoskeletal disorders in the Eastern Mediterranean Region (EMR). METHODS: The burden of musculoskeletal disorders was calculated for the EMR's 22 countries between 1990 and 2013. A systematic analysis was performed on mortality and morbidity data to estimate prevalence, death, years of live lost, years lived with disability and disability-adjusted life years (DALYs). RESULTS: For musculoskeletal disorders, the crude DALYs rate per 100 000 increased from 1297.1 (95% uncertainty interval (UI) 924.3-1703.4) in 1990 to 1606.0 (95% UI 1141.2-2130.4) in 2013. During 1990-2013, the total DALYs of musculoskeletal disorders increased by 105.2% in the EMR compared with a 58.0% increase in the rest of the world. The burden of musculoskeletal disorders as a proportion of total DALYs increased from 2.4% (95% UI 1.7-3.0) in 1990 to 4.7% (95% UI 3.6-5.8) in 2013. The range of point prevalence (per 1000) among the EMR countries was 28.2-136.0 for low back pain, 27.3-49.7 for neck pain, 9.7-37.3 for osteoarthritis (OA), 0.6-2.2 for rheumatoid arthritis and 0.1-0.8 for gout. Low back pain and neck pain had the highest burden in EMR countries. CONCLUSIONS: This study shows a high burden of musculoskeletal disorders, with a faster increase in EMR compared with the rest of the world. The reasons for this faster increase need to be explored. Our findings call for incorporating prevention and control programmes that should include improving health data, addressing risk factors, providing evidence-based care and community programmes to increase awareness.

The global burden of injury: incidence, mortality, disability-adjusted life years and time trends from the Global Burden of Disease study 2013.

BACKGROUND: The Global Burden of Diseases (GBD), Injuries, and Risk Factors study used the disability-adjusted life year (DALY) to quantify the burden of diseases, injuries, and risk factors. This paper provides an overview of injury estimates from the 2013 update of GBD, with detailed information on incidence, mortality, DALYs and rates of change from 1990 to 2013 for 26 causes of injury, globally, by region and by country. METHODS: Injury mortality was estimated using the extensive GBD mortality database, corrections for ill-defined cause of death and the cause of death ensemble modelling tool. Morbidity estimation was based on inpatient and outpatient data sets, 26 cause-of-injury and 47 nature-of-injury categories, and seven follow-up studies with patient-reported long-term outcome measures. RESULTS: In 2013, 973 million (uncertainty interval (UI) 942 to 993) people sustained injuries that warranted some type of healthcare and 4.8 million (UI 4.5 to 5.1) people died from injuries. Between 1990 and 2013 the global age-standardised injury DALY rate decreased by 31% (UI 26% to 35%). The rate of decline in DALY rates was significant for 22 cause-of-injury categories, including all the major injuries. CONCLUSIONS: Injuries continue to be an important cause of morbidity and mortality in the developed and developing world. The decline in rates for almost all injuries is so prominent that it warrants a general statement that the world is becoming a safer place to live in. However, the patterns vary widely by cause, age, sex, region and time and there are still large improvements that need to be made.

Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010.

BACKGROUND: Non-fatal health outcomes from diseases and injuries are a crucial consideration in the promotion and monitoring of individual and population health. The Global Burden of Disease (GBD) studies done in 1990 and 2000 have been the only studies to quantify non-fatal health outcomes across an exhaustive set of disorders at the global and regional level. Neither effort quantified uncertainty in prevalence or years lived with disability (YLDs). METHODS: Of the 291 diseases and injuries in the GBD cause list, 289 cause disability. For 1160 sequelae of the 289 diseases and injuries, we undertook a systematic analysis of prevalence, incidence, remission, duration, and excess mortality. Sources included published studies, case notification, population-based cancer registries, other disease registries, antenatal clinic serosurveillance, hospital discharge data, ambulatory care data, household surveys, other surveys, and cohort studies. For most sequelae, we used a Bayesian meta-regression method, DisMod-MR, designed to address key limitations in descriptive epidemiological data, including missing data, inconsistency, and large methodological variation between data sources. For some disorders, we used natural history models, geospatial models, back-calculation models (models calculating incidence from population mortality rates and case fatality), or registration completeness models (models adjusting for incomplete registration with health-system access and other covariates). Disability weights for 220 unique health states were used to capture the severity of health loss. YLDs by cause at age, sex, country, and year levels were adjusted for comorbidity with simulation methods. We included uncertainty estimates at all stages of the analysis. FINDINGS: Global prevalence for all ages combined in 2010 across the 1160 sequelae ranged from fewer than one case per 1 million people to 350,000 cases per 1 million people. Prevalence and severity of health loss were weakly correlated (correlation coefficient -0·37). In 2010, there were 777 million YLDs from all causes, up from 583 million in 1990. The main contributors to global YLDs were mental and behavioural disorders, musculoskeletal disorders, and diabetes or endocrine diseases. The leading specific causes of YLDs were much the same in 2010 as they were in 1990: low back pain, major depressive disorder, iron-deficiency anaemia, neck pain, chronic obstructive pulmonary disease, anxiety disorders, migraine, diabetes, and falls. Age-specific prevalence of YLDs increased with age in all regions and has decreased slightly from 1990 to 2010. Regional patterns of the leading causes of YLDs were more similar compared with years of life lost due to premature mortality. Neglected tropical diseases, HIV/AIDS, tuberculosis, malaria, and anaemia were important causes of YLDs in sub-Saharan Africa. INTERPRETATION: Rates of YLDs per 100,000 people have remained largely constant over time but rise steadily with age. Population growth and ageing have increased YLD numbers and crude rates over the past two decades. Prevalences of the most common causes of YLDs, such as mental and behavioural disorders and musculoskeletal disorders, have not decreased. Health systems will need to address the needs of the rising numbers of individuals with a range of disorders that largely cause disability but not mortality. Quantification of the burden of non-fatal health outcomes will be crucial to understand how well health systems are responding to these challenges. Effective and affordable strategies to deal with this rising burden are an urgent priority for health systems in most parts of the world. FUNDING: Bill & Melinda Gates Foundation.

Disability-adjusted life years (DALYs) for 291 diseases and injuries in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010.

BACKGROUND: Measuring disease and injury burden in populations requires a composite metric that captures both premature mortality and the prevalence and severity of ill-health. The 1990 Global Burden of Disease study proposed disability-adjusted life years (DALYs) to measure disease burden. No comprehensive update of disease burden worldwide incorporating a systematic reassessment of disease and injury-specific epidemiology has been done since the 1990 study. We aimed to calculate disease burden worldwide and for 21 regions for 1990, 2005, and 2010 with methods to enable meaningful comparisons over time. METHODS: We calculated DALYs as the sum of years of life lost (YLLs) and years lived with disability (YLDs). DALYs were calculated for 291 causes, 20 age groups, both sexes, and for 187 countries, and aggregated to regional and global estimates of disease burden for three points in time with strictly comparable definitions and methods. YLLs were calculated from age-sex-country-time-specific estimates of mortality by cause, with death by standardised lost life expectancy at each age. YLDs were calculated as prevalence of 1160 disabling sequelae, by age, sex, and cause, and weighted by new disability weights for each health state. Neither YLLs nor YLDs were age-weighted or discounted. Uncertainty around cause-specific DALYs was calculated incorporating uncertainty in levels of all-cause mortality, cause-specific mortality, prevalence, and disability weights. FINDINGS: Global DALYs remained stable from 1990 (2·503 billion) to 2010 (2·490 billion). Crude DALYs per 1000 decreased by 23% (472 per 1000 to 361 per 1000). An important shift has occurred in DALY composition with the contribution of deaths and disability among children (younger than 5 years of age) declining from 41% of global DALYs in 1990 to 25% in 2010. YLLs typically account for about half of disease burden in more developed regions (high-income Asia Pacific, western Europe, high-income North America, and Australasia), rising to over 80% of DALYs in sub-Saharan Africa. In 1990, 47% of DALYs worldwide were from communicable, maternal, neonatal, and nutritional disorders, 43% from non-communicable diseases, and 10% from injuries. By 2010, this had shifted to 35%, 54%, and 11%, respectively. Ischaemic heart disease was the leading cause of DALYs worldwide in 2010 (up from fourth rank in 1990, increasing by 29%), followed by lower respiratory infections (top rank in 1990; 44% decline in DALYs), stroke (fifth in 1990; 19% increase), diarrhoeal diseases (second in 1990; 51% decrease), and HIV/AIDS (33rd in 1990; 351% increase). Major depressive disorder increased from 15th to 11th rank (37% increase) and road injury from 12th to 10th rank (34% increase). Substantial heterogeneity exists in rankings of leading causes of disease burden among regions. INTERPRETATION: Global disease burden has continued to shift away from communicable to non-communicable diseases and from premature death to years lived with disability. In sub-Saharan Africa, however, many communicable, maternal, neonatal, and nutritional disorders remain the dominant causes of disease burden. The rising burden from mental and behavioural disorders, musculoskeletal disorders, and diabetes will impose new challenges on health systems. Regional heterogeneity highlights the importance of understanding local burden of disease and setting goals and targets for the post-2015 agenda taking such patterns into account. Because of improved definitions, methods, and data, these results for 1990 and 2010 supersede all previously published Global Burden of Disease results. FUNDING: Bill & Melinda Gates Foundation.

Improvement of short-term outcomes with VR-based safety training for work at heights.

Serious games and virtual reality offer engaging learning opportunities and a cost-effective solution within an immersive and safe environment for safety training in construction. However, there have been few examples of safety training for work at heights developed using these technologies, especially commercial training. To fill this literature gap, a new VR-based safety training was developed and compared with lecture-based training across time. We conducted a quasi-experiment with a non-equivalent group design with 102 workers from six construction sites in Colombia. Learning objectives, observations from training centers, and national regulations were considered during the design of the training methods. Training outcomes were assessed using Kirkpatrick's model. We found that both training approaches were effective in improving knowledge test results and self-reported attitudes in the short-term; and risk-perception, self-reported behavior and safety climate in the long-term. In particular, participants of the VR-based training got significantly higher results in knowledge and reported higher attitudes (commitment and motivation) than participants of the lecture-based training. We suggest that safety managers and practitioners should invest in VR using serious games as an alternative to training programs based on short-term outcomes. Future work is needed to test VR for long-term outcomes.

Patterns of change of multisite pain over 1 year of follow-up and related risk factors.

BACKGROUND: Multisite musculoskeletal pain is common and disabling. This study aimed to prospectively investigate the distribution of musculoskeletal pain anatomically, and explore risk factors for increases/reductions in the number of painful sites. METHODS: Using data from participants working in 45 occupational groups in 18 countries, we explored changes in reporting pain at 10 anatomical sites on two occasions 14 months apart. We used descriptive statistics to explore consistency over time in the number of painful sites, and their anatomical distribution. Baseline risk factors for increases/reductions by ≥3 painful sites were explored by random intercept logistic regression that adjusted for baseline number of painful sites. RESULTS: Among 8927 workers, only 20% reported no pain at either time point, and 16% reported ≥3 painful sites both times. After 14 months, the anatomical distribution of pain often changed but there was only an average increase of 0.17 painful sites. Some 14% workers reported a change in painful sites by ≥3. Risk factors for an increase of ≥3 painful sites included female sex, lower educational attainment, having a physically demanding job and adverse beliefs about the work-relatedness of musculoskeletal pain. Also predictives were as follows: older age, somatizing tendency and poorer mental health (each of which was also associated with lower odds of reductions of ≥3 painful sites). CONCLUSIONS: Longitudinally, the number of reported painful sites was relatively stable but the anatomical distribution varied considerably. These findings suggest an important role for central pain sensitization mechanisms, rather than localized risk factors, among working adults. SIGNIFICANCE: Our findings indicate that within individuals, the number of painful sites is fairly constant over time, but the anatomical distribution varies, supporting the theory that among people at work, musculoskeletal pain is driven more by factors that predispose to experiencing or reporting pain rather than by localized stressors specific to only one or two anatomical sites.

The effectiveness of virtual safety training in work at heights: A literature review.

Virtual environment techniques are technologies that can be used for safety training, and deliver significant advantages (e.g. risk-free, immersive learning). However, no studies have assessed the effectiveness of this training for work at heights (WAH). This paper aimed to synthesize the outcomes criteria for measuring the effectiveness of virtual safety training of WAH in different work sectors. A total of 658 records were identified through an explorative search of relevant citations from 2010 onwards. Only 21 documents were considered and classified according to the training goal: improvement of knowledge, skills or attitudes. Outcomes criteria of virtual safety training were analyzed according to Kirkpatrick's model. The results support practitioners and safety managers by providing an inventory of training methods, evaluation indicators and evaluation effects. Further recommendations are made for the design of an effective training assessment.

Assessment of work-related hand and elbow workloads using measurement-based TLV for HAL.

Direct-measurement-based methods for assessing workloads of the hand or elbow in the field are rare. Aim of the study was to develop such a method based on the Threshold Limit Value for Hand Activity Level (TLV for HAL). Hence, HAL was quantified using kinematic data (mean power frequencies, angular velocities and micro-pauses) and combined with electromyographic data (root-mean-square values) in order to generate a measurement-based TLV for HAL (mTLV for HAL). The multi-sensor system CUELA including inertial sensors, potentiometers and a 4-channel surface electromyography module was used. For wrist and elbow regions, associations between mTLV for HAL and disorders/complaints (quantified by odds ratios (OR [95%-confidence interval])) were tested exploratively within a cross-sectional field study with 500 participants. Higher workloads were frequently significantly associated with arthrosis of distal joints (9.23 [3.29-25.87]), wrist complaints (2.89 [1.63-5.11]) or elbow complaints (1.99 [1.08-3.67]). The new method could extend previous application possibilities.

Validity of self-reported mechanical demands for occupational epidemiologic research of musculoskeletal disorders.

OBJECTIVES: To describe the relation of the measured validity of self-reported mechanical demands (self-reports) with the quality of validity assessments and the variability of the assessed exposure in the study population. METHODS: We searched for original articles, published between 1990 and 2008, reporting the validity of self-reports in three major databases: EBSCOhost, Web of Science and PubMed. Identified assessments were classified by methodological characteristics (eg, type of self-report and reference method) and exposure dimension was measured. We also classified assessments by the degree of comparability between the self-report and the employed reference method, and the variability of the assessed exposure in the study population. Finally, we examined the association of the published validity (r) with this degree of comparability, as well as with the variability of the exposure variable in the study population. RESULTS: Of the 490 assessments identified, 75% used observation-based reference measures and 55% tested self-reports of posture duration and movement frequency. Frequently, validity studies did not report demographic information (eg, education, age, and gender distribution). Among assessments reporting correlations as measure of validity, studies with a better match between the self-report and the reference method, and studies conducted in more heterogeneous populations tended to report higher correlations [odds ratio (OR) 2.03, 95% confidence interval (95% CI) 0.89-4.65 and OR 1.60, 95% CI 0.96-2.61, respectively]. CONCLUSIONS: The reported data support the hypothesis that validity depends on study-specific factors often not examined. Experimentally manipulating the testing setting could lead to a better understanding of the capabilities and limitations of self-reported information.

Effect of Time Elapsed since Last Pruner Maintenance on Upper-Extremity Biomechanics during Manual Flower Cutting.

OBJECTIVE: Manual flower cutting imposes large biomechanical demands on workers' upper extremities. Solutions are required to reduce these demands. This study investigated the effect of time elapsed since the last pruner maintenance on the biomechanical demands of the upper extremities during flower-cutting operations. METHODS: Sixteen experienced workers were recruited. All workers performed flower cutting 1, 15, and 30 days after standard pruner maintenance, including cleaning, adjustment, and sharpening. The outcomes included kinematics of the wrist, elbow, and forearm; muscular activity of the extensor carpi radialis, extensor carpi ulnaris, flexor carpi radialis, flexor carpi ulnaris, biceps and medium deltoids of the dominant arm; and self-reported effort. RESULTS: On average across muscles, a 15-day delay (from 1 to 15 and from 15 to 30 days) in the execution of pruner maintenance increased over 8% the median recorded muscular activity as measured by the percentage of the maximum voluntary contraction of the root mean square signal. An increase in time since last pruner maintenance resulted in an increase in the 90th percentile pronation-supination posture (larger excursion toward pronation); the median and the 90th percentile velocity of the wrist and elbow; and the 90th percentile acceleration in the pronation-supination direction. There was an increase in perceived effort as measured by a Borg scale as time since last maintenance increased from 1 to 15 days. CONCLUSION: Increasing the frequency of pruner maintenance procedures can effectively reduce workers' mechanical exposures during manual flower-cutting operations. Companies should implement daily maintenance programs considering their implementation capacity and expected benefits.

Job rotation: Effects on muscular activity variability.

Job rotation strategies have been used for years as an administrative intervention to reduce the risk of musculoskeletal disorders. The benefits of job rotation have been hypothesized to occur via changes in muscular activity variability (MAV). However, the effect of job rotation on MAV has not been fully analyzed in a literature review. A wide search was conducted to identify studies testing the effect of different job rotation strategies on MAV. Twenty-six studies of acceptable quality were included. Several studies on different types of tasks supported the view that job rotation can increase muscular activity variability, particularly with strategies such as alternating tasks and pace changes. However, it remains uncertain whether such variability changes immediately translate into benefits for the worker because little evidence was found that showed simultaneous changes in different muscular groups. Additionally, variability was occasionally achieved at the expense of average activity in the assessed muscles.

Correctness of Self-Reported Task Durations: A Systematic Review.

Objectives: Duration of tasks in a job is an essential interest in occupational epidemiology. Such duration is frequently measured using self-reports, which may, however, be associated with both bias and random errors. The present systematic literature review examines the correctness of self-reported durations of tasks, i.e. the extent to which they differ from more valid reference data due to either systematic or random errors, and factors influencing this correctness, with particular emphasis on the assessment of exposures of relevance to musculoskeletal disorders. Methods: The search for relevant studies included the databases ISI Web of Science, MEDLINE, EBSCO HOST, Proquest, and Psycnet. Results: Thirty-two articles were identified; of which, 23 examined occupational tasks and 9 examined non-occupational tasks. Agreement between self-reports and a more correct reference was reported for, in total, 182 tasks. Average proportional errors were, for most tasks, between -50% (i.e. underestimations) and +100%, with a dominance of overestimations; 22% of all results considered overestimations of 100% or more. For 15% of the 182 reported tasks, the mean difference between the self-reported and the reference duration value was <5%, and 20% of the 182 mean differences were between 5 and 20%. In general, respondents were able to correctly distinguish tasks of a longer duration from shorter tasks, even though the actual durations were not correct. A number of factors associated with the task per se appeared to influence agreement between self-reports and reference data, including type of task, true task duration, task pattern across time (continuous versus discontinuous), and whether the addressed task is composed of subtasks. The musculoskeletal health status of the respondent did not have a clear effect on the ability to correctly report task durations. Studies differed in key design characteristics and detail of information reported, which hampers a formal aggregation of results. Conclusions: The correctness of self-reported task durations is, at the best, moderate at the individual level, and this may present a significant problem when using self-reports in task-based assessment of individual job exposures. However, average self-reports at the group level appear reasonably correct and may thus be a viable method in studies addressing, for instance, the relative occurrence of tasks in a production system. Due to the disparity of studies, definite conclusions on the quantitative effect on agreement of different modifiers are not justified, and we encourage future studies specifically devoted to understanding and controlling sources of bias in self-reported task durations. We also encourage studies developing decision support for when to apply or avoid self-reports to measure task durations, depending on study purpose and occupational setting.

Assessment of Whole-Body Vibration Exposure in Mining Earth-moving Equipment and Other Vehicles Used in Surface Mining.

This study characterized whole-body vibration exposures in a set of vehicles that operate in open-pit mines and compared three different daily exposure parameters based on the ISO 2631-1:1997 and ISO 2631-5:2004 standards. Full-shift, 6 to 12-hour, continuous whole-body vibration measurements were collected from 11 representative types of vehicles in terms of hours of operation and number of vehicles used. For each type of vehicle, the exposure parameters (A(8), VDV(8), and Sed(8)) were calculated for each axis (x, y, and z), and in addition, shear or horizontal (∑xy) and vector sum (∑xyx) whole-body vibration exposure. Findings showed that: (i) substantially higher shear and vector sum whole-body vibration exposures indicated relatively high levels of exposure on the non-predominant axis; (ii) the predominant axis of exposure varied across the different type of vehicles; (iii) there were differences in whole-body vibration exposure parameters regarding the standards-based predictions of potentially adverse health outcomes (the impulsive exposure parameters VDV(8) and Sed(8) were higher and reduced acceptable vehicle operation times by one-half to two-thirds relative to A(8) exposures); and (iv) based on the predominant exposures and the time to reach daily vibration action limits, the operation of most mining vehicles would be limited to less than 8 hours a day. Differences in whole-body vibration exposure parameters impact the prediction of potentially adverse health outcomes and may introduce some uncertainty regarding how to best characterize a vehicle operator's actual exposure.

Epidemiological Differences Between Localized and Nonlocalized Low Back Pain.

STUDY DESIGN: A cross-sectional survey with a longitudinal follow-up. OBJECTIVES: The aim of this study was to test the hypothesis that pain, which is localized to the low back, differs epidemiologically from that which occurs simultaneously or close in time to pain at other anatomical sites SUMMARY OF BACKGROUND DATA.: Low back pain (LBP) often occurs in combination with other regional pain, with which it shares similar psychological and psychosocial risk factors. However, few previous epidemiological studies of LBP have distinguished pain that is confined to the low back from that which occurs as part of a wider distribution of pain. METHODS: We analyzed data from CUPID, a cohort study that used baseline and follow-up questionnaires to collect information about musculoskeletal pain, associated disability, and potential risk factors, in 47 occupational groups (office workers, nurses, and others) from 18 countries. RESULTS: Among 12,197 subjects at baseline, 609 (4.9%) reported localized LBP in the past month, and 3820 (31.3%) nonlocalized LBP. Nonlocalized LBP was more frequently associated with sciatica in the past month (48.1% vs. 30.0% of cases), occurred on more days in the past month and past year, was more often disabling for everyday activities (64.1% vs. 47.3% of cases), and had more frequently led to medical consultation and sickness absence from work. It was also more often persistent when participants were followed up after a mean of 14 months (65.6% vs. 54.1% of cases). In adjusted Poisson regression analyses, nonlocalized LBP was differentially associated with risk factors, particularly female sex, older age, and somatizing tendency. There were also marked differences in the relative prevalence of localized and nonlocalized LBP by occupational group. CONCLUSION: Future epidemiological studies should distinguish where possible between pain that is limited to the low back and LBP that occurs in association with pain at other anatomical locations. LEVEL OF EVIDENCE: 2.

Global and National Burden of Diseases and Injuries Among Children and Adolescents Between 1990 and 2013: Findings From the Global Burden of Disease 2013 Study.

IMPORTANCE: The literature focuses on mortality among children younger than 5 years. Comparable information on nonfatal health outcomes among these children and the fatal and nonfatal burden of diseases and injuries among older children and adolescents is scarce. OBJECTIVE: To determine levels and trends in the fatal and nonfatal burden of diseases and injuries among younger children (aged <5 years), older children (aged 5-9 years), and adolescents (aged 10-19 years) between 1990 and 2013 in 188 countries from the Global Burden of Disease (GBD) 2013 study. EVIDENCE REVIEW: Data from vital registration, verbal autopsy studies, maternal and child death surveillance, and other sources covering 14,244 site-years (ie, years of cause of death data by geography) from 1980 through 2013 were used to estimate cause-specific mortality. Data from 35,620 epidemiological sources were used to estimate the prevalence of the diseases and sequelae in the GBD 2013 study. Cause-specific mortality for most causes was estimated using the Cause of Death Ensemble Model strategy. For some infectious diseases (eg, HIV infection/AIDS, measles, hepatitis B) where the disease process is complex or the cause of death data were insufficient or unavailable, we used natural history models. For most nonfatal health outcomes, DisMod-MR 2.0, a Bayesian metaregression tool, was used to meta-analyze the epidemiological data to generate prevalence estimates. FINDINGS: Of the 7.7 (95% uncertainty interval [UI], 7.4-8.1) million deaths among children and adolescents globally in 2013, 6.28 million occurred among younger children, 0.48 million among older children, and 0.97 million among adolescents. In 2013, the leading causes of death were lower respiratory tract infections among younger children (905.059 deaths; 95% UI, 810,304-998,125), diarrheal diseases among older children (38,325 deaths; 95% UI, 30,365-47,678), and road injuries among adolescents (115,186 deaths; 95% UI, 105,185-124,870). Iron deficiency anemia was the leading cause of years lived with disability among children and adolescents, affecting 619 (95% UI, 618-621) million in 2013. Large between-country variations exist in mortality from leading causes among children and adolescents. Countries with rapid declines in all-cause mortality between 1990 and 2013 also experienced large declines in most leading causes of death, whereas countries with the slowest declines had stagnant or increasing trends in the leading causes of death. In 2013, Nigeria had a 12% global share of deaths from lower respiratory tract infections and a 38% global share of deaths from malaria. India had 33% of the world's deaths from neonatal encephalopathy. Half of the world's diarrheal deaths among children and adolescents occurred in just 5 countries: India, Democratic Republic of the Congo, Pakistan, Nigeria, and Ethiopia. CONCLUSIONS AND RELEVANCE: Understanding the levels and trends of the leading causes of death and disability among children and adolescents is critical to guide investment and inform policies. Monitoring these trends over time is also key to understanding where interventions are having an impact. Proven interventions exist to prevent or treat the leading causes of unnecessary death and disability among children and adolescents. The findings presented here show that these are underused and give guidance to policy makers in countries where more attention is needed.

Classification of neck/shoulder pain in epidemiological research: a comparison of personal and occupational characteristics, disability, and prognosis among 12,195 workers from 18 countries.

To inform case definition for neck/shoulder pain in epidemiological research, we compared levels of disability, patterns of association, and prognosis for pain that was limited to the neck or shoulders (LNSP) and more generalised musculoskeletal pain that involved the neck or shoulder(s) (GPNS). Baseline data on musculoskeletal pain, disability, and potential correlates were collected by questionnaire from 12,195 workers in 47 occupational groups (mostly office workers, nurses, and manual workers) in 18 countries (response rate = 70%). Continuing pain after a mean interval of 14 months was ascertained through a follow-up questionnaire in 9150 workers from 45 occupational groups. Associations with personal and occupational factors were assessed by Poisson regression and summarised by prevalence rate ratios (PRRs). The 1-month prevalence of GPNS at baseline was much greater than that of LNSP (35.1% vs 5.6%), and it tended to be more troublesome and disabling. Unlike LNSP, the prevalence of GPNS increased with age. Moreover, it showed significantly stronger associations with somatising tendency (PRR 1.6 vs 1.3) and poor mental health (PRR 1.3 vs 1.1); greater variation between the occupational groups studied (prevalence ranging from 0% to 67.6%) that correlated poorly with the variation in LNSP; and was more persistent at follow-up (72.1% vs 61.7%). Our findings highlight important epidemiological distinctions between subcategories of neck/shoulder pain. In future epidemiological research that bases case definitions on symptoms, it would be useful to distinguish pain that is localised to the neck or shoulder from more generalised pain that happens to involve the neck/shoulder region.

Descriptive Epidemiology of Somatising Tendency: Findings from the CUPID Study.

Somatising tendency, defined as a predisposition to worry about common somatic symptoms, is importantly associated with various aspects of health and health-related behaviour, including musculoskeletal pain and associated disability. To explore its epidemiological characteristics, and how it can be specified most efficiently, we analysed data from an international longitudinal study. A baseline questionnaire, which included questions from the Brief Symptom Inventory about seven common symptoms, was completed by 12,072 participants aged 20-59 from 46 occupational groups in 18 countries (response rate 70%). The seven symptoms were all mutually associated (odds ratios for pairwise associations 3.4 to 9.3), and each contributed to a measure of somatising tendency that exhibited an exposure-response relationship both with multi-site pain (prevalence rate ratios up to six), and also with sickness absence for non-musculoskeletal reasons. In most participants, the level of somatising tendency was little changed when reassessed after a mean interval of 14 months (75% having a change of 0 or 1 in their symptom count), although the specific symptoms reported at follow-up often differed from those at baseline. Somatising tendency was more common in women than men, especially at older ages, and varied markedly across the 46 occupational groups studied, with higher rates in South and Central America. It was weakly associated with smoking, but not with level of education. Our study supports the use of questions from the Brief Symptom Inventory as a method for measuring somatising tendency, and suggests that in adults of working age, it is a fairly stable trait.