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The primary aim of this study was to determine if occupational exposure to whole-body vibration (WBV) was associated with reporting neck pain. A cross-sectional study was conducted on a sample of the general population living in northern Sweden, aged 24-76 years. Data was retrieved through a digital survey that collected subjectively reported information on exposure to WBV and biomechanical exposures as well as neck pain. The study included 5,017 participants (response rate 44%). Neck pain was reported by 269 men (11.8%) and 536 women (20.2%). There was a statistically significant association between reporting occupational exposure to WBV half the time or more (adjusted OR 1.91; 95% CI 1.22-3.00) and reporting neck pain. In gender-stratified analyses, the same pattern was observed in men, while there were too few women to determine any association. We conclude that occupational exposure to whole-body vibration was associated with neck pain in men.

Cold sensitivity, a common and disabling sequela of hand injury, can be assessed using the Cold Intolerance Symptom Severity (CISS) questionnaire, rating symptoms on a scale from 4 to 100. The primary objective of this study was to define a clinical cut-off for abnormal cold sensitivity based on the CISS score in a healthy working-age population. The secondary objective was to investigate how age, gender and previous injuries and diseases influence CISS scoring. In this study, 1239 out of 1582 selected healthy subjects of working age living in northern Sweden completed the questionnaire, yielding a response rate of 78%. The 95th percentile for the CISS score was 49.5 for men and 53.0 for women. The effects of age, gender and previous injuries and diseases were minor and not considered clinically relevant. The results support that a CISS score above 50 should be considered as abnormal cold sensitivity. Level of evidence: III

Background Cold exposure is an underrecognized occupational hazard that may increase the risk of peripheral nerve entrapment. The aim of this study was to determine if self-reported occupational exposure to contact and ambient cooling was associated with symptoms of carpal tunnel syndrome (CTS). Methods In this mainly cross-sectional study, surveys were conducted on a population-based sample of men and women between 18 and 70 years of age, living in northern Sweden. Cold exposure and presence of symptoms suggestive of CTS were subjectively reported. Associations between exposure and outcome were evaluated using logistic regression. Results The study included 2,703 women and 2,314 men, with a median age of 60 years (interquartile range 19). Symptoms of CTS were reported by 453 (9.2%). Being highly occupationally exposed (almost always) to contact cooling of the hands was associated with reporting CTS (OR 3.20; 95% CI 1.62–6.33), as was ambient cooling (OR 2.00; 95% CI 1.03–3.88) and severe ambient cooling (OR 4.02 95% CI 2.09–7.71), after adjusting for age, gender, body mass index, current daily smoking, diabetes mellitus, joint disease, and hand-arm vibration exposure. The point estimates increased with longer daily exposure duration. For workers exposed to severe ambient cooling for more than half of their working hours, in addition to performing heavy manual handling every day, the OR for reporting CTS was 7.25 (95% CI 3.88–13.53), with a positive additive interaction effect (expressed as relative excess risk due to interaction) of 4.67. Conclusions Self-reported occupational exposure to contact and ambient cooling was associated with symptoms suggestive of CTS. There were statistically significant positive exposure–response patterns for time spent exposed to contact and ambient cooling at work in relation to reporting symptoms of CTS. Positive additive interaction effects between cold exposure and heavy manual handling were also found. Since there was important potential uncontrolled confounding regarding repetitive wrist movements and forceful gripping, the results need to be confirmed by other studies, preferably with longitudinal design and more detailed exposure assessment.

Objective To determine if occupational exposure to cold environments is associated with incident airway symptoms in previously healthy workers. Methods A prospective, survey-based, closed-cohort study was conducted on a sample of 5017 men and women between 18 and 70 years of age, living in northern Sweden. Data on occupation, occupational and leisure-time cold exposure, airway symptoms, general health, and tobacco habits were collected during the winters of 2015 (baseline) and 2021 (follow-up). Stepwise multiple logistic regression was used to determine associations between baseline variables and incident airway symptoms. Results For individuals working at baseline, without physician-diagnosed asthma or chronic obstructive pulmonary disease, reporting any occupational cold exposure was associated with incident wheeze (OR 1.41; 95% CI 1.06–1.87) and incident productive cough (OR 1.37; 95% CI 1.06–1.77), but not incident long-standing cough (OR 0.98; 95% CI 0.74–1.29), after adjusting for age, body mass index, daily smoking, and occupational physical workload. Detailed analysis of the occupational cold exposure rating did not reveal clear exposure–response patterns for any of the outcomes. Conclusions Occupational cold exposure was robustly associated with incident wheeze and productive cough in previously healthy workers. This adds further support to the notion that cold air is harmful for the airways, and that a structured risk assessment regarding occupational cold exposure could be considered for inclusion in the Swedish workplace legislation. Further studies are needed to elaborate on exposure–response functions, as well as suggest thresholds for hazardous cold exposure.

Purpose Work ability can be measured by the work ability index (WAI), and work-related questions measuring productivity loss in terms of quality and quantity of work. Dentists have high occupational risk of musculoskeletal pain and the exposure of ergonomic strain is already high during dental education. The aim was to evaluate work ability and productivity among dentists, and to identify gender differences and associations with sleep, stress, and reported frequent pain. Methods The study population comprised 187 dentists (123 women and 64 men) who had been working as dentists between 5 and 12 years. Participants completed a questionnaire regarding sleep, stress, presence of pain at different sites, work ability assessed by WAI, and productivity in terms of quality and quantity of work. Results Poor sleep quality and high level of stress were reported by 31% and 48.1% of participants, respectively, with no gender differences and no association with age. The prevalence of frequent pain ranged 6.4–46.5% with shoulders being the most prevalent site. Thirty-three percent reported reduced work ability. Poor sleep, high amount of stress, and multi-site pain were associated with decreased work ability. Conclusions A high prevalence of pain was shown among dentists. Decreased work ability in terms of productivity loss was associated with poor sleep quality, high amount of stress, and multi-site pain. Preventive actions at the workplace should promote good musculoskeletal health, and measures taken, both individual and organizational, to minimize the risk of high, persistent stress and work-related pain.

ObjectivesThe aim was to assess the association between occupational biomechanical exposure and the occurrence of radial nerve entrapment (RNE) in construction workers over a 13-year follow-up period.MethodsA cohort of 229 707 male construction workers who participated in a national occupational health surveillance programme (1971–1993) was examined prospectively (2001–2013) for RNE. Height, weight, age, smoking status and job title (construction trade) were obtained on health examination. RNE case status was defined by surgical release of RNE, with data from the Swedish national registry for out-patient surgery records. A job exposure matrix was developed, and biomechanical exposure estimates were assigned according to job title. Highly correlated exposures were summed into biomechanical exposure scores. Negative binomial models were used to estimate the relative risks (RR) (incidence rate ratios) of RNE surgical release for the biomechanical factors and exposure sum scores. Predicted incidence was assessed for each exposure score modelled as a continuous variable to assess exposure–response relationships.ResultsThe total incidence rate of surgically treated RNE over the 13-year observation period was 3.53 cases per 100 000 person-years. There were 92 cases with occupational information. Increased risk for RNE was seen in workers with elevated hand-grip forces (RR=1.79, 95% CI 0.97 to 3.28) and exposure to hand-arm vibration (RR=1.47, 95% CI 1.08 to 2.00).ConclusionsOccupational exposure to forceful handgrip work and vibration increased the risk for surgical treatment of RNE.

Objectives: To characterise cold sensitivity using a semi-structured interview, physical examination, thermal quantitative sensory testing (QST), and laser speckle contrast analysis (LASCA). Methods: Eight women and four men, ages 22–74, with cold sensitivity were interviewed and examined by an occupational physician. Thermal perception thresholds were established using QST, on the pulp of the index and little finger of the most affected hand. Skin perfusion in the dorsum of the hand was measured using LASCA, at baseline, after two-minute 12°C water immersion, and during rewarming. Results: The physical examination yielded few findings indicative of vascular or neurosensory pathology. One subject (8%) had impaired thermal perception thresholds. LASCA at baseline showed absent proximal-distal perfusion gradients in six subjects (50%), and a dyshomogeneous perfusion pattern in five (42%). Perfusion on a group level was virtually unchanged by cold stress testing (median 52.5 PU; IQR 9.0 before versus 51.3 PU; IQR 27.2 afterwards). Conclusions: Physical examination and thermal QST offered little aid in diagnosing cold sensitivity, which challenges the neurosensory pathophysiological hypothesis. LASCA indicated disturbances in microvascular regulation and could prove a useful tool in future studies on cold sensitivity.

Tobacco smoking is an injurious habit associated with a number of chronic disorders. Its influence on disc metabolism and degeneration including lumbar spinal stenosis (LSS) has been investigated in the literature.We aimed to investigate whether tobacco smoking is an independent risk factor for undergoing surgical intervention for LSS.This is a prospective cohort study.The patient sample of 331,941 workers was derived from a Swedish nationwide occupational surveillance program for construction workers.The outcome measure included the incidence of undergoing surgical intervention for LSS in tobacco smokers versus no smokers.At inclusion, age, sex, body mass index (BMI), workers' job title, and self-reported smoking habits were registered. The workers were divided into four categories: never smoked, former smoker, moderate current (1-14 cigarettes/day), and heavy current (≥15 cigarettes/day). Patients who underwent a surgically treated LSS were defined using the relevant International Classification of Diseases (ICD) disease code derived from the Swedish National Patient Register.A total of 331,941 participants were included in the analysis. Forty-four percent of the participants were non-smokers, 16% were former smokers, 26% were moderate smokers, and 14% were heavy smokers. The vast majority of construction workers were males (95%). During the average follow-up of 30.7 years, 1,623 participants were surgically treated for LSS. The incidence rate ratio (IRRs) of LSS varied across smoking categories, with the highest values found in heavy smokers. Compared with non-smokers, all smoking categories show an increased incidence of surgically treated LSS. The findings were consistent even when the comparison was performed for participants with BMIs between 18.5 and 25 and for participants aged between 40 and 74 years.Tobacco smoking is associated with an increased incidence of surgically treated LSS. The effect seems to be dose related, whereby heavy smokers have a higher risk than moderate or former smokers.

Background: Raynaud's phenomenon and neurosensory symptoms are common after hand-arm vibration exposure. Knowledge of early signs of vibration injuries is needed. Aims: To investigate the risk of developing Raynaud's phenomenon and paraesthesia in relation to sensation of cold hands in a cohort of male employees at an engineering plant. Methods: We followed a cohort of male manual and office workers at an engineering plant in Sweden for 21 years. At baseline (1987 and 1992) and each follow-up (1992, 1997, 2002, 2008), we assessed sensation of cold, Raynaud's phenomenon and paraesthesia in the hands using questionnaires and measured vibration exposure. We calculated risk estimates with univariate and multiple logistic regression analyses and adjusted for vibration exposure and tobacco usage. Results: There were 241 study participants. During the study period, 21 individuals developed Raynaud's phenomenon and 43 developed paraesthesia. When adjusting the risk of developing Raynaud's phenomenon for vibration exposure and tobacco use, the odds ratios were between 6.0 and 6.3 (95% CI 2.2-17.0). We observed no increased risk for paraesthesia in relation to a sensation of cold hands. Conclusions: A sensation of cold hands was a risk factor for Raynaud's phenomenon. At the individual level, reporting a sensation of cold hands did not appear to be useful information to predict future development of Raynaud's phenomenon given a weak to moderate predictive value. For paraesthesia, the sensation of cold was not a risk factor and there was no predictive value at the individual level. Originally published in thesis in manuscript form.

Aim To identify possible risk factors for cold sensitivity, by comparing cases to controls with regard to demographic and anthropometric characteristics, previous illnesses and injuries as well as ambient exposures. Methods Through a questionnaire responded to by the general population (n=12,627) cold sensitivity cases (n=502) and matched controls (n=1,004) were identified and asked to respond to a second questionnaire with focus on different aspects of cold sensitivity, hereditary factors, previous diseases, medication, tobacco use as well as exposure to ambient cold climate and hand-arm vibration (HAV). Results In total, 997 out of 1506 study subjects answered the second questionnaire, 374 cases and 623 match controls. Identified risk factors among the cases were frostbite of the hands Odds Ratio (OR) 10.3 (95% confidence interval (CI) 5.5-19.3), rheumatic disease OR 3.1 (95% CI 1.7-5.7), upper extremity nerve injury OR 2.0 (95% CI 1.3-3.0), and vascular disease OR 1.9 (95% CI 1.2-2.9). Sex differences in risk factors were HAV exposure for men and cold exposure for women increased the risk of cold sensitivity. Rheumatic diseases and migraine increased the risk of cold sensitivity among women but not among men. Conclusions The present study shows that cold sensitivity is associated with both inherent factors, acquired conditions and external exposures. Among acquired conditions, frostbite, vascular disease, nerve injury, joint disorders and migraine are significantly related to the reporting of cold sensitivity. Among external exposures, both cold climate and HAV exposure are significantly associated to cold sensitivity, and thus suitable targets for primary preventive measures. There was a difference in risk factors related to sex. HAV exposure for men and cold exposure for women increased the risk of cold sensitivity. Originally included in thesis in manuscript form with title [Cold sensitivity and associated factors: a case-control study performed in northern Sweden] CHINS

OBJECTIVES: The aim of this study was to determine the association between occupational biomechanical exposures and occurrence of surgically treated ulnar nerve entrapment (UNE). METHODS: A cohort of 229 689 male construction workers who participated in a national occupational health surveillance program (1971–1993) were examined prospectively over a 13-year case ascertainment period (2001–2013) for surgically treated UNE. Job title (construction trade), smoking status, height, weight and age were recorded on examination. Job titles were merged into occupational groups of workers performing similar work tasks and having similar training. Occupational biomechanical exposure estimates were assigned to each occupational group with a job exposure matrix (JEM) developed for the study. Negative binomial models were used to assess the relative risks for each biomechanical exposure and the sums of highly correlated biomechanical exposures. Surgical treatment of UNE was determined via a linkage with the Swedish Hospital Outpatient Surgery Register. RESULTS: There were 555 cases of surgically treated UNE within the cohort. Workers exposed to forceful hand-grip factors had a 1.4-fold higher relative risk (95% CI 1.18–1.63) of undergoing surgical treatment for UNE compared to unexposed workers. Occupational groups comprising workers exposed to forceful hand-grip work showed the highest risks for UNE and included concrete workers, floor layers, ground preparatory workers, rock blasters, and sheet-metal workers. CONCLUSION: Forceful hand-grip work increases the risk for surgically treated ulnar nerve entrapment.

The present study assessed full-shift trunk and upper arm postural exposure amplitudes, frequencies, and durations among Swedish airport baggage handlers and aimed to determine whether exposures differ between workers at the ramp (loading and unloading aircraft) and baggage sorting areas.Trunk and upper arm postures were measured using inclinometers during three full work shifts on each of 27 male baggage handlers working at a large Swedish airport. Sixteen of the baggage handlers worked on the ramp and 11 in the sorting area. Variables summarizing postures and movements were calculated, and mean values and variance components between subjects and within subject (between days) were estimated using restricted maximum likelihood algorithms in a one-way random effect model.In total, data from 79 full shifts (651h) were collected with a mean recording time of 495min per shift (range 319-632). On average, baggage handlers worked with the right and left arm elevated60° for 6.4% and 6.3% of the total workday, respectively. The 90th percentile trunk forward projection (FP) was 34.1°, and the 50th percentile trunk movement velocity was 8° s(-1). For most trunk (FP) and upper arm exposure variables, between-subject variability was considerable, suggesting that the flight baggage handlers were not a homogeneously exposed group. A notable between-days variability pointed to the contents of the job differing on different days. Peak exposures (90°) were higher for ramp workers than for sorting area workers (trunk 0.6% ramp versus 0.3% sorting; right arm 1.3% ramp versus 0.7% sorting).Trunk and upper arm postures and movements among flight baggage handlers measured by inclinometry were similar to those found in other jobs comprising manual material handling, known to be associated with increased risks for musculoskeletal disorders. The results showed that full-shift trunk (FP) and, to some extent, peak arm exposures were higher for ramp workers compared with sorting workers.

Objective The aim was to examine if exposure to whole-body vibration (WBV) increases the risk for hospitalization due to lumbar disc herniation. Methods The study basis is a cohort of 288,926 Swedish construction workers who participated in a national occupational health surveillance programme from 1971 until 1992. Job title, smoking habits, body weight, height and age were registered at the examinations. Assessment of WBV were made for each of the constituent occupations by constructing a job-exposure matrix (JEM). Exposure to WBV was graded on a scale from 0 to 5. In addition, the occurrence of hospitalization due to lumbar disc herniation from January 1st 1987 until December 31st 2010 was collected from a linkage with the Swedish Hospital Discharge Register. Poisson regressions were used to estimate relative risk with 95 percent confidence intervals (95% CI), adjusting for age, height, weight and smoking, using white-collar workers and foremen as a reference group. Results There was an increased risk for hospitalization due to lumbar disc herniation for workers in the construction industry exposed to medium to high WBV compared to white-collar workers and foremen 1.35 (1.12–1.63). When restricting the analyses to include workers 30–49 years of age at the time of the hospital admission the risk was 1.69 (95% CI 1.29–2.21). Conclusion This study further supports that occupational exposure to whole-body vibration increases the risk for hospitalization due to lumbar disc herniation. Electronic supplementary material The online version of this article (10.1007/s00420-018-1316-5) contains supplementary material, which is available to authorized users.

Objectives: The objectives of this study are to investigate the relation between obesity and labour force exit via diagnosis-specific disability benefits, and whether physical workload modifies this association. Methods: A longitudinal analysis was performed among 3 28 743 Swedish construction workers in the age of 15-65 years. Body weight and height were measured at a health examination and enriched with register information on disability benefits up to 37 years later. Diagnoses of disability benefits were categorised into cardiovascular diseases (CVDs), musculoskeletal diseases (MSDs), mental disorders and others. A job exposure matrix, based on self-reported lifting of heavy loads and working in bent forward or twisted position, was applied as a measure of physical workload. Cox proportional hazards regression analyses were performed, and the relative excess risk due to interaction (RERI) between obesity and physical workload was calculated. Results: Obese construction workers were at increased risk of receiving disability benefits (HR 1.70, 95% CI 1.65 to 2.76), mainly through CVD (HR 2.30) and MSD (HR 1.71). Construction workers with a high physical workload were also more likely to receive a disability benefit (HR 2.28, 95% CI 2.21 to 2.34), particularly via MSD (HR 3.02). Obesity in combination with a higher physical workload increased the risk of disability benefits (RERI 0.28) more than the sum of the risks of obesity and higher physical workload, particularly for MSD (RERI 0.44). Conclusions: Obesity and a high physical workload are risk factors for disability benefit. Furthermore, these factors are synergistic risk factors for labour force exit via disability benefit through MSD. Comprehensive programmes that target health promotion to prevent obesity and ergonomic interventions to reduce physical workload are important to facilitate sustained employment.

Purpose To describe the self-reported ambient cold exposure in northern Sweden and to relate the level of cumulative cold exposure to the occurrence of sensory and vascular hand symptoms. We hypothesize that cold exposure is positively related to reporting such symptoms. Methods A questionnaire about cold exposure and related symptoms was sent out to 35,144 subjects aged 18–70 years and living in northern Sweden. Results A total of 12,627 out of 35,144 subjects returned the questionnaire (response rate 35.9%). Subjects living in the rural alpine areas reported more extensive cold exposure both during work and leisure time compared to the urbanized coastal regions. Frostbite in the hands was present in 11.4% of men and 7.1% of women, cold sensitivity was present in 9.7 and 14.4%, and Raynaud’s phenomenon was present in 11.0% of men and 14.0% of women. There was a positive association between cumulative cold exposure and neurovascular hand symptoms. Conclusion The present study demonstrates that the cold environment in northern Sweden might be an underestimated health risk. Our hypothesis that cold exposure is positively related to reporting of neurovascular hand symptoms was supported by our findings. In addition, such symptoms were common not only in conjunction with an overt cold injury. Our results warrant further study on pathophysiological mechanisms and suggest the need for confirmatory prevalence studies to support national public health planning. Electronic supplementary material The online version of this article (doi:10.1007/s00420-017-1221-3) contains supplementary material, which is available to authorized users.

PURPOSE: To investigate whether exposure to cold could influence the thermal perception thresholds in a working population. METHODS: This cross-sectional study was comprised of 251 males and females and was carried out at two mines in the northern part of Norway and Sweden. The testing included a baseline questionnaire, a clinical examination and measurements of thermal perception thresholds, on both hands, the index (Digit 2) and little (Digit 5) fingers, for heat and cold. RESULTS: The thermal perception thresholds were affected by age, gender and test site. The thresholds were impaired by experiences of frostbite in the fingers and the use of medication that potentially could affect neurosensory functions. No differences were found between the calculated normative values for these workers and those in other comparative investigations conducted in warmer climates. CONCLUSIONS: The study provided no support for the hypothesis that living and working in cold climate will lead to impaired thermal perception thresholds. Exposure to cold that had caused localized damage in the form of frostbite was shown to lead to impaired thermal perception.

Prospective cohort study.To study biomechanical factors in relation to symptomatic lumbar disc disease.The importance of biomechanical factors in lumbar disc disease has been questioned in the past decade and knowledge from large prospective studies is lacking.The study basis is a cohort of 263,529 Swedish construction workers who participated in a national occupational health surveillance program from 1971 until 1992. The workers' job title, smoking habits, body weight, height, and age were registered at the examinations. The occurrence of hospitalization due to lumbar disc disease from January 1, 1987, until December 31, 2003, was collected from a linkage with the Swedish Hospital Discharge Register.There was an increased risk for hospitalization due to lumbar disc disease for several occupational groups compared with white-collar workers and foremen. Occupational groups with high biomechanical loads had the highest risks, for example, the relative risk for concrete workers was 1.55 (95% confidence interval [CI], 1.29-1.87). A taller stature was consistently associated with an increased risk. The relative risk for a man of 190- to 199-cm height was 1.55 (95% CI, 1.30-1.86) compared with a man being 170- to 179-cm height. Body weight and smoking were also risk factors, but weaker than height. Workers in the age span of 30 to 39 years had the highest relative risk (RR = 1.87; 95% CI, 1.58-2.23) compared with those aged 20 to 29 years, whereas men aged 60 to 65 years had a lower risk (RR = 0.86; 95% CI, 0.68-1.09).This study indicates that factors increasing the load on the lumbar spine are associated with hospitalization for lumbar disc disease. Occupational biomechanical factors seem to be important, and a taller stature was consistently associated with an increased risk.

To quantify variance components of hand-arm vibration exposure from data collected in a laboratory study of four different angle grinders.Four different angle grinders were sent to seven laboratories for grinding tests by three operators at each laboratory. Vibration in both the throttle and support handles was measured. For one grinder, the experimental set-up was repeated and two measurements were collected for that specific grinder.At least one-third of the estimated variability is attributable to the wheel and less than one-third to the operator. In repeated experiments, between-occasion, operator and wheel factors explained 4, 29 and 17% of the total variability, respectively.Since measured vibrations in the support and throttle handles are significantly differed, measurements should be taken at both locations. Factors influencing vibration variability include the presence/absence of an auto balance unit, wheel and operator, but other factors remain to be elucidated.

Background. Local freezing cold injuries are common in the north and sequelae to cold injury can persist many years. Quantitative sensory testing (QST) can be used to assess neurosensory symptoms but has previously not been used on cold injury patients.Objective. To evaluate neurosensory sequelae after local freezing cold injury by thermal and vibrotactile perception thresholds and by symptom descriptions.Design. Fifteen patients with a local freezing cold injury in the hands or feet, acquired during military training, were studied with QST by assessment of vibrotactile (VPT), warmth (WPT) and cold (CPT) perception thresholds 4 months post-injury. In addition, a follow-up questionnaire, focusing on neurovascular symptoms, was completed 4 months and 4 years post-injury.Results. QST demonstrated abnormal findings in one or both affected hands for VPT in 6 patients, for WPT in 4 patients and for CPT in 1 patient. In the feet, QST was abnormal for VPT in one or both affected feet in 8 patients, for WPT in 6 patients and for CPT in 4 patients. Freezing cold injury related symptoms, e.g. pain/discomfort when exposed to cold, cold sensation and white fingers were common at 4 months and persisted 4 years after the initial injury.Conclusions. Neurosensory sequelae after local freezing cold injury, in terms of abnormal thermal and/or vibration perception thresholds, may last at least 4 months after the initial injury. Symptoms such as pain/discomfort at cold exposure, cold sensations and white fingers may persist at least 4 years after the initial injury.Keywords: case series; neurovascular; quantitative sensory testing; military; frostbite; Sweden(Published: 17 February 2014)Citation: Int J Circumpolar Health 2014, 73: 23540 - http://dx.doi.org/10.3402/ijch.v73.23540

OBJECTIVES: This study compared the cost efficiency of observation and inclinometer assessment of trunk and upper-arm inclination in a population of flight baggage handlers, as an illustration of a general procedure for addressing the trade-off between resource consumption and statistical performance in occupational epidemiology. METHODS: Trunk and upper-arm inclination with respect to the line of gravity were assessed for three days on each of 27 airport baggage handlers using simultaneous inclinometer and video recordings. Labor and equipment costs associated with data collection and processing were tracked throughout. Statistical performance was computed from the variance components within and between workers and bias (with inclinometer assumed to produce “correct” inclination angles). The behavior of the trade-off between cost and efficiency with changed sample size, as well as with changed logistics for data collection and processing, was investigated using simulations. RESULTS: At similar total costs, time spent at trunk and arm inclination angles >60 ° as well as 90^th percentile arm inclination were estimated at higher precision using inclinometers, while median inclination and 90th percentile trunk inclination was determined more precisely using observation. This hierarchy remained when the study was reproduced in another population, while inclinometry was more cost-efficient than observation for all three posture variables in a scenario where data were already collected and only needed to be processed. CONCLUSIONS: When statistical performance was measured only in terms of precision, inclinometers were more cost-efficient than observation for two out of three posture metrics investigated. Since observations were biased, inclinometers consistently outperformed observation when both bias and precision were included in statistical performance. This general model for assessing cost efficiency may be used for designing exposure assessment strategies with considerations not only of statistical but also cost criteria. The empirical data provide a specific basis for planning assessments of working postures in occupational groups.

Objectives The objective of this study was to investigate exposure to polycyclic aromatic hydrocarbons (PAH) from asphalt fumes among Swedish road pavement workers and determine whether any effects could be detected with genotoxic tests. Methods The study included 28 nonsmoking road pavers and 30 nonsmoking referents. The concentration of PAH was determined in the breathing zone of the road pavers. 1-Hydroxypyrene was analyzed before and after shifts of asphalt work and during the afternoon for referents. Sister chromatid exchanges (SCE) and micronuclei (MN) were determined in peripheral lymphocytes. Results Several 3- or 4-ring PAH were found, and the analysis indicated that they occurred in bitumen fumes rather than in traffic fumes. The average total concentration of PAH was 2.3 (range 0.2-23.8) mg/m3. The concentration of 1-hydroxypyrene in urine was higher for the road pavers than for the referents, but there was no significant difference between the pre- and postshift values of the road pavers. The road pavers had no significant increase in SCE or MN. Conclusion The study showed that Swedish road pavers have an increased exposure to PAH from bitumen fumes, but no genotoxic effects could be detected by SCE or MN tests.

There are numerous factors including physical, biomechanical, and individual that influence exposure to hand-transmitted vibration (HTV) and cause variability in the exposure measurements. Knowledge of exposure variability and determinants of exposure could be used to improve working conditions. We performed a quasi-experimental study, where operators performed routine work tasks in order to obtain estimates of the variance components and to evaluate the effect of determinants, such as machine-wheel combinations and individual operator characteristics.Two pre-defined simulated work tasks were performed by 11 operators: removal of a weld puddle of mild steel and cutting of a square steel pipe. In both tasks, four angle grinders were used, two running on compressed air and two electrically driven. Two brands of both grinding and cutting wheels were used. Each operator performed both tasks twice in a random order with each grinder and wheel and the time to complete each task was recorded. Vibration emission values were collected and the wheel wear was measured as loss of weight. Operators' characteristics collected were as follows: age, body height and weight, length and volume of their hands, maximum hand grip force, and length of work experience with grinding machines (years). The tasks were also performed by one operator who used four machines of the same brand. Mixed and random effects models were used in the statistical evaluation.The statistical evaluation was performed for grinding and cutting separately and we used a measure referring to the sum of the 1-s r.m.s. average frequency-weighted acceleration over time for completing the work task (a(sa)). Within each work task, there was a significant effect as a result of the determinants 'the machine used', 'wheel wear', and 'time taken to complete the task'. For cutting, 'the brand of wheel' used also had a significant effect. More than 90% of the inherent variability in the data was explained by the determinants. The two electrically powered machines had a mean a(sa) that was 2.6 times higher than the two air-driven machines. For cutting, the effect of the brand of wheel on a(sa) was ~0.1 times. The a(sa) increased both with increasing wheel wear and with time taken to complete the work task. However, there were also a number of interaction effects which, to a minor extent, modified the a(sa). Only a minor part (1%) of the total variability was attributed to the operator: for cutting, the volume of the hands, maximum grip force, and body weight were significant, while for grinding, it was the maximum grip force. There was no clear difference in a(sa) between the four copies of the same brand of each machine.By including determinants that were attributed to the brand of both machine and wheel used as well as the time taken to complete the work task, we were able to explain90% of the variability. The dominating determinant was the brand of the machine. Little variability was found between operators, indicating that the overall effect as due to the operator was small.

To study whether work in a cold environment increased the risk of musculoskeletal symptoms in the neck and low back among construction workers.This cross-sectional study is based on a cohort of male workers in the Swedish construction industry that participated in regular health examinations through a nationwide occupational health service. The analysis is based on workers examined from 1971 to 1974, who answered a questionnaire including questions about neck and back pain. The cohort consists of 134,754 male workers, including 16,496 office workers and foremen. The health examinations of the workers were conducted in provinces covering Sweden from the south to the north, and temperature data were collected for the provinces. In the analyses, the results were adjusted for age, BMI and use of nicotine.The prevalence's of neck and low back pain were higher among manual construction workers than among foremen and office workers (24.3 vs. 8.6 % and 16.5 vs. 6.2 %, respectively); the corresponding adjusted ORs for low back and neck pain were 1.59 (95 % CI 1.52-1.66) and 1.39 (95 % CI 1.30-1.49), respectively. Workers in the northern and central provinces had higher ORs for low back and neck pain compared to workers in the southern province. The test for trends showed an increased risk of developing low back and neck pain with decreased outdoor temperature.Outdoor work in a cold environment may increase the risk of low back and neck pain.

Background The aim of this study was to investigate whether perceived exertion, perceived comfort and working technique is associated with the incidence of neck and upper extremity symptoms among professional computer users. Methods At baseline a self-administered questionnaire was distributed to 853 participants from 46 different work sites (382 men and 471 women) who, at baseline, had been free from neck and upper extremity symptoms during the preceding month. Work-related exposures, individual factors, and symptoms from the neck and upper extremities were assessed. Observations of working technique were performed by ergonomists using an ergonomic checklist. Incidence data were collected by means of 10 monthly questionnaires, asking for information on the occurrence of neck, shoulder and arm/hand symptoms. Perceived exertion was rated on a modified Borg RPE scale ranging from 0 (very, very light) to 14 (very, very strenuous). Perceived comfort was rated on a 9-point scale ranging from -4 (very, very poor) to +4 (very, very good) in relation to the chair, computer screen, keyboard, and computer mouse. Results The median follow up time was 10.3 months. The incidence of symptoms from the neck, shoulders and arm/hands were 50, 24 and 34 cases per 100 person years, respectively. Higher perceived exertion in the neck, shoulder or arm/hands was associated with an increased risk of developing symptoms in the corresponding body region. Moreover, a dose-response relationship between the level of exertion and the risk of developing symptoms was recorded for all three regions. There was an association between low comfort and an increased risk for neck symptoms, but not for shoulder and arm/hand symptoms, although a trend towards such an association (not statistically significant) could be seen. Working technique was, in this study, not associated with the risk of developing symptoms in any of the investigated body regions. Conclusion There was a strong association between high perceived exertion and the development of neck, shoulder, and arm/hand symptoms. Moreover, there was an association between poor perceived comfort and neck pain. Surveillance of computer users may include perceived exertion and comfort to target individuals at risk for neck and upper extremity symptoms.

This study examines the effect of changing the floor from a 2-mm homogenous vinyl floor to a 4-mm heterogeneous vinyl floor (1.5-mm wear layer and 2.5-mm foam layer) on musculoskeletal symptoms in the lower extremities and low back among nursing assistants in a geriatric care centre. A pre-post design with a reference group consisting of nursing assistants from a similar geriatric care centre was used. Follow-up measurements were carried out 12 and 24 months after the intervention by means of questionnaires. At the 1-year follow-up, the pain intensity score in the feet of the intervention group had decreased compared with the baseline value and remained statistically significant at the 2-year follow-up. The decrease in pain intensity score of the feet in the intervention group was statistically significantly different from the reference group, both after 1 and 2 years.The results show the importance of flooring in the workplace with regard to reducing musculoskeletal symptoms. Appropriate flooring is especially important in the female-dominated health care sector, where workers must stand or walk for long periods.

OBJECTIVES: The aim of this study was to examine the association between white fingers, cold environment, and exposure to hand–arm vibration (HAV). The hypothesis was that working in cold climate increases the risk of white fingers. METHODS: The occurrence of white fingers was investigated as a cross-sectional study in a cohort of Swedish male construction workers (N=134 757). Exposure to HAV was based on a job-exposure matrix. Living in the north or south of Sweden was, in a subgroup of the cohort, used as an indicator of the exposure to cold environment (ie, living in the north meant a higher exposure to cold climate). The analyses were adjusted for age and use of nicotine products (smoking and snuff). RESULTS: HAV-exposed workers living in a colder climate had a higher risk for white fingers than those living in a warmer climate [odds ratio (OR) 1.71, 95% confidence interval (95% CI) 1.42–2.06]. As expected, we found that HAV-exposed workers had an increased risk compared to controls (OR 2.02, 95% CI 1.75–2.34). The risk for white fingers increased with increased level of exposure to HAV and also age. CONCLUSIONS: Cold environment increases the risk for white fingers in workers occupationally exposed to HAV. The results underscore the need to keep exposure to HAV at workplaces as low as possible especially in cold climate.

To describe upper arm postures and movements among female hairdressers, including the variability between hairdressers, between days within hairdresser, and between tasks, as a basis for understanding the characteristics of exposures in the job, considering possible sources of variation and recovery, and discussing appropriate exposure assessment strategies.Data on upper arm postures were collected using inclinometers during four working days the same week from 28 female hairdressers working in 13 salons. Twenty of the hairdressers noted customer on and off times in a diary, to allow separate analyses of customer tasks (CT) and auxiliary non-customer tasks (AT), including breaks. For a number of posture and movement variables, mean values and variance components between subjects (BS) and within subjects between days (BD) were estimated using restricted maximum likelihood algorithms in one-way random effect models.For the 20 hairdressers with diaries, CT accounted for 279 min (58%) (SD(BS) = 39 min and SD(BD) = 85 min) of the working day and AT and breaks for 207 min (42%) (SD(BS) = 46 min and SD(BD) = 88 min). The hairdressers worked with the right arm elevated60 degrees for 6.8% of the whole job (SD(BS) = 2.8% and SD(BD) = 2.0%). On average, the hairdressers worked with the right arm elevated60 degrees for 9.0% of the time during CT, compared to 3.7% during AT, resulting in a contrast between tasks of 0.35.Hairdressers may be at risk for developing musculoskeletal disorders in the neck and shoulders due to a considerable occurrence of highly elevated arms, especially during CT. On the other hand, we do not find reasons to classify hairdressing as a job with too little variation. Posture variability between days within hairdressers was in the same order of magnitude as that between hairdressers, suggesting that 'typical' workdays do not exist. The exposure contrast between CT and AT for variables describing elevated arm postures indicates that for these variables a simple task-based approach for estimating job exposure could be successful.

Analysis of repeated cross-sectional surveys.To investigate the prevalence of neck-shoulder-arm pain and concurrent low back pain and psychological distress in a geographical area over a 16-year period.A large number of studies have shown that nonspecific neck, shoulder, and arm pain is a very common symptom in the general population. However, few studies have followed the prevalence of neck-shoulder-arm pain within a geographical area, in order to investigate time-trends.This study provides an analysis of questionnaire data collected every 4 years between 1990 and 2006 on the prevalence of neck-shoulder-arm pain and concurrent low back pain or psychological distress in the County of Stockholm, Sweden (response rate: 61%-69%). All individuals aged 21 to 64 years (n = 1976-26,611) were included in the study.Over the 16-year period, the prevalence of self-reported neck-shoulder-arm pain rose slightly, from 22.8% to 25.0% among females (prevalence rate ratio [PRR]: 1.10) and from 12.8% to 15.4% among males (PRR: 1.21). The prevalence of neck-shoulder-arm pain with concurrent low back pain also rose slightly, from 8.4% to 10.8% among females (PRR: 1.28) and from 5.3% to 6.6% among males (PRR: 1.24). In contrast, the prevalence of neck-shoulder-arm pain with concurrent psychological distress rose more substantially, from 4.4% to 8.5% among females (PRR: 1.91) and from 2.0% to 4.3% among males (PRR: 2.18). All prevalence rates rose between 1990 and 2002, and decreased in 2006 compared to 2002. The gender gap in prevalence did not change over time.Although the prevalence of neck-shoulder-arm pain and concurrent symptoms decreased in 2006 compared to 2002, it is still too early to conclude that we have reached and passed the peak of the "epidemic" of neck-shoulder-arm pain.