Dose-response relationship between lung function and chest imaging response to silica exposures in artificial stone manufacturing workers.

BACKGROUND: Occupational exposure to artificial stone, a popular material used for countertops, can cause accelerated silicosis, but the precise relationship between silica dose and disease development is unclear. OBJECTIVES: This study evaluated the impact of silica exposure on lung function and chest imaging in artificial stone manufacturing workers. METHODS: Questionnaire and spirometry assessments were administered to workers in two plants. A high-exposure subset underwent further evaluation, including chest CT and DLco. Weighting factors, assigned as proxies for silica exposure, were based on work tasks. Individual cumulative exposures were estimated using area concentration measurements and time spent in specific areas. Exposure-response associations were analyzed using linear and logistic regression models. RESULTS: Among 65 participants, the mean cumulative silica exposure was 3.61 mg/m3-year (range 0.0001 to 44.4). Each 1 mg/m3-year increase was associated with a 0.46% reduction in FVC, a 0.45% reduction in FEV1, and increased lung function abnormality risk (aOR = 1.27, 95% CI = 1.03-1.56). Weighting factors correlated with cumulative exposures (Spearman correlation = 0.59, p < 0.0001), and weighted tenure was associated with lung function abnormalities (aOR = 1.04, 95% CI = 1.01-1.09). Of 37 high-exposure workers, 19 underwent chest CT, with 12 (63%) showing abnormal opacities. Combining respiratory symptoms, lung function, and chest X-ray achieved 91.7% sensitivity and 75% specificity for predicting chest CT abnormalities. CONCLUSION: Lung function and chest CT abnormalities occur commonly in artificial stone workers. For high-exposure individuals, abnormalities on health screening could prompt further chest CT examination to facilitate early silicosis detection.

Contributions of Ergonomics, Psychological Factors, and Sleep Disturbances to Lower Back Pain Among Taiwanese Workers.

OBJECTIVE: We investigated the contributions of ergonomics, psychological factors, and sleep disturbances to lower back pain (LBP). METHODS: A nationwide survey of sampled 27,508 (2.6‰) Taiwanese workers was conducted in 2010. Definition of outcome was LBP affecting work performance in the past year. Predictor variables included age, body mass index, ergonomic factors, job control, psychological demands, and sleep disturbances. Mutually adjusted relative risks were examined using general linear models, followed by aPAR. RESULTS: 18,353 workers were included in the multivariate regression model. The three first significant risk factors to LBP included heavy lifting or awkward posture, sleep disturbances, and high psychological demands (aPAR = 13.5%, 8.7%, 5.7% respectively in men and 6.1%, 11.8%, 5.9% in women). CONCLUSIONS: In addition to ergonomic exposure, sleep disturbances and high psychological demands significantly contributed to LBP.

Incorporating Exposure Measurement Data from Similar Exposure Scenarios to Inform Exposure Modeling Estimates: A Demonstration Using Cluster Analysis and Bayesian Modeling.

Addressing occupational health and safety concerns early in the design stage anticipates hazards and enables health professionals to recommend control measures that can best protect workers' health. This method is a well-established tool in public health. Importantly, its success depends on a comprehensive exposure assessment that incorporates previous exposure data and outcomes. Traditional methods for characterizing similar occupational exposure scenarios rely on expert judgment or qualitative descriptions of relevant exposure data, which often include undisclosed underlying assumptions about specific exposure conditions. Thus, improved methods for predicting exposure modeling estimates based on available data are needed. This study proposes that cluster analysis can be used to quantify the relevance of existing exposure scenarios that are similar to a new scenario. We demonstrate how this method improves exposure predictions. Exposure data and contextual information of the scenarios were collected from past exposure assessment reports. Prior distributions for the exposure distribution parameters were specified using Stoffenmanager® 8 predictions. Gower distance and k-Medoids clustering algorithm analyses grouped existing scenarios into clusters based on similarity. The information was used in a Bayesian model to specify the degree of correlation between similar scenarios and the scenarios to be assessed. Using the distance metric to characterize the degree of similarity, the performance of the Bayesian model was improved in terms of the average bias of model estimates and measured data, reducing from 0.77 (SD: 2.0) to 0.49 (SD: 1.8). Nevertheless, underestimation of exposures still occurred for some rare scenarios, which tended to be those with highly variable exposure data. In conclusion, the cluster analysis approach may enable transparent selection of similar exposure scenarios for factoring into design-phase assessments and thereby improve exposure modeling estimates.

Body volume estimation equation for male laborers in Taiwan.

The purpose of this study was to develop a body volume (BV) estimation equation for male laborers in Taiwan with body weight (W) and stature height (H) as initial estimators. A three-dimensional (3D) body scanner and a 3D foot scanner were used to measure the 3D range data of 100 male laborers in this study. Subjects' BV was extracted from the 3D body model, and H and W were used as independent variables in regression analysis. The results show that the final BV estimation equation is BV = 1122.927 × W0.972, with R2 = 0.949. Thirty extra male subjects were scanned to compare this BV estimation equation with those in previous studies. The results show that this BV estimation equation had the smallest absolute mean difference at 1.1458 L and the smallest standard error of the estimate at 2.48% in comparison.

Will daytime occupational noise exposures induce nighttime sleep disturbance?

BACKGROUND: Nighttime environmental noise affects sleep quality. However, the effects of daytime occupational noise remain unclear. METHODS: A quasi-experiment of 48 participants who had been employed for at least six months in two hospital cafeterias. The participants were randomly designated to be assessed on high- and low-noise workdays for 8 h or low- and high-noise workdays, separated by a washout period of 14 days. Subsequently, pure tone audiometry, autonomic nervous system (ANS) function tests, serum cortisol tests, and polysomnography were conducted. RESULTS: For the 40 participants in the study, the 8-h time-weighted average of personal noise exposed on high- and low-noise workdays was 76.8 dBA (standard deviation, SD: 6.2) and 61.0 dBA (SD: 7.1), respectively. Participants with higher personal noise exposure during the day were found to have a lower percentage of slow wave sleep (percent change of mean value: -1.287%; 95% CI: -2.602%, -0.037%) and lower sleep efficiency (-0.267%; 95% CI: -0.525%, -0.008%). In addition, after work, personal noise exposure was revealed to be related to increased serum cortisol levels (1.698%; 95% CI: 0.887%, 2.528%), and sympathetic activity as measured by low frequency/high frequency (3.000%; 95% CI: 1.294%, 4.706%) and blood pressures by cold pressor test (systolic: 5.163%; 95% CI: 2.780%, 7.537%) (diastolic: 3.109%; 95% CI: 1.604%, 4.614%). CONCLUSIONS: Daytime occupational noise exposure had sustained effects on nighttime sleep quality, specifically on slow wave sleep and sleep efficiency. These disturbances could be partially explained by post-shift elevated cortisol and ANS activity. The psychosocial and metabolic consequences of poorer sleep quality induced by occupational noise exposure warrant further investigation.

Field evaluation of personal sampling methods for multiple bioaerosols.

Ambient bioaerosols are ubiquitous in the daily environment and can affect health in various ways. However, few studies have been conducted to comprehensively evaluate personal bioaerosol exposure in occupational and indoor environments because of the complex composition of bioaerosols and the lack of standardized sampling/analysis methods. We conducted a study to determine the most efficient collection/analysis method for the personal exposure assessment of multiple bioaerosols. The sampling efficiencies of three filters and four samplers were compared. According to our results, polycarbonate (PC) filters had the highest relative efficiency, particularly for bacteria. Side-by-side sampling was conducted to evaluate the three filter samplers (with PC filters) and the NIOSH Personal Bioaerosol Cyclone Sampler. According to the results, the Button Aerosol Sampler and the IOM Inhalable Dust Sampler had the highest relative efficiencies for fungi and bacteria, followed by the NIOSH sampler. Personal sampling was performed in a pig farm to assess occupational bioaerosol exposure and to evaluate the sampling/analysis methods. The Button and IOM samplers yielded a similar performance for personal bioaerosol sampling at the pig farm. However, the Button sampler is more likely to be clogged at high airborne dust concentrations because of its higher flow rate (4 L/min). Therefore, the IOM sampler is a more appropriate choice for performing personal sampling in environments with high dust levels. In summary, the Button and IOM samplers with PC filters are efficient sampling/analysis methods for the personal exposure assessment of multiple bioaerosols.

Risks of musculoskeletal disorders among betel quid preparers in Taiwan.

BACKGROUND: Betel quid chewing is common in Taiwan. The work of betel quid preparers is characterized by long hours of static work, awkward working posture and highly repetitive hand/wrist motion. However, the musculoskeletal health of betel quid preparers receives very little attention. METHODS: The Chinese version of the Standardized Nordic Musculoskeletal Questionnaire (NMQ) was administered, and electrogoniometers and electromyography were used in this cross-sectional study to characterize the hand/wrist motion of the subjects. Physical examinations on the thumbs and wrists of the subjects were conducted by means of Phalen's test and Finkelstein's test, respectively. RESULTS: Among the 225 participants, more than 95% attributed their musculoskeletal complaints to their work, and shoulder, neck, hand/wrist, and lower back discomfort were most frequently reported. More than 70% of the preparers did not seek medical treatment for their musculoskeletal problems. Based on the physical examination, 24% of the participants had suspected symptom of either carpal tunnel syndrome (CTS) or DeQuervain's tenosynovitis. The instrumental measurements indicated that betel quid preparation is characterized by extreme angle ranges and moderate repetition of wrist motion as well as low forceful exertion. CONCLUSIONS: This study concludes that betel quid preparers are a high risk group of developing musculoskeletal disorders (MSDs). Future studies by electrogoniometers and detailed physical examination on betel quid preparers are needed to determine the predisposing factors for CTS. Some intervention measures to prevent MSDs and to lessen psychological stress for this group of workers are strongly suggested.

Shoe sole tread designs and outcomes of slipping and falling on slippery floor surfaces.

A gait experiment was conducted under two shoe sole and three floor conditions. The shoe soles and floors were characterized by the tread and groove designs on the surface. The coefficients of friction (COF) on the floor in the target area were measured. The subjects were required to walk on a walkway and stepping on a target area covered with glycerol. The motions of the feet of the subjects were captured. Gait parameters were calculated based on the motion data. Among the 240 trials, there were 37 no-slips, 81 microslips, 45 slides, and 77 slips. It was found that the condition with shoe sole and floor had both tread grooves perpendicular to the walking direction had the highest COF, the shortest slip distance, and the lowest percentages of slide and slip. The condition with shoe sole and floor had both tread grooves parallel to the walking direction had the lowest COF and the longest slip distance among all experimental conditions. The Pearson's correlation coefficients between slip distance and slip velocity, time to foot flat, foot angle, and compensatory step length were 0.82 (p<0.0001), 0.33 (p<0.0001), -0.54 (p<0.0001), and -0.51 (p<0.0001), respectively.

Effectiveness of leg movement in reducing leg swelling and discomfort in lower extremities.

Various occupations required that workers stand for long periods, causing discomfort and pain. This study considered the effectiveness of three leg movements in relieving discomfort of the lower extremities during long periods of standing at work. Ten paid male subjects with no history of problems of the lower extremities were enrolled in this study. They performed three leg movements on a hard floor while standing for 4 h in a laboratory setting. Each 1 h experimental test had two phases - 50 min of standing, followed by 10 min of rest. During the period of standing, one the following leg movements was made. No movement (no change in posture), ankle movement (twice, for 2 min each time), and hip movement (twice, for 2 min each time). Observations revealed that the three leg movements yielded different degrees of lower limb swelling. The percentage changes in thigh (1.22%) and shank (1.32%) circumferences were largest during prolonged standing without any movement and lowest during prolonged standing with ankle movement (0.61%) and hip movement (0.80%). The relationship between perceived discomfort and standing time was determined. The subjects perceived the most shank discomfort (5.8) during the 4 h test without any movement. Leg movement greatly influenced perceived discomfort of the shank. The results of this study suggested that workers should move their ankles and hips for a short period following prolonged standing for 30 min to reduce lower extremity discomfort.

Influence of shoe/floor conditions on lower leg circumference and subjective discomfort during prolonged standing.

Many occupations require workers to stand for prolonged periods, which can cause both discomfort and pain. This study examines the effects of different shoe and floor conditions on standing discomfort in the workplace and laboratory. Two experiments were conducted. Experiment 1 enrolled 10 subjects who performed a computer task under two floors and shoe conditions while standing for 4 h in a laboratory. Experiment 2 involved 14 subjects who stood for 4 h throughout their shift on two different floors in a real work situation (i.e., a field experiment). Analytical results demonstrate that floor type and time standing significantly affected subjective ratings for leg discomfort and circumferential shank measurements in both the laboratory and field studies. Shoe condition significantly affected subjective ratings for leg discomfort. We conclude that shoe/floor conditions and prolonged standing influence worker lower extremity discomfort during prolonged standing. These analytical findings suggest that common ergonomic interventions, such as modifying the flooring on which workers stand might some what alleviate leg edema for workers standing for 4 h shifts in laboratory and field settings. Nevertheless, prolonged standing for even 1 h without rest showed negative effects and should be avoided when possible.

Assessment of slip resistance under footwear materials, tread designs, floor contamination, and floor inclination conditions.

Slip and fall incidences are common in our daily lives. They are not only important environmental safety issues but also important occupational safety and health problems. The purpose of this study was to use the Brungraber Mark II to measure the friction so as to investigate the effects of the shoe sole, surface condition and the inclined angle of the floor and their interactions on friction coefficient. The results of the study showed the effects of all the main factors and their interactions were significant (p<0.001). Engineering designs & ergonomic interventions in slip & fall prevention should take these factors in full consideration.

Prevalence of musculoskeletal disorders and job exposure in Taiwan oyster shuckers.

BACKGROUND: Oyster shucking is characterized by long hours of static work, awkward working posture, and highly repetitive hand/wrist motion. The objectives of this study were to investigate the prevalence of musculoskeletal discomfort and kyphosis in oyster shuckers in Taiwan as well as the biomechanical features of oyster shucking. METHODS: The Chinese version of the Standardized Nordic Musculoskeletal Questionnaire was successfully collected from 234 oyster shuckers. The characteristics of workstation, hand/wrist motion angles, and muscular exertion in shucking oysters were recorded. Measurements to identify kyphosis were also taken from the subjects and a control group. RESULTS: Among the participated oyster shuckers, low back (75.2%), hand/wrist (60.3%), shoulder (44.0%), and elbow (27.8%) discomfort were reported most frequently. The prevalence of low back discomfort in oyster shuckers was higher than various groups of workers who need long hours of seated position. Those who worked on tables had fewer musculoskeletal complaints in shoulder and elbow (P < 0.05) than those not. Additionally, oyster shuckers were more prone to kyphosis than the general population (P < 0.001). CONCLUSIONS: Oyster shuckers are observed to have high prevalence of musculoskeletal discomfort and kyphosis. Introduction of ergonomic design to oyster shucking workshops is strongly suggested.

Perceived job stress and health complaints at a bank call center: comparison between inbound and outbound services.

This study investigated how perceived job stress and health status differ, as well as the relationships to inbound (incoming calls) versus outbound (outgoing calls) calling activities, for call center workers in a bank in Taiwan. The sample bank employed 289 call center workers at the time of the survey, ranging in age from 19 to 54 yr old. Data were obtained on individual factors, health complaints, perceived level job stress, and major job stressors. Overall, 33.5% of outbound operators and 27.1% of inbound operators reported frequently or always experiencing high stress at work, however, the differences between inbound and outbound operators were insignificant. "Having to deal with difficult customers" was the most frequent job stressor for all workers. Musculoskeletal discomfort, eye strain, and hoarse or sore throat were the most prevalent complaints among call center workers. The relationship between perceived job stress and health complaints indicated that workers who perceived higher job stress had significantly increased risk of multiple health problems, including eye strain, tinnitus, hoarse or sore throat, chronic cough with phlegm, chest tightness, irritable stomach or peptic ulcers, and musculoskeletal discomfort (with odds ratios ranging from 2.13 to 8.24). These analytical results suggest that perceived job stress in the call center profoundly affected worker health. This study identified main types of job stressors requiring further investigation.

Ergonomic risk factors for the wrists of hairdressers.

This study utilized a portable data logger to measure the wrist angles and forearm flexor and extensor electromyography (EMG) of 21 hairstylists. The hairstylists were divided into two groups, one with 11 barbers (9 males and 2 females) specializing in men's hairdressing, and one with 10 hairdressers (2 males and 8 females) specializing in women's hairdressing. The standard haircut task was divided into three subtasks: hair cutting, washing and blow-drying. The mechanical exposures of the overall task and subtasks were quantified to compare how subtasks, occupational groups, and gender groups differ. Experimental results show that the average time to finish a woman's haircut (51.4min) is significantly longer than that for a man's haircut (35.6min) (p<0.005). Female hairstylists had significantly greater EMG activity than male hairstylists did (p<0.001). The non-dominant hands of hairdressers have significantly higher overall wrist velocity than those of barbers (p<0.005). Analytical results suggest that the relatively higher force exertion and wrist velocity of female hairstylists combined with prolonged exposure may account for the higher rate of hand/wrist pain in female hairdressers than in male barbers.

Physical discomfort and psychosocial job stress among male and female operators at telecommunication call centers in Taiwan.

The prevalence of job stress, distributions of major job stressors, and associations between perceived job stress levels and multiple physical discomforts are assessed via a cross-sectional study of 1023 male and female operators at telecommunication call centers in Taiwan. Cases of discomfort are identified via questionnaire surveys requiring respondents to self-reported symptoms of discomfort. Information is obtained on demographics, health status, perceived job stress levels, major job stressors and psychosocial job characteristics. Multivariate logistic regression models are developed to predict physical discomfort in nine body areas. 'Eye strain', 'hoarse or painful throat' and 'musculoskeletal discomfort' are the most pronounced and prevalent complaints after prolonged work time at call centers. Female operators had higher prevalence of physical discomfort than male operators for all body areas. 'Encountering difficult customers' ranked as the most important job stress factor among both male and female operators. Working in a call center for more than 4 years is strongly associated with discomfort in all body areas (odds ratio ranges from 1.65 to 2.15). Analysis of risk factors vs. physical discomfort reveals that operators who perceive higher job stress have significantly increased risk of several health complaints, including eye strain, tinnitus, hoarse or painful throat, chronic cough with phlegm, chest tightness, irritable stomach or peptic ulcers, frequent urination and musculoskeletal discomfort.

Gender and age distribution of occupational fatalities in Taiwan.

This study analyzed fatal occupational injuries in Taiwan. One thousand eight hundred ninety work-related accident reports filed in the years 1996-1999 were extracted from the annual publication of the Council of Labor Affairs (CLA). These data were analyzed in terms of gender, age and work experience of the accident victim as well as accident type and the work-related source of injury to identify significant contributing factors. The CLA data showed that work-related falls were the leading cause of work-related fatalities in both male and female workers (38.2% of male victims and 39.2% of female victims). Gender differences were also noted in the accident type and age of the injured workers. Male workers had a significantly higher prevalence of fatal occupational injuries than female workers throughout the analyzed period (7.4 compared to 0.9 per 100,000 full-time workers). Young males aged 24 years or less had the highest rate of fatal occupational injuries. The finding that gender and age are major factors in occupational injuries is a significant finding in the field of occupational safety and may be helpful for developing accident prevention programs.

Determination of hand surface area as a percentage of body surface area by 3D anthropometry.

This study investigates the hand surface area (HSA) and palm surface area (PSA) percentages of body surface area (BSA). The HSA and PSA of 135 men and 135 women were measured by scanner and incorporated into an existing BSA database to derive %HSA/BSA and %PSA/BSA using five stature heights and three body weights in accordance with population distribution. Allowing for various degrees of specificity, the mean %HSA/BSA and mean %PSA/BSA were found to be 2.29% (0.24%) and 0.89% (0.09%), respectively. Gender and body weight group were significant factors.

Design and feasibility study of an integrated pointing device apparatus for individuals with spinal cord injury.

Despite the commercial availability of numerous computer-pointing devices, many severely disabled individuals still rely on customized equipment to operate computers. This study presents a novel Integrated Pointing Device Apparatus (IPDA) that integrates numerous commercial pointing devices. The novel IPDA, which complies with a standard USB 1.1 interface, is compatible with most tested computer-pointing devices and flexibly integrates commercial computer devices, tailoring them to suit individual needs. By using simple integrated circuit design and low-cost electronic components, this low-cost apparatus is easily maintained. The feasibility of the IPDA was evaluated by four subjects with high-level cervical (C4-5) spinal cord injury (SCI). Participants performed normal move-and-click and drag-and-drop tasks typically performed by computer pointing devices. Each participant not able to use a traditional computer mouse or trackball were able to operate a computer adequately with the IPDA and three including one operating a trackball with his chin, operated computers easily and smoothly. This feasibility study showed that the IPDA effectively integrates commercial pointing devices, thereby providing the possibility for some people with SCI to obtain computer operability. This study demonstrated the advantages of flexibility, low cost, and acceptable efficiency of the novel IPDA.

Enhancement of operational efficiencies for people with high cervical spinal cord injuries using a flexible integrated pointing device apparatus.

OBJECTIVE: To investigate the effectiveness of a universal integrated pointing device apparatus (IPDA), which can integrate numerous commercial pointing devices and can be controlled by various combinations of available movements, for people with cervical spinal cord injury (SCI) who cannot operate standard computer pointing devices. DESIGN: An exploratory quasi-experimental design. All subjects were required to perform specific mouse-operating (continuous-clicking, target-acquisition, drag-and-drop) tasks. People with SCI received clinical assessments and were classified into 2 groups based on pointing device used: group A, who used standard mouse devices, and group B (IPDA combinations), who were unable to use standard mouse devices. The measures of group A and group B were compared. SETTING: Rehabilitation science center of a medical institution. PARTICIPANTS: Thirty-seven people with high cervical SCI and 30 able-bodied subjects. INTERVENTION: The IPDA. MAIN OUTCOME MEASURES: The efficiency of the people with SCI in each mouse-operation task was expressed as a percentage of that for able-bodied subjects (%NL). RESULTS: Group B displayed similar operational efficiency in performing the drag-and-drop tasks ( approximately 30% NL) to group A, although they exhibited worse efficiency than group A in performing the other tasks (P<.05). Operational efficiencies of all tasks had negative relationships with age by using linear regression analysis (adjusted r(2)>.36, P<.001). The use of pointing devices was associated with American Spinal Injury Association Impairment Scale (P<.001), completeness (P<.001), and muscle strength (P<.01), particularly finger flexor muscle strength, but not with neurologic level or muscle tone. CONCLUSIONS: The IPDA could help most people with high cervical SCI who could not use commercial mouse devices to achieve acceptable operational efficiencies. Pointing devices were assigned based on the underlying SCI severity and muscle strength, particularly finger flexor muscle strength.