The impact of shift starting time on sleep duration, sleep quality, and alertness prior to injury in the People's Republic of China.

Early shift start time and night shifts are associated with reduced sleep duration and poor sleep quality that often lead to increased fatigue levels, performance decrements and adverse safety and health outcomes. This study investigates the impact of shift starting time on sleep patterns, including the duration and quality of sleep and alertness/sleepiness at the time of injury, in a large epidemiological field study of hospitalized adults with severe work-related hand injury in the People's Republic of China (PRC) from multiple industries with severe work-related traumatic hand injury were recruited from 11 hospitals in three industrially-developed cities in the PRC: Ningbo, Liuzhou and Wuxi. Analysis of covariance (ANCOVA) was used to compare sleep duration, sleep quality and alertness/sleepiness across 3 h increments of shift start time, while adjusting for age, gender, work hours, shift duration, day of injury and several transient work-related factors. Effect modification by gender was also evaluated. Seven-hundred and three hospitalized adults (96.4%) completed a face-to-face interview within 4 days of injury; 527 (75.0%) were male, with a mean (±SEM) age of 31.8 ± 0.4 years. Overall, these adults worked relatively long weekly (55.7 ± 0.6 h) and daily hours (8.6 ± 0.07 h). Average sleep duration prior to injury was 8.5 h (±0.07), and showed significant variations (p value <0.05) across shift starting time increments. Overall mean prior sleep duration was shortest for individuals starting shifts from "21:00-23:59" (5.6±0.8 h) followed by midnight "00:00-02:59" (6.1 ± 0.6 h). However, a statistically significant interaction (p < 0.05) was observed between gender and shift starting time on mean sleep duration. For males the shortest sleep duration was 5.6 h ("21:00-23:59") and for females the shortest was 4.3 h ("24:00-02:59" and "15:00-17:59"). Sleep quality (generally quite well) and alertness/sleepiness based on the KSS (generally alert) did not vary significantly across shift starting time. Results suggest that sleep duration is shortest among injured PRC adults starting shifts late night and early morning. However, with more than 8.5 h of sleep on average work days, Chinese slept much longer than typical US day workers (Sleep in America Poll, 2012, 6:44 on workdays, 7:35 on free days), and this may help to explain higher than expected alertness/sleepiness scores at the time of injury.

Predictors of return to work and duration of absence following work-related hand injury.

The aims of the study were to explore the situation and the potential determinants of return-to-work (RTW) and the absence duration following work-related hand injury, and to provide evidence for the future intervention strategy of improving RTW. A prospective cohort of workers with work-related hand injury from three selected hospitals in East China was followed up on the outcomes of RTW up to 8 months after discharge. Demographic and clinical data were collected during admission; economic factors, psychological factors and RTW outcomes were, respectively, investigated using a structured questionnaire via phone call after discharge from the hospitals in 0.5 month, 2 months, 4 months and 8 months. Univariate analysis and Cox regression model were used to examine the associations between potential determinants and outcomes of the RTW. Out of the 246 cases, 192 (78.1%) eventually returned to work with the median duration of the absence of 44.0 days during the 8-month follow-up. Factors from demographic, clinical, economic and psychological domains affected RTW in the univariate analyses. Receiving timely treatment at outpatient clinics, less serious injury, no tendon trauma and no skin loss were found to be significantly beneficial to RTW, while workers with the decreased monthly salary during absence and lower pre-injury salary were likely to take longer sick leave. Most of the workers successfully achieved RTW after work-related hand injury. Proper clinical treatment and rehabilitation, as well as economic and social support seem to have played vital roles in prompting RTW that should be prioritised for the intervention strategy.

The effects of rest breaks, work shift start time, and sleep on the onset of severe injury among workers in the People's Republic of China.

OBJECTIVE: The aim of the present study was to investigate the effects of the duration and timing of rest breaks on traumatic injury risk across a shift in a relatively large sample of hospitalized workers with severe work-related hand injury in the People's Republic of China (PRC). METHODS: Hospitalized workers from multiple industries with severe work-related traumatic hand injury were recruited from 11 hospitals in three industrially-developed cities in the PRC: Ningbo, Liuzhou, and Wuxi. Cox regression was used to compare time into the work shift of injury across categories of rest breaks, while evaluating several potential covariates including age, gender, work hours, work start time and duration, injury day and time, duration and quality of last sleep, alertness/sleepiness, job control, and several transient work-related factors. Effect modification by work shift start time was also evaluated. RESULTS: With four days of injury, 703 hospitalized workers completed a face-to-face interview. After adjusting for significant covariates, workers with rest breaks of 1-30, 31-60, and >60 minutes were able to work significantly (P<0.001) longer into their work shift without an injury (>5 hours) then those with no rest break. A significant interaction was also observed between rest break status and start time of the work shift. CONCLUSION: The results of this study suggest that rest breaks of any duration have a significant effect on delaying the onset of a work-related injury, which is modified by the time of day in which a shift begins.

A case-crossover study of work-related acute traumatic hand injuries in the People's Republic of China.

OBJECTIVE: The aim of this study was to quantify potential transient risk factors for occupational acute hand injury among hospitalized workers in the People's Republic of China (PRC). METHODS: Participants were recruited from 11 medical facilities in 3 cities of the PRC. A face-to-face interview was used to collect information on the occurrence of 8 potential risk factors within a 90-minute time period before an acute traumatic hand injury and during a control period within the month before the injury. The reliability of reporting transient risk factors was assessed, and a case-crossover design was used to estimate the injury incidence risk ratio (IRR) of each risk factor. RESULTS: In total,703 hospitalized workers completed the interview (527 male, 176 female), with a mean age of 31.8 [standard deviation (SD) 10.3] years. The median time interval between injury and interview was four days. Thirty percent of participants had a crush injury and 25.7% had an amputation. Using malfunctioning machinery/tools/material, performing a task with a different method, working overtime, and wearing gloves were found to have good reliability in test-retest examination [intra-class correlation coefficient (ICC)>0.9]. The IRR of a hand injury were markedly increased while using malfunctioning machinery/tools/material [110.4, 95% confidence interval (95% CI) 97.4-125.2], performing a task with a different method than usual (84.3, 95% CI 67.7-105.1), or being distracted (69.6, 95% CI 57.9-83.7). Gender and size of company were associated with differences in glove usage. CONCLUSIONS: The results suggest the importance of transient, potentially modifiable factors in the etiology of occupational acute hand injury in the PRC. Regular maintenance of machinery/tools, work practice controls, and avoiding distractions should be priorities for reducing the risk of occupational acute hand injuries.

Prediction of return to work outcomes under an injured worker case management program.

INTRODUCTION: Many factors affect worker return to work (RTW) after occupational injury, among which effective case management strategies play a particularly vital role in prompting workers for a successful RTW. Objectives This study aimed at predicting the RTW outcome and optimizing the intervention scheme of a case management program initiated in China. METHODS: A retrospective cohort was formed with 523 injured workers treated at a rehabilitation center for work injuries in southern China. The social demographic information, medical data and intervention process were extracted from the medical records of the rehabilitation center. A Cox Regression Model was used to examine the predictors of RTW case management. RESULTS: 261 patients (77.9%) out of the 335 valid subjects successfully returned to work after median absence duration of 36.0 days. A computer skills training program was a positive factor for RTW outcomes (hazard ratio 1.5, P < 0.001). Psychological counseling was possibly an important measure to improve RTW with a hazard ratio of 3.4 (95% CI 0.94-16, P > 0.05). Disability adjustment accommodations did not specifically benefit RTW. Education level, family's attitude to RTW, personal perceptions about social support for RTW, and injury severity were significantly associated with outcomes of RTW. CONCLUSIONS: It was implied that RTW intervention should be focused on a specific skill reconstruction and training which was presumably related with labor market needs. However, tailored psychological counseling and disability adjustment activity should not be ignored in RTW.

Retrospective occupational exposure assessment for case-control and case-series epidemiology studies based in Shanghai China.

To provide exposure information for epidemiology studies conducted in Shanghai from 2001 to 2008, we completed retrospective exposure assessments (EA) of benzene and other hazards. Interviewers administered questionnaires to subjects from Shanghai area hospitals. An initial exposure screening by EA staff members, blinded as to case-control status, stratified jobs into exposed, unexposed, or uncertain categories prior to review by a separate expert panel (EP). Resources for the EA included job/industry-specific questionnaire responses by subjects, short-term benzene area concentration measurements from a Shanghai regulatory agency database, Chinese literature for qualitative and short-term quantitative measurements, on-site investigations, summaries of technology changes, and selected task simulations with concurrent benzene concentration measurements. An EP in Shanghai completed semi-quantitative benzene exposure assignments, with categories of 0 to 4 corresponding to intensity ranges of none, <1, 1 to 10, >10 to 100, and >100 mg/m(3). For other hazards, sources included the EP's knowledge of the industries and Chinese and Western literature. For benzene, 20% of the EAs selected by a stratified random process were evaluated by two alternate methods. The study database of potential cases and controls included 18,857 jobs from the subjects' work histories. From 818 individuals initially screened as probably benzene exposed, 964 jobs underwent further review. From subjects with final diagnoses, 755 jobs qualified for inclusion in the final database for any study. For other exposures, the EA considered 17,893 jobs from 7654 subjects for possible exposures and were in the final study database. Of these, 2565 individuals had exposures of study interest from their 4909 exposed jobs. The prevalent exposures included agricultural chemicals, petroleum products, and metals. The EA involved extensive information assembly and exposure assignment by an EP and periodic reviews. The methods described went beyond those typically applied in past general population studies and may have provided improved information for the epidemiologic analyses. However, sufficient, reliable measured historical data are lacking to evaluate this conclusion.

Case management after long-term absence from work in China: a case report.

INTRODUCTION: Return-to-work (RTW) after occupational injuries is an important and challenging issue. Case managers are expected to play a vital role in successful RTW. In China, RTW intervention is in its early phase and requires further research and practice. OBJECTIVES: This case report describes Mr. H's RTW process for illustrating the work of a case management team in China. Suggestions on developing and optimizing the process in China are given. METHODS: After 9 years of absence from work due to severe burn injuries at work, Mr. H was referred for RTW interventions. Mr. H received social and occupational rehabilitation services of 3 months, and the following workplace visits and work trials. After the job placement, the case manager continued the liaison with the worker and employer. RESULTS: Mr. H showed positive changes in occupational and social adjustment after the case management interventions. This was reflected from the shift from the contemplation to action stage on the Lam Assessment of Stages of Employment Readiness. Despite he did not show significant changes on functional capacity and fear avoidance beliefs, Mr. H passed the job credential test and was offered a maintenance technician position at a new company. Both the worker and the employer were satisfied with the outcome of the case management. CONCLUSIONS: The RTW interventions carried out by the case managers appeared to be effective within the Chinese system. The results suggested that professional training of case managers, RTW-related policies and technological standards, early integrated interventions should be further developed in China. Disability Adjustment Group Therapy and RTW Support Groups perhaps are useful approaches in workers' returning to work.

Retraction: Serum Fluoride Level and Children's Intelligence Quotient in Two Villages in China.

The paper entitled "Serum Fluoride Level and Children's Intelligence Quotient in Two Villages in China" by Xiang Quanyong et al, which was published online on 17 December 2010, has been withdrawn.

[Predictors of return to work after occupational injury in a locomotive enterprise].

OBJECTIVE: To identify the potential determinants of return to work (RTW) following work-related injury. METHODS: A historical cohort of workers with occupational injury in a state-owned locomotive vehicle company in central China was followed up for RTW. Demographic, employment and medical information was retrieved from the company archival documents; and post-injury information was interviewed by questionnaires. Univariate analysis and Cox Regression Model were used to examine the associations between potential determinants and outcomes of RTW. RESULTS: Three hundred of the 323 included cases (92.9%) eventually returned to work after the median absence of 43 days (average of 49.2 days). Factors from socio-demographic, clinical, economic and psychological domains were found affecting RTW in the univariate analyses. The multivariate analysis indicated that age, injury severity, injury locus, injury nature, pain in the injury locus, self-reported health status and pre-injury monthly salary were significant determinants of RTW. CONCLUSIONS: There are multidimensional factors affecting RTW after occupational injury. Proper clinical treatment and rehabilitation, as well as economic and social support to facilitate workers' RTW would be the priorities for intervention. Future studies should be conducted in a larger representative sample to confirm the findings and to develop a multidisciplinary intervention strategy towards promoting RTW.

[Synergistic interaction between MMP-3, VDR gene polymorphisms and occupational risk factors on lumbar disc degeneration].

OBJECTIVE: To explore the synergistic interaction between MMP-3,VDR gene polymorphisms and occupational risk factors on lumbar disc degeneration. METHODS: A case-control study including 178 cases of lumbar disc degeneration and 284 controls was carried out through questionnaire and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology. Additive model was used to analyze the synergistic interaction between gene polymorphisms and occupational risk factors. RESULTS: The non-conditional logistic regression analysis showed that bending/twisting, whole-body vibration, heavy physical workload, alleles 5A of MMP-3 (6A5A/5A5A) and A of VDR-Apa (AA/Aa) were significantly associated with lumbar disc degeneration(OR = 4.06, 8.96, 5.46, 1.96 and 1.70, respectively, P < 0.05). There were synergistic interactions between the mutation genotype 5A of MMP-3 and whole-body vibration exposure, between the mutation genotype 5A of MMP-3 and bending/twisting, and between the mutation genotype A of VDR-Apa and whole-body vibration exposure (SI: 13.27, 2.91 and 2.35 respectively, P < 0.05). CONCLUSION: People with the mutation genotypes 5A of MMP-3 and/or A of VDR-Apa may have the increased risk of developing lumbar disc degeneration if they are exposed to whole-body vibration and/or bending/twisting.

Determinants of return to work after occupational injury.

INTRODUCTION: The promotion of return to work (RTW) following occupational injury benefits injured workers, their families, enterprises and the society. The identification of the potential determinants would be helpful in improving RTW rate and minimizing the duration of absenteeism following injury. OBJECTIVES: The aim of the study was to identify the potential determinants of RTW following work-related injury. METHODS: A historical cohort of workers with occupational injury in a state-owned locomotive vehicles company in central China was followed up on the outcomes of RTW. Demographic, employment and medical information was retrieved from the company archival documents; and post-injury information was interviewed by structured questionnaires. Univariate analysis and Cox Regression Model were used to examine the associations between potential determinants and outcomes of RTW. RESULTS: Three hundred of the 323 cases (92.9%) eventually returned to work after the median absence of 43 days. Factors from socio-demographic, clinical, economic, and psychological domains affected RTW in the univariate analyses. The multivariate analysis indicated that age, injury severity, injury locus, injury nature, pain in the injury locus, self-report health status and pre-injury monthly salary were significant determinants of RTW. CONCLUSIONS: There were multidimensional factors affecting RTW after occupational injury. Proper clinical treatment and rehabilitation, as well as economic and social support to facilitate workers' RTW would be the priorities upon intervention. Future studies should be conducted in larger representative samples to confirm the findings and to develop a multidisciplinary intervention strategy towards promoting RTW.

Patterns of work-related traumatic hand injury among hospitalised workers in the People's Republic of China.

OBJECTIVES: This study describes the type, location and severity of work-related acute traumatic hand injuries of 560 workers treated in 11 hospitals in three economically active cities in the People's Republic of China (PRC) over a 2-year period. METHODS: A structured questionnaire was used to collect participant's information. Log-linear and logistic models were constructed to identify factors associated with injury occurrence and severity, respectively. RESULTS: Participants (n=560) had a mean age of 31.7 years (SD 10.5), 74.4% were men. 85.4% of participants were employed in manufacturing industries; 51.7% of 750 injuries were to the left hand. The index finger was injured most often and the most severe injury occurred to the right thumb. 68.3% of participants had only a single type of injury (29.7% crushes, 25.7% amputations and 18.5% fractures). Severe injuries occurred most often while working with food products (79.2% severe), furniture (72.2%), non-metallic mineral products (71.4%) and wood products (70.6%). Powered machines were involved in 59.5% of injuries. Injury frequency was associated with gender (male vs female, odds ratio (OR) 2.9, 95% CI 2.4 to 3.5) and company size (100 employees, OR 2.5, 95% CI 2.1 to 3.1). Injury severity was associated with gender (male vs female OR 0.6, 95% CI 0.4 to 0.9) and powered machine use (OR 2.2, 95% CI 1.3 to 3.7). CONCLUSIONS: The present study suggests that working in manufacturing industries and working with powered machines are the primary sources of severe hand injuries in hospitalised workers in economically active areas of the PRC.

Matrix metalloproteinase-3 and vitamin d receptor genetic polymorphisms, and their interactions with occupational exposure in lumbar disc degeneration.

OBJECTIVES: To investigate the occupational and genetic risk factors inducing lumbar disc degeneration in a Chinese population, and to explore their synergistic interactions. METHODS: A case-control study involving 178 low back pain patients with lumbar disc degeneration and 284 controls was carried out. Five types of work-related factors were investigated using questionnaires. Polymerase chain reaction and restriction fragments length polymorphism was used to detect the polymorphisms of MMP-3 (matrix metalloproteinase-3)(rs731236), VDR-Taq (vitamin D receptor-Taq) and VDR-Apa (vitamin D receptor-Apa)(rs35068180). Rothman's synergy index was used to measure the synergistic interactions between gene polymorphisms and occupational risk factors. RESULTS: Family history of lumbar disc diseases, back injury history, whole-body vibration, bending/twisting, heavy physical workload, age, mutation alleles 5A of MMP-3 and A of VDR-Apa were significantly associated with lumbar disc degeneration (OR=12.70, 11.79, 8.96, 5.46, 1.05, 1.96 and 1.70, respectively, p<0.05). Synergistic interactions existed between the mutation allele 5A of MMP-3 and whole-body vibration exposure, the mutation allele 5A of MMP-3 and bending/twisting, and the mutation allele A of VDR-Apa and bending/twisting (SI=13.27, 2.91, 2.35, respectively, p<0.05). CONCLUSIONS: The results of this study suggest that gene-occupation interaction might play a certain role in exaggerating lumbar disc degeneration. There is a possibility that subjects who carry mutation alleles 5A of MMP-3 and/or A of VDR-Apa are more vulnerable to lumbar disc degeneration when they are exposed to whole-body vibration and/or bending/twisting under ergonomic loads.

Benzene exposure in industries using or manufacturing paint in China--a literature review, 1956-2005.

A systematic review of the Chinese literature was conducted from 1956 to 2005. The survey included both online and manual searching, as well as expert discussions aimed at providing insight into factors affecting benzene exposure levels in paint/coatings industries. Data extracted from 204 papers included: (1) year of occurrence, (2) type of paint/coatings products, (3) type of industries where the products were used or produced, (4) job titles and work activities, (5) type of literature searched, (6) working conditions whenever data were available, and (7) exposure levels. Most benzene measurements were short-term samples for comparison with the Chinese maximum allowable concentration standard. The accuracy and precision of the sampling and analytical methods were not reported. The distribution of benzene concentrations was tested and found to fit neither normal nor lognormal distributions. Analysis of variance (comparison for more than two groups) and t-test (comparison for two groups) were conducted on Blom-transformed benzene concentration data. The overall median benzene exposure levels were 215, 82, 31, and 6 mg/m(3) during the periods 1956-1978, 1979-1989, 1990-2001, and 2002-2005, respectively. Mean benzene exposure was significantly lower for paint manufacturing than paint spraying. No significant difference was found among paint types and benzene exposure for paint application. Benzene exposure was significantly higher in workplaces judged to have poor ventilation. No significant differences were found in benzene exposure as a function of industry type. Even though substantially lower when compared with levels in the past, recent benzene exposure measurements suggested that many facilities in the paint/coatings industries in China still have benzene concentrations that are above the current China occupational exposure limit for benzene (6 mg/m(3) as a time-weighted average). Benzene concentrations from the present exercise, while not directly supporting quantitative retrospective exposure estimating, provide insight on relative benzene exposure for painting tasks in the reported industries over time.

Application of bayesian methods to exposure assessment of area concentrations at a rubber factory.

The present study estimated area concentrations of airborne benzene in several workshops using Bayesian methods based on available historical measurements. A rubber products factory utilizing benzene was investigated. Historical measurements of benzene concentrations, expert experiences, and deterministic modeling were utilized in a Bayesian Method to estimate area concentrations. Historical concentrations (n=124) were available with the geometric mean of 15.3 mg/m(3). The geometric mean of the current field measurements on the workstations ranged from 0.7 to 89.0 mg/m(3). One of the seven historical geometric means by work locations significantly differed from the field measurements for equivalent locations, but none of the geometric means of Bayesian estimates were significantly different from the field measurement results. The Bayesian methods based on the historical measurements appeared to be a useful tool for more closely estimating area concentrations shown by field data than that predicted only using historical measurements.

[A psychophysical evaluation of NIOSH Lifting Equation in a Chinese young male population: a pilot study].

OBJECTIVE: To determine the maximum acceptable weight of lift (MAWL) in a Chinese young male population, and examine whether the revised weight limit recommended by the US. National Institute for Occupational Safety and Health can be used for Chinese workers. METHODS: Eleven young male college students participated in the experiment. The psychophysical approach was used to determine the MAWL with the different frequencies of lift, the heart rate and the self-evaluation. The weight was lifted from the floor to the work-table (760 mm). The results were compared with the recommended weight limit (RWL) and the MAWL by Snook. RESULTS: The MAWL of young male was 34.1 kg while the MAWL with frequency of 1, 4 and 8/min was 17.4, 14.7 and 12.2 kg respectively. The overall MAWL were lower than RWL of NIOSH and the results of Snook. CONCLUSION: The NIOSH 1991 equation such as load constant and frequency multiple should be revised when the NIOSH limits is used in Chinese population.