Exposure to neurotoxic chemicals is of particular concern when it occurs during early development. The immature brain is highly vulnerable prenatally and is therefore at risk due to occupational exposures incurred by pregnant women. A systematic search of the literature has been performed with emphasis on epidemiological studies on female workers and the neurodevelopment of their children. The majority of recent occupational studies focused on organic solvents and pesticides, which were associated with neurobehavioral impairments in the progeny. Additional evidence on environmental exposures demonstrates the vulnerability of the developing brain to substances like lead and methylmercury. Despite the evident hazards involved, the number of occupational cohort studies carried out in this field is very low. However, the lack of evidence for assumed neurotoxicants should not divert the attention by occupational health researchers and practitioners from the need to protect pregnant workers. Due to the vulnerability of the brain during early development, a precautionary approach to neurodevelopmental toxicity needs to be applied in occupational health.
Occupational Contact Dermatitis (OCD) is one of the most common work-related diseases. High risk occupations are in health care, hairdressing, food sector and metal industry. OCD tends to become chronic; persistent OCD often results in impaired quality of life and loss of work ability. The purpose of this article is to review the present knowledge on the factors which determine individual susceptibility to acquire OCD. Recent discoveries regarding genes involved in the skin barrier, inflammatory response and biotransformation of xenobiotics provide more insight in the individual susceptibility for OCD. Knowledge of the factors which predispose to OCD is useful in occupational health practice for the application of preventive measures and for career guidance for apprentices and workers in high risk occupations.
The hypersensitivity dermatitis induced by trichloroethylene (TCE) exposure was influenced by individual genetic susceptibility factors. In this paper, a case-control study was conducted to investigate effects of various genotypes and phenotypes of N-Acetyltransferases (NATs) on individual susceptibility to the disease. The study consists of 111 patients with hypersensitivity dermatitis and 154 healthy TCE-exposed workers. Polymerase chain reaction-restriction fragment length polymorphism was used to detect the polymorphic sites of NAT1 at nt 1095 and 1088 and the sites of NAT2 at nt 481, 590, and 857. Logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (95%CI). The results reveal that subjects with intermediate or slow acetylators of NAT2 have a 2.01 fold (95%CI=1.14-3.54) higher risk for the disease than subjects with the fast acetylators. When non-fast NAT2 phenotype (intermediate and slow acetylators) and a slow NAT1 phenotype were combined, the risk for the disease was significantly increased (OR=2.71, 95%CI 1.29-5.70) to the level higher than that observed for NAT2 non-fast acetylators phenotype alone. These findings suggest that slow metabolic phenotype of NAT2 maybe one of risk factor for TCE-induced hypersensitivity dermatitis and combined slow acetylator phenotypes of NAT1 and NAT2 further increase such risk.
The incidence of serious poisoning caused by occupational cadmium exposure has declined over the past four decades due to improvements in the work environment. However, long-term low-level exposure to cadmium needs to be addressed. For workers in industries that handle cadmium, it is necessary to consider the daily cadmium intake from contaminated foods such as cereals and rice in addition to the occupational exposure, since workers might be exposed to higher levels of cadmium from a combination of these sources. Cadmium accumulates in the renal cortex by the long-term exposure along with increased concentrations of metallothionein, an important protein for protection from cadmium toxicity. However, some individuals have lower metallothionein levels despite increased cadmium accumulation in the kidneys. This article describes the strategy method for analyzing individual susceptibility to cadmium toxicity and genetic polymorphisms of metallothionein, with reference to the current status of occupational cadmium exposure.
The aim of the present study is to demonstrate the empirical distinctiveness of workaholism and work engagement by examining their relationships with well-being in a sample of 776 Japanese employees. We expected that workaholism is associated with unwell-being (i.e., high psychological distress and physical complaints, low job and family satisfaction, and low job performance), whereas work engagement is associated with well-being. Well-validated questionnaires were used to measure workaholism (DUWAS), work engagement (UWES), and well-being (BJSQ, HPQ). Structural Equation Modeling showed that, as expected, workaholism was positively associated with ill-health (i.e., psychological distress and physical complaints) and negatively associated with life satisfaction (i.e., job and family satisfaction) and job performance. In contrast, work engagement was negatively associated with ill-health and positively associated with life satisfaction and job performance. These findings suggest that workaholism and work engagement are two different kinds of concepts, which are negatively and positively related to various indicators of well-being, respectively.
To examine if sense of coherence (SOC) can reduce the adverse effects of job stress on mental health status, self-administered questionnaires were distributed among 740 workers in a manufacturing industry. The questionnaire contained SOC, Job Content Questionnaire (JCQ), and General Health Questionnaire (GHQ-12). Complete answers were recovered from 466 workers (62.8%), consisting of 387 males and 79 females, with ages of 45.1±12.0 yr, and used for the analysis. The logistic regression analysis revealed the followings: Both for males and females, high GHQ was significantly associated with scores on SOC and JCQ job demand subscale, i.e. the mental health status was adversely related to job demand whereas it was positively associated with SOC. Similarly, the mental health status was affected adversely by managerial work in males, whereas was positively by co-workers support in females. Thus, high SOC enables workers to cope with their job demand, which is a potent job stressor, indicating that SOC is an important factor determining their coping ability to job stress for both genders. Male managerial employees may cope with their strong job stress because of high SOC, protecting their mental health status. Social support seems also significant for prevention of mental well-being of female workers from work-related stressors.
This cross-sectional study examined the relationship between temperament, job stress, and overcommitment using the Temperament Evaluation of Memphis, Pisa, Paris and San Diego-Autoquestionnaire version (TEMPS-A) and a scale of the effort-reward imbalance (ERI) model. In July 2004, self-administered questionnaires were distributed to all employees in a Japanese IT service company through the company postal system. Total response rate was 63% (N=874), with 730 completed questionnaires. Information collected included individual attributes, employment and organizational characteristics. The TEMPS-A and the Japanese version of the ERI questionnaire were self-administered. The completed data of 637 personal computer technical support staff (87%) were used in a hierarchical regression analysis. Our results showed that depressive and anxious temperaments attenuate the influence of working hours and influence effort and rewards independently. While actual working hours had more impact on perceived high effort, our findings regarding rewards suggest that understanding anxious and depressive temperaments has a significant role in stress self-management. Temperaments explained 36% of the variance of overcommitment, and the variance was more than that of mean working hours. Our research has provided meaningful insights into occupational health, which could assist employees in self-management of job stress and contribute to better adaptation at the workplace.
There are considerable individual differences in cognitive performance deficits resulting from extended work hours and shift work schedules. Recent progress in sleep and performance research has yielded new insights into the causes and consequences of these individual differences. Neurobiological processes of sleep/wake regulation underlie trait individual variability in vulnerability to performance impairment due to sleep loss. Trait vulnerability to sleep loss is observed in the laboratory and in the work environment, even in occupational settings where (self-)selection pressures are high. In general, individuals do not seem to accurately assess the magnitude of their own vulnerability. Methods for identifying workers who are most at risk of sleep loss-related errors and accidents would therefore be helpful to target fatigue countermeasure interventions at those needing them most. As yet, no reliable predictors of vulnerability to sleep loss have been identified, although candidate genetic predictors have been proposed. However, a Bayesian forecasting technique based on closed-loop feedback of measured performance has been developed for individualized prediction of future performance impairment during ongoing operations. Judiciously selecting or monitoring individuals in specific tasks or occupations, within legally and ethically acceptable boundaries, has the potential to improve operational performance and productivity, reduce errors and accidents, and save lives. Trait individual variability in responses to sleep loss represents a major complication in the application of one-size-fits-all hours of service regulations―favoring instead modern fatigue risk management strategies, because these allow flexibility to account for individual vulnerability or resilience to the performance consequences of extended work hours and shift work schedules.
The purpose of this study was to characterize the recovery pattern of sleep following simulated, four successive night shifts in ten healthy men (22.9 ± 3.2 yr). Poor sleep was defined as sleep efficiency of 80% or lower as determined actigraphically. The results showed that four (rapid, slow, pseudo, and incomplete) patterns of sleep recovery were observed over three recovery sleep periods. The rapid and slow recovery pattern represented immediate and slow return to baseline level prior to the nightshifts, respectively. The pseudo recovery pattern demonstrated poor sleep at the 3rd recovery sleep period, despite transient recovery at the 2nd sleep period. The incomplete recovery pattern was characterized by consistently poorer sleep during the entire recovery period. The correlation analysis indicated that sleep habits (bed time and variation of wake time) prior to the experiment were significantly related to the recovery patterns, rather than performance and alertness during the night shifts.
Vibration-induced white finger (VWF) is a disorder seen in workers exposed to hand-transmitted vibration, and is characterized by cold-induced vasospasms and finger blanching. Because overweight people with metabolic syndrome are pre-disposed to developing peripheral vascular disorders, it has been suggested that they also may be at greater risk of developing VWF if exposed to occupational vibration. We used an animal model of metabolic syndrome, the obese Zucker rat, to determine if metabolic syndrome alters vascular responses to vibration. Tails of lean and obese Zucker rats were exposed to vibration (125 Hz, 49 m/s2 r.m.s.) or control conditions for 4 h/d for 10 d. Ventral tail arteries were collected and assessed for changes in gene expression, levels of reactive oxygen species (ROS) and for responsiveness to vasomodulating factors. Vibration exposure generally reduced the sensitivity of arteries to acetylcholine (ACh)-induced vasodilation. This decrease in sensitivity was most apparent in obese rats. Vibration also induced reductions in vascular nitric oxide concentrations and increases in vascular concentrations of ROS in obese rats. These results indicate that vibration interferes with endothelial-mediated vasodilation, and that metabolic syndrome exacerbates these effects. These findings are consistent with idea that workers with metabolic syndrome have an increased risk of developing VWF.
In the light of global industrialization, much attention has been focused on occupational factors and their influence on the health and welfare of workers. This was a cross sectional study using stratified sampling technique based on industry sizes. The study sampled 24 industries, 6 were small scale industries and 9 each for medium and large scale industries. From the 24 industries, a total of 500 respondents for the questionnaire was taken. For occupational health and safety standards that industries have to comply with, there was low compliance among small-scale industries relative to the medium and large scale industries. Only one industry had an air cleaning device for cleaning contaminated air prior to emission into the external community. Among the 500 respondents, majority were female (88.8%), single (69.6%) and worked in the production or assembly-line station (87.4%). Sickness absenteeism was relative high among the workers in this study accounting for almost 54% among females and 48% among males. Many of the workers also reported of poor performance at work, boredom, tardiness and absenteeism. For association between work factors and personal factors, the following were found to be statistically significant at p=0.05. Boredom was associated with lack of skills training, lack of promotion, disincentives for sick leaves, poor relationship with boss and poor relationships with employers. On the other hand, poor performance was also associated with lack of skills training, lack of promotions, job insecurity, and poor relationship with employers. From the data generated, important issues that must be dealt with in work organizations include the quality of work life, and health and safety issues. Based on these findings, we can conclude that there are still issues on occupational health and safety (OHS) in the target site of export processing zones in the Philippines. There must be an active campaign for OHS in industries that are produce for the global market such as the target industries in this study.
The present study was to describe the input/process and evaluate the effectiveness of Taiwanese Workplace Health Promotion Initiatives based on employees' perspectives. This study employed a cross-sectional design by a structured questionnaire that was completed by 842 employees in 30 workplaces that participated in the Taiwan Workplace Health Promotion (WHP) Initiatives which supported by Ministry of Health from 2004 to 2006. The results found that the employees generally agreed that WHP improved their personal health skills. There was a lower level of agreement with respect to other input/process domains such as workplace healthy policy, workplace supportive health environments and WHP activities and services and the WHP effectiveness. With regard to the prediction of WHP effectiveness, the domain of workplace health activities/services could only predict 50.5% of the variation of the effectiveness in a regression model. Three domains of workplace ― health activities/services, personal health skills and supportive health environments ― were significantly correlated to the agree level of health promotion effectiveness. The results suggest that companies that intend initiating health promotion programs need to conduct a detailed assessment of the nature of the workplace settings and the perceptions of employees.
This study aimed to examine the effects on language and visual working memory of the follicle, luteal, and menstruation phases. The subjects were 12 female students. We added visual information and the assignment of experimental tasks, which requires the faculty of sight, to the previous study; therefore, this study has an index of visual and linguistic working memory. Computer-based tasks formulated by the authors, using the working memory that actively retains the information as the index, were used for experiments of 30 min during the follicle, luteal, and menstruation phases. After completion of the experiment of each phase, blood samples were collected in order to clearly distinguish the three phases of the subjects' menstrual cycle, and the session order was counter-balanced. The results showed that mental workload was higher in the luteal phase and stress was more easily felt. Indefinite complaints were most frequent during the menstruation phase, but task performance was good regardless of the indefinite complaint. It suggested that when the same tasks were performed during three phases, the sympathetic nerve was ascendant.
A questionnaire survey was undertaken to identify the current status of respirator usage in manufacturing work environments subject to gas/vapor chemicals exposure in Korea and to suggest improvements to enhance the effectiveness of respirator usage. The number of target companies included 17 big companies, 110 small & mid-size companies, and 5 foreign companies, and the number of respondents included 601 workers and 69 persons in charge of respirators (PCR). The results explained clearly that respirator programs in practice were extremely poor in small & mid-sized companies. The findings indicated that the selection of respirators was not appropriate. Quarter mask including filtering facepiece was the most common facepiece form for respirator and was worn by sixty-four percent. Not a little proportion of respondents (33%) complained about the fit: faceseal leakage between the face and facepiece. A filtering facepiece with carbon fiber filter was used as a substitution for a gas/vapor respirator. Another result was that the PCR respondents' perception of the administration of respirators was very low. The results of this survey suggest that regal enforcement of respiratory protection programs should be established in Korea. On the basis of these findings, respiratory protection programs should include respirator selection, maintenance, training, and fit testing.
Sizing based on 3D anthropometric data may lead to significant improvement in fitting comfort of wearing products. However, the required computational load is a common problem in 3D data processing. In a previous study, wavelet analysis was adopted to establish a multi-resolution description of 3D anthropometric data to reduce computational load and modeling complexity. K-means clustering was subsequently performed on the decomposed 3D samples. This study further examines the influence of decomposition level on clustering results. As a case study, 378 face samples, 447 head samples and 432 upper head samples were analyzed. Cluster membership variation on five different resolution levels was examined by using Cluster Membership Accuracy Rate (CMAR), which denotes the clustering consistency on the decomposed levels compared with the clustering results on the original data sets. For the face data sets, the CMAR values on the five decomposition levels are 100, 99.21, 97.88, 93.92 and 93.39%, respectively; for upper heads, the CMAR values are 99.3, 99.1, 98.4, 92.1 and 84.3%, respectively; while for whole heads, the CMAR values are 99.3, 98.2, 95.1, 85.5 and 77.9%, respectively. These results indicate that clustering on the third decomposition level is proper for face and head scans in reducing computational load while maintaining at least 95% clustering accuracy.