The master clock of the biological rhythm, located in the suprachiasmatic nucleus of the anterior hypothalamus, synchronizes the molecular biological clock found in every cell of most peripheral tissues. The human circadian rhythm is largely based on the light-dark cycle. In night shift workers, alteration of the cycle and inversion of the sleep-wake rhythm can result in disruption of the biological clock and induce adverse health effects. This paper offers an overview of the main physiological mechanisms that regulate the circadian rhythm and of the health risks that are associated with its perturbation in shift and night workers. The Occupational Physician should screen shift and night workers for clinical symptoms related to the perturbation of the biological clock and consider preventive strategies to reduce the associated health risks.
The role of metallothionein (MT)-like cadmium (Cd) binding protein (MTLCdBP) in protecting the testes against Cd toxicity was examined. In the acute Cd exposure treatment, cadmium chloride was intraperitoneally injected at 2 mg Cd/kg to Wistar male rats. In the chronic Cd toxicity treatments, 20 mg Cd/kg/d was orally administered for 5 d a week for 5, 10, and 15 wk. MT (-I,-II) and MTLCdBP were measured using ELISA and Cd-Hem methods, respectively. Testicular tissues were immunostained with antibodies of MT-I,-II, MT-III, and MTLCdBP. Expression of HO1, OGG, iNOS, COX2, and p53 was measured by RT-PCR. Cd concentration in the testis increased dose-dependently in response to Cd exposure. MTLCdBP concentration increased markedly with increasing Cd accumulation. Significant increases in expression of iNOS, HO1, COX2, and OGG1 were observed in the acute exposure treatment. In the chronic oral administration group, expression of MT-I, MT-II, MT-III, iNOS, HO1, and COX2 did not change. Positive immunostaining of MTLCdBP was observed in testicular interstitial tissue. In the testis protected from Cd toxicity, MTLCdBP induction increased significantly with increasing Cd accumulation. Our results suggest that MTLCdBP plays an important role in protecting the testis against Cd toxicity.
The aims of the present study were to investigate what kind of anxiety radiation decontamination workers have, and to analyze what factors are associated to presence or absence of their anxieties. A self-administered questionnaire was conducted, which included 10 anxiety items. A logistic regression model was then used to determine what factors were related to increased anxiety. Of 531 workers who completed the questionnaire, 477 (91.6%) complained of at least one of the 8 anxiety items. The most common anxiety item was job security (41.8%), and the least common item was working hours (6.0%). The logistic regression analysis revealed that the most common causes of related to presence of anxiety was heat illness and the most common causes of related to absence of anxiety was having someone available for consultation. The current study revealed the kinds of anxiety, and the factors associated with presence or absence of each anxiety among radiation decontamination workers. These results provide important implications for the improvement of educational content and occupational health management for radiation decontamination workers in the future.
Low back pain (LBP) is a common problem in manufacturing workers. Several strategies have been proposed in order to reduce the pain and/or improve functionality. Among them, lumbar supports are a common solution prescribed for lumbar pain relief. Most of the studies in the literature only consider subjective sensations of the workers for evaluation assessment. This study applies biomechanical tests (a flexion-relaxation test and a functional movement evaluation test) to analyse the effectiveness of flexible lumbar supports in functionality and disability versus placebo intervention, consisting of kinesiotape placed on the low back without any stress. 28 workers participated in the study, randomised in control and intervention groups with a two months’ intervention. None of the biomechanical tests showed statistical differences in between-groups pre-post changes. No benefits of wearing a flexible lumbar support during the workday have been found in these assembly-line workers versus placebo intervention.
This study aimed to describe sleep quality and explore factors associated with poor sleep quality in Thai intercity bus drivers. A cross-sectional design was employed with a sample of intercity bus drivers from 4 bus transportation companies. The Thai-PSQI was used to identify sleep quality, and the Thai Berlin Questionnaire used to assess sleep apnea risk. Data analysis included descriptive statistics and logistic regression. A total of 338 surveys were analyzed. All bus drivers were male; almost 66% of the bus drivers were defined as poor sleepers, and 18.1% were assessed as being at high risk for obstructive sleep apnea. Working night shifts (OR=20.6), rotating day or night shifts (OR=17.0), alcohol consumption (OR=2.7), being married (OR=3.1), and not exercising (OR=2.3) were related to poor sleep quality. The majority of the Thai intercity bus drivers in our study reported poor sleep quality indicating that action is required at both company and individual levels to encourage the adoption of healthy lifestyles and improvement of working conditions.
Our aim was to determine differences in thermal comfort during simulated one-day parcel home delivery between summer and winter. Six young healthy males performed experiments in summer (up to 31°C) and winter (up to 8°C). After baseline measurement in a chamber, subjects drove a truck to a prespecified location for outside measurements. They performed 4 sets of 100-m walk with carrying 5-kg plate during the first 50-m walk at 100 m/min, separated by 7-min driving in each of the morning and the afternoon. Subjects could ingest water ad libitum in outside and set the cockpit temperature by themselves during driving. Thermal sensation and comfort were recorded using a subjective scale at the first and the last sets of each morning and afternoon session, while esophageal temperature (Tes) was monitored (thermocouples). Body weight was measured before and the end of experiment. We found that 1) whole-body comfort decreased in summer and the decrease was greater than winter with higher Tes and 2) changes in body weight were 0.7 and 0.3 kg through whole day in summer and winter, respectively. In summary, thermal comfort during working worsened in summer, possibly related with higher core temperature and greater decrease in body weight.
The standard ISO 8996 provides methods for the determination of metabolic rate from measured oxygen consumption (MVO2), as well as simplified estimation algorithms based on heart rate (MHR). We quantified the accuracy of these methods by comparing MHR with MVO2 measured in 373 climatic chamber experiments under different workloads and widely varying heat stress conditions. While our results confirmed the 5% accuracy level for MVO2, MHR considerably overestimatedMVO2 due to the rise in core temperature concomitantly increasing heart rate by approximately 30 bpm/°C resulting in an overall error of 43%. After individually correcting for this bias the accuracy was 10–15% as stipulated by the standard. Thus, methods correcting for the thermal component of heart rate, e.g. by introducing intermittent resting periods of sufficient length of at least five min when investigating heat stress at workplaces, should become a mandatory element in the ongoing revision of the relevant standards.
We aimed to determine hepatitis B virus (HBV) prevalence and risk factors for health care workers (HCWs) to contract HBV infection in a referral hospital in the Democratic Republic of Congo. From October 2015 to August 2016, we recruited 97 HCWs (55 males and 42 females, aged 41.2 ± 10 yr) from Kisantu St. Luke’s Hospital, a Congolese referral hospital located in the province of Kongo Central. Serum samples were assayed for HBV markers using ELISA. A questionnaire was used to record the HCWs’ demographics, medical histories, and risk factors. The overall prevalence of exposure to HBV infection [HBsAg+, and/or hepatitis B core antibody (anti-HBc)+] was 56.7% (55/97). HBsAg positivity was found in 18.6% (18/97) of the HCWs whereas 29.9% (29/97) were anti-HBc positive. Approximately 8.2% (8/97) of the HCWs tested positive for both HBsAg and anti-HBc. Being a physician [odds ratio (OR)=2.8 (95% CI: 1.34–12.23)], a laboratory technician [OR=3.35 (95% CI: 1.35−5.21)], and having multiple sex partners [OR=3.05 (95% CI: 1.13−9.09)] were found to be factors associated with HBV infection. Exposure to HBV is common among HCWs at Kisantu St. Luke’s Hospital. Isolated HBsAg was also prevalent among them. There is a high risk that HBV could be spread to others. Therefore, there is an urgent need for HBV screening, treatment, and vaccination policies.
In Japan, the agricultural working environment has undergone significant changes from self-employment to enterprises and employees. As the structure of the agricultural industry changes, there has been a growing interest in occupational health and safety because agriculture is a hazardous industry. However, the public is not aware of the actual situation regarding occupational accidents in agricultural enterprises because most Japanese farmers are not necessarily required to report occupational accidents. The aim of this study is to explore the risk factors regarding occupational accidents for Japanese agricultural employees. We conducted a cross-sectional study among 1,606 employees at 101 agricultural enterprises in Japan. Information on occupational accidents, personal characteristics, and working conditions was collected by questionnaires. A total of 337 valid responses were obtained. Of these respondents, 104 (30.9%) experienced occupational accidents. Multiple logistic regression analysis revealed that permanent employment (OR 3.67, 95% CI, 1.84–7.33), pesticide use (OR 2.61, 95% CI, 1.52–4.47), and long working hours (OR 1.76, 95% CI, 1.15–2.68) were associated with the risk of occupational accidents. This study revealed the risk factors for occupational accidents for Japanese agricultural employees. It is suggested that work-hour restrictions for permanent employees might contribute to reducing occupational accidents.
In the globalized and rapidly evolving work environment, deficiencies in job design are a common reason that employees must sometimes complete tasks that are not directly connected to their occupational role. Individuals with a clear vision of their occupational role and duties in particular, such as psychologists, might consider such tasks as an offense to self. According to the “Stress-as-Offense-to-Self” (SOS) concept, so-called “illegitimate tasks” do not respect a person’s occupational identity—threatening the self through disrespect. We investigated perceived appreciation as an underlying mechanism mediating between illegitimate tasks and reduced job satisfaction after one year through three studies conducted in two European countries. Using data from 50 psychologists who graduated from a German university, Study 1 revealed that perceived appreciation explained the relationship between illegitimate tasks and job satisfaction after one year. Studies 2 and 3 confirmed this finding using data from 67 and 183 Swiss employees working in fields of psychology. In particular, illegitimate tasks affected the perception of appreciation immediately and in the long term, which in turn affected the psychologists’ job satisfaction (contagion model). Our results illustrate the importance of perceived appreciation as a mechanism that mediates between illegitimate tasks and job satisfaction of psychologists.