Phenylglyoxylic acid (PhGA) and mandelic acid (MA) are two popular urinary markers of occupational exposure to styrene, but PhGA has been considered to be relatively unstable when urine samples are stored. This study was initiated to examine the stability of PhGA in urine under two storage conditions, i.e., at room temperature (at 25˚C) and in refrigeration (at 4˚C) for up to 14 days. The experiments showed that no substantial decrease was observed in either PhGA or MA even at room temperature within one day, but, depending on urine samples, a gradual decrease in PhGA took place both at 4˚C and more markedly at 25˚C when kept for a week. Further reduction was observed in two weeks even at 4˚C. No reduction was observed in MA up to two weeks both at 4˚C and at 25˚C. The observation on stability of MA and limited stability of PhGA (i.e., no significant decrease for 4 days when stored as refrigerated) was confirmed by a repeated experiment. Further analyses disclosed that PhGA when stored at 4˚C tended to be more unstable when urine samples were alkaline (e.g., at pH 8) rather than acidic (e.g., at pH 6 or below), but the trend varied subject to individual samples. Thus, the practical recommendation is that urine samples should be analyzed on the day of collection if all possible, or kept at 4˚C, or more preferably at -20˚C. Refrigeration will allow storage of up to 4 days without substantial decrease in either PhGA or MA.
The relationship between oxidative stress and carcinogenic metals including nickel and cadmium is a matter of interest. To assess the oxidative stress status of workers exposed to nickel and cadmium simultaneously, we determined urinary excretion of 8-hydroxyguanine (8-OH-Gua), a urinary oxidative stress marker. Our subjects were 66 (64 males and 2 females) nickel-cadmium battery workers. Spot urine and blood samples were collected. The levels of cadmium in blood (Cd-B) and nickel in urine (Ni-U) were determined by graphite furnace atomic absorption spectrophotometry. 8-OH-Gua in urine was analyzed using a high performance liquid chromatography-electrochemical detector (HPLC-ECD) system. Data on age, sex, duration of present work and smoking status were also obtained from each subject. Creatinine-adjusted 8-OH-Gua was significantly correlated with age, Ni-U and Cd-B in univariate analysis, while multivariate analysis revealed that Ni-U and Cd-B were significant independent variables and that these two biological exposure indices were positively correlated with 8-OH-Gua. The data were also analyzed in the context of mixture toxicity. The subjects were divided into groups based on median level of Ni-U and Cd-B (2.86 μg/g creatinine and 0.23 μg/dl, respectively). Workers with high Ni-U/high Cd-B (Group IV) had the highest levels of 8-OH-Gua levels (GM (GSD), 21.7(2.0)), followed by those with high Ni-U/low Cd-B (11.5(1.6) Group III), those with low Ni-U/high Cd-B (8.9(1.9) Group II), and those with low Ni-U/low Cd-B (8.5(1.5) Group I). The p values of Students' t-tests between Group I and Group II, III and IV were 0.847, 0.050 and <0.001, respectively. The combined effect of Cd and Ni on the urinary excretion of 8-OH-Gua departed from additivity.
Objective is to assess the relationships of job hazards, individual characteristics, and risk taking behavior to occupational injuries of coal miners. This case-control study compared 245 male underground coal miners with injury during the previous two-year period with 330 matched controls without injury during the previous five years. Data were collected via face-to-face interview and analyzed using the conditional logistic model. Handling material, poor environmental/working conditions, and geological/strata control- related hazards were the main risk factors: adjusted ORs 5.15 (95% CI 2.42-10.9), 2.40 (95% CI 1.29-4.47), and 2.25 (95% CI 1.24-4.07) respectively. Their roles were higher among the face-workers than among the non-face-workers. No formal education, alcohol consumption, disease, big-family, and risk-taking behavior were associated with injuries (2.36≤ORs≤10.35), and the findings were similar for both face and non-face workers. Prevention should focus on handling material, poor environmental condition, especially addressing workers with no formal education, alcohol consumption, disease, big family size, and risk-taking behavior.
Objective is to clarify whether nursing assistance tools (a mat with attached handles, a pair of trousers with knee pads and a waist holding belt) prevent musculoskeletal pain, such as low back pain and upper arm pain, and depression, and improve the burden on the lower back and upper arm among staff in schools for disabled children. This study design was a non-randomized intervention trial. The subjects were 41 staff in two schools for disabled children in Japan. Nursing assistance tools were used with the intervention group to help with their nursing activities. We investigated the one-month prevalence of low back pain and the degree of burden on the lower back using a questionnaire at the baseline and at the end point 4 to 6 months later. The prevalence of low back pain did not change significantly in either group. In the intervention group, the prevalence of upper arm pain decreased from 47.6% at the baseline to 23.8% at the end point (p=0.063). The percentage of participants with a high level of burden on the lower back from excretory nursing activity decreased from 57.1% at the baseline to 33.3% at the end point (p=0.063) in the intervention group. These results suggest that nursing assistance tools may prevent upper arm pain and improve the burden on the lower back among staff in schools for disabled children; however, these tools did not significantly prevent low back pain and depression.
Envisioning a cooling method and aiming at maximum feasibility and simplicity, we designed an experimental intervention-control study based on non-refrigerated water usage, consisting of pouring 2 l of 23.0˚C water simultaneously on head and hands for one minute, after every 20 min of exertion. The subjects were 11 fit male individuals between 19 and 26 yr old. Each individual participated in one control and one intervention measurement in a climatic chamber at 35˚C and 60% humidity (31.5˚C WBGT) on different days. Heart rate, rectal, esophageal, skin and external ear canal temperatures were monitored constantly. Each experiment consisted of 10 min of basal recording followed by 3 intervals of 20 min of cycling and 15 min of rest. Stabilometry and visual reaction time tests were performed before and after each resting period. A questionnaire evaluating equilibrium, concentration, alertness and tiredness was administered at the beginning and at the end of every experiment. Paired t-test analysis revealed significant improvements in subjective parameters (all p<0.05), as well as skin (p<0.05), external ear canal (p<0.01) and esophageal (p<0.05) temperatures during the rest periods. Repeated measurement analysis of variance revealed significant cooling in all the aforementioned temperatures except the esophageal temperature (p=0.28). Other parameters were not significantly different. Our findings indicate that this method has subjective and physiologic positive effects, and thus can be used as a complementary low cost method to cool subjects safely.
To explore the relationship of occupational stress and social support with health-related behaviors of smoking, alcohol usage and physical inactivity, a cross-sectional survey was conducted among 561 offshore oil installation workers of a Chinese state-owned oil company. They were investigated with a self-administered questionnaire about socio-demographic characteristics, occupational stress, social support and health-related behaviors. Logistic regression analysis was used to study the association between occupational stress, social support and health-related behaviors and adjusted for age, educational level, marital status, duration of offshore work and job title. Of 561 workers, 218 (38.9%) were current smokers, 124 (22.1%) current drinkers, and 354 (63.1%) physically inactive in their leisure time. Further multivariate logistic regression analysis indicated that: (1) Current smoking was significantly negatively related with perceived stress from "Safety" (OR=0.74; 95% CI=0.58~0.94) and lack of supervisors' instrumental support (OR=0.34; 95% CI=0.18~0.65); (2) Current drinking was significantly positively related to perceived stress from "Interface between job and family/social life" (OR=1.32; 95% CI=1.02~1.70) and "Organizational structure" (OR=1.35; 95% CI=1.06~1.74), but was significantly negatively related to poor emotional support from friends (OR=0.54; 95% CI=0.62~0.96); (3) Physical inactivity after work was significantly positively associated with perceived stress from "Safety" (OR=1.44; 95% CI=1.16~1.79) and lack of instrumental support from both supervisors (OR=1.74; 95% CI=1.16~2.65) and friends (OR=1.68; 95% CI=1.06~2.42). The findings suggest that psychosocial factors of occupational stress and social support at offshore oil work might affect workers' health-related behaviors in different ways.
The aim of this study was to investigate the effects of shift work on nutrient intakes, including macronutrient intake and micronutrient intake, in a large sample size. The study population included 2,254 male manual workers, 20-59 yr of age, employed in a factory. A self-administered diet history questionnaire was used. The subjects were classified into 3 groups according to their work schedule: (i) fixed day workers; (ii) shift workers without midnight shifts; and (iii) shift workers with midnight shifts. The nutrient intakes of the groups were compared by age group. There was a significant difference in nutrient intakes between subjects aged 20-29 yr and those aged 30 yr and over. Among subjects aged 20-29 yr, the energy density value for saturated fat and the energy adjusted intakes of calcium, potassium, vitamin A, and vitamin B1 were the lowest among shift workers with midnight shifts. Among subjects aged 30 yr and over, the total energy intake was the highest among shift workers with midnight shifts; the difference was significant compared to fixed day workers. Shift workers with midnight shifts had the highest intake of cereals among subjects 30 yr of age and older. In conclusion, there were no significant differences in nutrient intakes between fixed day workers and shift workers without midnight shift. Shift work, particularly midnight shift work, affected nutrient intake. The impact of shift work on nutrient intakes differed by age and the type of shift work.
Workplace violence, a possible cause of job stress, has recently become an important concern in occupational health. This study determined the prevalence of workplace violence and its risk factors for employees at a psychiatric hospital in Taiwan. A questionnaire developed by ILO/ICN/WHO/PSI was first translated and validated. It was then used to survey the prevalence of workplace violence in the last 12 months experienced by all nursing aides, nurses, and clerks at the hospital. Multiple logistic regression models were constructed to discover the determinants of violence. A total of 222 out of 231 surveyed workers completed a valid questionnaire. The one-year prevalence rates of physical violence (PV), verbal abuse, bullying/mobbing, sexual harassment, and racial harassment were 35.1, 50.9, 15.8, 9.5, and 4.5%, respectively. The prevalence of PV at this hospital was higher than that reported by other countries for the health sector. A high anxiety level was associated with the occurrence of PV. These results need to be corroborated by future investigation. A training program may be required for high risk groups to reduce workplace violence.
Over the past decades, emphasis has been placed on the changing nature of work and new forms of risk that could negatively affect employee health and safety. These are mainly associated with new types of occupational hazards that have been termed psychosocial. Issues such as work-related stress, bullying and harassment are now receiving attention on a global basis and efforts have been made to address them at the workplace level. However, it has been acknowledged that despite developments of policy in this area, there still appear to be a broad science-policy gap and an even broader one between policy and practice. The WHO Network of Collaborating Centers in Occupational Health has, since the late 1990s, been supporting a dedicated program of work on psychosocial factors and work-related stress. Part of the Network's work is currently focusing on the translation of existing knowledge into practice in the area of psychosocial risk management. This program has identified that the optimum way forward lies in the development of a European framework for psychosocial risk management. This framework will serve as the basis for coordination of research activities and preventive action with an emphasis on evidence based interventions and best practice on an international basis.