In order to better characterize acute and subchronic toxicities of chloroform and to provide its basic toxicity data for risk assessment of humans exposed to chloroform in work and living environments, mice and rats of both sexes were exposed by inhalation to chloroform at different concentrations from 500 to 8,000 ppm for 6 h/d × 5 d/wk × 2 wk and from 12 to 400 ppm for 6 h/d × 5 d/wk × 13 wk. The kidneys, liver and nasal cavity were primarily damaged by the inhalation exposure. Acute death occurred at 12 ppm in male mice, 1,000 ppm in female mice and 2,000 ppm in male and female rats. The 13-wk exposures induced renal lesions in male mice, hepatic and nasal lesions in female mice and renal, hepatic and nasal lesions in male and female rats. Susceptibility to the acute and subchronic toxicities was higher in male mice than female mice, and higher in mice than in rats. No-observed-adverse-effect-levels (NOAELs) and lowest-observed-adverse-effect-levels (LOAELs) were determined for the renal, hepatic and nasal endpoints of animals exposed to chloroform for 13 wk. For the hepatic endpoint, NOAEL was 100 ppm in male mice, 50 ppm in female mice and female rats and 100 ppm in male rats. For the renal endpoint, LOAEL was 12 ppm in male mice, and NOAEL was 25 ppm in male rats and 100 ppm in female rats. For the nasal endpoint, LOAEL was 12 ppm and 25 ppm in the mice and the rats of both sexes, respectively.
The purpose of this study was to clarify the physiological and psychological effects on car-drivers and their passengers. Heart rate, respiratory frequency, salivation, and subjective symptoms were measured before, 3 min and 6 min after starting at speeds ranging from 80 to 120 km/h. Vibration frequency and acceleration of the drivers and passengers’ heads were simultaneously determined. The heart rate and respiratory frequency ratios of the drivers travelling at 110 km/h were 1.04, and 1.15 at 6 min after starting, whereas those of the passengers were 1.06 and 1.15, respectively. With respect to the salivation rate ratios, a decrease was noted at all the travelling speeds of both drivers and passengers. In drivers travelling at 110 km/h, a repression value of 0.72 to the baseline of one was noted, and a repression value of 0.91 was noted in the passengers. Pleasant and unpleasant indexes, at 120 km/h was 1.26 times higher than that obtained at 90 km/h. It was considered that in all the measurements the variations were caused by physiological and psychological changes mainly induced by vibration frequency and acceleration of the head.
A cross-sectional study with a self-administered questionnaire was conducted in order to examine the association between low back pain and smoking. The subjects analyzed were 6,891 adults aged 40-69 yr, who lived in a downtown district in Isesaki City, Gunma, Japan. There was a positive association between cigarette smoking and low back pain in men. The age-adjusted odds ratios of low back pain were 1.32 (95% confidence interval (Cl) 1.10, 1.57) for 1-20 cigarettes smoked per day and 1.40 (95% Cl 1.11, 1.76) for 21 or more. The association had similar strength after adjustment for alcohol consumption, physical exercise, body mass index, non-musculoskeletal disease, education, occupation, and whether living with parents, living with a child or children, or living alone. The multivariate odds ratios for low back pain were 1.29 (95% Cl 1.03, 1.62) for 1-20 cigarettes smoked per day and 1.36 (95% Cl 1.03, 1.80) for 21 or more. In conclusion, smoking was significantly related to low back pain, even if adjusted for other potential risk factors.
Objective—To clarify the mechanisms of excessive risk of cardiovascular disease among taxi drivers, the effects of taxi driving with long work hours on taxi drivers’ blood pressure and heart rate variability were examined. Methods—We measured the physical activity level, ambulatory blood pressure, and Holter ECG in 34 healthy middle-aged male taxi drivers over one work day and the two following non-work days. The subjects worked for a 24-h period starting at 07:00, then rested from work for 48 h. Ambulatory blood pressure was recorded automatically at 30-min intervals over the 72-h period. Holter ECG records were also kept for the 72 h, and temporal changes in the R-R interval were analyzed by the complex demodulation method (CDM). The amplitude of the high frequency (HF) components (central frequency 0.30 Hz), and the ratio of low-frequency components (central frequency 0.09 Hz) to high-frequency components (L/H) was calculated. Results—Blood pressure during the work day was significantly higher than that during the non-work days, with a stronger effect in the hypertensive subjects. There were no significant overall differences in heart rate variability between the work day and the non-work days, but the temporal patterns of HF and L/H on the work day revealed a potent effect of reversed-phased circadian rhythm for work at night. Conclusions—Long duty taxi driving raises blood pressure and may increase cardiovascular risk as a result. The conflict between the circadian rhythms of autonomic nervous activity and work activity at night may also result in increased risk.
This study evaluates the effectiveness of a participatory workplace risk assessment team (the intervention) in reducing the rate and severity of musculoskeletal and non-musculoskeletal injuries among a cohort of 137 cleaners within a hospital setting. The date, workers’ compensation claims cost and hours lost from work were obtained for each injury occurring during the 4-yr pre-intervention and 3-yr post-intervention period. The age, gender and hours worked during the study period, were ascertained for every cleaner whether injured or not. For musculoskeletal injuries, the intervention was associated with significant reductions of two-thirds in injury rate, 65% in workers’ compensation claims cost per hour worked, and 40% in hours lost per hour worked. Cleaners also experienced a significant two-third post-intervention reduction in non-musculoskeletal injury rate; but the corresponding changes in severity rates were not significant. The intervention supports the adoption of a participatory approach to reducing the rate and consequence of musculoskeletal injuries in the workplace.
The purpose of the study was the evaluation of electromagnetic field (electric field strength of 20 V/m, f=50 Hz and magnetic field strength of 2 A/m, f=50 Hz) effects on the antioxydative activity in steelworkers’ red blood cells and plasma. The plasma GSH-Px (EC 18.104.22.168) activity, MDA and ceruloplasmin levels as well as SOD (EC 22.214.171.124.), CAT (EC 126.96.36.199) and GSH-Px (EC 188.8.131.52) in red blood cells were measured. Statistically significant decreases in red blood cells SOD and GSH-Px activities, a CAT activity increase and plasma MAD increase and a ceruloplasmin decrease were found in workers exposed for 3-10 yr and for longer than 10 yr to electromagnetic fields. No statistically significant changes in the parameters evaluated were found among steelworkers employed for shorter than 3 yr. All changes observed among workers exposed to electromagnetic fields result in adaptative responses by activating systems controlling the balance of body oxidative mechanisms.
The aim of the study was the evaluation of the influence of electromagnetic fields (electric field strength of 20 V/m, f=50 Hz and magnetic field strength of 2 A/m, f=50 Hz) on the concentrations of vitamin A, vitamin E (α- and γ-tocopherol), and selenium, which represent non-enzymatic antioxidants, in the plasma of steelworkers exposed to such a field. The cohort was divided into 3 study groups: group 1, workers employed for less than 3 yr; group 2, employed for 3-10 yr; and group 3, employed for more than 10 years. Analysis of the results obtained revealed a statistically significant decrease in plasma vitamin A, α-, and γ-tocopherol concentrations in the study groups as well as a marked increase in plasma selenium concentrations in group 2 and 3. These changes suggest that the electromagnetic fields studied cause an increase in free-radical process activity in steelworkers.
Objectives—Associations between serum butyryl cholinesterase activity in female greenhouse workers and information from a questionnaire on work, use of personal protective equipment, and lifestyle were evaluated. Methods—Data were gathered for 571 female greenhouse workers by means of a questionnaire and serum cholinesterase analyses (butyrylthiocholin-assay). Results—The mean concentration of butyryl cholinesterase in serum was 6.50 kU/l. Serum butyryl cholinesterase activity was significantly decreased by the use of oral contraceptives (p<0.001). Among women with re-entry intervals less than 24 h, serum butyryl cholinesterase activities were significantly reduced. Within this group of women, only those not using gloves during the manual handling of plant cultures had significantly reduced serum butyryl cholinesterase activities (p=0.028). Conclusions—Use of oral contraceptives is an important confounder in studies on serum butyryl cholinesterase activity. If re-entry intervals were below 24 h, serum butyryl cholinesterase activity was significantly inhibited, but use of gloves protected the women from such exposures.
Aims—The present study was to determine the cadmium (Cd) concentrations in ordinarily consumed foods and beverages in Japan. Methods—Cd concentrations in 519 foods and beverages purchased from a local market were measured with the flame or flameless atomic absorption spectrophotometer (AAS). Results—The Cd concentration in each food group was as follows: cereals 0.004-0.380 μg/g, potatoes<0.01-0.08 μg/g, sugars and sweeteners<0.01 μg/g, pulses<0.010-0.220 μg/g, nuts and seeds<0.01-0.18 μg/g, vegetables (grown in soil) <0.001-0.128 μg/g, vegetable (grown by means of hydroponics) <0.001-0.002 μg/g, fruits<0.001-0.033 μg/g, mushrooms<0.01-0.19 μg/g, algae 0.040-2.380 μg/g, fish<0.01-0.02 μg/g, shellfish<0.010-5.050 μg/g, meats<0.001-0.100 μg/g, eggs<0.001 μg/g, milk<0.010 μg/g, fats and oils<0.001-0.001 μg/g, confectioneries<0.020-0.100 μg/g, beverages<0.01-0.13 μg/g, seasoning and spices<0.01-0.06 μg/g, and various supplement tablets<0.001-0.036 μg/g. Conclusion—A database of Cd content in foods was compiled. Cd in cereals varied from 0.004 to 0.380 ug/g. Algae, shellfish and pulses contained much higher concentrations of Cd. Vegetables grown by hydroponic cultivation contained only a very low or undetectable amount of Cd. Estimation of dietary Cd intake from the database could provide a reasonable method for estimating the relative contributions of different food groups to dietary Cd intake.
Changes such as the greater diversification of work arrangements, either the result of or enabled by the rise of information communication technology, are testing many long-standing practices and assumptions in the workplace. The emergence of the virtual organization and telework raises serious management questions including work organization, worker evaluation and knowledge management. These changes, however, also have a growing but little understood impact on health management. The aim of this paper is to explore attitudes to health management and the incidence of illness for home-based teleworkers. After a brief outline of major changes in organizational and management practices as well as research trends in the area of health and telework, it presents a set of field data on home-based workers in Japan, and links the findings to a future research agenda. The survey data indicate that health management issues do exists for this group of workers and that a worrying proportion of respondents experienced health conditions detrimental to work performance that went untreated. Additionally, a somewhat cavalier attitude towards safe work practices indicated either low worker awareness of, or low priority for, minimizing health risks. This was often compounded by the lack of a traditional mitigating third party such as a regular employer. These findings suggest that conventional organizational criteria for sickness may be being replaced by more elastic concepts of health and sickness in the virtual workplace.
Sickness absence among hospital personnel with different work types was compared. Sickness absence records were collected for all personnel in the Faculty of Medicine, Prince of Songkla University, a medical school in southern Thailand with a 750-bed teaching hospital, from October 1995 to September 1998, and analysed using descriptive statistics and negative binomial regression. Doctors and nurses recorded lower rates of short-term sickness absence (< 3 d) than other workers. Doctors also recorded the lowest rate of long-term absence (≥ 3 d), whereas other medical personnel and manual workers had higher rates of long-term sickness absence than other workers. These differences were only slightly influenced by sex, age and marital status. Rates of short-term sickness absence were higher in males, older and married personnel. A higher grade of employment was associated with lower sickness absence, both short- and long-term, and accounted for much of the actual differences among work types. Nevertheless, significant differences across work type remained after adjustment for socio-demographic and other work-related variables. The findings of this study would provide new baseline information regarding sickness absence patterns among hospital staff in this particular setting, but there is still a need to distinguish among the true reasons for reported sickness absence, particularly short-term absence, in order to set up an appropriate health promotion programme among the staff of this hospital.
Epoxy resins have been widely used in commercial applications, and their adverse health effects have been mostly reported in occupational settings. The most frequent adverse effects are irritation or allergic mechanisms involving the dermal and respiratory systems. Sensitization is usually caused by low molecular weight or short-chain compounds1). We report here two workers exposed to an epoxy resin and a newly developed epoxy hardener, alkylamine, who developed severe dermatitis. The chemicals were used as components of asphalt. We identified the epoxy hardener as the causative material in the dermatitis by a patch test.