Background: It has been difficult to make reliable hazard assessments of manufactured nanomaterials, because the nanomaterials form large agglomerations in both in vitro and in vivo studies. Objective: In the New Energy and Industrial Technology Development Organization (NEDO) Project of Japan, the physicochemical properties of many manufactured nanomaterials are being measured, and in vitro and in vivo studies are being performed to determine which endpoints are correspond to the hazards and risks of nanomaterials. Focusing on titanium dioxide, fullerenes and carbon nanotubes, we introduce findings made in inhalation and intratracheal installation studies overseas, and together with the findings made in the NEDO project, and also assess the hazards presented by manufactured nanomaterials. Results and Conclusion: A project by NEDO has succeeded in ensuring the stability of dispersion (nanoscale <100 nm) of manufactured nanomaterials, and is developing hazard assessments of manufactured nanomaterials. In these interim reports, the acceptable exposure concentration of titanium dioxide and fullerene was proposed to be 1.2 mg/m3 and 0.8 mg/m3 respirable dust in working environment, respectively.
Objectives: To examine the effects of multiple types of work-family spillover (work-to-family negative spillover, WFNS; family-to-work negative spillover, FWNS; and work-family positive spillover, WFPS) on psychological distress among Japanese dual-earner couples with preschool children. Methods: 2,346 parents completed questionnaires measuring work-family spillover, work- and family-specific variables (i.e., job demands and resources, family demands and resources), and psychological distress. A hierarchical multiple regression analysis was conducted by entering demographic characteristics (gender, age, age of the youngest child, and job contract) in step 1, job demands and resources in step 2, family demands and resources in step 3, work-family spillover in step 4, and three two-way interactions between types of work-family spillover and gender in the final step. Results: Both WFNS and FWNS were positively related to psychological distress after controlling for demographic characteristics and domain specific variables (i.e. job and family demands/resources), and FWNS (β=0.26) had a stronger relation with psychological distress than WFNS (β=0.16). Although WFPS was significantly and negatively related to psychological distress, the relationship was weak (β=-0.05). In addition, two-way interactions of WFNS and FWNS with gender were found; the impact of both WFNS and FWNS on psychological distress is stronger for females than for males. No significant interaction effect was observed between WFPS and gender. Conclusions: In this study of Japanese dual-earner couples with preschool children, work-family negative spillover had a stronger relationship with psychological distress than positive spillover. Gender had a moderating effect on the relationship between negative spillover and psychological distress.
Objective: The purpose of the study was to investigate the prevalence of voice disorders and associated risk factors among primary school teachers in Hong Kong. Methods: A cross-sectional survey was conducted based on a random sample of 20 primary schools in Hong Kong. A total of 714 full-time primary school teachers were invited to participate in the survey. Data were collected through a self-administered questionnaire addressing the prevalence of voice disorders and potential risk factors. Stepwise logistic regression was used to assess the associations between voice disorders and the different risk factors. Results: The response rate for the questionnaire was 69.7% (498/714). Among the teachers who responded, 348 (69.9%) had suffered from a voice disorder in the past 12 mo. Thirty-one teachers (8.9%) rated their voice disorders as minimal, 124 (35.6%) as mild, 151 (43.4%) as moderate, and 42 (12.1%) as severe. Of the 348 teachers reporting voice disorders, 215 (61.8%) had sought professional help for their voice problems. The univariate analyses showed that the factors significantly associated with voice disorders included talking quietly (p=0.018), using a microphone (p=0.002), speaking against background noise (p<0.001), consuming alcohol (p=0.027), and having a history of asthma (p=0.001), colds (p=0.012), sinusitis (p=0.039), or laryngitis (p<0.001). After adjusting for potential confounds, the significant risk factors included speaking against background noise (adjusted OR=1.8), alcohol consumption (adjusted OR=0.40), history of asthma (adjusted OR=3.3), or laryngitis (adjusted OR=4.2). Conclusions: Approximately 70% of the sampled primary school teachers were affected by voice disorders. A substantial proportion of the effected teachers suffered both functional and psychological adverse effects. The findings indicate an urgent need for further investigation to identify the risk factors for voice disorders and to develop preventive strategies for primary school teachers.
Objectives: To determine the relationship between semen quality and exposure to pesticide residues. Methods: A cross-sectional study was conducted among male farmers from 3 different communities in Sabah, Malaysia. A total of 152 farmers participated in this study of whom 62 farmers had been exposed to either paraquat or malathion or both to varying extents. Questionnaires were designed to record a history of pesticides exposure and other potential risk factors among farmers. All semen samples were collected, processed and analyzed by qualified personnel based on WHO guidelines. Volume, pH, sperm concentration, motility, morphology and WBC count were examined and recorded. The association between pesticide exposure and semen parameters was highly significant. Results: The mean values of volume, pH, sperm concentration, motility, and WBC count were significantly less in the exposed group than in compared with the non-exposed group, with p<0.005. Those who were exposed to pesticides had greater risk of having abnormal semen parameters than those in with the non exposed group, with p values of less than 0.05. The comparison between semen qualities such as lower sperm count, motility and higher percentage of sperm abnormality of those exposed to different types of pesticides (paraquat and malathion) showed no significant differences. Conclusion: The results showed a significant decline in semen quality with a decline in sperm count, motility and higher percent of teratospermia among subjects with pesticide exposure, and those who were exposed to pesticides had significantly 3 to 9 times greater risk of having abnormal semen parameters.
Objectives: To explore the separate and combined effects of work and family stress on menstrual disorders and fibrocystic changes in Chinese working women. Methods: Data were obtained from a cross-sectional study of 1,642 female railway workers. The Effort-Reward Imbalance Questionnaire and Family Stress Scale were used to measure work stress and family stress, respectively; the menstrual and breast conditions were evaluated by gynecologic interview and a medical examination. Multivariate log-binomial regression was performed to analyze the associations. Results: Menstrual disorders were found in 59.3% of female workers, and 54.8% had fibrocystic changes. The risk of menstrual disorders was significantly elevated with respect to work and family stress. The highest risk was found in the group with combined exposure to both work and family stress (RR with 95% CI 1.33 (1.18-1.49)). No significant association between stress and fibrocystic changes was observed. Conclusions: Menstrual disorders were associated with stress from work and family life, but not fibrocystic changes, in working women. Tailored intervention measures reducing the burden of stressful psychosocial work and family environment are needed to improve women's reproductive well-being.
Objective: The purpose of this study was to assess whether workplace bullying mediates between job strain, evaluated by the job demand-control model, and symptoms of depression and sleep disturbance. Methods: The subjects in this cross-sectional study were recruited from all the workers (N=2,634) at 50 organizations in Japan. Due to missing data, the numbers of subjects included in the analyses varied from 1,646 to 2,062 (response rates varied from 62.5% to 78.2%). Job strain and workplace social support, workplace bullying, depression, and sleep disturbance were assessed using the Japanese versions of the Job Content Questionnaire, the Negative Acts Questionnaire, the Center for Epidemiologic Studies Depression Scale, and the Pittsburgh Sleep Quality Index, respectively. Mediation analysis followed the approach outlined by Baron and Kenny. We quantitatively estimated the mediation effects and tested their significance after adjustment for various combinations of demographic variables and workplace social support. Results: Total effects of job strain index on depression or sleep disturbance were all positive and significant (p<0.05) in both genders. Mediation effects of workplace bullying were also all positive and significant (p<0.05) in both genders. Even after adjustment for workplace social support, the mediation effects were decreased, especially in women, but remained significant (p<0.05). Conclusions: Workplace bullying seems to play important roles in the relationships of job strain with depression or sleep disturbance in both genders.
Objectives: Workplace smoking cessation programs can increase smoking cessation rates, improve employee health, reduce exposure to second-hand smoke, and decrease costs. To assist with the development of such programs, we conducted a Global Workplace Smoking Survey to collect information on workplace attitudes towards smoking cessation programs. Methods: Data were collected from 1,403 employers (smoking and non-smoking) and 3,525 smoking employees participating in surveys in 14 countries in Asia, Europe, and South America in 2007. Results were weighted to ensure that they were representative of smokers and employers at companies with the specified number of employees. Results: More than two-thirds of employers (69%) but less than half of employees (48%) indicated that their company should help employees with smoking cessation. Approximately two-thirds of employees and 81% of employers overall felt that smoke-free policies encourage cessation, but fewer individuals from Europe (vs. from Asia or South America) agreed with this. In companies with a smoke-free policy, 76% of employees and 80% of employers felt that their policy had been somewhat, very, or extremely effective in motivating employees to quit or reduce smoking. Employers and employees differed substantially regarding appropriate methods for encouraging cessation, with more employees favouring financial incentives and more employers favouring education. Conclusions: Both employees and employers value smoke-free workplace programs and workplace cessation support activities, although many would like their companies to offer more support. These results will be useful for organizations exploring means of facilitating smoking cessation amongst employees.
Objectives: Agricultural workers chronically exposed to complex mixtures of pesticides are at increased risk of acute and chronic toxicity of these compounds. Enzyme activities are among the biomarkers that may be used to detect the effects of pesticides before adverse clinical health effects occur. The aims of this study were to ascertain the relationships between paraoxonase 1 (PON1) and other serum enzymes and to investigate whether long-term exposure to pesticides affects these relationships in Tunisian agricultural workers. Methods: The activities of butyrylcholinesterase (BChE), aminotransferases, gamma glutamyl transferase (GGT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and creatine kinase (CK) were measured in plasma from workers chronically exposed to pesticides using an Integra 400 plusTM system. PON1 activity was measured using konelab 30TM system. Results: Significant increases in aminotransferases, CK, LDH and ALP activities were found in workers exposed to pesticides. However, BChE and PON1 activities were decreased significantly in these subjects. In addition, PON1 activity was positively correlated with both BChE and GGT activities in these workers. Conclusion: This study suggests that pesticides lead to alteration of serum enzymes and that chronic exposure to pesticides might contribute to explain the positive correlation between PON1 and GGT, perhaps in order to protect BChE and simultaneously induce detoxification of pesticides.
Objectives: The aim of this study was to investigate the difference in productivity between those who are depressed and those who are not. Methods: A cross-sectional study of depressive and non-depressive employees at a workplace was performed. Data was collected between April and June 2008 through self-reported questionnaires including the Stanford Presenteeism Scale. One thousand employees participated in this study. Inappropriate responses including missing data or non-relevant responses were excluded. Finally, data of 612 subjects was analyzed using the SPSS program. Results: The productivity of employees with depression was lower than that of employees without depression. The difference in productivity loss due to impaired presenteeism was significantly different between the two groups, but the productivity loss due to absenteeism was not. Conclusions: From the results of this study, we can deduce that depression among employees leads to productivity loss. Therefore, we must consider the management of depression in the workplace and improve the activities of occupational nurses and doctors during the mental health screening of employees.
Objectives: This study was designed to investigate the early dynamic state of hydrofluoric acid (HFA) in blood and urine as a model of accidental occupational exposure to a subtoxic dose of HFA. It was also aimed at determining the relationship between the kinetics and harmful effects of HFA on the kidney. Methods: Rats received a single intravenous injection of HFA (3.2, 6.4, or 9.6 (LD5) mg/kg) or saline. The volume of each injection was 1 ml and the concentrations of HFA were 0.1, 0.2, and 0.3%, respectively. Ionized fluoride (F) was measured for the biological monitoring of HFA. Serum F concentrations were determined at 0, 5, 10, 30, 60, 120, and 300 min. Pharmacokinetic parameters were calculated with two-compartment modeling. Urine was directly collected from bladder for 300 min to determine the extent of the renal damage. Results: AUC0→300 values were significantly higher in the 9.6 mg/kg group than in the 3.2 and 6.4 groups. The total body clearance, V1, V2 and Vss were significantly lower in the 6.4 and 9.6 mg/kg groups than in the 3.2 mg/kg group. These results indicate that HFA was retained in blood. This could be a result of renal dysfunction. NAG/Cr and glucose excretion amount in urine were increased, and the clearance rate of F, urine volume and excretion amounts of electrolytes were decreased in the 9.6 mg/kg group compared with the saline group. These findings indicate renal tubular damage and a decrease in the amount of excretion of HFA from the kidney. Conclusions: We consider that acute nephrotoxicity of HFA caused renal injury, and the harmful effects of HFA were subsequently aggravated by its delayed metabolism.