Andropause symptoms and sickness absence in Japanese male workers: a prospective study.

OBJECTIVE: The purpose of the study was to investigate the association between andropause symptoms and sickness absence in Japanese male workers over 2 years. METHODS: A baseline survey asking about andropause symptoms, along with blood sampling for testosterone level, was conducted in June 2009. A total of 418 men (mean age = 52.4 years, SD = 8.6) participated and were followed through 2011. Hazard ratios (HRs) and 95% confidence intervals (CIs) for sickness absence were calculated using Cox proportional hazard models. RESULTS: During the follow-up period, 31 of 35 participants who took sickness absences had physical illnesses. A higher andropause symptom score was associated with an increased risk of sickness absence. Testosterone deficiency (<350 ng/dL) was not associated with sickness absence. Among the subscales of andropause symptoms, the somatic symptom score was positively associated with sickness absence, whereas testosterone deficiency combined with high sexual symptoms was not associated with sickness absence. Results were similar when limited to sickness absence because of physical illness. No significant interaction between andropause symptoms and testosterone deficiency was found. CONCLUSIONS: Non-specific andropause symptoms unrelated to testosterone deficiency were positively associated with sickness absence.

Association Between Cortisol to DHEA-s Ratio and Sickness Absence in Japanese Male Workers.

PURPOSE: This study aimed to investigate the association between serum levels of cortisol and dehydroepiandrosterone sulfate (DHEA-s) and sickness absence over 2 years in Japanese male workers. METHOD: A baseline survey including questions about health behavior, along with blood sampling for cortisol and DHEA-s, was conducted in 2009. In total, 429 men (mean ± SD age, 52.9 ± 8.6 years) from whom blood samples were collected at baseline were followed until December 31, 2011. The hazard ratios (HR) and 95% confidence intervals (CI) for sickness absence were calculated using a Cox proportional hazard model, adjusted for potential confounders. RESULTS: Among 35 workers who took sickness absences, 31 had physical illness. A high cortisol to DHEA-s ratio increased the risk of sickness absence (crude HR = 2.68, 95% CI 1.12-6.41; adjusted HR = 3.33, 95% CI 1.35-8.20). The cortisol to DHEA-s ratio was linearly associated with an increased risk of sickness absence (p for trend < .050). Single effects of cortisol and DHEA-s levels were not associated with sickness absences. This trend did not change when limited to absences resulting from physical illness. CONCLUSION: Hormonal conditions related to the hypothalamus-pituitary-adrenocortical axis and adrenal function should be considered when predicting sickness absence. The cortisol to DHEA-s ratio may be more informative than single effects of cortisol and DHEA-s levels.

Confirmation of Maslow's Hypothesis of Synergy: Developing an Acceptance of Selfishness at the Workplace Scale.

This study aimed to develop a new Acceptance of Selfishness at the Workplace Scale (ASWS) and to confirm Maslow's hypothesis of synergy: if both a sense of contribution and acceptance of selfishness at the workplace are high, workers are psychologically healthy. In a cross-sectional study with employees of three Japanese companies, 656 workers answered a self-administered questionnaire on paper completely (response rate = 66.8%). Each questionnaire was submitted to us in a sealed envelope and analyzed. The ASWS indicated high internal consistency (Cronbach's alpha = 0.86). Significant (p < 0.001) positive moderate correlations between ASWS scores and job control scores support the ASWS's convergent and discriminant validity. Significant (p < 0.001) associations of ASWS scores with psychological distress and work engagement supported the ASWS's criterion validity. In short, ASWS was a psychometrically satisfactory measure. Significant (p < 0.05) interactions between a sense of contribution and acceptance of selfishness at the workplace in linear regression models showed that when those two factors are low, psychological distress becomes high. However, when a sense of contribution and acceptance of selfishness are high, work engagement also becomes high. Thus, Maslow's hypothesis of synergy was confirmed.

Modification Effects of Changes in Job Demands on Associations Between Changes in Testosterone Levels and Andropause Symptoms: 2-Year Follow-up Study in Male Middle-Aged Japanese Workers.

PURPOSE: The purpose of this longitudinal study was to ascertain if changes in job demands modify associations between changes in testosterone levels and andropause symptoms in male Japanese workers. METHOD: A baseline survey including job demands and the Aging Males' Symptoms scale, lifestyle factors, and blood levels of testosterone was conducted in 2007. Among 192 men (mean age ± SD 52.2 ± 7.6 years) who completed all relevant questionnaires and provided blood at baseline, 104 men (50.9 ± 7.2 years) were followed up in 2009. Changes of variables in 2 years were calculated (data of follow-up minus those of baseline). RESULTS: Testosterone levels were increased significantly, whereas job demands and somatic symptoms were reduced significantly, at follow-up. Changes in testosterone levels were negatively associated with changes in total andropause symptoms, psychological symptoms, and sexual symptoms (standardized ß = -0.27, -0.24, and, -0.29, p < 0.05, respectively), after adjustment for confounders. Changes in job demands were positively associated with changes in somatic symptoms (standardized ß = 0.21, p < 0.05). Significant interactions of changes in testosterone levels and job demands were noted for changes in psychological symptoms (standardized ß = 0.26, p < 0.05). For men with a 1-SD reduction in job demands, negative associations between changes in testosterone levels and psychological symptoms were intensified, but not for men with a 1-SD increase in job demands. CONCLUSION: Andropause symptoms may be affected by changes in testosterone levels and job demands. Change in job demands may modify associations between changes in testosterone levels and andropause symptoms.

Associations of workplace bullying and harassment with stress reactions: a two-year follow-up study.

The purpose of this prospective study was to investigate the effect of the patterning of workplace bullying and harassment over two time points (chronic, remission, onset, and never) on psychological and physical stress reactions. The subjects were 543 workers at welfare facilities for the elderly in Japan who completed a self-administered questionnaire at Time 1 (from August to September, 2009) and at Time 2 (from September to October, 2011). Workplace bullying and harassment were assessed using the Negative Acts Questionnaire (NAQ). Stress reactions were assessed using the Brief Job Stress Questionnaire. In the multiple logistic regression analyses, onset of person-related bullying was significantly (p<0.05) positively associated with both psychological and physical stress reactions at Time 2. Chronic form of person-related bullying was significantly (p<0.05) positively associated with psychological stress reaction at Time 2. Onset of sexual harassment was significantly (p<0.05) positively, and remission of sexual harassment was significantly (p<0.05) negatively associated with physical stress reaction at Time 2. Onset and chronic form of person-related bullying and onset of sexual harassment can cause stress reactions. Remission of sexual harassment can terminate physical stress reaction.

Family-related opinions and stressful situations associated with psychological distress in women undergoing infertility treatment.

The purpose of this study is to investigate how family-related opinions and stressful situations are related to psychological distress in women undergoing infertility treatment. The subjects in this cross-sectional study were recruited from female patients undergoing infertility treatment (n = 2540) at 70 infertility treatment institutions in Japan. Because of non-participation or missing data, the number of subjects included in the analysis was 635 (response rate, 25.0%). The family-related opinions and stressful situations were evaluated using the original questions. Psychological distress was assessed using a self-report measure, the Kessler Six-question Psychological Distress Scale (K6). The K6 scores of the following participants were significantly (p < 0.05) and independently high: those with more frequent miscarriage/stillbirth/abortions, those with repeated miscarriages as the cause of infertility, those with infertility of unknown causes, those living with no child, those having a low joint income with their partner, those with the opinion that "women should devote themselves to their household duties" those who had considered stopping treatment, those without the opinion that "married life without children is favorable" and those who had experienced stressful situations such as inadequate explanation by doctors, frustration of multiple failed attempts, differences of opinion with the partner, and lack of knowledge regarding when to stop treatment. Family-related opinions and stressful situations associated with psychological distress in women undergoing infertility treatment are outlined. The results of this study may contribute to the prevention of and care for psychological distress in female patients undergoing infertility treatment.

Reliability, validity, and significance of assessment of sense of contribution in the workplace.

The purpose of this study was to assess the validity and reliability of the Sense of Contribution Scale (SCS), a newly developed, 7-item questionnaire used to measure sense of contribution in the workplace. Workers at 272 organizations answered questionnaires that included the SCS. Because of non-participation or missing data, the number of subjects included in the analyses for internal consistency and validity varied from 1,675 to 2,462 (response rates 54.6%-80.2%). Fifty-four workers were included in the analysis of test-retest reliability (response rate, 77.1%). The SCS showed high internal consistency (Cronbach's α coefficients in men and women were 0.85 and 0.86, respectively) and test-retest reliability (intraclass correlation coefficient = 0.91). Significant (p < 0.001), positive, moderate correlations were found between the SCS score and scores for organization-based self-esteem and work engagement in both genders, which support the SCS's convergent and discriminant validity. The criterion validity of the SCS was supported by the finding that in both genders, the SCS scores were significantly (p < 0.05) and inversely associated with psychological distress and sleep disturbance in crude and in multivariable analyses that adjusted for demographics, organization-based self-esteem, work engagement, effort-reward ratio, workplace bullying, and procedural and interactional justice. The SCS is a psychometrically satisfactory measure of sense of contribution in the workplace. The SCS provides a new and useful instrument to measure sense of contribution, which is independently associated with mental health in workers, for studies in organizational science, occupational health psychology and occupational medicine.

Associations of job stress indicators with oxidative biomarkers in Japanese men and women.

Some researchers have suggested that oxidative damage may be one of the mechanisms linking job stress with coronary heart disease. The aim of this study was to investigate the association between job stress indicators and oxidative biomarkers. The study included 567 subjects (272 men, 295 women) who answered questionnaires related to their work and underwent a medical examination. Job stress evaluated using the demands-control-support model was measured using the Job Content Questionnaire. Effort-reward imbalance was measured using the Effort-Reward Imbalance Questionnaire. Urinary hydrogen peroxide (H2O2) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were measured by the modified ferrous ion oxidation xylenol orange version-1 method and enzyme-linked immunosorbent assay, respectively. In men, the changes in the odds ratios for high urinary H2O2 associated with a 1-standard-deviation (SD) increase in worksite social support were 0.69 (95% confidence interval (CI) 0.53, 0.91) univariately and 0.68 (95%CI 0.51, 0.90) after adjustment for covariates. The change in the odds ratio for high urinary H2O2 associated with a 1-SD increase in effort-reward ratio was 1.35 (95% CI 1.03, 1.78) after adjustment for covariates. In women, there were no significant associations of the two job stress indicators with urinary H2O2 and 8-OHdG levels after adjustment for covariates (p > 0.05).

Associations of workplace bullying and harassment with pain.

The aim of this study was to investigate associations of workplace bullying and harassment with headache, stiffness of the neck or shoulders, lumbago, and pain of two or more joints. The subjects in this cross-sectional study were recruited from workers (n = 1,913) at 35 healthcare or welfare facilities in Japan. Because of non-participation or missing data, the number of subjects included in the analysis varied (response rate ≥ 77.1%). Workplace bullying and harassment were assessed using the Negative Acts Questionnaire. Depression was assessed using the Brief Job Stress Questionnaire. The frequency of pain experienced by workers in the previous month was evaluated using a four-point scale. Many of the associations of person-related bullying, work-related bullying, and sexual harassment with headache, stiffness of the neck or shoulders, lumbago, and pain of two or more joints were positive and significant (p < 0.05). Even after adjustment for depression, some of the associations remained significant (p < 0.05). For example, changes in the prevalence ratio for headache associated with a 1-point increase in the work-related bullying score were 1.05 (95% confidence interval (CI) 1.01 to 1.09) in men and 1.03 (95% CI 1.01 to 1.05) in women after adjustment for age, marital status, employment status, work shift, and depression.

Circulating nitrite and nitrate are associated with job-related fatigue in women, but not in men.

A recent study indicated that serum nitrite and nitrate (NOx) is inversely associated with general fatigue. The purpose of this study was to confirm the negative association between nitric oxide (NO) and fatigue and to examine whether NO can prevent fatigue caused by job strain. The subjects, 570 workers (272 men and 298 women), answered self-administered questionnaires and underwent a medical examination. Job strain was measured using the Job Content Questionnaire. Fatigue was evaluated using the Profile of Mood States. Venous blood samples were collected after overnight fasting. Plasma NOx concentration was determined by the ozone-based chemiluminescence assay. Plasma NOx levels were significantly (p < 0.05) negatively associated with fatigue even after adjustment for job strain and potential confounders in women, but not in men. Significant (p < 0.05) interactions showed that, in women, as the level of the job strain worsened, fatigue was exacerbated, but the plasma NOx seemed to buffer the association, even after adjustment for potential confounders and the interaction between job strain and vegetable intake. In women, NO seemed to be inversely associated with fatigue and to buffer the association between job strain and fatigue, but not in men.

Job demands as a potential modifier of the association between testosterone deficiency and andropause symptoms in Japanese middle-aged workers: a cross-sectional study.

OBJECTIVE: The present study investigated whether job demands modify the association between low levels of testosterone and andropause symptoms. STUDY DESIGN: Participants were Japanese middle-aged workers in a middle-size company. Blood samples were drawn to determine serum levels of testosterone. Participants completed a self-report questionnaire that included 5 items from the Job Content Questionnaire (JCQ) that assesses job demands, the Aging Males' Symptoms (AMS) scale as well as questions regarding health behaviors and history of disease. Analysis of data was limited to the 183 men who completed all components of the questionnaire and provided blood samples (mean age=51.9 years, SD=7.7, age range 34-67 years). MAIN OUTCOME MEASURES: The AMS which comprises three symptom sub-scales: somatic, psychological, and sexual. RESULTS: Men with low testosterone levels (<349 ng/dL) had more psychological andropause symptoms than those with high levels. In men with high psychological job demands, compared to men with low job demands, testosterone levels were positively associated with the total score for andropause symptoms and scores for somatic and psychological symptoms. CONCLUSIONS: Level of job demands may intensify the effect of testosterone deficiency on andropause symptoms.

The relationship between social capital and self-rated health in a Japanese population: a multilevel analysis.

OBJECTIVE: The aim of this study was to use a multilevel analysis to examine whether cognitive and structural dimensions of regional social capital were associated with individual health outcomes after adjusting for compositional factors. METHODS: Data from the Japanese General Social Surveys project, a nationwide study with a two-stage stratified random sampling method conducted in 2000, 2001, 2002, 2005, and 2006, were aggregated and used for the multilevel analysis (n = 11,702). We examined whether both cognitive and structural aspects of social capital (social trust, neighborhood safety, and social participation) were associated with the self-rated health (SRH) of residents from 118 regions after adjustment for compositional factors. RESULTS: Social trust and existing neighborhood safety were negatively associated with poor SRH, whereas the effect of social participation was not significant. Social trust was still negatively associated with poor SRH after adjusting for individual demographic factors and socioeconomic status (p = 0.001). In contrast, neighborhood safety and social participation did not reach significance after adjusting for compositional factors. CONCLUSION: Based on the results of this study, social trust was associated with health outcomes. Further study is needed to clarify the path linking regional trust in others to individual health outcomes in the Japanese population.

[Associations between workplace bullying, harassment, and stress reactions of professional caregivers at welfare facilities for the elderly in Japan].

OBJECTIVE: The purpose of this study was to describe workplace bullying experienced by professional caregivers at welfare facilities for the elderly in Japan and to confirm its effects on stress reactions. METHODS: A cross-sectional survey was carried out using self-administered questionnaires in 2009 of all the employees working in rural area of facilities for long-term care. Among the 1,233 respondents who filled out all questionnaires concerning stress reactions the Japanese version of the Negative Acts Questionnaire (NAQ) (response rate: 63.9%), we analyzed 897 professional caregivers. We measured stress reactions by using the stress reaction scores of the Brief Job Stress Questionnaire (29 items) and workplace bullying and harassment by using NAQ. We used the unpaired t-test and analysis of covariance (ANCOVA) to compare crude and adjusted average stress reactions with groups classified on the basis of each subscale of the NAQ or all of them. RESULTS: About 40% of both men and women suffered from "malicious gossip" and over 60% of both men and women experienced "someone withholding necessary information so that their work gets complicated". Among women, scores of the lack of vigor and fatigue were significantly higher in caregivers targeted by person-related bullying than those not targeted (p<0.05). Scores of depression were significantly higher in caregivers targeted by work-related bullying than those not targeted (p<0.05). Scores of anxiety were significantly higher among caregivers targeted by sexual harassment than those not targeted (p<0.05). Among men, scores of the lack of vigor were significantly lower in caregivers targeted by work-related bullying than those not targeted (p<0.05). CONCLUSIONS: Among women, workplace bullying or harassment could may aggravate effects on psychological stress responses. While among men, work-related bullying was positively associated with vigor.

The relationship between joint pain and climate conditions in Japan.

This study aimed to determine whether there was any association between the regional climate and the proportion of people with joint pain. Regional climate data between 1971 and 2000 were obtained from the Japan Meteorological Agency. The variables used in the cluster analysis included sunlight hours, amount of precipitation, number of days with precipitation, and temperature. The regional proportion of people with joint pain was obtained from the National Survey for Health in 2001. After performing a cluster analysis, one-way ANOVA and Welch's test were used to determine whether the climate characteristics of the clusters were significantly different. Within each cluster, stepwise multiple linear regression analyses were performed. We found that sunlight hours showed a direct, negative association with the proportion of people with joint pain (adjusted R2=0.532, p=0.016) in cluster 1, which was characterized as the region with the fewest total hours of sunlight, less precipitation, a modest number of rainy days, and low temperature. In the other clusters, the regional female population rate (cluster 2) and the senior population rate (cluster 3, 4) were the primary predictors. We concluded that the degree of exposure to sunlight may play a crucial role in prevention of joint pain. This finding should encourage people to set aside some time for staying outdoors in their daily lives.

Workplace bullying could play important roles in the relationships between job strain and symptoms of depression and sleep disturbance.

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.

Possible health-protecting effects of feeling useful to others on symptoms of depression and sleep disturbance in the workplace.

OBJECTIVES: The aim of this study was to examine the health-protecting effects of feeling useful to others on symptoms of depression and sleep disturbance in the workplace, as well as its buffering effects on associations between stressful work environments and symptoms of depression and sleep disturbance. METHODS: The subjects of this cross-sectional survey were 773 Japanese workers (response rate: 64.8%) of five organizations. Feelings of being useful to others were assessed with one simple question used in a previous study. Psychosocial work environment, sleep disturbance, and depressive symptoms were assessed using the Japanese versions of the Effort-Reward Imbalance Questionnaire, the Pittsburgh Sleep Quality Index, and the 28-item General Health Questionnaire, respectively. We tested for linear and interactive effects with hierarchical regression analyses. RESULTS: Feeling useful to others was significantly (p<0.05) and negatively associated with scores of depression and sleep disturbance both in the univariate analyses and after adjusting for age in both genders. Significant (p<0.05) interactions showed that, in both genders, as the effort-reward balance worsened, symptoms of depression increased, but feeling useful to others buffered the associations. CONCLUSIONS: The results support the notion that feeling useful to others in both genders in the workplace has possible health-protecting effects.

C-reactive protein is associated with cigarette smoking-induced hyperfiltration and proteinuria in an apparently healthy population.

Although cigarette smoking is known to be an important risk factor for renal disease, the mechanism by which smoking induces progressive renal disease in a healthy population has not been established. We hypothesized that oxidative stress (measured as 8-iso-prostaglandin F(2α), 8-iso-PGF2a), inflammation (highly sensitive C-reactive protein (CRP), hs-CRP) and nitric oxide may be associated with an alteration in the estimated glomerular filtration rate (eGFR) and proteinuria in otherwise healthy smokers. A total of 649 eligible subjects were classified according to their smoking status. Plasma NOx was measured using ozone-based chemiluminescence, urinary 8-iso-PGF2a was measured using enzyme immunoassay and serum hs-CRP was measured using a latex aggregation nephelometry method. The levels of 8-iso-PGF2a and hs-CRP increased in current smokers (P=0.001 and P=0.029, respectively), although there was not an increase in the NOx level. The prevalence of a high eGFR increased in light smokers (odds ratio (OR) 1.15 (95% confidence interval (CI), 0.61-2.17)) and heavy smokers (OR 2.33 (95% CI, 1.06-5.10)) when compared with non- and past smokers (P for trend=0.024). The multivariable-adjusted mean values of the eGFR in current smokers, reported from the lowest to the highest quintiles of hs-CRP levels, were 82.1, 85.1, 86.4 and 88.5 ml per min per 1.73 m² (P for trend=0.027). The mean values of proteinuria were 28.6, 34.6, 37.2 and 39.5 mg g⁻¹ creatinine (P for trend=0.003). The correlation coefficient between hs-CRP and eGFR was increased significantly (P=0.03) across non- (r=0.03), past (r=-0.17), light (r=0.13) and heavy smokers (r=0.31). In conclusion, cigarette smoking is a risk factor for renal function alteration in healthy smokers and is characterized by a high eGFR and a high urinary protein associated with an increase in the hs-CRP. This finding suggests that hs-CRP may help mediate the alteration of renal function in smokers.

Evaluation of pyrogallol-induced cytotoxicity in catalase-mutant escherichia coli and mutagenicity in Salmonella typhimurium.

We evaluated pyrogallol cytotoxicity using Escherichia coli strains that express mammalian catalase gene derived from catalase mutant mice (Cs(b)) and wild-type (Cs(a)), and pyrogallol mutagenicity by Ames test. Pyrogallol was more toxic to Cs(b) rather than to Cs(a) (p < 0.05), while catalase, superoxide dismutase and ascorbic acid decrease the toxic effect. Pyrogallol also showed mutagenic effect (mutagenic index = 3.8 for 10 micromol pyrogallol/plate) while ascorbic acid (19.4% reduction, p < 0.001) and naringin (35.1% reduction, p < 0.001) played a protective role against it. Pyrogallol cytotoxicity and mutagenicity seem to be attributable, at least in part, to reactive oxygen species formation. This study also suggests that newly established catalase mutant E. coli is probably useful in hazard identification of oxidative chemicals.

Interactive effects of job stress and body mass index on over-eating.

OBJECTIVES: Recent prospective evidence drawn from the Whitehall II cohort reported by Kivimäki et al. implies that stressful situations are related to decreased body weight in thin men and increased body weight in obese men, whereas no corresponding interactive effects are observed in women. The mechanism underlying this phenomenon remains unknown, and the purpose of this study was to confirm our hypothesis that the relevant mechanism is behavioral (e.g., over-eating). METHODS: The subjects of this survey were 607 Japanese workers (response rate: 60.5%) in four organizations. The questionnaire solicited demographic information and included the Bulimia scale of the Eating Disorder Inventory-EZ to measure tendencies toward over-eating as well as the Japanese version of the Effort-Reward Imbalance Questionnaire (ERIQ). Body mass index (BMI) was calculated on the basis of data obtained during medical check-ups. We tested for linear and interactive effects with hierarchical regression analyses. RESULTS: BMI was significantly (p<0.05) associated with over-eating both univariately and after adjusting for age in both sexes. Significant (p<0.05) interactions showed that ERIQ effort scores and effort-reward ratios were more positively associated with over-eating in men with higher BMIs, and ERIQ reward and financial remuneration scores were more negatively associated with over-eating in men with higher BMIs. No corresponding interactive effects were observed among women. CONCLUSIONS: The results demonstrate that stressful situations are more associated with over-eating in men with higher BMIs. This might explain, in part, the mechanism underpinning the interactive effects proposed by Kivimäki et al.

Assessment of workplace bullying and harassment: reliability and validity of a Japanese version of the negative acts questionnaire.

OBJECTIVES: Interest in workplace bullying and harassment has been increasing in Japan. At present, the Negative Acts Questionnaire (NAQ) is one of the most frequently used questionnaires for assessing these issues. The purpose of this study was to develop a Japanese version of the NAQ. METHODS: We translated the original version of the NAQ using a back-translation method. Participants in this study were recruited from 737 workers at a manufacturing company in Japan. Data were obtained from questionnaires completed by 517 respondents (response rate: 70.1%). RESULTS: We used a cross-validation approach. A three-factor model was obtained from exploratory factor analyses. The confirmatory factor analysis for this model revealed values of 0.94, 0.91, 0.95, and 0.054 for the goodness-of-fit index, the adjusted goodness-of-fit index, the comparative fit index, and the root mean square error of approximation, respectively. Pearson's correlation coefficients for the NAQ scores with the Job Content Questionnaire (JCQ) support scores and the Effort-Reward Imbalance Questionnaire scores for respect and job security were significant (p<0.001) and the direction of these associations were consistent with our expectations, with the exceptions of the correlations between the NAQ sexual harassment score and the JCQ support scores. Cronbach's alpha coefficients for the scores on the entire NAQ scale and on three subscales (person-related bullying, work-related bullying, and sexual harassment) were 0.90, 0.84, 0.60, and 0.60, respectively. CONCLUSIONS: A Japanese version of the NAQ was developed and it appears to have acceptable levels of internal consistency reliability and factor- and construct-validity.