Bridging perceived organizational support with learning motivation and work engagement: the mediating role of focus on opportunity.

OBJECTIVES: Perceived Organizational Support (POS) represents the extent to which employees believe their organization values their contributions and well-being. While higher POS is associated with increased work engagement and learning motivation, the intricacies of this relationship, especially the mediation by Occupational Future Time Perspective (OFTP), are not well understood. METHODS: We conducted an online survey of 2,046 working individuals aged 20-69 to assess the relationships between POS and two outcome variables, Learning Goal Orientation (LGO), and work engagement with multiple regression analyses for all ages and in the younger age group (under 45). Then, the mediating effects of Focus on Opportunity (FOO) - a primary component of OFTP- on these relationships were examined. RESULTS: Of 2046 participants, 887 were younger than 45 years old. Younger participants, predominantly more educated and inclined towards professional jobs, exhibited higher LGO but lower work engagement compared to their older counterparts. POS showed positive correlations with LGO, and FOO significantly mediated the relationship, especially in the young group. Furthermore, a positive relationship between POS and work engagement was noted, with FOO as a partial mediator. CONCLUSIONS: POS correlates positively with both LGO and work engagement across various age demographics, with FOO critically mediating this relationship. To enhance employee engagement and learning motivation, organizations should emphasize bolstering both POS and FOO.

Association between workaholism and headaches causing presenteeism: A cross-sectional study in Japan.

OBJECTIVES: This study investigates the association between workaholism and headaches causing presenteeism among Japanese employees. METHODS: Used data from self-reporting questionnaire and annual health checkups. Workaholism was assessed using the Dutch Workaholic Scale and headaches causing presenteeism were identified as the symptom hindering work. We performed a logistic regression analysis adjusted for covariates. RESULTS: Among 5,802 respondents, 3.7% cited headaches as the symptom hindering work. We found an association between workaholism and such headaches (Odds ratios [OR]: 1.05, 95% confidence intervals [CI]: 1.03-1.08). Both working excessively (OR: 1.08, 95% CI: 1.04-1.12) and working compulsively (OR: 1.10, 95% CI: 1.05-1.15) subscales were also related. CONCLUSIONS: Workaholism may lead to productivity loss due to headaches, and addressing workaholism can prevent this loss. Combining health examination data with work hours data may enable the early detection of workaholism.

Relationship between diabetes treatment status and occupational accidents.

AIMS: To evaluate the relationship between diabetes treatment status and occupational accidents. METHODS: A cross-sectional study was conducted using an online questionnaire survey completed in March 2022 among workers aged 20 years or older. The questionnaire included questions about diabetes treatment status and occupational accidents. The association between the treatment status of diabetes and occupational accidents was examined using a logistic regression analysis. RESULTS: The study included 25,756 participants with no diabetes, 1,364 participants receiving diabetes treatment, 177 participants who had interrupted diabetes treatment, and 396 participants who needed diabetes treatment but had not seen a doctor. Compared with those with diabetes treatment, the odds ratio of occupational accidents among participants without diabetes was 0.40 (95% CI: 0.32-0.49), the odds ratio among participants with interrupted diabetes treatment was 4.15 (95% CI: 2.86-6.01), and the odds ratio among participants who needed diabetes treatment but had not seen a doctor was 1.25 (95% CI: 0.89-1.77). CONCLUSIONS: This study showed that diabetes treatment status was related to occupational accidents, and it may be important for workers with diabetes to be supported to balance their diabetes management and their work commitments.

Relationship Between Firm Size and Perceived Organizational Support and the Moderating Role of Supervisor Support: A Nationwide Cross-sectional Study.

OBJECTIVE: The study aims to explore the relationship between firm size and perceived organizational support (POS) and to investigate how supervisor support might moderate this relationship. METHODS: The study involved a cross-sectional questionnaire survey in Japan with 25,648 participants. Assessing POS through eight-question. Firm size was categorized into small (2-49 employees), medium (50-999), and large (1000 or more). Coefficients were estimated using multiple regression analyses. RESULTS: The analysis revealed that medium and large firms had lower POS compared to small firms, with the difference being more pronounced in medium firms. A positive interaction between firm size and supervisor support was observed for POS. CONCLUSIONS: This study found that although POS is more likely to be lower in medium and large firms than in small firms, the effect of supervisor support on improving POS is stronger.

Treatment status of psychiatric disorders and falls in the workplace among Japanese workers: a nationwide cross-sectional study.

OBJECTIVES: In Japan, the most common injury requiring sick leave is a fall in the workplace; therefore, it is very important to prevent falls. Most measures to prevent falls involve aspects of the workplace environment and safety. However, few measures consider the perspective of individual health. We investigated the relationship between psychiatric disorders and falls in the workplace and whether treatment status for a psychiatric disorder is associated with workplace falls. METHODS: We conducted a cross-sectional study among workers aged 20 years or older in Japan from February 28 to March 3, 2022. In total, the data of 27 693 participants were analyzed. We used a questionnaire to query participants' status of treatment for any psychiatric disorder and whether they had experienced a fall in the workplace. The association between treatment for a psychiatric disorder and workplace falls was examined using logistic regression analysis. RESULTS: Compared with participants receiving appropriate treatment for a psychiatric disorder, the odds ratio (OR) of a workplace fall was significantly lower among participants who did not require treatment for a psychiatric disorder, at 0.56 (95% CI: 0.47-0.66; P < .001); the OR of a workplace fall was significantly higher among participants whose treatment for a psychiatric disorder was interrupted, at 1.47 (95% CI: 1.21-1.78; P < .001), after adjusting for age, sex, household income, number of workplace employees, sleeping hours, exercise habits, and psychological distress. CONCLUSIONS: Our findings suggest that receiving appropriate treatment for psychiatric disorders may contribute to preventing falls in the workplace.

Health and productivity management initiatives to promote worker health and improve the workplace environment at the Fukushima Daiichi nuclear power plant.

BACKGROUND: Since the Fukushima Daiichi nuclear power plant (FDNPP) accident in 2011, measures have been taken to address occupational health risks, such as heat illness and infectious diseases, and ensure fitness for duty with the Tokyo Electric Power Company and its contractors. However, with the decommissioning operations set to span several decades and an aging workforce, there arose a need for proactive occupational health strategies that not only addressed these risks but also promoted employee health and created a comfortable work environment. With the Japanese government's promotion of health and productivity management (HPM) for corporations, an HPM-based initiative was launched at the FDNPP in 2019. CASE: We designed an HPM questionnaire tailored to the unique conditions at the FDNPP for contractors in 2019. Subsequently, we adjusted the questionnaire annually in light of evolving societal contexts and insights derived from contractors' feedback. This initiative also involved the annual recognition of outstanding contractors. These efforts have led to a steady increase in the number of contractors participating in the HPM survey, with respondents' scores continually improving. We also emphasized dissemination of HPM practices from contractors to their subcontractors due to the complex subcontracting structure at FDNPP, and our results showed that more contractors have been extending these efforts to their subcontractors. CONCLUSIONS: Our findings suggest that individual contractors are steadily enhancing their HPM efforts. We are committed to continually offering support to advance HPM throughout the FDNPP.

Association between exposure to technological advances in the workplace and work engagement: a prospective cohort study.

OBJECTIVES: The study objective was to measure the association between exposure to technological advances and work engagement, adjusting for personal and workplace factors. METHODS: We conducted a nationwide online longitudinal survey study in Japan. The sample was stratified to represent Japanese workforce conditions. Work engagement was measured using the Japanese version of the Utrecht Work Engagement Scale-9. Exposure to technological advances was measured using a single question with Likert scale responses. Industry characteristics that were more/less likely to be replaced by automation were also measured. Linear regression was used for statistical analysis. RESULTS: There were 16 629 participants. We found that exposure to technological advances was associated with work engagement after adjustment for age, sex, education, income, and industry characteristics. We observed a significant interaction between age and exposure to technological advances (coefficient 0.891, P < .001), and conducted an age-stratified linear regression analysis. The significant association between age and exposure to technological advances reduced as age increased, and disappeared after adjustment for baseline work engagement. CONCLUSIONS: Longitudinal observations showed that exposure to technological advances was not significantly associated with work engagement.

Work engagement among older workers: a systematic review.

OBJECTIVES: Given current labor force conditions, including population aging, keeping older workers engaged in work and motivated is important. Aging may alter the effects that psychological and environmental factors have on work engagement. We conducted a systematic review to understand the features of work engagement among older workers. METHODS: A systematic search was conducted in July 2022 using 4 databases. The review included relevant articles that focused on participants aged 40 years and older. RESULTS: Fifty articles were selected for our review, which were grouped into 5 categories: (1) studies examining the relationship between chronological age and work engagement, (2) studies investigating the moderating effects of age on the relationship between job-related psychological factors and work environment factors and work engagement, (3) studies comparing the relationship of job-related psychological factors and work environment factors with work engagement across different age groups, (4) studies exploring the relationship between work engagement and retirement intentions or continued employment beyond retirement age, and (5) other studies discussing work engagement in the context of older workers. Most articles focused on workers in Europe and the United States and used observational study designs. CONCLUSIONS: Work engagement increases with age, and is mainly mediated by increased emotional regulation. In addition, age moderates the relationships between various job-related psychological and work-environmental factors and work engagement. Work engagement is associated with working beyond retirement age. Organizations should understand the characteristics of work engagement among older workers and make age-conscious efforts to support them in adapting to social changes.

Sociodemographic factors affecting not receiving COVID-19 vaccine in Japan among people who originally intended to vaccinate: a prospective cohort study.

Objective: Vaccine hesitancy is a major issue for acquiring herd immunity. However, some individuals may go unvaccinated owing to inhibitory factors other than vaccine hesitancy. If there is even a small number of such people, support is needed for equitable vaccine distribution and acquiring herd immunity. We investigated sociodemographic factors that affected not undergoing COVID-19 vaccination in Japan among individuals who had strong intention to vaccinate before beginning the vaccination. Methods: We conducted this prospective cohort study on workers aged 20-65 years from December 2020 (baseline), to December 2021 using a self-administered questionnaire survey. There were 27,036 participants at baseline and 18,560 at follow-up. We included 6,955 participants who answered yes to this question at baseline: "Would you like to receive a COVID-19 vaccine as soon as it becomes available?" We applied multilevel logistic regression analyses to examine the association between sociodemographic factors and being unvaccinated at follow-up. Results: In all, 289 participants (4.2%) went unvaccinated. The odds ratios (ORs) for being unvaccinated were significantly higher for participants aged 30-39 and 40-49 than those aged 60-65 years. Being divorced, widowed, or single, having low income, and having COVID-19 infection experience also had higher ORs. Discussion: We found that some participants who initially had strong intention to vaccinate may have gone unvaccinated owing to vaccine side effects and the financial impact of absenteeism due to side effects. It is necessary to provide information repeatedly about the need for vaccination as well as social support to ensure that those who intend to vaccinate are able to do so when aiming for acquiring herd immunity through vaccination against COVID-19 as well as other potential infection pandemics in the future.

Protocol of a study to benchmark occupational health and safety in Japan: W2S-Ohpm study.

We aim to conduct a prospective cohort study to benchmark occupational health and safety in Japan. Here, we describe the detailed protocol for the baseline survey based on the Checklist for Reporting Results of Internet E-Surveys. We conducted the baseline survey for the prospective cohort study in 2022. Our target population was workers in Japan aged 20 years or older, who we sampled to be representative of the Japanese workforce, stratified by sex, age, and region. Among 59,272 registered monitors who answered the initial screening questions, 29,997 completed the survey. After excluding 2,304 invalid responses, we used 27,693 valid participants in our final analysis. The number and mean age of men were 15,201 (55%) and 46 years; those of women were 12,492 (45%) and 45 years. With respect to sex, age, and regional composition, our sampling was representative of Japan's working population. Our sampling for employment status and industry yielded almost the same proportions as a government-led representative sampling of workers in Japan.

The Japanese version of the occupational future time perspective scale: A validation study.

OBJECTIVE: This study aimed to develop and validate a Japanese version of the Occupational Future Time Perspective scale (OFTP-J) and assess its structural validity, construct validity, internal consistency, and test-retest reliability among Japanese workers. METHODS: The online survey was conducted with 2046 participants who met the eligibility criteria. The Japanese version of the OFTP scale was developed through translation and back-translation processes. Confirmatory factor analysis was performed to evaluate the structural validity. Pearson's correlations were computed to assess construct validity, and Cronbach's alpha coefficients were calculated to determine internal consistency. Test-retest reliability was examined using Cohen's weighted kappa coefficients and intraclass correlation coefficients. RESULTS: The confirmatory factor analysis supported an 8-item model with three factors (i.e., focus on opportunities, perceived remaining time, and focus on limitations) for the Japanese version of the OFTP scale. The scale demonstrated high internal consistency, with Cronbach's alpha coefficients ranging from 0.81 to 0.92. Construct validity was supported by significant correlations between the OFTP scale and its subscales, possible antecedents (age, self-rated health, and job control), and possible outcomes (learning goal orientation, job crafting, and work engagement). Test-retest reliability was confirmed with moderate agreement. CONCLUSIONS: The OFTP-J was found to be reliable and valid. It can be used to measure OFTP among Japanese workers and facilitate comparative research with the original English version. The OFTP-J provides valuable insights into the learning motivation and work engagement of the aging workforce.

Inequality in workplace support for various types of precarious workers compared with permanent workers in Japan: A cross-sectional study.

OBJECTIVES: The purpose of this study was to examine, by sex, whether precarious workers in Japan receive less support in the workplace than permanent workers. METHODS: We conducted a cross-sectional study using an online questionnaire in 2022. We stratified participants by sex and performed modified Poisson regression analysis. The outcomes were support from supervisors, co-workers, occupational health professionals, and no one. Adjusted prevalence ratios (aPR) were calculated for contract workers, part-time workers, and dispatched workers, using permanent workers as reference. RESULTS: This study had 21 047 participants. For men, 87.9% were permanent workers; for women, 50.7% were permanent workers and 37.3% were part-time workers. For workplace support, 47.5% of men and 45.2% of women selected superiors; 41.8% of men and 50.5% of women selected colleagues; 16.8% of men and 6.2% of women selected occupational health professionals. Female contract workers were less likely to receive support from their supervisors (aPR 0.88) or co-workers (aPR 0.89). Male part-time workers were less likely to be supported by their co-workers (aPR 0.86). Dispatched workers were less likely to be supported by their supervisors (men aPR 0.71, women aPR 0.84) and co-workers (men aPR 0.73, women aPR 0.77). Part-time and dispatched workers were less likely to receive support from occupational health professionals. CONCLUSIONS: Precarious workers could get less workplace support than permanent workers. This may contribute to occupational health problems with precarious workers.

Seeking Treatment Profile of Male Shift Workers With Hypertension and Diabetes.

OBJECTIVE: This study was identified seeking treatment for hypertension and diabetes among male shift workers. METHOD: This retrospective cohort study included nine large companies in Japan. Data were collected from health checkup, health insurance records, and self-administered questionnaires in 2017 and 2020. Data were analyzed using Kaplan-Meier curves and Cox regression. RESULT: Person-days shift workers and day workers seeking treatment for hypertension were 41,604 and 327,301, respectively and, for diabetes, were 7326 and 60,735, respectively. The log ranks were statistically significant. Shift workers were 46% and 56% less likely to seek treatment for hypertension and diabetes, respectively, than day workers were after adjustment for age, marital status, education level, and intention to modify lifestyle (model 2) ( P < 0.01). CONCLUSIONS: Male shift workers are less likely to seek treatment for hypertension and diabetes compared with day workers.

Workplace Social Support and Work Engagement Among Japanese Workers: A Nationwide Cross-sectional Study.

OBJECTIVES: We investigated the relationship between employees' perceptions of the number of sources of workplace social support and work engagement and whether each type of workplace social support is independently related to work engagement. METHODS: A cross-sectional study was conducted using a questionnaire survey in Japan. In total, 12,017 participants were analyzed. Participants were asked about 4 sources of workplace social support: supervisors, colleagues/subordinates, occupational health staff, and external counselors contracted by the workplace. Work engagement was measured using the 9-item Utrecht Work Engagement Scale. Coefficients were estimated using multiple regression analyses. RESULTS: The coefficient of work engagement increased as the number of sources of perceived workplace social support increased. Each support was also positively related to work engagement. CONCLUSIONS: Organizations should develop systems comprising various sources of workplace social support to increase employee work engagement.

Vallitalea longa sp. nov., an anaerobic bacterium isolated from marine sediment.

A novel bacterium, strain SH18-1T, was isolated from marine sediment collected near Sado Island in the Sea of Japan. This strain was strictly anaerobic, Gram-stain-negative, non-spore-forming, rod-shaped, motile, and mesophilic. It grew at 15-40 °C (optimum, 30-35 °C), at a NaCl concentration of 0.2-5.0 % (w/v; optimum, 1.5-2.5 %), and at pH 5.5-8.5 (optimum, pH 7.0). Results of 16S rRNA gene phylogenetic analysis showed a similarity value of 97.49 % between strain SH18-1T and Vallitalea guaymasensis Ra1766G1T, which was the most closely related species. The genome size of strain SH18-1T was 5.71 Mb and its G+C content was 30.2 mol%. Genome sequence analyses for comparison between strain SH18-1T and V. guaymasensis Ra1766G1T showed values lower than the threshold for species demarcation determined using the Genome-to-Genome Distance Calculator and the Average Nucleotide Identity Calculator. Elemental sulphur, sulphate, thiosulphate, sulphite, fumarate, nitrate, and nitrite were not used as terminal electron acceptors. The major fatty acids in strain SH18-1T were iso-C15 : 0, anteiso-C15 : 0, and C16 : 0, and the detected polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphoglycolipid, glycolipid, three unidentified phospholipids, and one unidentified polar lipid. From these results, strain SH18-1T (=NBRC 115488T=DSM 114058T) is suggested to represent a novel species of the genus Vallitalea and the name Vallitalea longa sp. nov. is proposed.

Physiological and genomic analyses of cobalamin (vitamin B12)-auxotrophy of Lysobacter auxotrophicus sp. nov., a methionine-auxotrophic chitinolytic bacterium isolated from chitin-treated soil.

A novel bacterium, designated 5-21aT, isolated from chitin-treated upland soil, exhibits methionine (Met) auxotrophy and chitinolytic activity. A physiological experiment revealed the cobalamin (synonym, vitamin B12)(Cbl)-auxotrophic property of strain 5-21aT. The newly determined complete genomic sequence indicated that strain 5-21aT possesses only the putative gene for Cbl-dependent Met synthase (MetH) and lacks that for the Cbl-independent one (MetE), which implies the requirement of Cbl for Met-synthesis in strain 5-21aT. The set of genes for the upstream (corrin ring synthesis) pathway of Cbl synthesis is absent in the genome of strain 5-21aT, which explains the Cbl-auxotrophy of 5-21aT. This strain was characterized via a polyphasic approach to determine its taxonomic position. The nucleotide sequences of two copies of the 16S rRNA gene of strain 5-21aT indicated the highest similarities to Lysobacter soli DCY21T(99.8 and 99.9 %) and Lysobacter panacisoli CJ29T(98.7 and 98.8 %, respectively), whose Cbl-auxotrophic properties were revealed in this study. The principal respiratory quinone was Q-8. The predominant cellular fatty acids were iso-C15:0, iso-C16:0 and iso-C17:1 ω9c. The complete genome sequence of strain 5-21aT revealed that the genome size was 4 155 451 bp long and the G+C content was 67.87 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain 5-21aT and its most closely phylogenetic relative L. soli DCY21T were 88.8 and 36.5%, respectively. Based on genomic, chemotaxonomic, phenotypic and phylogenetic data, strain 5-21aT represents a novel species in the genus Lysobacter, for which the name Lyobacter auxotrophicus sp. nov. is proposed. The type strain is 5-21aT (=NBRC 115507T=LMG 32660T).

Supervisors' Work Engagement Is Associated With Interactivity and Carefulness in Supporting Subordinates: A Cross-sectional Study Using Text Mining in Japan.

OBJECTIVE: This study aimed to structure supervisory support and clarify the relationship between supervisors' work engagement and support for their subordinates. METHODS: We conducted a cross-sectional study in a manufacturing company using a questionnaire survey. Supervisors provided open-ended responses regarding the provision of support for their subordinates. Using text mining, we structured these descriptions into multiple categories, assigned words to them, and analyzed frequently mentioned categories by the level of work engagement. RESULTS: We obtained responses from 729 participants that included 13,968 words. We structured supervisory support by three categories (contents, direction, and attitude toward support) and 11 subcategories. As supervisors' work engagement increased, the rates of mentioning information retrieval, information transmission, and carefulness increased. CONCLUSIONS: Supervisors with work engagement could communicate with each other and be careful in providing support to their subordinates.

Personal infection prevention behaviors and campaign to encourage travel during COVID-19: A cross-sectional study.

Introduction: The Go To Travel campaign in Japan was launched to subsidize travel and accommodation costs for tourists through vouchers that could be used at domestic destinations. Infection prevention behavior can lead to refraining from travel owing to infection concerns; conversely, taking preventive action can promote travel. There is a lack of information about the association between infection prevention behaviors and desire to travel. During a pandemic of infection, there is the difficult challenge of balancing the promotion of infection prevention behavior with economic revitalization. Thus, we examined the relationship between personal infection prevention behaviors and using Go To Travel. Methods: We conducted a cross-sectional study of 26,637 workers who responded to a large-scale questionnaire survey about COVID-19 in Japan. We built multilevel logistic regression models adjusted for confounders to assess the association between each personal infection prevention behavior and using Go To Travel. We analyzed the seven infection prevention behavior individually: wearing a mask when among other people; disinfecting hands with alcohol before going indoors; washing hands after using the toilet; gargling upon returning home; opening a window to ventilate a room; carrying an alcohol sanitizer; and disinfecting hands after touching objects outside. Results: Among the 26,637 participants, 7,959 (30%) used Go To Travel. For "wearing a mask in the presence of others" and "washing hands after using the toilet," the majority of respondents answered "almost always: 86.5 and 85.6% respectively. Action "carrying alcohol disinfectant" was the least implemented, with 36.9% of respondents saying "almost never." Two of the seven preventive behaviors ("disinfecting hands with alcohol before going indoors" and "carrying alcohol disinfectant") were positively related to using Go To Travel, that is, the more of these actions they took, the more they used Go To Travel (p for trend <0.001). Conclusions: To balance pandemic preparedness with economic preparedness, it is also necessary to promote travel when the infection situation is calm. However, since human mobility can be a factor that exacerbates the infection situation, it is necessary to promote more infection prevention behaviors among individuals. We confirmed that Go To Travel users were basically doing a good infection prevention behaviors, but they tended not to wash their hands after touching things or carry alcohol sanitizer. It is necessary to encourage these measures to be taken when traveling.

Intraoperative Acoustic Evaluation of Living Human Knee Cartilage-Comparison with Respect to Cartilage Degeneration and Aging.

OBJECTIVE: The objective of the study was to evaluate the mechanical properties of living human knee cartilage using our ultrasonic device, and to compare the measurements with respect to cartilage degeneration and aging. DESIGN: A total of 95 knees which had undergone arthroscopic knee surgery, from 88 patients, were included in the study, with informed consent. All procedures were reviewed and approved by the ethical committee of our hospital. In the study group, there were 41 men, 47 women, 39 right knees, and 56 left knees. The conditions primarily included knee osteoarthritis and anterior cruciate ligament rupture. The mean operative age was 44.1 years old (range = 10-83). We compared mechanical properties of the knee cartilage with respect to aging and gender, in comparison with normal cartilage. A P value of <0.05 represented statistical significance. RESULTS: In the context of the International Cartilage Repair Society (ICRS) classification of cartilage degeneration (grade 0-3), the signal intensity in grade 0 was significantly larger than that in grade 1, 2, or 3. The thickness in grade 0 was significantly higher than that in grade 1, 2, or 3. Normal cartilage in older women had the lowest signal intensity and the least cartilage thickness among all the groups. CONCLUSION: The ultrasonic system we developed was able to detect early degenerative changes in living cartilage in knees. The lowest signal intensity and least cartilage thickness in normal cartilage among older women were correlated to a large prevalence of knee osteoarthritis in women. LEVEL OF EVIDENCE: Level IV, case series.

Relationship between haematological data and radiation doses of TEPCO workers before and after the FDNNP accident.

We evaluated the correlation between radiation dose and the medical examination data of Tokyo Electric Power Company Holdings, Inc (TEPCO) employees working during the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011. This study included 2164 male TEPCO workers who received periodic medical examinations from March 2006 to January 2013. First, we conducted log-linear regression analyses using the haematological data of 585 emergency workers and confounding factors to examine the effect of internal radiation exposure in March 2011. Since external radiation exposure was a major influence, we then evaluated the correlation between both internal and external radiation dose and the haematological data of 1801 emergency workers and confounding factors before and after the accident. Among 585 workers, internal radiation exposure in March 2011 alone was mainly due to thyroid doses (0.1-10 Gy) but not to bone marrow (BM) doses (0.01-1 mGy). Compared to before and after the accident, we found that the levels of monocytes, eosinophils (Eos) and basophils increased slightly, whereas the frequency of smoking and alcohol consumption decreased substantially. External dose exposure was positively correlated with haemoglobin (Hb), red blood cell and Eos but negatively correlated with age, haematocrit and frequency of alcohol consumption. Among these variables, Hb exhibited the strongest correlation with external dose. Regarding the correlation with Hb, although there is a possibility that confounding factors other than exposure were not evaluated, our findings on emergency workers can serve as a reference for the evaluation of health conditions during the emergency period of future nuclear-related accidents.