Key issues in Japan's public health centers to prepare for future pandemics: a text mining study using a topic model.

BACKGROUND: In Japan, over 450 public health centers played a central role in the operation of the local public health system in response to the COVID-19 pandemic. This study aimed to identify key issues for improving the system for public health centers for future pandemics. METHODS: We conducted a cross-sectional study using an online questionnaire. The respondents were first line workers in public health centers or local governments during the pandemic. We solicited open-ended responses concerning improvements needed for future pandemics. Issues were identified from these descriptions using morphological analysis and a topic model with KHcoder3.0. The number of topics was estimated using Perplexity as a measure, and Latent Dirichlet Allocation for meaning identification. RESULTS: We received open-ended responses from 784 (48.6%) of the 1,612 survey respondents, which included 111 physicians, 330 nurses, and 172 administrative staff. Morphological analysis processed these descriptions into 36,632 words. The topic model summarized them into eight issues: 1) establishment of a crisis management system, 2) division of functions among public health centers, prefectures, and medical institutions, 3) clear role distribution in public health center staff, 4) training of specialists, 5) information sharing system (information about infectious diseases and government policies), 6) response to excessive workload (support from other local governments, cooperation within public health centers, and outsourcing), 7) streamlining operations, and 8) balance with regular duties. CONCLUSIONS: This study identified key issues that need to be addressed to prepare Japan's public health centers for future pandemics. These findings are vital for discussions aimed at strengthening the public health system based on experiences from the COVID-19 pandemic.

Evaluation of workplace infection prevention and control measures for COVID-19: A prospective cohort study in Japan.

Background: Encouraging the implementation of infection prevention and control (IPC) measures has been necessary to prevent workplace infections caused by the coronavirus disease 2019 (COVID-19). However, the effectiveness of these measures in reducing infections has not been thoroughly evaluated. We evaluated employees' COVID-19 infection rates in relation to the implementation of IPC measures at their workplaces to identify effective workplace measures. Methods: This prospective cohort study was conducted between December 2020 and December 2021 using Internet-based self-assessment questionnaires, with 11,982 participants included from the baseline. To estimate whether implementing workplace IPC measures was associated with COVID-19 incidence rates among participants, we estimated multivariate-adjusted relative risk (RR) using a log-binomial model. Results: After adjusting for sex, age, education, household members, occupation-related factors, and personal preventive behaviors, requesting ill employees to refrain from going to work showed significantly lower COVID-19 infection rates than not requesting it (RR: 0.56, 95% CI: 0.34-0.91, p = 0.019). Conclusions: Employees restricted from reporting to work when ill had significantly lower COVID-19 infection rates than those who did not follow this measure. The results indicated that not coming to work when ill was effective in reducing COVID-19 infections at the workplace. We suggest that companies proactively adopt this policy and encourage their employees to comply with it.

Health and Work Performance Consequences of Working From Home Environment: A Nationwide Prospective Cohort Study in Japan.

OBJECTIVES: The physical work environment while working from home (WFH) is a key component of WFH, which, if inadequate, can impair workers' health and work functioning. We investigated environmental factors in WFH and worsening of work functioning. METHODS: A 1-year prospective cohort study was conducted involving 2530 Japanese workers who worked from home. Environment while WFH was assessed using binary subjective assessments based on existing guidelines. Existence of impaired work function was assessed using the Work Functioning Impairment Scale. We performed multilevel logistic regression analysis nested in the prefecture of residence. RESULTS: Lack of room/space for concentration, lack of enough light and foot space, inadequate temperature and humidity, and use of a sitting table were associated with work functioning impairment. CONCLUSIONS: An inappropriate environment while WFH can have a negative impact on workers' health.

Impact of COVID-19 Infection on Work Functioning in Japanese Workers: A Prospective Cohort Study.

Background: The impact of COVID-19 infection on workers' work function persists even after the acute phase of the infection. We studied this phenomenon in Japanese workers. Methods: We conducted a one-year prospective cohort study online, starting with a baseline survey in December 2020. We tracked workers without baseline work functioning impairment and incorporated data from 14,421 eligible individuals into the analysis. We estimated the incidence rate ratio for new onset of work functioning impairment due to COVID-19 infection during follow-up, using mixed-effects Poisson regression analysis with robust variance. Results: Participants reporting infection between January and December 2021 showed a significantly higher incidence of new work functioning impairment (adjusted incidence rate ratio: 2.18, 95% confidence interval: 1.75-2.71, p < 0.001). The formality of the recuperation environment correlated with a higher risk of work functioning deterioration in infected individuals (p for trend <0.001). Conclusion: COVID-19-infected workers may continue to experience work difficulties due to persistent, post-acute infection symptoms. Companies and society must urgently provide rehabilitation and social support for people with persistent symptoms, recognizing that COVID-19 is not just a transient acute infection.

What is the role of occupational physicians in the workplace during the COVID-19 pandemic in Japan? A qualitative interview study.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has had various impacts on businesses and workers worldwide. The spread of infection has been reported through cluster outbreaks in the workplace, and World Health Organization has emphasized workplace infection control measures. Occupational physicians (OPs) are expected to actively support employers' efforts to minimize the damage of the pandemic. However, there is little research on the role of these specialists during a pandemic. Clarification of the contributions of OPs to health and safety at the workplace in the COVID-19 pandemic would be beneficial to ensure that OPs can be effectively deployed in the next pandemic. METHODS: We employed semi-structured interviews and qualitative content analysis of the interview transcripts. Twenty OPs were selected as priority candidates from among 600 OPs certificated of the JSOH, and thirteen who met the eligibility criteria agreed to participate. The online interviews were conducted in November and December 2020 with thirteen OPs. We extracted meaning units (MUs) from interview transcripts according to the research question: "What was the role of OP in the COVID-19 pandemic?" and condensed and abstracted them into codes and categorized them. Validity was confirmed by additional 5 OPs interviews. RESULTS: A total of 503 MUs were extracted from the transcripts. These were abstracted into 10 sub-categories and two categories. Categories 1 and 2 dealt with "Role in confronting the direct effects of the pandemic" and "Role in confronting the indirect effects of the pandemic" and accounted for 434 (86.3%) and 69 (13.7%) MUs, respectively. These results were validated by another 5 interviews. CONCLUSION: This study identified the role of OPs in Japan in the COVID-19 pandemic. The results showed that they made a wide range of contributions to the direct and indirect effects of the pandemic. We hope our findings will help OPs during future pandemics or other long-term emergency situations.

A prospective cohort study of presenteeism and poverty among Japanese workers during the COVID-19 pandemic.

OBJECTIVES: This study examined the association of presenteeism with experiences of poverty among Japanese workers during the COVID-19 pandemic. METHODS: A prospective cohort study of Japanese workers was conducted using an Internet monitoring survey. The baseline survey was conducted in December 2020, and a follow-up survey in December 2021. Of the 27 036 workers who participated, 18 560 (68.7%) completed the follow-up survey. The 11 081 who reported that they were not in financial difficulty in the baseline survey were included in the analysis. The degree of work functioning impairment was assessed at baseline using the Work Functioning Impairment Scale (WFun). Households' experience of not being able to pay for food and clothing was identified in the follow-up survey. The odds ratios (ORs) of presenteeism determined by WFun associated with poverty were estimated using a multilevel logistic model. The multivariate model included age, sex, marital status, job type, income, education, smoking, alcohol consumption, number of employees in the workplace, and the incidence rate of COVID-19 by prefecture at baseline. RESULTS: In the multivariate model, the odds ratio of experiencing food insecurity increased with high WFun score: compared with WFun scores of 13 or less, the OR was 1.87 (95% CI: 1.43-2.43, P < .001) for WFun scores of 14 or more and 3.26 (95% CI: 2.58-4.12, P < .001) for WFun scores of 21 or more. CONCLUSIONS: In addition to labor productivity, the adverse effects of presenteeism on social security-related concerns such as poverty require further attention.

Estimation of the Thyroid Equivalent Doses to Residents in Areas Affected by the 2011 Fukushima Nuclear Disaster Due to Inhalation of 131I Based on Their Behavioral Data and the Latest Atmospheric Transport and Dispersion Model Simulation.

ABSTRACT: It has been challenging to obtain reliable estimates of thyroid equivalent doses (TEDs) to residents involved in the 11 March 2011 Fukushima Daiichi Nuclear Power Plant (FDNPP) accident because of the shortage of direct human measurements associated with 131I, the largest contributor to the dose of concern. The present study attempted to perform the estimation of the TEDs by inhalation of 131I to residents from Namie-town, one of the most radiologically-affected municipalities, by means of the latest atmospheric transport and dispersion model (ATDM) simulations with the Worldwide version of System for Prediction of Environmental Emergency Dose Information (WSPEEDI) ver. 2, coupled with personal behavioral data containing the history of the whereabouts of individuals shortly after the accident. We analyzed 1,637 residents who underwent direct measurements with whole-body counters several months after the accident and provided their personal behavioral data. We divided the subjects into two groups based on whether the distances between their locations and the FDNPP were >20 km as of 15:00 on 12 March in relation to the timepoint of the hydrogen explosion at the Unit 1 Reactor building. As a result, the 90th percentile TEDs of the 1,249 prompt evacuees and 388 late evacuees were 3.9 mSv (adult)-6.8 mSv (10-y-old) and 24.1 mSv (adult)-35.6 mSv (5-y-old), respectively, excluding 16 persons whose TEDs exceeded 50 mSv. The 90th percentile (median) TEDs to 1-y-old children (not included in the subjects) for the prompt and late evacuation groups were 8.1 (1.0) mSv and 36.3 (19.7) mSv, respectively. Additionally, this study provided the evidence to support the view that the explosive event at the Unit 1 Reactor building on the afternoon of 12 March 2011 could have caused the critical group among Namie-town's residents, whereas the largest release event on 15 March gave relatively small doses to the residents because their exposure took place mostly at sites that were distant from the FDNPP. However, the present dose estimation has potentially large uncertainty at the individual level; further validations are thus necessary.

Relationship Between Support for Workers With Illness and Work Functioning Impairment in Japan During the COVID-19 Pandemic.

OBJECTIVE: This study examined the relationship between job accommodations for workers with poor health and work functioning impairment during the COVID-19 pandemic. METHODS: An internet survey was conducted in December 2020. We included 24,429 subjects for analysis. One question was used to determine whether subjects needed job accommodations from their company to continue working in their current health condition. The odds ratios (ORs) of the necessity of job accommodations for sick workers associated with work functioning impairment were estimated using multilevel logistic regression analysis. RESULTS: The OR of work functioning impairment among sick workers not receiving job accommodations was 5.75 (95% confidence interval (CI): 5.34 to 6.20, P  < 0.001) and those receiving job accommodations was 1.88 (95% CI: 1.69 to 2.08, P  < 0.001) compared to healthy workers. CONCLUSIONS: This study suggests that providing job accommodations to workers with poor health may improve their work functioning impairment.

Relationship between support for workers with illness and work functioning impairment in Japan during the COVID-19 pandemic

ObjectiveThis study examined the relationship between job accommodations for workers with poor health and work functioning impairment during the COVID-19 pandemic. MethodsAn internet survey was conducted in December 2020. We included 24,429 subjects for analysis. One question was used to determine whether subjects needed job accommodations from their company to continue working in their current health condition. The odds ratios (ORs) of the necessity of job accommodations for sick workers associated with work functioning impairment were estimated using multilevel logistic regression analysis. ResultsThe OR of work functioning impairment among sick workers not receiving job accommodations was 5.75 (95% confidence interval (CI) 5.34-6.20, p<0.001) and those receiving job accommodations was 1.88 (95% CI 1.69-2.08, p<0.001) compared to healthy workers. ConclusionsThis study suggests that providing job accommodations to workers with poor health may improve their work functioning impairment.

PROBABILISTIC ANALYSES OF 131I THYROID ACTIVITY IN PERSONS WITH SURFACE CONTAMINATION IN DIRECT MEASUREMENT WITH A STANDING-TYPE WHOLE-BODY COUNTER AS AN EMERGENCY RESPONSE IN A RADIOLOGICAL INCIDENT.

The authors' previous study suggested that a simple standing-type whole-body counter called FASTSCAN (Canberra, Meriden, CT, USA), widely installed throughout Japan after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in March 2011, could be used for thyroid measurements in internal dose assessment after a future radiological incident accompanied by the release of 131I into the environment. The present study performed Monte-Carlo simulations using a computational human phantom with several patterns of body surface contamination and used the results to formulate a method for probabilistic analyses of 131I thyroid activity in persons with surface contamination. The major advantage of this method is that the upper limit of the thyroid activity can be determined from the relative frequency distribution without identifying where body surface contamination remains. Therefore, this method is especially effective for use in the early phase of a radiological incident when time and resources are limited, making it difficult to physically remove all body surface contamination for the purpose of gaining more accurate population-wide thyroid screening measurements. As a case study of the FDNPP accident, the proposed method was applied to the results of in vivo measurements for a male subject with body surface contamination. In comparing the probabilistic analyses before and after removal of the subject's contaminated work clothes, the uncertainty of the relative frequency distribution of 131I thyroid activity was reduced by their removal. Therefore, in terms of accurate estimates and avoidance of radiation exposure from their contaminated clothes, efforts to remove body surface contamination still should be made as much as possible in the chaotic situation of the early phase of a radiological incident.

Estimation of the Early Cs-137 Intake of Evacuees from Areas Affected by the 2011 Fukushima Daiichi Nuclear Power Plant Accident Based on Personal Behavioral Data and the Latest Atmospheric Transport and Dispersion Model Simulation.

ABSTRACT: More than 9 y have passed since the 2011 nuclear disaster in Fukushima Prefecture, Japan. During this period, much effort has been spent on the dose reconstruction for Fukushima residents; however, the estimation of the internal dose due to the potential intake of the short-lived radionuclides (mainly iodine-131) has been challenging because of the lack of direct human measurements at the early phase of the accident. Our previous study revealed that the residual cesium body contents observed in delayed whole-body counter (WBC) measurements of residents from Namie-town, one of the most affected municipalities, varied greatly with the timepoint of their evacuations on 12 March 2011 when the first explosive event occurred at the accident site; i.e., the late evacuees had much higher residual cesium body contents compared to the prompt evacuees. The present study thus aimed to clarify this finding by reproducing the exposure situation based on the evacuees' personal behavioral data in combination with the latest atmospheric transport and dispersion model (ATDM) simulation for 356 selected subjects in adult and 15-y (13-17 y) age groups. The results demonstrated that the ATDM simulation-based method could reasonably reproduce the subjects' exposure situation, supporting the previous finding. However, the residual cesium-137 body contents calculated by this method were only 10%-20% of those in the subjects' WBC measurements. This large discrepancy was considered to be caused by both the present method's underestimation and the overestimation of the subjects' early intake in the WBC measurements due to a conservative intake scenario not assuming potential additional intake. Additional studies are needed to further clarify the reasons for the discrepancy and to evaluate the magnitude of the inhalation dose in the accident.

Risk prediction for new-onset atrial fibrillation using the Minnesota code electrocardiography classification system.

BACKGROUND: Few risk models are available to predict future onset of atrial fibrillation (AF) in workers. We aimed to develop risk prediction models for new-onset AF, using annual health checkup (HC) data with electrocardiogram findings. METHODS AND RESULTS: We retrospectively included 56,288 factory or office workers (mean age = 51.5 years, 33.0% women) who underwent a HC at a medical center and fulfilled the following criteria; age ≥ 40 years, no history of AF, and greater than 1 annual follow-up HC in 2013-2016. Using Cox models with the Akaike information criterion, we developed and compared prediction models for new-onset AF with and without the Minnesota code information. We externally validated the discrimination accuracy of the models in a general Japanese population cohort, the Hisayama cohort. During the median 3.0-year follow-up, 209 (0.37%) workers developed AF. Age, sex, waist circumference, blood pressure, LDL cholesterol, and γ-GTP were associated with new-onset of AF. Using the Minnesota code information, the AUC significantly improved from 0.82 to 0.84 in the derivation cohort and numerically improved from 0.78 to 0.79 in the validation cohort, and from 0.77 to 0.79 in the Hisayama cohort. The NRI and IDI significantly improved in all and male subjects in both the derivation and validation cohorts, and in female subjects in both the validation and the Hisayama cohorts. CONCLUSIONS: We developed useful risk model with Minnesota code information for predicting new-onset AF from large worker population validated in the original and external cohorts, although study interpretation is limited by small improvement of AUC.

Intake Ratio of 131I to 137CS Derived from Thyroid and Whole-body Doses to Residents of Iwaki City in Japan's Fukushima Prefecture.

ABSTRACT: It is very important to determine the precise internal thyroid doses of Fukushima residents involved in the 2011 Fukushima nuclear disaster, particularly for small children. This has been challenging due to the lack of direct human measurements to identify 131I, the biggest contributor to the thyroid doses. We previously used a dataset of late whole-body counter (WBC) measurements targeting 134Cs and 137Cs for the thyroid dose estimation in comparison with the intake ratios of 131I to 137Cs (or 134Cs) derived from thyroid and whole-body doses individually obtained from different subject groups, assuming simultaneous acute intake via inhalation. Herein, we applied the same method to the doses of residents in Iwaki city (located south of the Fukushima Daiichi Nuclear Power Plant) with a relatively high activity ratio (131I/137Cs) for the ground deposition density. Our analyses revealed that the intake ratio (131I/137Cs) for the Iwaki residents was 4.2-4.3, which is relatively consistent with the values obtained in other studies (average 3.0-5.0). No regional difference in the intake ratios from other areas was observed, but further studies are required to determine the accurate intake ratio in the early phase of the accident, in particular focusing on the reasonable interpretation of results of the late WBC measurements to evaluate the actual Cs intake.

Difference in the Cesium Body Contents of Affected Area Residents Depending on the Evacuation Timepoint Following the 2011 Fukushima Nuclear Disaster.

Estimating the internal thyroid dose received by residents involved in the 2011 Fukushima Daiichi Nuclear Power Plant (FDNPP) accident has been a challenging task because of the shortage of direct human measurements related to the largest contributing radioisotope to the dose, I. In a previous dose estimation, we used the results of whole-body counter (WBC) measurements targeting Cs and Cs, based on the assumption that these radioisotopes were incorporated at the same time as I in the early phase of the accident. The main purpose of this study was to clarify whether the trace of the early intake remained in the WBC measurements that were started several months after the accident. In the present work, WBC data of 1,639 persons from Namie town, one of the heavily contaminated municipalities, were analyzed together with their evacuation behavior data. The results demonstrated that the cesium detection rate in the WBC results was several times higher in the late evacuees [who evacuated outside the 20-km radius of the FDNPP at 3:00 p.m. (Japanese Local Time) on 12 March or later] compared to the prompt evacuees (who evacuated before 3:00 p.m. on 12 March). Among the adults, the cesium detection rates (and the 90th percentile values of the Cs intake) of the prompt and late evacuees were about 20% (5.4 × 10 Bq) and 60% (1.6 × 10 Bq), respectively. Approximately 20% of the individuals analyzed were categorized as late evacuees. These differences in cesium would be caused by exposure to the radioactive plume in the afternoon on 12 March, which was likely to influence the late evacuees. On the other hand, the intake on 15 March, when the largest release event occurred, was expected to be relatively small for Namie town's residents. In conclusion, the trace of the early intake remained in the WBC measurements, although this would not necessarily be true for all subjects. The results obtained from this study would provide useful information for the reconstruction of the early internal thyroid doses from radioiodine in the future.

Reassessment of Internal Thyroid Doses to 1,080 Children Examined in a Screening Survey after the 2011 Fukushima Nuclear Disaster.

The dose reconstruction of populations potentially affected by the accident at the Fukushima Daiichi nuclear power plant in March 2011 is of great importance. However, it has been difficult to assess internal thyroid doses to Fukushima residents (mainly from their intake of I) due to the lack of direct measurements. For the residents, only about 1,300 data points related to I are available, and 1,080 of the data points were obtained from the screening campaign that was conducted by the Nuclear Emergency Response Local Headquarters at the end of March 2011 in Kawamata Town, Iwaki City, and Iitate Village. Here, we reassessed thyroid doses to 1,080 subjects aged ≤15 y old using new age-specific conversion factors to determine I thyroid contents from net signals of the devices used, with consideration for the possible uncertainty related to the measurements. The results demonstrated that thyroid equivalent doses to the subjects were <30 mSv (excluding outliers). We also demonstrate dose distributions of each age group from the above three municipalities and those of subjects from Minamisoma City and Fukushima City. One of the findings was that the I intake was similar among different age groups in each of the three municipalities. This was consistent with the assumption that ingestion was a dominant route of intake rather than inhalation. The range of thyroid doses to Iitate Village residents was similar to that to Iwaki City residents even though the I concentration in tap water was much higher in Iitate Village than Iwaki City. The range of thyroid doses to Minamisoma City residents was similar to that to Iitate Village and Iwaki City residents, and the range for Fukushima City residents was smallest among the five municipalities. Since the major route of intake has remained unclear, this paper presents the plausible upper and lower thyroid doses, between which the actual doses are thought to mostly exist, based on two intake scenarios: single inhalation and repeated ingestion. Further research is thus necessary to extract useful evidence from the individual evacuation behaviors for improving the present internal thyroid dose assessment.

DEVELOPMENT OF A PELTIER TYPE CLOUD CHAMBER WITH WIDE VIEW FIELD.

Cloud chamber contributes to radiation education by facilitating observation of particle tracks formed by radiation. Peltier-based chamber achieves cooling without the need for dry ice,. we developed a cloud chamber based on peltier thermoelectric modules and has a multilayered heat insulation system to maintain a stable cool environment. It produces sharp particle tracks without requiring a dark room for observing the tracks. Its large top window (diameter of 12.5 cm) provides a relatively wider observation field capable of accommodating five to six students at a time.

PRELIMINARY TECHNICAL DISCUSSION ON A NEW RADON AND ITS PROGENY CONTINUOUS MONITOR USING TWO-FILTER METHOD.

Focusing on the scalability of Two-Filter Method, we started to develop a monitor for the concentration of radon and its progeny. In this study, we investigated the influence of a high-humidity environment on measuring radon concentration, and the influence of the decay chamber of the monitor on the measurement. In the high-humidity test, the conversion factor of (Bqm-3)/(cpm) tends to raise with increasing humidity. On the measurement of radon progeny, existence of the decay chamber of the monitor makes measurement sensitivity lower under environments of little aerosols. Radon concentration measurement by the developed monitor could be influenced by environmental humidity, and that counting loss could occur due to deposition of radon progeny inside of the decay chamber. Correction relating these would be needed based on the data of calibration tests.

Respiratory resistance among adults in a population-based cohort study in Northern Japan.

BACKGROUND: Forced oscillation technique (FOT) is a noninvasive method used to measure respiratory system resistance (Rrs) and reactance (Xrs) during quiet breathing, which has been extensively studied in clinical settings. The distribution of measured FOT values was previously assessed in a community-based cohort study. In this study, we aimed to confirm the distribution of measured FOT values in a different cohort in order to investigate the relationship between these values and patient clinical and biological data. METHODS: We reviewed FOT data and relevant patient clinical and biological information collected from the Community-Based Cohort Study (CommCohort Study), carried out between 2013 to 2016 as a part of the Tohoku Medical Megabank project (TMM). In total, 16,231 adults were enrolled in the study (Male/Female: 4886/11,345). RESULTS: Significant gender differences were observed in distributions of Rrs and Xrs values at 5 Hz (termed R5 and X5, respectively). R5 values in males were lower than those in females, while X5 values in males were slightly less negative. High R5 values were strongly associated with high BMI, short height, smoking status in males, high serum IgE level, and high peripheral blood eosinophil count. CONCLUSION: The present distribution values and their relation to clinical and biological data should provide useful insights for clinical settings and serve as a helpful guide in implementing FOT. Forced oscillation technique, respiratory system resistance, respiratory system reactance, gender difference, obesity.