The aim of the present study was to reveal characteristic patterns of fatigue feelings on consecutive night shifts by a questionnaire for work-related fatigue feelings “Jikaku-sho shirabe”. Ten healthy males (Mean ± SD: 22.9 ± 3.2 years old) participated in the experiment. Participants were required to attend the laboratory for nine consecutive nights under the following conditions: adaptation sleep (0:00-7:00), simulated day shift (10:00-18:00), baseline sleep (0:00-7:00), directly followed by four simulated night shifts (22:00-9:00) and the subsequent daytime sleep (12:00-18:00), three recovery nights (0:00-7:00) and two simulated day shifts (10:00-18:00). During each simulated shift, participants were required to complete an English transcription task (30 min), a performance test battery (20 min) and break (10min) every hour. Fatigue feelings were evaluated by “Jikaku-sho shirabe”, which was proposed by the Industrial Fatigue Research Committee of the Japan Occupational Health in 2002. This questionnaire consists of 25 subjective fatigue symptom items that are categorized into 5 factors: feeling of drowsiness (Factor I), feeling of instability (Factor II), feeling of uneasiness (Factor III), feeling of local pain or dullness (Factor IV), and feeling of eyestrain (Factor V). For each item, respondents are requested to estimate the intensity of the feelings as “Disagree at all,” “Agree scarcely,” “Agree slightly,” “Agree considerably,” and “Agree strongly.” These five intensities were assigned scores of 1 to 5 points, respectively. Hierarchical cluster analysis suggested that there might be at least three variation patterns of fatigue feelings on the consecutive night shifts (i.e. Clusters A, B and C). On the basis of subjective fatigue symptom items of each cluster, the patterns in Clusters A, B and C might reflect the loads of the reticular activating system, musculoskeletal and central nervous systems, and limbic system, respectively. For Clusters A and C, significant improvements were observed with the increase of the number of night shifts (F(11,99)=3.07, p<0.01, F(11,99)=3.37, p<0.01, respectively). On the other hand, Cluster B deteriorated with the progress of the simulated night shifts. Taken together, we suggest that the characteristic patterns of fatigue feelings on consecutive night shifts might represent dissociation among the feelings induced by several loads.
(San Ei Shi 2008; 50: 133-144)

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In June 2005 the press reported that many former employees of a company which used asbestos, and individuals who lived near the company’s factory, had been diagnosed with mesothelioma. This finding triggered concern and alarm in Japan. In response, many “asbestos clinics” were formed, and recognized medical institutions began to implement asbestos-related health examinations. We conducted a nationwide questionnaire survey to evaluate the activities in, and the challenges for, these medical institutions. We received 137 valid responses, more than half of which were from clinics and hospital-based “asbestos clinics” instigated after the “Kubota shock.” Among the asbestos exposure history interviewing practices, job histories of the interviewee were prioritized, over place of residence, and possible exposure of family members. Standard questionnaires were utilized by over 70% of respondents. The practitioners reported problems with lack of manpower and evaluation of asbestos exposure. Examinees consulted attending physicians on a wide range of matters including asbestos-related diseases, asbestos exposure, and financial compensation. It is predicted that asbestos-related diseases in general, and mesothelioma in particular, will increase in the future. Accordingly, early detection and treatment should be accorded high priority. The organizations we surveyed have important roles to play. Although resources are limited, effective diagnosis and treatment are essential, and a system assisting organizations to make accurate and efficient identification of asbestos exposure hazards is imperative.
(San Ei Shi 2008; 50: 145-151)

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