Toshiteru Okubo

Estimation of the Optimal Cut Off Point in a New Immunological Faecal Occult Blood Test in a Corporate Colorectal Cancer Screening Programme

Objective –To estimate the optimal cut off point in a new immunological method (OC-Hemodia®) for faecal occult blood testing (FOBT). Setting –A corporate colorectal cancer screening programme in Japan. Method –The screening programme targeted colorectal cancer and adenomatous polyps ≥ 10 mm, and was conducted on 27 860 participants (age ⩾ 40) during 1991–92. The follow up consisted of diagnostic management by total colonoscopy on positive screened subjects exceeding the manufacturer recommended cut off level of 50 ng/ml faecal haemoglobin, and the identification of false negative cases by health insurance claims. The optimal cut off point was estimated by the positive predictive value, receiver operating characteristic (ROC) curve, and a cost effectiveness analysis. In this study evaluation was carried out only for cancer as the target disease. Results –At the current cut off level of 50 ng/ml the sensitivity and specificity were 86.5% and 94.9%. When the optimal cut off point was estimated the highest positive predictive value was obtained at 250–350 ng/ml. The ROC curve showed that the sum of sensitivity and specificity is maximised at 50 ng/ml, but evaluation of the ratio, change in sensitivity/change in false positive rate, pointed to higher optimal cut off points, showing marked changes occurring at about 200 ng/ml. The average cost per case was lowest at 250–300 ng/ml. Overall, the optimal cut off point was estimated to be about 200 ng/ml, at which the sensitivity and specificity of the test would be 77.5% and 98.9%, respectively. Conclusion –The optimal cut off point of the new immunological method of FOBT was estimated to be about 200 ng/ml, a value which, more than the current cut off value, favours specificity over sensitivity.

A Prospective Cohort Study of Chromium Plating Workers in Japan

A prospective cohort study was conducted in 415 small-scale chromeplating plants in Japan to examine the mortality of platers employed between 1970 and 1976. A group of 1,193 male metal platers was identified in 1976 and divided into a chromium plater subgroup (n = 626) and a nonchromium plater subgroup (n = 567). Both subgroups were followed from 1976 through December 1987. Among specific causes of death, only lung cancer was found to be significantly higher than expected for all platers (16 observed, 8.9 expected; SMR 179; 95% CI 102-290). This elevated SMR, however, was not statistically significant in either of the two plater subgroups. The SMR for lung cancer of the chromium plater subgroup was highest among those exposed for the shortest period and among those exposed in the most remote calendar years.

Recent State and Future Scope of Occupational Health in Japan

Recent State and Future Scope of Occupational Health in Japan: Toshiteru Okubo. Occupational Health Training Center, University of Occupational and Environmental Health, Japan—The most significant characteristic of the working population of Japan is aging. The increase in the senior population puts substantial pressure on the health insurance and pension systems and many health insurance organizations have decided to cut down voluntary programs on occupational health. The nature of occupational diseases has changed from health impairments caused by a single prominent occupational factor to unspecific health problems caused by the combinedeffect of both occupational and non‐ occupational factors. Diseases occurring through this mechanism are called work‐related diseases, in contrast to typical occupational diseases. It is no longer effective to simply remove a single hazardous environmental factor, as has been the major approach in occupational health. A comprehensive approach is more important than ever. Health promotion in the work place is therefore one of the most important services in Japan. Along with the improvement of the work environment, workers’ values regarding labor have also changed and they seek working conditions better than the threshold level to prevent health hazards11) . Under these conditions the basic concept of occupational health should not be limited to only minimizing the minus health effects, but it should introduce the idea of seeking positive health. Positive health always seeks to improve health from any level, but up to now medical science has paid very little attention to positive health and there is lack of knowledge and experience. The highest priority of research in this field is therefore to be found in the development of positive health indicators.

Impact of factors indicating a poor prognosis on stroke rehabilitation effectiveness

This study examines the impact of factors indicating a poor prognosis on rehabilitation effectiveness of 124 first stroke patients admitted to a comprehensive rehabilitation unit in Kitakyushu, Japan. A multiple regression model, employing a forced entry of variables guided by prior studies on these factors, found four significant factors. Lack of motivation, urinary incontinence, each 10 years of age, and each days delay from stroke onset to the commencement of rehabilitation reduced the rehabilitation effectiveness by 20%, 15%, 4%, and 0.1% respectively. The values of beta-coefficients showed that onset-rehabilitation delay and lack of motivation were relatively important in our model. These findings are consistent with clinical impressions and provide useful information for planning stroke rehabilitation programmes.

Comprehensive periodic health examination: impact on health care utilisation and costs in a working population in Japan.

STUDY OBJECTIVE--To examine the impact of a comprehensive periodic health examination programme on health care utilisation and costs in a working population. DESIGN--A cohort method was used to observe the trends in health care utilisation and costs for a group of local government employees from 1 February 1986 until 31 January 1992, during which time (in 1988) a comprehensive periodic health examination programme had been introduced. Health care utilisation was measured by a claim rate per employee (number of claims in a year divided by number of employees) and a utilisation rate per 100 employees (number of employees who submitted at least one claim in a year divided by number of employees x 100). Health care costs were measured by claim costs per employee (total cost of claims divided by number of employees). National and prefectural changes in per capita health care costs were used for the adjustment of claim costs. Internal comparisons were made in relation to the intensiveness of the periodic health examinations administered before the introduction of the comprehensive programme. SETTING--Fukuoka Prefecture, Japan. PARTICIPANTS--A total of 19,146 local government employees (12,455 men, 6691 women) who worked in small cities, towns, and villages in Fukuoka Prefecture throughout the study period participated. MAIN RESULTS--Both the claim and utilisation rates showed an increase in 1988 when the comprehensive programme was introduced. After adjustment for the national changes in per capita health care costs and the aging effect of the study participants, substantial increases in claim costs were noted after introduction of the comprehensive programme. The programme had a greater but short term effect of increasing the health care utilisation of those who had received less intensive periodic health examinations before 1988, but no similar effect on claim costs was noted. CONCLUSIONS--The comprehensive programme had some role in increasing health care utilisation and costs. Its effect on costs was confirmed when the general population or another population was used as a reference. When comparisons were made internally, the comprehensive programme was seen to have had a greater but short term effect of increasing the utilisation of those who had previously received less intensive health examinations to equalise the health care utilisation and costs within the study population.

A special University of Occupational and Environmental Health in Japan

Shows how the Occupational and Environmental Health University in Japan, with its Institute of Ecological Sciences, delivers several unique national and international courses for Japanese and foreign students. Staff of the university also provide advice and assistance to other training centres and industry.

Interpersonal awareness and smoking behavior in the workplace.

A questionnaire survey was conducted in small-scale production companies in Japan to examine “interpersonal awareness” and smoking behavior in the workplace. Interpersonal awareness (IA) of smokers is defined as awareness of other peoples presence when smoking. Study participants were 1048 smokers and 744 nonsmokers, contrasted by worksite: office or production. Controlling for selected baseline variables, office work smokers, who smoked more in the workplace than production work smokers (77.4% vs 51.6%, p<.001), had a higher IA in the workplace (75.5% vs 58.9%, p<.001) but did not differ in IA at home (69.7% vs 66.0%). in male smokers of both worksites, degree of IA in the workplace correlated positively with that at home (r3=.36, p<.001, office; r3=.45, p<.00l, production), and daily cigarette consumption correlated negatively with degree of IA at home (r8=-.44, p<.00l, office; r3=-.17, p<.001, production). A predilection for smoking more at home than in the workplace correlated with higher IA in the workplace for male office smokers (r8=-.21, p<.01). In contrast, a predilection for smoking more at home than in the workplace correlated with lower degree of IA at home for production smokers of both sexes (r3= 20, p<.001, male; r3=.53, p<.05, female). Interpersonal awareness is deemed an Important behavioral factor for smoking workers.