Comparative study on the activities of part-time occupational physicians in Japan between 2008 and 2016: effects of the stress-check program.

The Ministry of Health, Labor, and Welfare of Japan recommends that an occupational physician (OP) play an important role in implementing the stress-check program since 2015. This study aimed to compare the activities and encountered difficulties of Japanese part-time OPs in 2008 and 2016, and to investigate the effects of the stress-check program. Questionnaires were sent via mail to 946 part-time OPs in Kyoto prefecture in 2016. Completed questionnaires were returned by 181 OPs who were private practitioners or physicians in hospitals, and served as OPs on a part-time basis. In 2016, OPs utilized long hours for activities related to general health examination and to stress-check. Hours for specific health examination, health and hygiene education, health promotion activity, development of a comfortable workplace, and guidance of workers on sick leave reduced from 2008 to 2016. A total of 62% OPs frequently encountered difficulties in the stress-check-related activities in 2016. Many OPs also reported difficulties in the mental health care and the prevention of health hazard due to overwork both in 2008 and 2016. Enforcement of the stress-check program in 2015 changed the activities of part-time OPs in Japan. OPs should be given opportunities to gain more information in this area.

Significant but weak spousal concordance of metabolic syndrome components in Japanese couples.

OBJECTIVE: This study was initiated to investigate if spousal concordance in metabolic syndrome (MS) components exist in Japan. METHODS: In all, 756 couples (mean age: 48.9 and 47.3 years for husbands and wives, respectively) were identified. Each subject was classified as an MS, MS reserves (MSRES) or no risk of MS (NonMS) case after Japanese Ministry of Health, Labour and Welfare (JMHLW) criteria. Criteria of the National Cholesterol Education Program and of the Joint Interim Statement were also applied. RESULTS: With Japanese Ministry of Health, Labor and Welfare (JMHLW) criteria, MS, MSRES and NonMS cases accounted for 11.9, 14.7 and 73.4 % in husbands and 1.6, 3.7 and 94.7 % in wives. Waist circumference (WC), body mass index (BMI), systolic blood pressure (SBP) and hemoglobin A1c (HbA1c) showed significant correlation (p < 0.01). Correlation was also significant (p < 0.05) for mean blood pressure (MBP) and fasting plasma glucose (FPG). When adjusted for age, correlations were significant only for WC, BMI and HbA1c. Furthermore, none of the correlation coefficients were greater than 0.2. Logistic regression analyses did not suggest significant mutual influence in MS status between the couples. CONCLUSIONS: Spousal concordance in MS components was detected for WC, BMI, SBP, MBP, FPG and HbA1c, but the correlation was generally weak and modest in Japanese couples.

Activities of private clinic- or hospital-based occupational physicians in Japan.

The present study was initiated to examine the activities of private clinic- or hospital-based occupational physicians (OPs) and to identify difficulties the OPs encountered in their occupational health service (OHS). A questionnaire was sent by mail to 557 OPs in Kyoto prefecture, Japan. Effective answers were obtained from 86 OPs who were private practitioners or physicians in hospitals and served as OPs on a part-time basis. Considering 3 h as a unit, a majority (92%) served <1 to 2 units/month. The leading fields of OHS provided by the OPs were general health examination and its follow-up, prevention of overwork, and mental health care, as well as support of workers on sick leave to return to work. OPs wished to allocate more time for maintenance and management of work and the work environment, mental health care, work area rounding, and attendance at the safety and health committee meetings. Difficulties were encountered most often in the management of mental ill health and overwork, and support of employees' return to work. Many OPs also reported difficulties with industrial hygiene-related issues such as risk assessment, and maintenance and management of work and the work environment. The present survey identified difficulties that were frequently encountered by private clinic- and hospital-based OPs in their practice of OHS; these include issues on mental health, overwork and industrial hygiene. The needs to offering OPs specific opportunities to gain information and skills in these areas are stressed.

Use of organic solvents in large research institutions in Japan.

OBJECTIVES: Laboratories in research institutions use organic solvents in research and development. Nevertheless, the types of solvents in use have been seldom reported. This study was initiated to elucidate types of organic solvents used in large research institutions in Japan, with a focus on possible different use among research fields. METHODS: In 2010-2011, 4517 laboratories in seven large research institutions were visited. In accordance with legal stipulations, air in each laboratory was collected in polyvinyl fluoride bags and analyzed by direct injection into a gas-chromatograph for 47 types of organic solvents. In evaluation, the laboratories were grouped by 5 research fields, i.e., agriculture, biology, medicine, natural science, and technology and engineering. RESULTS: Types of organic solvents commonly used in research activities were not diverse. Those commonly used were chloroform and 1,2-dichloroethane out of 7 Group 1 organic solvents (with high toxicities); 6 organic solvents, i.e., acetone and methyl alcohol in general, ethyl acetate, hexane and toluene in technology and engineering laboratories; and xylenes in medical fields out of 40 Group 2 organic solvents (with relatively low toxicities). Judging from solvent vapor concentrations, work environments in more than 99 % of laboratories were considered adequate. Nevertheless, use of chloroform in high-performance liquid chromatography (HPLC) resulted in inadequate environments in 30 laboratories (0.7 %). CONCLUSIONS: Organic solvents commonly used were not very diverse. Work environments in research laboratories were generally good, but the environment with use of chloroform in HPLC analysis remained yet to be improved.

Association of past diseases with levels of cadmium and tubular dysfunction markers in urine of adult women in non-polluted areas in Japan.

BACKGROUND AND OBJECTIVES: Whereas information has been accumulating on the association of anemia and other diseases with cadmium (Cd) burden, histories of past diseases of the examinees are often not taken in account when the results of health examination are evaluated for cadmium exposure-related health effects on general populations. The present study was initiated to examine the possible association of previous diseases with Cd exposure parameters, taking advantage of compiled data on adult women. METHODS: Data were cited from previous publications of this research group on Cd, α1-microglobulin (α1-MG), ß2-microglobulin (ß2-MG), N-acetyl-ß-D-glucosaminidase (NAG) and urine density makers (i.e., creatinine and specific gravity) in the urine of more than 17,000 adult women in non-polluted areas in Japan. Information on previous disease history together with age and smoking habits was obtained by self-administered questionnaires, and 13,031 never-smoking women were selected for the present analyses. To compare the cases with disease history, control cases were randomly selected after stratification by 5 years of age at a ratio of one case to three controls from those with no disease history; summation for all age strata made up the control groups for the disease group in concern. The random sampling to set up control groups was repeated three times in total. The difference between the disease group and control groups was considered valid in cases the difference was statistically significant (p ≦ 0.05), in all three cases after correction (or non-correction) for urine density, and the same results were obtained when compared with the three different control groups. RESULTS: In the anemia group, Cd-U was higher over corresponding three control groups, although none of α1-MG-U, ß2-MG-U or NAG-U showed significant changes. In the diabetes mellitus group, NAG-U was higher than in the controls, but such differences were not observed in Cd-U or ß2-MG-U. The elevation in α1-MG-U was not reproducible. In the case of the hypertension group, the elevations in Cd-U, α1-MG-U, and ß2-MG-U were observed, but changes in NAG-U could not be confirmed. In the analysis of dose-response relationship, the diabetes mellitus group showed increases in the slope for ß2-MG-U and in the intercept for NAG-U. No changes in dose-response relationship were observed in other disease groups as compared with the corresponding control groups. CONCLUSIONS: Care should be taken in evaluating Cd-related health examination results for those with history of diseases such as hypertension, anemia and diabetes mellitus in particular.

Reference value and annual trend of white blood cell counts among adult Japanese population.

OBJECTIVES: This study was initiated to establish the reference values (the 95 % lower limit in particular) for white blood cell (WBC) counts in peripheral blood of general Japanese population. Additional attempts were made to examine whether the reference range had changed in the past 100 years, and which factors had induced such change in WBC counts. METHODS: Data employed were WBC counts of >100 thousand apparently healthy Japanese men, collected in 2002 and in 2010, respectively. Information on smoking habits was collected simultaneously. RESULTS: The distribution of WBC counts was essentially normal. Arithmetic mean (AM) WBC was 6,248 cells/mm(3) in 2002 and 6,162 cells/mm(3) in 2010. Based on the 2010 observation, 3 × 10(3) WBCs/mm(3) (after rounding of the figure) was identified as the 95 % lower limit of the reference value for the population. No clear age dependency was detected. Smoking induced elevation in WBC, whereas WBC returned to the level of never smokers after quitting for 3 or more years. CONCLUSIONS: Historical review disclosed a secular trend of decrease in WBC in the past 100 years, so that about 8 % of never-smoking men would be considered leukocytopenic according to the conventional cutoff of 4 × 10(3) cells/mm(3) as a screening level. Decreased smoking rates and improved general hygiene are discussed as possible factors for WBC count reduction. Thus, WBC count of 3 × 10(3) cells/mm(3) is recommended as the 95 % lower limit of the reference value for screening cases with reduced WBC counts.

Relation of child birth and breast-feeding burden with cadmium and tubular dysfunction marker levels in urine of adult women in non-polluted areas in Japan.

BACKGROUND AND OBJECTIVES: Cd absorption may be enhanced in association with iron (Fe) deficiency. Women have increased risks of Fe loss at the time of child birth as well as breast-feeding of children. Possible effects of these two factors were investigated in the present study. METHODS: Data were drawn from previous publications from this group on Cd and tubular dysfunction markers (i.e., α1-microglobulin, ß2-microglobulin, and N-acetyl-ß-D-glucosaminidase) in urine of adult women in non-polluted areas in Japan. Information including age, smoking, number of children, and types of child feeding was obtained by self-administered questionnaires at the time of urine sampling. In practice, 17,468 cases were available, from which 12,869 cases were employed in the present analyses after exclusion of smokers, former or current patients of anemia or hypertension, and those with incomplete answers. Lactation burden was scored after coding of breast, mixed, and bottle feeding with 2, 1, and 0 for each child followed by summation for all children born to a mother. In order to exclude possible effect of aging, women were stratified by 5 years of age to randomly select equal numbers of cases and controls, followed by summation for all ages for comparison. RESULTS: The arithmetic mean age and the geometric mean Cd (as observed) were 49.7 years and 1.13 µg/l urine. The number of children was 0-7, and lactation burden score ranged from 0-12. Multiple regression analyses were conducted with age and either number of children or lactation burden scores as independent variables and Cd as a dependent variable. The results showed that age was an influential variable. Comparison after matching for age showed that having 1, 2, or 3 children or lactation burden score up to 2 were associated with a significant increase in Cd. Lactation burden score up to 2 was also associated with increased Cd in urine and such trend persisted up to the highest score of 5-12. The results of trend tests were generally in agreement with these observations. Further comparison after age-matching showed that women having 2 or 3 children but no lactation burden had higher Cd than those with no children. In contrast, Cd was not higher for those having 2 or 3 children with substantial lactation scores (i.e., 2-4 or 3-6) than for those with the same number of children without lactation burden. CONCLUSIONS: Giving birth to 1-3 children was associated with an increase in urinary Cd, suggesting that child birth might be associated with elevation in Cd body burden. The effect of lactation is probably attributable to that of number of children. Further studies are necessary to examine whether the association is also observable in mothers who have 3 or more children.

Variation in benchmark dose (BMD) and the 95% lower confidence limit of benchmark dose (BMDL) among general Japanese populations with no anthropogenic exposure to cadmium.

BACKGROUND: The use of benchmark dose (BMD) and the 95% lower confidence limit of benchmark dose (BMDL) have been gaining popularity not only in experimental studies but also in epidemiological studies including those on toxicology of cadmium (Cd), a ubiquitous hazardous element in the environment. However, the reproducibility of BMD and BMDL values has seldom been examined. OBJECTIVES: This study was initiated to determine whether consistent BMD and BMDL values are obtained for similar non-exposed populations, i.e., the populations with no anthropogenic exposure to Cd in a single nation of Japan. METHODS: Cd (an exposure marker), α(1)-microglobulin (α(1)-MG), ß(2)-microglobulin (ß(2)-MG) and N-acetyl-ß-D-glucosaminidase (NAG) (three effect markers of tubular dysfunction) levels in the urine of adult Japanese women from five previous publications of this study group were examined. Overall, data were available for 17,375 cases (in 16 prefectures) regarding Cd, α(1)-MG and ß(2)-MG, and 6,409 cases (in ten prefectures) regarding NAG. The data were used to calculate BMD and BMDL values taking advantage of the hybrid approach (Budtz-JÇ¿rgensen et al. in Biometrics 57:698-706, 2001). It was possible to calculate BMD and BMDL values for α(1)-MG and ß(2)-MG for all of the 16 prefectures with 17,375 cases, whereas the values for NAG were successfully calculated for nine prefectures with 5,843 cases. RESULTS: The application gave BMD values of 1.92, 2.46 and 2.32 µg Cd/g cr for α(1)-MG, ß(2)-MG and NAG, respectively, and BMDL values of 1.83, 2.32 and 2.09 µg Cd/g cr. Large inter-prefectural variations were observed in the BMD and BMDL; there was about fourfold difference both in BMD and in BMDL calculated for α(1)-MG and ß(2)-MG in 16 prefectures, and the variation was greater (i.e., by about sevenfold) in BMD and BMDL for NAG in nine prefectures. A survey of relevant literature revealed variation in BMD and BMDL values of similar folds as observed in the present analyses in five studies of Japanese populations. Multiple regression analyses taking BMD or BMDL as a dependent variable and age, CR concentration and Cd concentration as independent variables showed both BMD and BMDL were significantly influenced by Cd concentration in cases of α(1)-MG and ß(2)-MG, whereas BMD and BMDL for NAG was by CR. CONCLUSIONS: Even when the analysis was conducted in a single nation, both BMD and BMDL for the Cd effect markers varied by ca. fourfold when examining α(1)-MG or ß(2)-MG and the values varied by ca. sevenfold for NAG among Cd-non-exposed populations. The most influential factors in the study population may include urine density and Cd levels in the urine.

Bi-linear dose--response relationship in general populations with low-level cadmium exposures in non-polluted areas in Japan.

BACKGROUND AND OBJECTIVES: Previous findings suggest that the dose (e.g., cadmium in urine)-response (e.g., tubular dysfunction markers in urine) relationship after environmental exposure to cadmium (Cd) may be in a shape of a hockey stick with a steep slope when Cd exposure exceeds a certain level, i.e., the point of flexion. However, less attention has been paid to the relation below the flexion point whether it is linear or not. The present study was initiated to examine through epidemiological analyses whether the assumption of linearity holds true when Cd exposure is low. METHODS: Data were cited from previous publications of this research group on Cd, α(1)-microglobulin (α(1)-MG), ß(2)-microglobulin (ß(2)-MG), N-acetyl-ß-D: -glucosaminidase (NAG), and creatinine (CR) in urine from more than 17,000 adult Japanese women. The cases were selected for age (50-59 years), urine specific gravity (1.010-1.030) and CR (0.3-3.0 g/l), and 5,306 cases were available after selection (the group selected in terms of age and urine density, or the AD-selected group). RESULTS: Statistical analyses of the AD-selected group revealed that the relation was not linear. In case of ß(2)-MG, the slope of the regression line between Cd as an independent variable and ß(2)-MG a dependent variable was steeper at lower Cd level (i.e., <2.5 µg/l) and shallower when Cd was higher, showing a clear trend of leveling off. The same was also the case for α(1)-MG and NAG. When Cd was 2.0-2.1 µg/l or higher, α(1)-MG, ß(2)-MG, and NAG were in excess of the 95%-tile values for the markers in more than 5% of the population. The significance of the observation was discussed in reference to existing criteria for Cd such as 2.5 or 5.2 µg/g cr or for ß(2)-MG of 300 µg/g cr. CONCLUSIONS: When the present observation of bilinear relation at low Cd exposure levels was combined with the previous observation of very sharp increase in responses among heavily exposed cases, it appeared likely that the overall relationship is tri-phasic in Cd dose-response relationship in humans. A substantial fraction (>5%) of the populations had the marker levels in excess of the 95%-tile values when Cd was ≥2 µg/l. Comparison with findings in reported literature suggests that the presence of such cases by itself may not necessarily mean a risk of tubular dysfunction and that other factors including Cd levels in urine should be considered together.

Organic solvent use in enterprises in Japan.

This study was initiated to elucidate possible changes in types of organic solvents (to be called solvents in short) used in enterprises in Japan through comparison of current solvent types with historical data since 1983. To investigate current situation in solvent use in enterprises, surveys were conducted during one year of 2009 to 2010. In total, workroom air samples in 1,497 unit workplaces with solvent use were analyzed in accordance with regulatory requirements. Typical use pattern of solvents was as mixtures, accounting for >70% of cases. Adhesives spreading (followed by adhesion) was relatively common in small-scale enterprises, whereas printing and painting work was more common in middle-scale ones, and solvent use for testing and research purpose was basically in large-scaled enterprises. Through-out printing, painting, surface coating and adhesive application, toluene was most common (being detected in 49 to 82% of workplaces depending on work types), whereas isopropyl alcohol was most common (49%) in degreasing, cleaning and wiping workplaces. Other commonly used solvents were methyl alcohol, ethyl acetate and acetone (33 to 37%). Comparison with historical data in Japan and literature-retrieved data outside of Japan all agreed with the observation that toluene is the most commonly used solvent. Application of trichloroethylene and 1,1,1-trichloroethane, once common in 1980s, has ceased to exist in recent years.

Organic solvent use in research institutions in Japan.

In 2008-2009, types of organic solvents used and air-borne vapor concentrations were surveyed in 1909 laboratories in four large research institutions in accordance with current regulations. The results were classified into 5 groups in terms of research fields (agriculture, biology, medicine, natural science, and technology and engineering) and evaluated after the regulatory rules. Laboratory air analyses by gas chromatography identified 5 and 20 solvents out of 7 Group 1 solvents and 40 Group 2 solvents, respectively; 10 solvents were used in more than 10% of the laboratories in each of the 5 research fields. The use of unmixed single solvent appeared to be unique in research laboratories in contrast to use of solvent mixtures in industrial facilities for production. Laboratories of technology and engineering fields used more various organic solvents more frequently, whereas use of xylenes appeared to be more specific to laboratories of bio-medical fields. Among the commonly used solvents, chloroform was the leading solvent to induce poorer results in regulatory classification (i.e., Class 3 in Administrative Control Classes) typically when applied in high pressure liquid chromatography which was too voluminous to be accommodated in a local exhaustion chamber.

Comparative evaluation of GFAAS and ICP-MS for analyses of cadmium in blood.

Cadmium in blood (Cd-B) is an important indicator, next to Cd in urine, in biological monitoring of exposure to Cd. The present study was initiated to examine compatibility in results of analysis for Cd-B between graphite furnace atomic absorption spectrophotometry (GFAAS) and inductively-coupled plasma mass-spectrometry (ICP-MS). For this purpose, 1,159 blood samples were collected from adult women (with no occupational exposure to Cd) in eight prefectures nation-widely in Japan. The samples were analyzed by the two methods; geometric mean (the maximum) concentrations were 1.22 (6.90) µg/l by ICP-MS, and 1.47 (7.40) µg/l by GFAAS. Statistical analyses showed that there was a close correlation between the results by the two methods. The regression line (with ICP-MS and GFAAS results as an independent variable and a dependent variable, respectively) had a slope close to one and an intercept next to zero to suggest that ICP-MS gave values compatible with that of GFAAS. Further analysis with the ratio of Cd-B by GFAAS over that by ICP-MS revealed that the two results were close to each other, and that the agreement was even closer when Cd-B was >2 µg/l. Thus, the two methods can be employed inter-convertibly when Cd-B is relatively high, e.g. >2 µg/l. Care may need to be practiced, however, for possible 'between methods' difference when Cd-B is low, e.g., ≤2 µg/l.

Closer correlation of cadmium in urine than that of cadmium in blood with tubular dysfunction markers in urine among general women populations in Japan.

OBJECTIVES: The objectives of the present study are to investigate whether cadmium in blood (Cd-B) and cadmium in urine (Cd-U) correlate with each other irrespective of age among general populations and which one of Cd-B or Cd-U correlates more closely with three renal tubular dysfunction markers in urine of α1-microglobulin (α1-MG-U), ß2-microglobulin (ß2-MG-U) and N-acetyl-ß-D-glucosaminidase (NAG-U). METHODS: Data on two exposure markers (Cd-B and Cd-U) and three effect markers (α1-MG-U, ß2-MG-U and NAG-U) were collected for 1,403 adult women in non-polluted areas all over Japan. Possible significance of correlation between the parameters and dependency on age was examined by simple and multiple regression analysis. RESULTS: Both Cd-B and Cd-U increased as a function of age. The two exposure markers correlated significantly with each other, and the Cd-U over Cd-B ratio also increased as a function of age. Although both Cd-B and Cd-U correlated significantly with the three effect markers, the correlation was closer for Cd-U than for Cd-B. CONCLUSIONS: Cd-U rather than Cd-B should be recommended as an exposure marker of choice in Cd biological monitoring of general populations. Effects of aging should be taken into account when evaluating study results.

Estimation of dietary Pb and Cd intake from Pb and Cd in blood or urine.

Successful trials were made to estimate the dietary daily intake of lead (Pb) and cadmium (Cd) via foods from the levels of the metals in blood or urine. In practice, 14 and 15 reports were available for Pb and Cd in blood (Pb-B and Cd-B), urine (Pb-U and Cd-U) and 24-h diet duplicates (Pb-D and Cd-D), respectively, from which 68 pairs each of Pb or Cd in blood and food duplicates [each being geometric mean (GM) values for the survey sites] were obtained. Regression analysis revealed that there was a significant correlation between Pb-B and Pb-D, and also between Cd-B and Cd-D, suggesting that it should be possible to estimate both Pb-D and Cd-D from Pb-B and Cd-B, respectively. For Cd-U, the number of available cases was limited (20 pairs), but a significant correlation was detected between Cd-U (as Cd-U(cr), or Cd levels in urine as corrected for creatinine concentration) and Cd-D. Care should be taken in estimating Pb-D from Pb-B, as the ratio of Pb-D over Pb-B may decrease as a function of increasing Pb-B levels. The Pb-D (µg/day) for typical Japanese women with Pb-B of 15 µg/l was best estimated to be 13.5 µg/day. No Cd-B- or Cd-U(cr)-dependent change was detected in case of Cd. The best estimate of Cd-D for Cd-B at 1.5 µg/l should be about 19.4 µg/day.

Low cadmium levels in urine of residents in two prefectures where cadmium levels in locally harvested brown rice are higher than in other prefectures in Japan.

Recent publications in Japan suggest that Cd in river beds and locally harvested rice tend to be higher in seven prefectures in the north-eastern part on the coast of the Sea of Japan (the high-Cd zone). The present study was initiated to investigate the current level of exposure to Cd and possible health effects among local populations in the zone. Thus, levels of Cd and three tubular dysfunction markers [i.e., α(1)-MG, ß(2)-MG, and N-acetyl-ß-D-glucosaminidase (NAG)] were examined in urine of local residents (700 and 704 adult women, respectively) in two prefectures (prefecture 1 and prefecture 7), which were located in the north-east (prefecture 1) and south-west ends (prefecture 7) of the high-Cd zone. Urinary Cd levels [e.g., 0.99 and 0.78 µg/l as geometric mean (GM) for observed (non-corrected) values, respectively] in prefecture 1 and prefecture 7 were comparable to the levels in other parts of Japan (All Japan-A; 0.99 µg/l). Correspondingly, GM values for α(1)-MG (2.29 and 1.99 mg/l vs. 2.17 mg/l for All Japan-A) and for ß(2)-MG (87 and 80 µg/l vs. 99 µg/l for All Japan-A) were not elevated, and NAG also stayed unchanged (2.89 and 2.87 units/l for prefecture 1 and prefecture 7, respectively). Evaluation in combination with the findings in other five prefectures in the zone suggests that Cd exposure is equal to the national average both in prefecture 1 and in prefecture 7, whereas Cd exposure appeared to be elevated in the central part of the zone. The observation appears to be on line with geographical location of the two prefectures that they are on the two ends of the zone of high natural Cd background.

Cadmium, chromium, lead, manganese and nickel concentrations in blood of women in non-polluted areas in Japan, as determined by inductively coupled plasma-sector field-mass spectrometry.

BACKGROUND: Background levels of metals of toxicological or industrial importance have been reported for several populations in the world. The information on the levels of metals of industrial, occupational or clinical importance in blood of general Japanese populations is however still scarce. OBJECTIVES: The objectives of the study were to establish background levels of Cd, Cr, Mn, Ni and Pb in blood of Japanese population using inductively coupled plasma-sector field mass spectrometry (ICP-SF-MS), which was expected to be sensitive enough to measure low-level Pb in blood of general populations. For this purpose, women, rather than men, were studied to minimize the effect of smoking. An additional objective was to examine possible contamination from devices in phlebotomy process. METHODS: Blood samples were collected in 2000's from 1,420 adult women in eight prefectures of no known anthropogenic environmental metal pollution in Japan, and the samples were subjected to ICP-SF-MS analyses after wet digestion with extra-pure nitric acid. Ultra pure water samples aspirated into blood sampling vacuum tubes were analyzed to detect possible metal contamination. RESULTS: Contamination of blood samples from phlebotomy device was detected for Cr and possibly for Mn and Ni, whereas it was below measurable levels with regard to Cd, Ni and Pb. Under this limitation, GM metal concentrations in blood were 1.23 µg/l for Cd, 0.55 µg/l for Cr, 13.2 µg/l for Mn, 1.81 µg/l for Ni and 15.8 µg/l for Pb. Cd and Pb tended to increase in association with age, whereas Cr, Mn and Ni tended to decrease. Smoking induced elevation both in Cd and in Pb in blood. It was also made clear that the ICP-SF-MS is reliable for measurements of Cd, Mn and Pb in blood allowing evaluation even on an individual basis, while the results of Cr and Ni should be reliable on a group basis (e.g., n ≥ 5). Limitation in compatibility was discussed between the results by ICP-SF-MS and that by traditional graphite furnace atomic absorption spectrometry. CONCLUSIONS: ICP-SF-MS is a reliable method of blood analysis for Cd, Mn and Pb even for the evaluation on an individual basis. Cr and Ni analyses should be reliable on a group basis, probably due to limited performance inherent to the analysis principle and matrix. Possible contamination from phlebotomy devices with Cr should be taken into account in evaluating the results.

Risk for non-obese Japanese workers to develop metabolic syndrome.

With regard to metabolic syndrome-related risks (MS risks), obese workers have been the focus of attention, and less attention has been paid to non-obese subjects as if they were free from the risks. The present analysis was initiated to know if no-obesity means no-MS risks. Participants of the study were 804 male workers, who showed no pathological findings in 12 MS-related and other health parameters in 2003, and had complete sets of data in 2008. They were classified by BMI in 2003 into lean (< 18.5), normal (> or = 18.5 to < 25) and obese groups (> or =25). Proportion of MS in 2008 was examined by use of the second phase of MS criteria. Proportions for the lean, normal and obese subjects who met MS criteria in 2008 were 3.2, 4.8 and 5.3%, respectively, with no significant difference in proportions among them. In the non-obese (i.e., lean+normal) group, age was not significantly influential to increase BMI. Thus, the MS risk exists even in non-obese young workers. Anti-MS effort should be directed not only to obese but to non-obese workers, and care should be extended irrespective of ages.

Activities of occupational physicians for occupational health services in small-scale enterprises in Japan and in the Netherlands.

OBJECTIVES: Occupational health service (OHS) for small-scale enterprises (SSEs) is still limited in many countries. Both Japan and the Netherlands have universal OHS systems for all employees. The objective of this survey was to examine the activities of occupational physicians (OPs) in the two countries for SSEs and to investigate their proposals for the improvement of service. METHODS: Questionnaires on types and sizes of the industries they serve, allocation of service hours (current and desired), sources of information for occupational health activities etc. were mailed in 2006 to 461 and 335 Japanese and Dutch OPs, respectively, who have served in small- and medium-scale enterprises. In practice, 107 Japanese (23%) and 106 Dutch physicians (32%) replied, respectively. RESULTS AND CONCLUSIONS: Total service time per month was longer for OPs in the Netherlands than OPs in Japan. Japanese OPs spent more hours for health and safety meetings, worksite rounds, and prevention of overwork-induced ill health (14-16% each). Dutch OPs used much more hours for the guidance of absent workers (48%). Thus, service conditions were not the same for OPs in the two countries. Nevertheless, both groups of OPs unanimously considered that employers are the key persons for the improvement of OHS especially in SSEs and their education is important for better OHS. The conclusions should be taken as preliminary, however, due to study limitations including low response rates in both groups of physicians.

Cadmium and tubular dysfunction marker levels in urine of residents in non-polluted areas with natural abundance of cadmium in Japan.

OBJECTIVES: Literature survey has suggested that cadmium (Cd) in the general environment is more abundant in the northern part of the coast on the sea of Japan. The present survey was initiated to examine if the exposure to Cd in the area has been higher than other parts of Japan, and if so, the higher exposure has been associated with tubular dysfunction among the local residents. METHODS: In three prefectures of Akita, Yamagata and Ishikawa in the region, adult women (about 700 subjects per prefecture) were invited to participate in the survey. Each of the participants provided informed consents, offered spot urine samples and filled questionnaires (on age etc.). The urine samples were analyzed for Cd, alpha(1)-microglobulin (alpha(1)-MG), beta(2)-microglobulin (beta(2)-MG) and N-acetyl-beta-D: -glucosaminidase, together with creatinine and specific gravity. The results were combined with published data on two other prefectures of Niigata and Toyama (both in the area), as well as Japan as a whole (all Japan-A excluding Niigata prefecture, which was studied separately in the present study), and subjected to analysis for possible difference from all Japan-A in terms of the levels of internal Cd burden, and prevalence of beta(2)-MG-uria. RESULTS: Geometric means (GMs) for urinary Cd in the five prefectures were in a range from a low of 1.20 to a high of 2.65 microg/l, being higher than the GM (0.99 microg/l) for all Japan-A. GMs for alpha(1)-MG (2.15-2.80 mg/l) and beta(2)-MG (99-107 microg/l) were only slightly higher or even lower than all Japan-A values depending on the prefectures. Elevation in the prevalence of beta(2)-MG-uria was significant in Akita prefecture, but the elevation in beta(2)-MG was not associated with elevation in Cd in urine. Literature survey on general population Cd epidemiology showed that Cd, alpha(1)-MG and beta(2)-MG levels in urine of the residents in the five prefectures were within the levels reported for non-polluted areas, and such was also the case for prevalence of beta(2)-MG-uria. CONCLUSIONS: In an over-all evaluation, no clear-cut evidence was available for increased prevalence of Cd exposure-associated renal tubular dysfunction among general populations in the five prefectures in the northern part on the coast of Sea of Japan than in other prefectures in Japan, despite moderate elevation in urinary Cd levels.