[Institutional measures and desired supports regarding COVID-19 pandemic among small and medium-sized enterprises: An interview study in Japan].

OBJECTIVES: Owing to the spread of COVID-19, many companies are likely to experience a significant impact on not only the safety and health of employees, but also on their businesses. The impact may be more severe for small and medium-sized enterprises (SMEs) than large enterprises, given their limited management resources. This study aims to clarify the good practices of institutional measures, the challenges in implementing these measures, and the required supports among SMEs. METHODS: The authors conducted an interview survey in August-October 2020 covering 27 SMEs in Japan regarding the infection control measures implemented and the desired supports in the future. Based on the content analysis, four researchers, comprising two occupational physicians and occupational health nurses each, extracted small categories by focusing on the commonality of codes, and gradually increased the degree of abstraction, subsequently extracting large categories. RESULTS: The study consolidated the implemented institutional measures into four categories: "making immediate decisions," "obtaining accurate information and sharing it with all employees," "strengthening infection control measures," and " launching efforts to continue business." In addition, challenges in implementing institutional measures were classified into five categories: "information gathering," "counter measures against unknown virus," "poor accessibility to Polymerase Chain Reaction (PCR) test," "consensus building," and "balancing business continuity and infection control." Furthermore, desired support in the future was classified into three categories: "information gathering," "accessibility to PCR test," and "compensation and subsidy." CONCLUSIONS: With taking the advantage of the characteristics of SMEs, not a few companies implemented the four categories of institutional measures. Therefore, it is imperative for SMEs to provide accurate information to employers for appropriately recognizing the risks. Accordingly, it is desirable for occupational health professionals at SMEs to provide support to employers to help them identify appropriate information.

The effects of a two-minute original exercise program supported by the workplace unit on the workers' work engagement: the "Bipoji" exercise.

[Purpose] This study examined whether workplace support of an exercise program would increase the workers' engagement. [Participants and Methods] Employees at two facilities of the Kyoto Industrial Health Association (the Uji branch and the headquarters) were recruited. A survey of 238 employees was conducted. A seminar was held, at the facilities, about the "Bipoji" exercise program and afterward the participants underwent different procedures. The Uji branch (the support group) supported the continuation of the program for two months. At the headquarters (the control group), the individual decided whether to continue the program. Data were collected at the time of the seminar (the baseline) and two months later. A questionnaire measured work engagement using the Utrecht Work Engagement Scale. [Results] At the follow-up, data were collected from 65 people (60.2%) from the support group and 97 people (74.6%) from the control group. The average change in the Utrecht Work Engagement Scale scores was 1.7 and -1.2, for the support group and the control group, respectively. When adjusted for background factors, the change was 1.6 and -1.2, for the support group and the control group, respectively. This indicates a significant increase in work engagement for the support group. [Conclusion] These results suggest that a workplace exercise program can improve work engagement.

[A two-year program to promote participatory workplace environmental improvements at small enterprises with fewer than ten employees].

OBJECTIVE: This study aimed to determine the influence of participatory workplace environmental improvement program on reducing job stress and workers' psychological distress at small enterprises (i.e., less than 10 employees). Furthermore, this study aimed to clarify important factors for success of this program as well. METHODS: The model program was tested in a small enterprise with eight employees between October 2014 and January 2017. Moreover, five employees participated in the annual work environment improvement workshops for two consecutive years. During both years, the New Brief Job Stress Questionnaire (80-item version) was used to measure work-related stress before (baseline) and after (post-three months and post-12 months) the workshops. To assess the extent of an intervention effect, the questionnaire data were analyzed using the Friedman test and the multiple comparison test annually. In addition, continuous data were analyzed during the two years. The statistical significance of the differences across time was determined at the p < .10 cutoff value because the number of participants was small. The effect size was also calculated. The participants were interviewed regularly. RESULTS: For both years, the employees implemented action plans within one month of completing the workshops. In the first year, the data for the Friedman test indicated a significant change in role conflict, job resources (workgroup-level), respect for individuals, fair personnel evaluations, work-self balance (positive), workplace social capital, and job satisfaction. In the multiple comparison test, significant changes manifested in role conflict and workplace social capital. In the second year, significant changes were found regarding role conflict and fair personnel evaluations for the Friedman test, demonstrating significant changes in role conflict in the multiple comparison test. As per the two-year survey results, the Friedman test indicated significant changes in role conflict, respect for individuals, and fair personnel evaluations, while the multiple comparison test demonstrated no significant changes. Over time, favorable changes were found regarding role conflict in the first year; however, undesirable changes were found regarding the other statistically significant items. The interviews revealed both positive and negative opinions. CONCLUSIONS: This study found the effects of the participatory workplace environment improvement program to be limited. Thus, the program should be improved to reduce its adverse effects as well as the participants' negative opinions.

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.

An international comparison of occupational health guidelines for the management of mental disorders and stress-related psychological symptoms.

BACKGROUND: We compared available guidelines on the management of mental disorders and stress-related psychological symptoms in an occupational healthcare setting and determined their development and reporting quality. METHODS: To identify eligible guidelines, we systematically searched National Guideline Clearinghouse, Guidelines International Network Library and PubMed. Members of the International Commission on Occupational Health (ICOH), were also consulted. Guidelines recommendations were compared and reporting quality was assessed using the AGREE II instrument. RESULTS: Of 2126 titles retrieved, 14 guidelines were included: 1 Japanese, 2 Finnish, 2 Korean, 2 British and 7 Dutch. Four guidelines were of high-reporting quality. Best described was the Scope and Purpose, and the poorest described were competing interests (Editorial independence) and barriers and facilitators for implementation (Applicability). Key recommendations were often difficult to identify. Most guidelines recommend employing an inventory of symptoms, diagnostic classification, performance problems and workplace factors. All guidelines recommend specific return-to-work interventions, and most agreed on psychological treatment and communication between involved stakeholders. DISCUSSION: Practice guidelines to address work disability due to mental disorders and stress-related symptoms are available in various countries around the world, however, these guidelines are difficult to find. To promote sharing, national guidelines should be accessible via established international databases. The quality of the guideline's developmental process varied considerably. To increase quality and applicability, guideline developers should adopt a common structure for the development and reporting of their guidelines, for example Appraisal of Guidelines for Research and Evaluation (AGREE) criteria. Owing to differences in social systems, developers can learn from each other through reviews of this kind.

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.