Entity

Time filter

Source Type


Ikeda M.,Kyoto Industrial Health Association Main Office | Moriguchi J.,Kyoto Industrial Health Association Mibu Office | Sakuragi S.,Kyoto Industrial Health Association Mibu Office | Ohashi F.,Kyoto Industrial Health Association Main Office
International Archives of Occupational and Environmental Health | Year: 2013

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, β2-microglobulin, and N-acetyl-β-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. © 2012 Springer-Verlag. Source


Ikeda M.,Kyoto Industrial Health Association Main Office | Moriguchi J.,Kyoto Industrial Health Association Mibu Office | Sakuragi S.,Kyoto Industrial Health Association Mibu Office | Ohashi F.,Kyoto Industrial Health Association Main Office
International Archives of Occupational and Environmental Health | Year: 2012

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. Data were cited from previous publications of this research group on Cd, α1-microglobulin (α1-MG), β2-microglobulin (β2-MG), N-acetyl-β-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). Statistical analyses of the AD-selected group revealed that the relation was not linear. In case of β2-MG, the slope of the regression line between Cd as an independent variable and β2-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 α1-MG and NAG. When Cd was 2.0-2.1 μg/l or higher, α1-MG, β2-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 β2-MG of 300 μg/g cr. 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. © 2011 Springer-Verlag. Source


Sakuragi S.,Kyoto Industrial Health Association Mibu Office | Moriguchi J.,Kyoto Industrial Health Association Mibu Office | Ohashi F.,Kyoto Industrial Health Association Main Office | Ikeda M.,Kyoto Industrial Health Association Main Office
Environmental Health and Preventive Medicine | Year: 2013

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/mm3 in 2002 and 6,162 cells/mm3 in 2010. Based on the 2010 observation, 3 × 103 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 × 103 cells/mm3 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 × 103 cells/mm3 is recommended as the 95 % lower limit of the reference value for screening cases with reduced WBC counts. © 2012 The Japanese Society for Hygiene. Source


Sakuragi S.,Kyoto Industrial Health Association Mibu Office | Takahashi K.,University of Occupational and Environmental Health Japan | Hoshuyama T.,University of Occupational and Environmental Health Japan | Moriguchi J.,Kyoto Industrial Health Association Mibu Office | And 3 more authors.
International Archives of Occupational and Environmental Health | Year: 2012

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), α1-microglobulin (α1-MG), β2-microglobulin (β2-MG) and N-acetyl-β-Dglucosaminidase (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, α1-MG and β2-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-Jǿrgensen et al. in Biometrics 57:698-706, 2001). It was possible to calculate BMD and BMDL values for α1-MG and β2-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 α1-MG, β2-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 α1-MG and β2-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 α1-MG and β2-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 α1-MG or β2-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. © Springer-Verlag 2012. Source


Ikeda M.,Kyoto Industrial Health Association Main Office | Fukui Y.,Kyoto Industrial Health Association Main Office | Ohashi F.,Kyoto Industrial Health Association Main Office | Sakuragi S.,Kyoto Industrial Health Association Mibu Office | Moriguchi J.,Kyoto Industrial Health Association Mibu Office
Biological Trace Element Research | Year: 2011

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, β 2-MG, and N-acetyl-β-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 β 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. © 2010 Springer Science+Business Media, LLC. Source

Discover hidden collaborations