Prevalence of metabolic syndrome associated with body burden levels of dioxin and related compounds among Japan's general population.

BACKGROUND: Environmental exposure to some persistent organic pollutants has been reported to be associated with a metabolic syndrome in the U.S. population. OBJECTIVES: We evaluated the associations of body burden levels of dioxins and related compounds with the prevalence of metabolic syndrome among the general population in Japan. METHODS: We conducted a cross-sectional study with 1,374 participants not occupationally exposed to these pollutants, living throughout Japan during 2002-2006. In fasting blood samples, we measured biochemical factors and determined lipid-adjusted concentrations of 10 polychlorinated dibenzo-p-dioxins (PCDDs), 7 polychlorinated dibenzofurans (PCDFs), and 12 dioxin-like poly-chlorinated biphenyls (DL-PCBs) all of which have toxic equivalency factors. We also performed a questionnaire survey. RESULTS: The toxic equivalents (TEQs) of PCDDs, PCDFs, and DL-PCBs and total TEQs had significant adjusted associations with metabolic syndrome, whether or not we excluded diabetic subjects. By analyzing each component of metabolic syndrome separately, the DL-PCB TEQs and total TEQs were associated with all components, and the odds ratios (ORs) in the highest quartile of DL-PCB TEQs in four of the five components were higher than those for PCDDs or PCDFs. We also found congener-specific associations with metabolic syndrome; in particular, the highest quartiles of PCB-126 and PCB-105 had adjusted ORs of 9.1 and 7.3, respectively. CONCLUSIONS: These results suggest that body burden levels of dioxins and related compounds, particularly those of DL-PCBs, are associated with metabolic syndrome. Of the components, high blood pressure, elevated triglycerides, and glucose intolerance were most closely associated with these pollutants.

Dietary intake of PCDDs/PCDFs and coplanar PCBs among the Japanese population estimated by duplicate portion analysis: a low proportion of adults exceed the tolerable daily intake.

Dietary intake of dioxins was estimated by duplicate portion analysis of consecutive 3-day food samples among 86 men and 288 women (aged 17-72 years), who were living in 75 different areas of 25 prefectures in Japan. The mean (median) intake of PCDDs+PCDFs, coplanar PCBs (co-PCBs), and total dioxins, expressed on the basis of toxicity equivalents (TEQ), was 0.46 (0.34), 0.59 (0.39), and 1.06 (0.79)pg/kg body weight/day, respectively. Dietary intake was highest in fishing areas, followed by farming and urban areas. In multiple regression analysis, TEQs of PCDDs+PCDFs, co-PCBs, and total dioxins were positively associated with age and intake amount of fish and shellfish, and milk and dairy products, and negatively associated with survey year. There were significant positive correlations between dietary intake and blood levels for TEQs of PCDDs+PCDFs, co-PCBs, and total dioxins (Pearson r=0.35-0.36). The proportion of those whose dietary intake exceeded the tolerable daily intake (TDI), set by the World Health Organization (4pg TEQ/kg/day) and European Union (2pg TEQ/kg/day), was estimated at 2.1% and 10.4%, respectively. However, these proportions were considered to be overestimated because of the effect of day-to-day within-person variation. Therefore, the ratio of within- and between-person variance was estimated by applying random effects one-way analysis of variance to repeated measurements for another group of 35 persons. When the effect of within-person variation of dietary intake was accounted for, the proportion of subjects whose long-term intake exceeded the TDI of WHO and EU decreased to 0.06% and 2.9%, respectively.

Associations of environmental exposure to dioxins with prevalent diabetes among general inhabitants in Japan.

The aim of this study was to evaluate the associations of environmental exposure to dioxins with diabetes among general inhabitants in Japan. A cross-sectional study was performed on 1374 participants, who were not occupationally exposed to dioxins, aged 15-73 years, living widely in 75 different residential areas of 25 prefectures in Japan through 2002-2006. Seven polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs), 12 dioxin-like polychlorinated biphenyls (PCBs), which are assigned a toxic equivalency factor, and biochemical factors were determined in fasting blood. A questionnaire survey on life-style including past history of diseases and treatments was also performed. We examined the associations of the accumulated toxic equivalents (TEQs) of PCDDs+PCDFs, dioxin-like PCBs and total dioxins with prevalent diabetes. Simple and partial correlation analyses revealed that HbA1c correlated with the accumulated TEQs of PCDDs+PCDFs, dioxin-like PCBs and total dioxins. In logistic regression analyses, the third and the highest quartiles of dioxin-like PCBs had adjusted odds ratios (ORs) of 3.07 (95% CI 1.16-8.81) and 6.82 (95% CI 2.59-20.1) compared to the reference (first plus second quartiles). On the other hand, the highest but not the third quartiles of PCDDs+PCDFs and total dioxins had significantly higher adjusted ORs compared to the respective references. These associations persisted when the subjects with poor liver or poor renal function were removed from the analysis. This recent representative data from general inhabitants in Japan showed associations of environmental exposure to dioxins, especially dioxin-like PCBs, with diabetes.

PCDDs/PCDFs and dioxin-like PCBs: recent body burden levels and their determinants among general inhabitants in Japan.

OBJECTIVE: The objective was to grasp the recent body burden levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (DL-PCBs) and to investigate their determinants among general inhabitants in Japan. METHODS: This study was performed on 1374 participants aged 15-73 years, who were not occupational exposure to PCDDs/PCDFs and DL-PCBs, living widely in 75 different residential areas of 25 prefectures in Japan. Seven PCDDs, ten PCDFs, twelve DL-PCBs, which are assigned a toxicity equivalent factor, and biochemical factors were determined in fasting blood. A questionnaire survey on life-style was also performed. RESULTS: The median of total toxicity equivalent (TEQ) was 20pgTEQ/g lipid. The TEQs of PCDDs/PCDFs, DL-PCBs and total TEQ increased with age. The intake frequency of fish-and-shellfish was positively associated with the TEQ of DL-PCBs in both sexes. Current smoking was negatively related to the TEQ of DL-PCBs in male subjects but not in female subjects. Feeding status was significantly related to the TEQs of PCDDs/PCDFs, DL-PCBs and total TEQ, being lowest in breast feeding and highest in never and bottle feeding. According to the results of subgroup analysis, parity was not associated with the TEQs. CONCLUSIONS: The fish-and-shellfish consumption may contribute to the accumulation of DL-PCBs, and smoking may induce some biological action for the elimination of DL-PCBs from the human body. Breast feeding is considered to be one of the major excretory pathways of PCDDs/PCDFs and DL-PCBs in women, while parity may not largely contribute to the elimination of these pollutants.

Variations in plasma selenium levels as a result of the menstrual cycle and pregnancy in healthy Japanese women.

Plasma levels of selenium (Se) were determined consecutively during a menstrual cycle of six women in three phases (i.e., menses, follicular, and luteal). To detect possible differences in relation to normal pregnancy, plasma levels of Se were also determined in paired samples of maternal and umbilical cord blood from 12 pregnant women. No periodic changes in the plasma Se levels were observed during the menstrual cycle. The intraindividual variation, estimated by coefficients of variation, ranged from 1.9% to 9.9% among the menstrual phases of the subjects. The plasma Se level during pregnancy did not differ significantly from those of nonpregnant women, and those in the second trimester and at delivery were at similar levels (1.58+/-.14 and 1.48+/-.20 mmol/L, respectively). Compared to the levels of maternal Se at delivery, the fetal cord plasma at birth had a significant lower Se level (1.23+/-.34 mmol/L, p<.05).

Fish intake, plasma omega-3 polyunsaturated fatty acids, and polychlorinated dibenzo-p-dioxins/polychlorinated dibenzo-furans and co-planar polychlorinated biphenyls in the blood of the Japanese population.

OBJECTIVES: To evaluate background exposure levels and determinants of the individual variations in the exposure to dioxins in Japan. METHODS: A cross-sectional study was performed on 131 men and 122 women (aged 20-76 years), who resided in five prefectures of Japan and had no occupational exposure to dioxins. Seven polychlorinated dibenzo-p-dioxins (PCDDs), ten polychlorinated dibenzo-furans (PCDFs) and 12 polychlorinated biphenyls (PCBs), which are assigned a toxicity equivalent factor, were determined in fasting blood. Biochemical analysis of plasma and a questionnaire survey on life-style, including dietary habit, were also performed. Factors associated with the levels of dioxin-related compounds in blood were evaluated by multiple linear regression. RESULTS: The median of total toxicity equivalents (TEQs) in men and women was 17 and 16 pg TEQ/g lipid, respectively, with no gender difference. After adjustment for age and other covariates, plasma concentrations of eicosapentaenoic acid, a biomarker of fish intake, were found to be positively associated with blood levels of total dioxin, PCDDs, PCDFs and PCBs, all of which were expressed on a TEQ basis (P<0.01). The frequency of intake of coastal fish, such as horse mackerel, mackerel and sardine, was also associated with TEQ-based concentrations of PCDFs (P=0.03) and PCBs (P=0.08). The intake of raw fish was positively related to total dioxins (P=0.06) and PCBs (P=0.03). CONCLUSIONS: The level of intake of marine fish, especially raw fish and coastal varieties, may be associated with increased blood levels of dioxin-related compounds among the population. Despite high fish consumption in Japan, the body burden of dioxins in the population was not found to be higher than that in western countries.

Fish eating and variations in selenium and mercury levels in plasma and erythrocytes in free-living healthy Japanese men.

The levels and its interindividual and intraindividual variations of selenium (Se) and mercury (Hg) in erythrocytes and plasma were investigated in seven healthy young men during a period of 10 wk, with emphasis on the relationship to the dietary intake of several defined food items. The intraindividual variation, estimated by coefficients of variation (CVs), was 9.9% for plasma Se (PSe), 9.5% for erythrocyte Se (ESe), 42.4% for PHg, and 11.7% for EHg on the average. Significant correlations were found for mean ESe levels in each subject and his fish-eating frequency during this study (r=0.752, p<0.01). Weekly PHg levels were also correlated with average fish-eating frequency in the corresponding week of blood collection (r=0.367, p<0.05). Fish intake within 24 h before blood collection influenced PHg levels significantly.