OBJECTIVEMaternal exposure to dioxins [polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (DFs)] during pregnancy is known to affect infant growth and neurodevelopment in humans and animals. The aim of this study was to investigate the relationship between newborn size and the concentration of dioxin isomers in breast milk and to subsequently evaluate the potential toxicity of each dioxin isomer among mothers living in sea coast areas who are at a high risk of contamination due to a high consumption of fish.

METHODSA total of 75 milk samples were obtained within 1 month of delivery from Japanese mothers living in the coastal areas of the Japan Sea. The relationships between the levels of seven dioxins and ten furan isomers in maternal breast milk, measured by high-resolution-gas chromatography/mass spectrometry, and the birth size of newborns, which is related to fetal growth, were investigated after adjustment for confounding factors.

RESULTSThe concentrations of 1,2,3,6,7,8-HxCDD (hexachlorodibenzo-p-dioxin), 2,3,4,7,8-PeCDF (pentachlorodibenzofuran), 2,3,4,6,7,8-HxCDF, and three dioxin toxic equivalent (TEQ) levels (PCDDs-TEQ, PCDFs-TEQ, and total-TEQ) in maternal breast milk were inversely correlated to newborn length even after adjustment for gestational weeks, infant sex, and maternal age and height. These isomers were abundant among the 17 isomers tested and reflected the TEQ levels. Only 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), the most toxic isomer, was negatively correlated with newborn head circumference, even after adjustment for gestational weeks, infant birth weight, and other confounding factors.

CONCLUSIONSBased on our results, fetal growth may be influenced by maternal total exposure to dioxins, but only exposure to 2,3,7,8-TCDD would appear to possibly affect fetal head size during pregnancy.

BACKGROUNDSeveral studies have suggested that the exposure to cadmium (Cd) increased mortalities from renal diseases, cardiovascular diseases and malignant neoplasm, including lung cancer and prostate cancer among inhabitants living in Cd-polluted areas and factory workers. This study aimed to assess the influence of environmental exposure to Cd on long term outcome of inhabitants living in an area polluted by Cd.

METHODSA 22-year follow-up study was conducted with 3119 inhabitants (1403 men and 1716 women) living in the Cd polluted Kakehashi River basin in Japan. The subjects were divided into 4 groups according to the amount of urinary Cd level (< 3.0 µg/g creatinine (Cr), 3.0 - 4.9 µg/g Cr, 5.0 - 9.9 µg/g Cr, and ≥ 10.0 µg/g Cr). Mortality was calculated by the person-years method. Hazards ratios (HR) and 95% confidence intervals (CI) were assessed by the Cox's proportional hazard model.

RESULTSCompared with urinary Cd < 3.0 µg/g Cr group, the HR of 5.0 - 9.9 µg/g Cr and ≥ 10.0 µg/g Cr groups were significantly increased after adjustment for age in both sexes: 1.24 (95%CI 1.01 - 1.51) and 1.48 (95%CI 1.17 - 1.90) for men; 1.64 (95%CI 1.17 - 2.28) and 1.78 (95%CI 1.27 - 2.50) for women. The most frequent cause of death was malignant neoplasm in men and cardiovascular diseases in women. The significant increase in mortality risk for cardiovascular diseases was observed in the subjects with ≥ 10 µg/g Cr in both sexes: 1.79 for men (95%CI 1.02 - 3.12) and 2.38 for women (95%CI 1.11 - 5.07). When the subjects were divided into 2 categories (< 20 µg/g Cr and ≥ 20 µg/g Cr), the HR of the urinary Cd ≥ 20 µg/g Cr group for nephritis and nephrosis were 4.82 (95%CI 1.07 - 21.61) in men and 7.92 (95%CI 1.77 - 35.33) in women, respectively. The significant increase was not observed for malignant neoplasm.

CONCLUSIONThese results suggest a dose-response relationship between Cd body burden and mortality for cardiovascular diseases, cerebrovascular diseases and nephritis and nephrosis.

Aged ; Aged, 80 and over ; Cadmium ; toxicity ; Cardiovascular Diseases ; mortality ; Cerebrovascular Disorders ; mortality ; Environmental Exposure ; adverse effects ; Female ; Follow-Up Studies ; Hazardous Substances ; Humans ; Japan ; Male ; Middle Aged ; Nephritis ; mortality ; Nephrosis ; mortality ; Proportional Hazards Models ; Risk Factors