Effects of maternal dioxin exposure on newborn size at birth among Japanese mother-infant pairs

<p><b>OBJECTIVE</b>Maternal 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.</p><p><b>METHODS</b>A 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.</p><p><b>RESULTS</b>The 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.</p><p><b>CONCLUSIONS</b>Based 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.</p>

Hiroshima survivors exposed to very low doses of A-bomb primary radiation showed a high risk for cancers

<p><b>OBJECTIVES</b>The aim of this study was to compare the risk for cancers of A-bomb survivors in the ongoing life span study (LSS) with unexposed groups consisting of the entire populations of Hiroshima prefecture and neighboring Okayama prefecture.</p><p><b>METHODS</b>The subjects consisted of the Hiroshima group reported in LSS report 12 (LSS-H group) and a control group (the entire populations of Hiroshima and Okayama-HPCG and OPCG, respectively). We estimated the expected number of deaths due to all causes and to cancers of various causes among the exposed survivors of the Hiroshima bombing in the LSS report 12 who died in the follow-up interval at ages similar to those of people in Hiroshima and Okayama prefectures who were aged 0-34 years at the time of the bombing in 1945. We compared the standardized mortality ratio (SMR) of the LSS-H group to that of the HPCG and OPCG (SMR-H and SMR-O, respectively).</p><p><b>RESULTS</b>Even at low and very low dose categories, the SMR-H and SMR-O were significantly high for all deaths, all cancers, solid cancers, and liver cancers in male subjects, and for uterus and liver cancers in female subjects, respectively. The results show that, if the dose estimations of the dosimetry system 1986 (DS86) are correct, there are significantly increased risks of cancer among even survivors exposed to the very low dose level.</p><p><b>CONCLUSIONS</b>The dose assumptions of DS86 have been criticized for underestimating doses in areas distant from the hypocenter. The contribution of residual radiation, ignored in LSS, and that of neutrons, underestimated by DS86, is suggested to be fairly high.</p>

Low fasting serum insulin in Japanese alcohol consumers does not imply improved coronary risk factors

<p><b>OBJECTIVE</b>The effects of alcohol consumption on coronary risk factors (CRFs) and insulin resistance (IR) have seemed equivocal in previous studies. This study aimed to clarify the implications of low fasting blood insulin observed in alcohol consumers as related to CRFs and IR.</p><p><b>METHODS</b>A cross-sectional observation in 2133 middle-aged healthy Japanese men for associations of increases in alcohol consumption, fasting serum insulin concentration and serum gammaglutamyltransferase (GGT) activity with the major CRFs of high systolic blood pressure (SBP), fasting serum glucose, triglycerides (TG), total- and LDL-cholesterol (tCh&LDLc) and low serum HDL-cholesterol (HDLc).</p><p><b>RESULTS</b>Increased alcohol consumption was related to higher SBP, serum GGT, glucose and HDLc, and lower serum LDLc and insulin. Although high serum insulin was significantly related to all of the CRFs in all nondrinkers, moderate drinkers consuming up to 59 ml of alcohol per day and excessive drinkers consuming more, the means of SBP, serum glucose and HDLc were significantly higher and serum LDLc was lower in drinkers than in nondrinkers at any level of serum insulin, indicating that the good and bad profiles of CRFs in alcohol consumers are independent of their low fasting serum insulin. High serum GGT related to increased alcohol consumption and/or body weight was significantly associated with high serum insulin and all of the CRFs in all categories of alcohol consumption.</p><p><b>CONCLUSIONS</b>Low fasting serum insulin observed in drinkers does not imply improved CRFs, and thus may not imply improved IR. High serum GGT may reflect increased IR in both drinkers and nondrinkers.</p>

Low Fasting Serum Insulin in Japanese Alcohol Consumers Does Not Imply Improved Coronary Risk Factors

Objective: The effects of alcohol consumption on coronary risk factors (CRFs) and insulin resistance (IR) have seemed equivocal in previous studies. This study aimed to clarify the implications of low fasting blood insulin observed in alcohol consumers as related to CRFs and IR. Methods: A cross-sectional observation in 2133 middle-aged healthy Japanese men for associations of increases in alcohol consumption, fasting serum insulin concentration and serum gamma-glutamyltransferase (GGT) activity with the major CRFs of high systolic blood pressure (SBP), fasting serum glucose, triglycerides (TG), total- and LDL-cholesterol (tCh & LDLc) and low serum HDL-cholesterol (HDLc). Results: Increased alcohol consumption was related to higher SBP, serum GGT, glucose and HDLc, and lower serum LDLc and insulin. Although high serum insulin was significantly related to all of the CRFs in all nondrinkers, moderate drinkers consuming up to 59 ml of alcohol per day and excessive drinkers consuming more, the means of SBP, serum glucose and HDLc were significantly higher and serum LDLc was lower in drinkers than in nondrinkers at any level of serum insulin, indicating that the good and bad profiles of CRFs in alcohol consumers are independent of their low fasting serum insulin. High serum GGT related to increased alcohol consumption and/or body weight was significantly associated with high serum insulin and all of the CRFs in all categories of alcohol consumption. Conclusions: Low fasting serum insulin observed in drinkers does not imply improved CRFs, and thus may not imply improved IR. High serum GGT may reflect increased IR in both drinkers and nondrinkers.