In-utero arsenic exposure and growth of infants from birth to 6 months of age: a prospective cohort study in rural Bangladesh.

Arsenic exposure in postnatal life impacts the growth of children, but little is known about the effect of in-utero arsenic exposure on growth very early in childhood. The aim of this study was to examine the associations between in-utero arsenic exposure and the growth of infants from birth to 6 months of age using monthly follow-up data. A prospective cohort study was conducted in rural areas of Bangladesh with 108 mother-infant pairs. This study identified a negative association between in-utero arsenic exposure and head circumference of infants 1-6 months of age (coefficient = -1.20, 95% confidence interval [CI]: -1.97, -0.42), and the effect was more pronounced in the earlier ages of 1-3 months (coefficient = -0.88, 95% CI: -1.70, -0.05). Because head circumference is considered as a surrogate of brain size, our findings suggest that in-utero arsenic exposure influences brain growth during an important developmental period.

Differences in the responses of three plasma selenium-containing proteins in relation to methylmercury-exposure through consumption of fish/whales.

Putative protective effects of selenium (Se) against methylmercury (MeHg) toxicity have been examined but no conclusion has been reached. We recently reported the lack of serious neurological symptoms in a Japanese fish-eating population with high intakes of MeHg and suggested a potential protective role for Se. Here, relationships between levels of Hg and Se in the blood and plasma samples, with a quantitative evaluation of Se-containing proteins, obtained from this population were examined. While levels of the whole-blood Hg (WB-Hg) and plasma Se (P-Se) showed a positive correlation, stratified analysis revealed that they correlated only in samples with higher (greater than the median) levels of MeHg. A food frequency questionnaire showed that consumption of fish/whales correlated with WB-Hg, but not with P-Se, suggesting that the positive correlation between WB-Hg and P-Se might not be the result of co-intake of these elements from seafood. Speciation of plasma Se revealed the differences in the responses of two plasma selenoproteins, glutathione peroxidase (GPx) and selenoprotein P (SePP), in relation to Hg exposure. In the high-Hg group, SePP showed a positive correlation with WB-Hg, but GPx did not. In the low-Hg group, neither SePP nor GPx showed any correlation with WB-Hg. These observations suggest that the increase in P-Se in the high-Hg group might be associated with an increase in SePP, which may, in turn, suggest an increased demand for one or more selenoproteins in various organs, for which SePP supplies the element.

Arsenic exposure increases maternal but not cord serum IgG in Bangladesh.

BACKGROUND: Thousands of pregnant women are exposed to arsenic (As), which has been shown to lead to a higher risk of maternal and infant morbidity. We hypothesized that As-induced modifications to the humoral immune system may be partly responsible, and examined the relationship between As and immunoglobulin G (IgG). METHODS: Pregnant women were recruited in As-contaminated rural areas in Bangladesh. Blood and urine samples, and questionnaire data were collected. We analyzed data from 202 pregnant women and a subset of 121 mother-infant pairs. Urinary As was measured on inductively coupled plasma-mass spectrometry and adjusted with specific gravity (U-AsSG ). Maternal (IgGmat ) and cord (IgGcord ) serum total IgG were measured using immunoturbidity assay. RESULTS: The geometric mean U-AsSG (n = 202) was 69 µg/L (range, 3.1-1356 µg/L). Urinary-AsSG was significantly associated with IgGmat (n = 202; (r = 0.24; 95% confidence interval [CI]: 0.10-0.36; P < 0.001) and remained so after the inclusion of maternal-associated variables in a multiple-regression model (ß = 1.26; 95%CI: 0.47-2.05; P < 0.01). U-AsSG , however, was not significantly associated with IgGcord (n = 121), while IgGmat and IgGcord were also not associated with each other. CONCLUSIONS: Maternal As exposure was positively associated with IgGmat but not IgGcord . Elevated IgGmat may have implications as regards maternal morbidity and the placental transfer of specific IgGs. Further studies are required to better understand how As may affect maternal and child health by modifying the humoral immune system.

Methylmercury exposure and neurological outcomes in Taiji residents accustomed to consuming whale meat.

Methylmercury (MeHg) is a major environmental neurotoxicant that causes damage to the central nervous system. In Japan, industrial emission of MeHg has resulted in MeHg intoxication in Minamata and Niigata, the so-called Minamata disease. Humans are exposed to MeHg derived from natural sources, primarily fish and fish predators. Therefore, MeHg continues to be an environmental risk to human health, particularly in susceptible populations that frequently consume substantial amounts of fish or fish predators such as whale. This study aimed to investigate the health effects of MeHg exposure in adults. The subjects were 194 residents (117 males, 77 females; age 20-85 years) who resided in the coastal town of Taiji, the birthplace of traditional whaling in Japan. We analyzed hair for mercury content and performed detailed neurological examinations and dietary surveys. Audiometry, magnetic resonance imaging, and electromyography were performed to diagnose neurological defects. Whole blood mercury and selenium (Se) levels were measured in 23 subjects. The geometric mean of the hair mercury levels was 14.9 µg/g. Twelve subjects revealed hair mercury levels >50 µg/g (NOAEL) set by WHO. Hair mercury levels significantly correlated with daily whale meat intake. These results suggested that residents in Taiji were highly exposed to MeHg by ingesting MeHg-contaminated whale meat. Multivariate regression analysis demonstrated no significant correlations between hair mercury levels and neurological outcomes, whereas some of the findings significantly correlated with age. A significantly positive correlation between whole blood mercury and Se levels was observed and the whole blood mercury/Se molar ratios of all subjects were <1. These findings suggested that sufficient Se intake might be one of causes of the absence of adverse effects of MeHg exposure in this study.

Fish advisories in the USA and Japan: risk communication and public awareness of a common idea with different backgrounds.

Some countries have established fish advisories to manage fish consumption to minimize methylmercury exposure. Our objective was to compare the fish advisories and the resultant consumer behavior in the United States of America (USA) and Japan. Both countries have national consumption guidelines, but American states enjoy greater independence in issuing guidelines for local water bodies and vary in the information that is provided for the public. The proportion of the American public that has heard of state fish advisories is thought to be close to 30%. There is a concern that this low level of awareness extends to pregnant women. In Japan, the current problem is the lack of comprehensive studies on the public awareness of fish advisories. Nonetheless, there is evidence that fish consumption has decreased in both countries. In USA, there is a possibility that the strong emphasis on mercury toxicity drives the general population towards a trend of lower fish consumption. In Japan, the fish advisory encourages seafood consumption for nutritional benefits. Consequently, the decrease may be due to the shift towards a "Western diet". Also, the Japanese fish advisory seems to be less active in advocating the issue of fish consumption and mercury exposure, which may be partly responsible for the possible lesser attention of the consumers. Cultural factors may explain for the baseline difference in consumption and account partly for the change in Japanese consumer behavior. However, the dissimilarities in fish advisories may also be responsible for the variations in consumer behavior.

Cord blood levels of toxic and essential trace elements and their determinants in the Terai region of Nepal: a birth cohort study.

The purpose of this study is to evaluate the cord blood level of toxic and trace elements and to identify their determinants in Terai, Nepal. One hundred pregnant women were recruited from one hospital in Chitwan, Nepal in 2008. The cord blood levels of toxic [lead (Pb), arsenic (As), and cadmium (Cd)], essential trace elements [zinc (Zn), selenium (Se), and copper (Cu)], demographic, socioeconomic, and behavioral variables were measured. The mean values of Pb, As, Cd, Zn, Se, and Cu in cord blood level were found as 31.7, 1.46, 0.39, 2,286, 175, and 667 µg/L, respectively. In the multivariate regression model, cord blood As levels from less educated mothers were higher than those from educated mothers (coefficient = -0.01, 95% confidence interval [CI] = -0.02-0.00). The maternal age was positively associated with the cord blood Cd level (coefficient = 0.02, 95% CI = 0.01-0.03), while it was negatively associated with the cord blood As level (coefficient = -0.01, 95% CI = -0.03--0.01). Cord blood levels of Pb, Zn, Se, and Cu were not associated with maternal age, socioeconomic status, living environment, and smoking status. As and Cd levels were relatively lower than those reported in previous studies in Asia, while the levels of Pb and the trace elements were similar. Less educated mothers are more likely to become a higher in utero As source to their fetus, and fetuses of older mothers were more likely to have higher in utero Cd exposure in Terai, Nepal.