Sequential hair mercury in mothers and children from a traditional riverine population of the Rio Tapajós, Amazonia: Seasonal changes

Riverine populations of the Brazilian Amazon depend on fish for their principal source of protein, which changes in availability with seasonal fluctuations in the aquatic ecosystem. We report seasonal (high and low waters) and interannual changes in total mercury and methylmercury concentrations in hair of subsistence fish-eaters from a traditional riverine village on the banks of the Rio Tapajós in the Brazilian Amazonia. Retrospective exposure assessment was conducted from hair concentrations in segments representative of 2 years. A total of 32 mothers and their 51 children were studied. They reported high fish consumption (4-14 times a week). Ranges of total mercury and methylmercury concentrations in hair were 1.0-51.0 and 0.5-41.4 μg g⁻¹, with means of 12.4 and 10.2 μg g⁻¹, respectively. The relative mean value for methylmercury was 80%. There was a significant correlation between mothers and children for both total-Hg (r=0.4826; P=0.003) and methyl-Hg (r=0.5214; P=0.004). Mercury concentrations along hair strands of individuals showed significant variation coinciding with seasonal high and low waters. The changes in the aquatic environment impacted fish species availability, which is reflected in the total and MeHg concentrations in hair.     

The mercury burden of the Czech population: An integrated approach

In this paper an integrated approach in assessment of the population exposure from various sources of total mercury (THg) oral intake in the Czech Republic is presented. The information on total mercury levels in diet, drinking water, surface urban soil and body fluids and tissues stem from the Czech national Environmental Health Monitoring System (EHMS) operated since 1994. The THg concentration was determined by the special atomic absorption spectrophotometer AMA 254. The data on THg content in food from the sales network were collected in 12 cities. The estimated average dietary intake representing more than 95% of weight of usual diet composition ranged 1–2% of the JECFA/FAO WHO provisional tolerable weekly intake (PTWI) value for total mercury (5 μg/kg b.w./week). Data on drinking water quality stem from the nationwide monitoring database. The content of THg in drinking water is generally low; only 0.2% of the Czech population supplied with drinking water from the distribution networks (total of 92% of the population) has a mercury intake from drinking water higher than 1% PTWI and not exceeding 5% PTWI. The estimation of potential mercury intake by unintentional consumption of soil in small children was based on THg content in surface soil of a total of 324 nursery schools in 24 cities and towns. Median value was 0.16 mg/kg. Human biomonitoring was performed in 9 Czech cities. In 2007, the mercury median values in blood of adults (N = 412) were 0.85 and 0.89 μg/l in males and in females, respectively; urine median value in adults was 1.10 μg/g creatinine. In 2008, the blood median value in children (N = 324) amounted to 0.35 μg/l; urine median value is 0.16 μg/g creatinine. In children's hair the median THg value was 0.18 μg/g. The correlation between fish consumption and blood THg levels was observed in both adults and children. Also the biomonitoring outputs did not reveal a substantial burden of the population.     

Prenatal and early childhood exposure to mercury and methylmercury in Spain, a high-fish-consumer country

Exposure to mercury, a risk factor for neurodevelopmental toxicity, was assessed in Spanish children (preschool children and newborns, n = 218) in a four-locations survey by performing mercury determination in hair. To assess the prenatal and children’s exposure and its potential risk, total mercury (THg) and methylmercury (MeHg) were analyzed and examined for associations with maternal sociodemographic characteristics and dietary intake through interviews and food frequency questionnaires. The mean THg in hair was 0.94 μg/g, ranging from 0.19 to 5.63 μg/g in preschool children and 1.68 μg/g (0.13–8.43 μg/g) in newborns. Associations between mercury levels in hair and fish consumption frequency were found regardless of the group evaluated. Neither other food item nor maternal covariates were associated with mercury levels in the newborn group. In children, the mean THg values among frequent fish consumers (more than four times per week) were almost threefold higher compared with non-consumers (1.40 vs. 0.49 μg/g). Newborns from mothers who had intake of fish two or more times per week exhibited nearly threefold higher hair levels than those who rarely or never consumed fish (2.26 vs. 0.78 μg/g). Finally, mercury levels in hair exceeded the EPA reference dose (RfD) of 0.1 μg Hg/kg body weight per day (equivalent to 1 μg Hg/g hair) in 42% of the population studied. Overall, we conclude that levels of mercury in Spain are among the highest in the non-exposed populations probably because of the relatively high fish consumption. J. Astray and B. Pérez-Gómez: On behalf of the Bio-Madrid Research Group.     

Hair mercury levels, fish consumption, and cognitive development in preschool children from Granada, Spain ,

The main source of human exposure to mercury is the consumption of fish contaminated with methylmercury, which may adversely affect early neurodevelopment. This study assessed mercury levels in hair of preschoolers in Spain, where fish consumption is elevated, with the aim of investigating the influence of their fish intake and other factors on mercury exposure, and evaluating their association with cognitive development. A population-based birth cohort from Granada (Spain) was studied at the age of 4 yr. Total mercury (T-Hg) levels were determined in children's hair, and daily fish intake was assessed by a food frequency questionnaire. The McCarthy Scales of Children's Abilities (MSCA) were used to assess children's motor and cognitive abilities. Complete data were gathered on 72 children, and multivariate analyses were performed to evaluate the influence of mercury exposure and fish intake on MSCA outcomes. Mean concentration of T-Hg in hair was 0.96 μg/g (95% confidence interval=0.76; 1.20 μg/g). T-Hg levels were associated with higher frequency of oily fish consumption, place of residence, maternal age, and passive smoking. After adjustment for fish intake, T-Hg levels ≥1 μg/g were associated with decrements in the general cognitive (−6.6 points), memory (−8.4 points), and verbal (−7.5 points) MSCA scores. Higher mercury exposure in children from this Mediterranean area was associated with cognitive development delay. Studies on the putative benefits of fish intake during early development should consider mercury exposure from different fish species.     

Associations of Prenatal Mercury Exposure From Maternal Fish Consumption and Polyunsaturated Fatty Acids With Child Neurodevelopment: A Prospective Cohort Study in Italy

Background

Mercury is a neurotoxin, and limited prenatal exposure to it can affect long-term child neurodevelopment. However, results of epidemiologic studies of such exposure have been inconsistent. We examined the association of prenatal mercury exposure from maternal fish consumption with child neurodevelopment in northern Italy.

Methods

A population-based cohort of 606 children and their mothers was studied from pregnancy to age 18 months. Mercury levels were measured in maternal hair and blood during pregnancy and in umbilical cord blood and breast milk. Levels of polyunsaturated fatty acids (PUFAs) were measured in maternal serum. Maternal and child intakes of fish were assessed by using a food frequency questionnaire. The Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III) was used to evaluate child neurodevelopment. Multivariate linear regression was used to examine the association of mercury exposure with BSID-III scores, after controlling for maternal fish intake, PUFAs during pregnancy, and several other confounders.

Results

Mean weekly fish intake during pregnancy was less than 2 servings. Mercury concentrations in biological samples were low (mean, 1061 ng/g in hair) and moderately correlated with fish intake, particularly of carnivorous species. Maternal ω-3 PUFA concentrations were poorly correlated with fish intake. Maternal intelligence quotient (IQ) and child intake of fish were significantly associated with neurodevelopment scores. In multivariate models, the level of Hg exposure was not associated with neurodevelopmental performance at 18 months.

Conclusions

In this Italian population, neurodevelopment at 18 months was associated with child intake of fresh fish and maternal IQ rather than with mercury exposure. The expected beneficial effect of maternal fish intake (from maternal ω-3 PUFAs) was not found.Key words: mercury, polyunsaturated fatty acids, nervous system development, fish, Bayley Scales of Infant and Toddler Development     

Lack of association of mercury with risk of wheeze and eczema in Japanese children: the Osaka Maternal and Child Health Study

Mercury can have profound and complicated effects on the immune system, and epidemiological evidence regarding the relationship between mercury exposure and allergic disorders has been sparse. We investigated the associations between mercury levels in maternal and children's hair and the risk of wheeze and eczema in Japanese children at 29–39 months of age. Study subjects were 582 Japanese mother–child pairs. Presence or absence of wheeze and eczema symptoms was determined based on the criteria of the International Study of Asthma and Allergies in Childhood. Adjustment was made for maternal age; residential municipality at baseline; maternal and paternal education; maternal and paternal history of allergic disorders; maternal energy-adjusted fish intake during pregnancy; maternal smoking during pregnancy; number of child's older siblings; child's sex; household smoking in the same room as the child; breastfeeding duration; and children's fish intake at the fourth survey. The prevalence of wheeze and eczema was 18.6% and 17.2%, respectively. The range of hair mercury levels was 0.26−6.05 μg/g in mothers and 0.13−9.51 μg/g in children. Neither maternal nor children's hair mercury levels were related to the risk of wheeze or eczema. Maternal and children's hair mercury levels in the second quartile were non-significantly inversely related to the risk of wheeze (adjusted odds ratios [95% confidence intervals] were 0.77 [0.41−1.44] and 0.57 [0.29−1.11], respectively) while those in the third quartile were non-significantly inversely associated with the risk of eczema (adjusted odds ratios [95% confidence intervals] were 0.77 [0.40−1.45] and 0.66 [0.33−1.30], respectively). The current study provides no evidence that hair mercury levels in either mothers or children are positively associated with the risk of wheeze or eczema in children aged 29–39 months in Japan, where fish intake is high.     

Total and methyl-mercury in hair and milk of mothers living in the city of Porto Velho and in villages along the Rio Madeira,Amazon, Brazil

High fish consumption and extended breastfeeding are hallmarks of traditional lifestyle in Western Amazonia. We studied sources of mercury exposure, fish-methylmercury (meHg) and dental-amalgam filling, in 75 urban and 82 rural lactating mothers. Total mercury was determined in all samples while meHg concentrations were determined in subsamples of milk (45) and hair (27) of urban mothers living in Porto Velho (PV) and in hair (46) and milk (37) of mothers living in traditional communities (TC) of the Rio Madeira. The TC mothers showed significantly higher median hair-Hg concentrations (8.2 μg g⁻¹) than PV mothers (1.3  μg g⁻¹). Median total Hg in milk of PV mothers (0.36 ng g⁻¹) was significantly lower (p = 0.0000) than that found in milk of TC mothers (2.30 ng g⁻¹). The median meHg concentrations in milk of TC mothers were also significantly higher (1.0 ng g⁻¹) than in milk of PV mothers (0.07 ng g⁻¹). For urban mothers with low fish consumption rates (and relatively higher dental amalgam fillings) the proportion of inorganic Hg in milk was higher (85%) than in TC (62%). In TC mothers 51% of breast milk Hg concentrations were above 2 ng g⁻¹ (world median concentrations), contrasting with 8% in PV mothers. Despite this, there was no significant correlation between total Hg concentrations in milk and either amalgam filling or daily fish consumption. Socioeconomic changes occurring in Western Amazonia are causing changes in fish-eating habits of urban mothers. However, traditional lifestyle and attendant high fish consumption in riverine populations can still impact total Hg and methylmercury concentrations in mothers’ milk and hair.     

Measles,mumps and rubella (MMR) vaccination has no effect on cognitive development in children – The results of the Polish prospective cohort study

Objectives

The aim of the study was to examine the hypothesis that MMR exposure has a negative influence on cognitive development in children. Furthermore, MMR was compared to single measles vaccine to determine the potential difference of these vaccines safety regarding children's cognitive development.

Methods

The prospective birth cohort study with sample consisted of 369 infants born in Krakow. Vaccination history against measles (date and the type of the vaccine) was extracted from physicians’ records. Child development was assessed using the Bayley Scales of Infant Development (BSID-II) up to 3rd year of life, Raven test in 5th and 8th year and Wechsler (WISC-R) in 6th and 7th year. Data on possible confounders came from mothers’ interview, medical records and analyses of lead and mercury level at birth and at the end of 5th year of life. Linear and logistic regression models adjusted for potential confounders were used to assess the association.

Results

No significant differences in cognitive and intelligence tests results were observed between children vaccinated with MMR and those not vaccinated up to the end of the 2nd year of life. Children vaccinated with MMR had significantly higher Mental BSID-II Index (MDI) in the 36th month than those vaccinated with single measles vaccine (103.8 ± 10.3 vs. 97.2 ± 11.2, p = 0.004). Neither results of Raven test nor WISC-R were significantly different between groups of children vaccinated with MMR and with single measles vaccine. After standardization to child's gender, maternal education, family economical status, maternal IQ, birth order and passive smoking all developmental tests were statistically insignificant.

Conclusion

The results suggest that there is no relationship between MMR exposure and children's cognitive development. Furthermore, the safety of triple MMR is the same as the single measles vaccine with respect to cognitive development.     

A mothers' perspective on fish and her child's fish consumption in Surakarta,Indonesia

BACKGROUD/OBJECTIVESUnderstanding the factors associated with fish consumption is necessary to determine strategies to improve the fish consumption particularly those high in omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA). The aim of this study was to analyse the correlation between a mother''s perspective on fish and actual fish consumption in their children.SUBJECTS/METHODSTwo hundred thirty-one elementary school children grade 3–6 and their mothers in Surakarta were recruited using multi stage random sampling for this study. Data was collected in July and August 2017. A validated questionnaire consisted of 3 topics including knowledge related to the health benefits and organoleptic properties of fish and cooking technique-related attitudes on fish were used to measure the mother''s response to the fish properties. A validated food frequency questionnaire and a food picture book of fish specifically designed for the survey were developed and used to assess fish consumption of the children. A χ² test was used to analyse the correlation between the mothers'' perspective on fish and their children''s fish consumption.RESULTSThe median fish consumption in children was 65 g/d with fried non-oily or lean fish, e.g., milkfish (locally called Bandeng) and catfish (locally called Lele) were consumed more than oily fish as well as processed fish products. Of all children, 31% met the fish consumption recommended by the Environmental Protection Agency-Food and Drug Administration 2017. There was no relationship between a mother''s knowledge related to health benefits, organoleptic properties and cooking technique-related attitude toward fish and her child''s fish consumption.CONCLUSIONSThe fish consumption of children is not influenced by their mother''s perspective on fish. Nutrition education strategies are warranted to improve fish consumption and maintain the optimal benefits by consuming fish, including fish high in n-3 LCPUFA.     

Fish Consumption Habits of Pregnant Women in Itaituba,Tapajós River Basin,Brazil: Risks of Mercury Contamination as Assessed by Measuring Total Mercury in Highly Consumed Piscivore Fish Species and in Hair of Pregnant Women

The Tapajós River basin in the Amazon region, Brazil is one of the most active gold mining areas in the world. In this study, we evaluated fish consumption habits and mercury exposure in 110 pregnant women in the city of Itaituba by measuring their total hair mercury concentrations. In addition, we investigated seasonal differences in mercury concentrations in two highly consumed piscivorous fish species, tucunaré (Cichla spp.) and pescada (Plagioscion squamosissimus). Total fish mercury concentrations (THg) during the dry season were 0.62±0.07 mg/kg for Cichla spp. and 0.73±0.08 mg/kg for P. squamosissimus. During the rainy season they were 0.39±0.04 and 0.84±0.08 mg/ kg, respectively. Of our participants 44 % declared that they ate Cichla spp. and 67 % P. squamosissimus. Mean mercury concentration in their hair was 1.6±0.2 mg/kg and was above the US Environmental Protection Agency (US EPA) reference dose of 1 mg/kg in 48 % of them. Mean fish THg concentrations were also above the joint Food and Drug Administration and US EPA safety limit of 0.5 mg/kg for P. squamosissimus during both seasons and for Cichla spp. during the dry season only. These results show that pregnant women should avoid consumption of these piscivorous fish species during pregnancy and call for a regular programme to monitor Hg levels in that area.Key words: Cichla spp., hair, methylmercury, Plagioscion squamosissimus     

Risk assessment of methylmercury based on internal exposure and fish and seafood consumption estimates in Taiwanese children

Fish and seafood consumption is a major source of human exposure to methylmercury (MeHg). This study evaluated the potential health risk of MeHg in Taiwanese children from fish and seafood consumption using a toxicokinetic model, hazard quotients and hazard indices (HIs). Two biomonitoring programs provided an important resource for blood specimens for assessing MeHg exposure in human populations. For internal exposures, total mercury (THg) was measured as a biomarker of MeHg in whole blood (WB) and red blood cells using inductively coupled plasma mass spectrometry and cold-vapor atomic absorption spectroscopy, respectively. The THg concentrations were used to estimate MeHg concentrations. Consumption of fish and seafood was assessed using the National Food Consumption database in Taiwan, while mercury concentrations in edible fish and seafood were collected from published studies in Taiwan. Our results indicated that 1) the highest median THg (representing estimated MeHg) daily intakes were found to decrease with increasing age in children consuming saltwater fish for age groups 0–3, 4–6, 7–12, and 13–18 years: 0.03?>?0.02?>?0.017?>?0.007 (μg?kg-BW^?1?day^?1); 2) HI greater than one, based on WB-THg, was found in 28% of 4–6-year-old children and 3) internal exposure estimates based on WB-THg, though slightly higher, were comparable to those based on fish and seafood consumption. The results support the use of dietary intake estimates as surrogates for internal blood MeHg levels in Taiwanese children to assess their exposure.     

Biomarkers of low-level mercury exposure through fish consumption in pregnant and lactating Slovenian women

In order to assess the mercury exposure of pregnant and lactating women in Slovenia, levels of total mercury (THg) and methylmercury (MeHg) were determined in hair, cord blood and breast milk. In addition, the frequency of fish consumption was estimated, because fish is generally the main pathway for human exposure to MeHg. Hair samples were collected from 574 women participating in this study, while cord blood and breast milk samples were collected from 446 and 284 women, respectively. As expected, the levels of THg in hair (median (Med)=297 ng/g, 10th percentile (P10)=73 ng/g, 90th percentile (P90)=781 ng/g), cord blood (Med=1.5 ng/g, P10=0.5 ng/g, P90=4.2 ng/g) and breast milk (Med=0.2 ng/g, P10=0.06 ng/g, P90=0.6 ng/g) were low, due to low consumption of fish (X=25 g/day). A significant linear correlation was found between levels of ln THg in hair and ln THg in cord blood (r=0.87, 95% confidence interval (CI): 0.84–0.89), between levels of ln THg in hair and ln MeHg in cord blood (r=0.94, 95% CI: 0.90–0.96) and between ln THg levels in cord blood and ln THg levels in breast milk (r=0.36, 95% CI: 0.25–0.47). Spearman's rank correlations between the frequency of fish consumption and THg in hair (r_s=0.35, 95% CI: 0.28–0.42), and between the frequency of fish consumption and THg in cord blood (r_s=0.43, 95% CI: 0.36–0.51) or MeHg in cord blood (r_s=0.31, 95% CI: 0.06–0.52) were weak. This could be due to the approximate information on fish consumption obtained from the questionnaires, the high variability of MeHg concentrations in fish and a relatively high proportion of inorganic mercury in the biomarkers which originates from sources other than fish. In conclusion, THg levels in cord blood, THg levels in hair and MeHg levels in cord blood are suitable biomarkers of low-level Hg exposure through fish consumption. Compared to cord blood, hair samples are easy to collect, store and analyse.     

Methylmercury Monitoring Study in Karakuwacho Peninsula Area in Japan

Methylmercury (MeHg) is a worldwide concern owing to its adverse health effects. To explore MeHg exposure burdens and the potential contributing factors in different subpopulations in a peninsula area (Karakuwacho) in Japan, a cross-sectional survey was performed. This study included 189 individuals from 102 families. The geometric means of total hair mercury (THg) were 5.74, 3.78 and 2.37 μg/g for adult males, females and children, respectively, of which 56.5 %, 30.9 % and 12.9 % had hair THg exceeding 5 μg/g, respectively. Tuna and mackerel were the common fish species that were positively correlated with hair THg levels in different subpopulations (standardized coefficient ranged from 0.20 to 0.58, p < 0.05). Frequent consumption of these fish species and a large amount of fish intake are likely major contributors of MeHg exposure in this area. Local-scale risk evaluation and risk communication should be highlighted in future studies.     

Hair mercury concentration and fish consumption: Risk and perceptions of risk among women of childbearing age

The purposes of this study were to assess the hair mercury concentration of women of childbearing age in Taiwan, and to calculate a hazard quotient (HQ) to evaluate the risk of fish consumption for these women. We also examined perceptions of risk associated with fish consumption and whether women in our study changed their habits in response to such risks. The average concentration of mercury was 1.73±2.12 μg g⁻¹ (range: 0.02-16.34 μg g⁻¹), exceeding the US EPA reference dose of 1 μg g⁻¹ in 52.9% of study subjects. The WHO tolerance limit of 10 μg g⁻¹ was exceeded in 1.5% of study subjects. Hair mercury concentration in groups who consumed fish was significantly higher than in groups who never consumed fish (p<0.05). The hazard quotient (exposure estimate/oral reference dose) exceeded 1.0 for 29% of subjects, based on the US EPA’s reference dose (0.1 μg kg⁻¹ d⁻¹), and the average HQ equaled 1.26. When told that some fish contain high levels of mercury that may be harmful for unborn babies, 67.6% of women still indicated that they would not change their amount of fish intake. The high hair mercury concentrations among women of childbearing age in Taiwan are a cause for concern, due to the effect on babies’ brain development. The government should provide specific information about risks and benefits of fish consumption for women to make risk-balancing decisions.     

Freshwater Fish–Consumption Relations With Total Hair Mercury and Selenium Among Women in Eastern China

Wild fish from Qiandao Hu, a reservoir in the Zhejiang Province in eastern China, have increased mercury (Hg) concentrations exceeding the World Health Organization’s (WHO) recommended guidelines. Due to the importance of freshwater biota in the local cuisine, dietary exposure to increased neurotoxic Hg is a concern in this region. An environmental hair-marker study was undertaken coincident with a cross-sectional epidemiologic study with 50 women age 17–46 years living in a Qiandao Hu fishing village. Diet, occupation, and other possible sources of Hg were recorded by way of questionnaires. Total mercury (THg) and selenium (Se) concentrations were measured in human hair samples and in important market fish species. Fish THg and Se concentrations were increased, with some fish concentrations >200 ng/g THg and 500 ng/g Se (wet weight [ww]). However, the average hair THg was low at 0.76 ± 0.51 μg/g dry weight, lower than the WHO’s no observable–adverse effect level (50 μg/g), whereas the average hair Se was 1.0 μg/g. Hair THg concentration was positively associated with the average mass of fish consumed weekly, indicating that fish consumption is the main contributor to hair THg in this geographic area. The age-related hair THg trend was not linear but instead demonstrated a rapid increase in THg before age 25 years, followed by consistent concentrations in all ages after age 25 years. There was a positive correlation (p < 0.001) between molar Se and Hg in the hair samples, suggesting a possible antagonistic relation. This is the first study examining the relation between dietary Hg exposure and hair THg in an eastern China community where freshwater fish, as opposed to marine fish, dominates the cuisine.     

Effects of methylmercury on neurodevelopment in Japanese children in relation to the Madeiran study

Objectives: A cross-sectional study was carried out to assess the effects of methylmercury exposure on neurodevelopment in Japanese children, in relation to the Madeiran cross-sectional study, and to estimate benchmark dose (BMD) levels using the data of two studies. Methods: Mercury levels in hair samples obtained from 327 Japanese mothers and their 7-year-old children, and methylmercury levels in the umbilical cord, were determined. Neurodevelopmental examinations, including the brainstem auditory evoked potential (BAEP), were performed on the children. Results: The medians of hair mercury were 1.63 (0.11–6.86) g/g for mothers and 1.65 (0.35–6.32) g/g for children, and a significant correlation was seen between the hair mercury levels in mothers and children. The maternal hair mercury was significantly correlated with the methylmercury in the umbilical cords obtained from 49 children. In 210 children whose mothers had not changed their dietary habits since pregnancy, most of the neurodevelopmental variables were not significantly related to hair mercury levels. The BAEP latencies were significantly shorter in the Japanese children than in the 113 Madeiran 7-year-old children, whose mothers had hair mercury of 1.12–54.5 (median 10.9) g/g. Significant relationships between the maternal hair mercury level and BAEP latencies (peaks III and V, and interpeak I–III) were found only in the merged data of Japanese and Madeiran children. When the lower 95% confidence limit of BMD (BMDL) was calculated, the BMDLs of mercury exposure for BAEP latencies in the merged data were between 6.9 and 10.5 g/g, and lower than those in the Madeiran children. Conclusions: It is suggested that Japanese children may ingest similar doses per body weight of methylmercury to their mothers. If maternal hair mercury was used as a proxy for mercury exposure at birth, no significant dose–effect associations with the BAEP latencies were observed in Japanese children with exposure levels below 6.9 g/g of hair mercury, but only when higher-level exposures from Madeiran children were included. The BMDL was lower for the merged data than for Madeiran children alone.     

胎儿期汞暴露对新生儿神经行为发育影响

目的 了解浙江省舟山市胎儿期汞暴露对新生儿神经行为发育影响,为采取干预措施提供参考依据。方法 采用自行设计调查表,对2006年3月-2007年7月在舟山市妇幼保健院整群随机抽取的418名新生儿母亲进行问卷调查,并检测新生儿脐带血汞及其母亲尿汞、血汞和发汞值,评定新生儿的神经行为发育情况。结果 新生儿脐带血汞平均汞含量为(7.9±4.7)μg/L;母亲尿汞、血汞和发汞平均汞含量为(2.8±3.2)μg/L、(5.7±4.0)μg/L和(1.2±0.7)mg/kg;Spearm an相关分析结果表明,新生儿脐带血汞与母亲尿汞、发汞和血汞,母亲尿汞与发汞、血汞,母亲发汞与血汞均呈正相关关系(P<0.01);除母亲发汞外,新生儿脐带血汞、母亲尿汞和血汞均随母亲怀孕期间吃鱼次数增多而增加(P<0.01);418名新生儿神经行为发育评分平均为(38.41±1.30)分,一般评估、原始反射、被动肌张力、主动肌张力和行为能力5个维度满分率分别为96.89%、94.98%、74.64%、65.55%和49.04%;多因素非条件Lo-gistic回归分析结果表明,新生儿脐带血汞含量≥18μg/L是新生儿NBNA得分的危险因素。结论 舟山市孕妇和新生儿汞暴露与食鱼有关;新生儿脐带血汞含量较高能影响新生儿神经行为发育。     

Maternal fish consumption, hair mercury, and infant cognition in a U.S. Cohort

Fish and other seafood may contain organic mercury but also beneficial nutrients such as n-3 polyunsaturated fatty acids. We endeavored to study whether maternal fish consumption during pregnancy harms or benefits fetal brain development. We examined associations of maternal fish intake during pregnancy and maternal hair mercury at delivery with infant cognition among 135 mother-infant pairs in Project Viva, a prospective U.S. pregnancy and child cohort study. We assessed infant cognition by the percent novelty preference on visual recognition memory (VRM) testing at 6 months of age. Mothers consumed an average of 1.2 fish servings per week during the second trimester. Mean maternal hair mercury was 0.55 ppm, with 10% of samples > 1.2 ppm. Mean VRM score was 59.8 (range, 10.9-92.5). After adjusting for participant characteristics using linear regression, higher fish intake was associated with higher infant cognition. This association strengthened after adjustment for hair mercury level: For each additional weekly fish serving, offspring VRM score was 4.0 points higher [95% confidence interval (CI), 1.3 to 6.7]. However, an increase of 1 ppm in mercury was associated with a decrement in VRM score of 7.5 (95% CI, -13.7 to -1.2) points. VRM scores were highest among infants of women who consumed > 2 weekly fish servings but had mercury levels 相似文献   

Methyl mercury and inorganic mercury in Swedish pregnant women and in cord blood: influence of fish consumption

We studied exposure to methyl mercury (MeHg) in Swedish pregnant women (total mercury [T-Hg] in hair) and their fetuses (MeHg in cord blood) in relation to fish intake. The women were recruited at antenatal care clinics in late pregnancy to participate in an exposure study of environmental pollutants. Fish consumption was evaluated using food frequency questionnaires including detailed questions on fish consumption. In addition, we determined inorganic mercury (I-Hg) and selenium (Se) in cord blood. On average, the women consumed fish (all types) 6.7 times/month (range 0-25 times/month) during the year they became pregnant. They reported less consumption of freshwater fish--species that might contain high concentrations of MeHg--during than before pregnancy. T-Hg in maternal hair (median 0.35 mg/kg; range 0.07-1.5 mg/kg) was significantly associated (R2 = 0.53; p < 0.001) with MeHg in cord blood (median 1.3 microg/L; range 0.10-5.7 microg/L). Both hair T-Hg and cord blood MeHg increased with increasing consumption of seafood (r = 0.41; p < 0.001 and r = 0.46; p < 0.001, respectively). Segmental hair analysis revealed that T-Hg closer to the scalp was lower and more closely correlated with MeHg in cord blood than T-Hg levels in segments corresponding to earlier in pregnancy. We found a weak association between Se (median 86 microg/L; range 43-233 microg/L) and MeHg in cord blood (r = 0.26; p = 0.003), but no association with fish consumption. I-Hg in cord blood (median 0.15 microg/L; range 0.03-0.53 microg/L) increased significantly with increasing number of maternal dental amalgam fillings.     

Risk for cognitive deficit in a population-based sample of U.S. children with autism spectrum disorders: variation by perinatal health factors

BackgroundFrom 30% to 60% of children with an autism spectrum disorder (ASD) have an IQ measure that falls in the intellectual disability (ID) range. It is not well studied whether, for children within this ASD subgroup, there is variation in the risk for low IQ based on a child's perinatal risk factors.Objective/HypothesesWe assessed whether preterm delivery and term small-for-gestational-age (tSGA) were associated with various measures of cognitive deficit among children with ASDs.MethodsA sample of 1129 singleton children born in 1994 and identified through school and health record review as having an ASD by age 8 years were selected from a U.S. population-based surveillance network. Mean IQ and dichotomous IQ outcomes indicating various levels of ID were examined according to whether a child was preterm (<37 weeks' gestation) or tSGA (term delivery and birth weight <10th percentile for gestational age of a U.S. referent). Results for the total sample and within race-ethnicity/maternal education strata were adjusted for child sex and ASD subtype classification.ResultsMean IQ was significantly (p < .05) lower in children delivered preterm (69.5) than term (74.5) and tSGA (69.3) than term appropriate-for gestational age (75.3). In stratified analyses, the preterm-IQ association was significant only among non-Hispanic white (NHW) children with maternal education at birth of high school or less; adjusted mean IQ was 8 points lower among those delivered preterm (65.4) than term (73.8). Term-SGA was associated with a significant 8-point deficit in adjusted mean IQ (75.5 vs. 83.8) in NHW children with maternal education greater than high school and a 6-point deficit that approached significance (68.4 vs. 74.5, p = 0.10) in NHW children with maternal education of high school or less. Non-Hispanic black children in both maternal education groups had significantly lower mean IQs than NHW children with little variation by preterm or tSGA.ConclusionsIn children with ASDs, the risk for concurrent ID or IQ deficit is associated with both preterm delivery and tSGA; these associations may vary by race-ethnicity and SES. Further studies of ASD-ID co-occurrence and the effectiveness of intervention strategies should consider both perinatal and sociodemographic factors.