Byung-Mi Kim

Interaction between GSTM1/GSTT1 Polymorphism and Blood Mercury on Birth Weight

Background Mercury (Hg) is toxic to both the reproductive and nervous systems. In addition, glutathione S-transferases (GSTs), which conjugate glutathione to a variety of electrophilic compounds, are involved in the detoxification of Hg. Objective In this study we examined the association between prenatal exposure to Hg and birth weight as well as the influence of GST polymorphisms. Methods The total Hg concentration in maternal and cord blood was measured from 417 Korean women and newborns in the Mothers and Children’s Environmental Health study from 2006 to 2008. Information on birth weight was collected from the patients’ medical records. The genotyping of glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) polymorphisms was carried out using polymerase chain reaction. Regression analysis was performed to determine the association between the blood Hg concentration and birth weight in mothers with GSTM1 and GSTT1 polymorphisms. Results The geometric mean levels of Hg in the maternal blood during late pregnancy and in cord blood were 3.30 μg/L and 5.53 μg/L, respectively. For mothers with the GSTT1 null genotype, elevated Hg levels in maternal blood during late pregnancy were associated with an increased risk of lower birth weight. For mothers with both GSTM1 and GSTT1 null genotype, both maternal and cord blood Hg levels were associated with lower birth weight. Conclusions This study suggests that the interactions of Hg with GSTM1 and GSTT1 polymorphisms play a role in reducing birth weight.

Prenatal exposure to PM10 and NO2 and children's neurodevelopment from birth to 24 months of age: Mothers and Children's Environmental Health (MOCEH) study

INTRODUCTION Previous studies have suggested adverse effects of maternal exposure to air pollution on neurodevelopment in early childhood. OBJECTIVES We aimed to investigate the association between prenatal exposure to particulates of less than 10 μm in diameter (PM10) and nitrogen dioxide (NO2) and neurodevelopment in children during the first 24 months of their lives. METHODS The MOCEH study is a prospective birth cohort study in South Korea. Average exposure levels to PM10 and NO2 during the entire pregnancy were estimated using the inverse distance weighting (IDW) method. A total of 520 mother-child pairs who completed neurodevelopmental assessments using the Korean Bayley Scale of Infant Development II (K-BSID-II) more than once at ages of 6, 12 and 24 months were included. Mental developmental index (MDI) and psychomotor developmental index (PDI) from the K-BSID-II were used as outcome variables. RESULTS There were negative associations between maternal exposure to PM10 and MDI (β=-2.83; p=0.003) and PDI (β=-3.00; p=0.002) throughout the first 24 months of life as determined by the generalized estimating equation (GEE) model. Maternal NO2 exposure was related with impairment of psychomotor development (β=-1.30; p=0.05) but not with cognitive function (β=-0.84; p=0.20). In a multiple linear regression model, there were significant effects of prenatal air pollution exposure on MDI (PM10: β=-4.60; p<0.001, NO2: β=-3.12; p<0.001) and PDI (PM10: β=-7.24; p<0.001, NO2: β=-3.01; p<0.001) at 6 months, but no significant association was found at 12 and 24 months of age. CONCLUSIONS The findings suggest that exposure to air pollution may result in delayed neurodevelopment in early childhood.

Population-attributable risk of low birthweight related to PM10 pollution in seven Korean cities.

To understand the preventable fraction of low birthweight (LBW) deliveries due to maternal exposure to air pollution during pregnancy in Korea, it is important to quantify the population-attributable risk (PAR). Thus, we investigated the association between maternal exposure to air pollution during pregnancy and LBW, and calculated the PAR for air pollution and LBW in seven Korean cities. We used birth records from the Korean National Birth Register for 2004. A geographic information system and kriging methods were used to construct exposure models. Associations between air pollution and LBW were evaluated using univariable and multivariable logistic regression, and the PAR for LBW due to air pollution was calculated. Of 177 660 full-term singleton births, 1.4% were LBW. When only spatial variation of air pollution was considered in each city, the adjusted odds ratios unit of particulate matter <10 microm in diameter (PM(10)) for LBW were 1.08 [95% confidence interval [CI] 0.99, 1.18] in Seoul, 1.24 [95% CI 1.02, 1.52] in Pusan, 1.19 [95% CI 1.04, 1.37] in Daegu, 1.12 [95% CI 0.98, 1.28] in Incheon, 1.22 [95% CI 0.98, 1.52] in Kwangju, 1.05 [95% CI 1.00, 1.11] in Daejeon and 1.19 [95% CI 1.03, 1.38] in Ulsan. The PARs for LBW attributable to maternal PM(10) exposure during pregnancy were 7%, 19%, 16%, 11%, 18%, 5% and 16% respectively. Because a large proportion of pregnant women in Korea are exposed to PM(10)--which is associated with LBW--a substantial proportion of LBW could be prevented in Korea if air pollution was reduced.

BTEX exposure and its health effects in pregnant women following the Hebei Spirit oil spill

OBJECTIVES We evaluated the health effects of exposure to BTEX (Benzene, Toluene, Ethylbenzene, m,p-Xylene, o-Xylene) in the Taean area after the Hebei Spirit oil spill. METHODS We used a questionnaire survey to look for health effects among 80 pregnant women 2 to 3 months following the Hebei Spirit oil spill. Their BTEX exposures were estimated using the CALPUFF method. We then used a multiple logistic regression analysis to evaluate the effects of BTEX exposure on the womens health effets. RESULTS Pregnant women who lived near the accident site reported more symptoms of eye irritation and headache than those who lived farther from the site. There was a trend of decreasing symptoms with an increase in distance from the spill site. Pregnant women exposed to higher ambient cumulative levels of Xylene were significantly more likely to report symptoms of the skin (OR 8.01 95% CI=1.74-36.76) in the first day after the accident and significantly more likely to report abdominal pain (OR 3.86 95% CI=1.02-14.59 for Ethylbenzene, OR 6.70 95% CI=1.82-24.62 for Xylene) during the 1st through 4th days following the accident. CONCLUSIONS This study suggests that exposure to BTEX from an oil spill is correlated with an increased risk of health effects among pregnant women. This implies the need to take proper measures, including the development of a national policy for environmental health emergencies and a plan for studying the short- and long-term chronic health effects associated with such spills.

Neurodevelopment in Early Childhood Affected by Prenatal Lead Exposure and Iron Intake.

AbstractNo safe threshold level of lead exposure in children has been recognized. Also, the information on shielding effect of maternal dietary iron intake during pregnancy on the adverse effects of prenatal lead exposure on childrens postnatal neurocognitive development is very limited. We examined the association of prenatal lead exposure and neurodevelopment in children at 6, 12, 24, and 36 months and the protective action of maternal dietary iron intake against the impact of lead exposure.The study participants comprise 965 pregnant women and their subsequent offspring of the total participants enrolled in the Mothers and Childrens environmental health study: a prospective birth cohort study. Generalized linear model and linear mixed model analysis were performed to analyze the effect of prenatal lead exposure and mothers dietary iron intake on childrens cognitive development at 6, 12, 24, and 36 months.Maternal late pregnancy lead was marginally associated with deficits in mental development index (MDI) of children at 6 months. Mothers having less than 75th percentile of dietary iron intake during pregnancy showed significant increase in the harmful effect of late pregnancy lead exposure on MDI at 6 months. Linear mixed model analyses showed the significant detrimental effect of prenatal lead exposure in late pregnancy on cognitive development up to 36 months in children of mothers having less dietary iron intake during pregnancy.Thus, our findings imply importance to reduce prenatal lead exposure and have adequate iron intake for better neurodevelopment in children.

Prenatal exposure to perfluorinated compounds affects thyroid hormone levels in newborn girls.

Perfluorinated compounds (PFCs) are ubiquitous in the environment and have been detected in humans and wildlife. Exposure to PFCs has decreased in the United States recently, while exposure to PFCs continues in Asian countries, which represents a public health concern. Various mechanisms by which PFCs affect fetal growth have been proposed, such as activation of peroxisome proliferators, disruption of thyroid hormones and changes in lipid metabolism. However, the overall evidence for an association with thyroid hormones is not strong. Therefore, we examined the effect of various prenatal PFCs on cord blood thyroid hormones: triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH) levels, and explored the endocrine disrupting effect of these PFCs on thyroid hormone levels in children according to gender. Two hundred and seventy-nine study participants were selected from among the enrolled participants in the Ewha Birth & Growth Retrospective Cohort, a retrospective birth cohort study conducted at Ewha Womans University Hospital, Seoul, Korea between 2006 and 2010. A generalized linear model was constructed to explore the association of PFCs and thyroid hormones. Further, an analysis stratified by gender was conducted. Our study shows that cord blood perfluoro n-pentanoic acid (PFPeA) was positively associated with cord blood T4 (p=0.01) level. Gender-specific analysis showed that prenatal PFCs: PFPeA and Perfluorohexane sulfonic acid (PFHxS) exposure significantly increased T4 (p<0.01) and T3 (p=0.03), respectively, while perfluorononanoic acid (PFNA) decreased TSH (p=0.04) concentration in newborn girls. Thus, prenatal PFC exposure may disrupt thyroid hormone homeostasis. Thyroid hormones play a crucial role in fetal development and may have gender specific action. Hence, these results are of utmost importance in high-risk groups, such as pregnant women and children.

The Perceived Symptom and Preventive Behavior Related to Asian Dust Event: in South Korean and Chinese

Recently rapid environmental changes due to desertification and industrialization in China make a threat to Korea, especially during Asian Dust Event (ADE). This study was aimed to compare symptoms and behaviors related to ADE between Korea and China. We conducted questionnaires on self-reported symptoms and behaviors before and during ADE. Korean and Chinese subjects were grouped into children, adults, and elderly by nation (n

Path analysis of prenatal mercury levels and birth weights in Korean and Taiwanese birth cohorts

Prospective cohort studies of the effect of mercury (Hg) exposure on birth weight have shown conflicting results. We combined data from Taiwanese and Korean birth cohorts, and assessed the effects of Hg exposure on birth weight. The first cohort was drawn from the Mothers and Childrens Environmental Health (MOCEH) study performed in Korea from 2006 to 2010. The second cohort was enrolled from 2004 to 2005 and included singleton term births from the Taiwan Birth Panel Study (TBPS). In total, 1147 pregnant women were included in this study. A pooled analysis was performed to obtain combined estimates of the association between prenatal total Hg exposure and birth weight. A significant negative association between maternal and cord blood Hg and birth weight in the high-Hg group (Hg level>25th percentile) was detected (maternal blood: β=-0.056; 95% CI, -0.100 to -0.013, cord blood: β=-0.075; 95% CI, -0.121 to -0.028). Hg level showed a negative coefficient in the path analysis, indicating an adverse effect on birth weight (total effects: β=-0.177, P=0.01 in MOCEH, β=-0.204, P=0.03 in TBPS), but fish consumption exhibited a strong positive coefficient. In addition, fish consumption exerted a significant indirect effect on birth weight through exposure to cord blood Hg. Exposure to hazardous contaminants and beneficial nutrients may be highly correlated in those who frequently consume fish. Moreover, Hg in cord blood may adversely affect birth weight.

Birth Weight of Mercury Concentrations of Maternal and Umbilical Cord Blood in Pregnant Women

We evaluated the relationship between birth weight and mercury exposure levels in Seoul, Korea, by following a cohort of pregnant women and the outcomes of their pregnancies between 2001-2005. Eighty-five pregnant women were recruited into this study after obtaining informed consent. Samples were collected at delivery from normal pregnant women who were living in the city of Seoul, Korea. Mercury concentrations in 85 sets of maternal and cord blood samples were measured using a gold-amalgam collection method. We used multiple regression analysis to analyze the effect of mercury exposure on birth weight. The mean levels of total mercury concentrations were 5.41(ppb) in maternal blood of pregnant women and 3.58(ppb) in umbilical cord blood. The mean concentration of umbilical cord blood mercury exposures was higher than the level recommended by WHO. There was a significant correlation between maternal and cord blood mercury concentrations. Mercury concentrations of umbilical cord blood was associated with birth weight. In addition, after adjusting for potential confounding factors, we found that mercury exposure may reduce the birth weight. This study suggests that exposure to mercury concentration during pregnancy contributes to the risk of low birth weight. Therefore, prenatal and environmental education for various and possible sources of mercury exposure might be necessary for the good health of babies. The finding of this study supports the construction of national policy for environmental health management.