Prospective association between phthalate exposure in childhood and liver function in adolescence: the Ewha Birth and Growth Cohort Study

BACKGROUND

Phthalate exposure is ubiquitous due to the widespread use of plastic products in daily life, and affects several health outcomes, including metabolic diseases. In this study, we evaluated the effects of phthalate exposure in childhood on liver function in adolescence.  METHODS: Among 164 Ewha Birth and Growth Cohort Study participants followed up during two exposure periods (when the children were aged 3-5 and 7-9 years), 126 were followed up at age 10-15 years. To investigate the relationship between phthalate exposure during the two periods and liver enzyme levels (ALT, AST, γ-GTP) in adolescence, differences between groups and the dose-response relationship were analyzed. In addition, we investigated differences in liver enzymes between groups based on the combined exposure levels (high or low) during the two periods. The interaction effect between phthalates and BMI on liver enzyme levels was evaluated, stratified by sex.  RESULTS: In the 3-5 year-old exposure period, ALT levels tended to increase as MECPP levels increased, while γ-GTP levels tended to increase as MiBP, MnBP, and ∑DBP levels increased. In addition, the group exposed to consistently high levels of phthalates at both time points had higher liver enzyme levels compared to the group that had lower exposure. In particular, the interaction effect between some phthalate metabolites and BMI in 3-5 year olds affected AST and γ-GTP levels in adolescence only in girls.

CONCLUSIONS

Exposure to phthalates in daily life during childhood affects liver enzyme levels in adolescence. Elevated liver enzyme levels are associated with the development of metabolic syndrome, implying that attention should be paid to phthalate exposure during childhood.

Association of paternal cadmium and other heavy metal exposure to birth outcomes using propensity score matching

BACKGROUND

Human exposure to cadmium has various effects on health, especially on male reproductive organs. Although it is widely known that prenatal maternal cadmium exposure can affect birth outcomes, the effect of paternal exposure to cadmium remains unclear.

OBJECTIVES

This study aimed to evaluate the effect of paternal cadmium exposure on fetal growth by considering maternal cadmium exposure and exposure to other heavy metals, namely mercury and lead.

METHODS

The Mothers and Children's Environmental Health (MOCEH) study is a prospective birth cohort study in Korea. Overall, 1313 families (father-mother-child triple) without child abnormalities and who completed paternal whole blood cadmium assessments were included in this study. Families were divided into two subgroups based on the blood sampling periods, namely early and late pregnancy. Subjects were selected as follows: one family triple with a high level of paternal cadmium and two triples with low levels of paternal cadmium, using the method of propensity score matching. And linear regression analyses were performed.

RESULTS

The group with high paternal cadmium exposure (80% or more; 1.93 μg/L) had lower birth weight infants compared to the group with low cadmium concentrations (β(se) = -0.21(0.10); p-value = 0.0283). After stratification by infant sex, prenatal paternal cadmium exposure significantly reduced the birth weight of females in subgroups of different sampling times, namely early pregnancy (β(se) = -0.52 (0.22); p-value = 0.0170) and late pregnancy (β(se) = -0.43 (0.18); p-value = 0.0160). Finally, after performing propensity score matching in the early pregnancy measurement group, it was found that the prenatal exposure of father to cadmium significantly reduced birth weight in females (β(se) = -0.72(0.25); p-value = 0.0047).

CONCLUSION

This study assessed the effect of paternal cadmium exposure on birth outcomes in family units consisting of a father, mother, and child. Prenatal paternal cadmium exposure negatively affected birth weight, especially that of female, considering covariates and other heavy metals exposure, namely mercury and lead.

Cohort profile: the Ewha Birth and Growth Study

With the introduction of life-course epidemiology, researchers realized the importance of identifying risk factors in early life to prevent chronic diseases. This led to the establishment of the Ewha Birth and Growth Study in 2001; the study is a prospective birth cohort designed to provide evidence of early life risk factors for a child's growth and health. Participants were recruited from those who visited Ewha Womans University Mokdong Hospital (a tertiary hospital in southwest Seoul, Korea) for prenatal care at 24-28 weeks of gestation. In total, 891 mothers enrolled in this study between 2001 and 2006 and their offspring (n=940) were followed-up. Regular check-up examinations of offspring were conducted at 3 years, 5 years, and 7 years of age and every year thereafter. To consider age-related health issues, extensive data were collected using questionnaires and measurements. In 2021, the study subjects will reach 19 years of age, and we are planning a check-up examination for early adulthood. About 20 years have passed since the cohort data were collected, and we have published results on childhood health outcomes associated with prenatal and birth characteristics, genetic and epigenetic characteristics related to childhood metabolism, the effects of exposure to endocrine disruptors, and dietary patterns in childhood. Recently, we started reporting on topics related to adolescent health. The findings will facilitate identification of early life risk factors for chronic diseases and the development of interventions for diseases later in life.

The Association of Ovarian Reserve with Exposure to Bisphenol A and Phthalate in Reproductive-aged Women

BACKGROUND

Exposure to endocrine disrupting chemicals (EDCs) that influence the hormonal and homeostatic systems is known to be associated with gynecologic health risks in many countries. In this study, we evaluated exposure to EDCs associated with diminished ovarian reserve (DOR) and gynecologic health risks.

METHODS

This cross-sectional study was performed from September 2014 to November 2014 and included 307 Korean reproductive-aged women. Anthropometric measurements, laboratory tests with urine and blood sampling and pelvic ultrasound examinations were performed.

RESULTS

Urinary bisphenol A (BLA) level was significantly higher in the DOR group with anti-Müllerian hormone lower than 25 percentile (1.89 ± 2.17 ug/g and 1.58 ± 1.08 ug/g, P < 0.05). Urinary mono-(2-ethyl-5-hydroxyhexyl) phthalate, mono-(2-ethyl-5-oxohexyl) phthalate and mono-N-butyl phthalate, and substrates of phthalate were evaluated and no significant difference was observed between the DOR group and non-DOR group. Logistic regression analysis suggested an increase in infertility in high BPA exposure group and the odds ratio (OR, 4.248) was statistically significant after adjustment for age, birth control pills, and the age of menarche, parity, and waist circumference. High phthalate exposure was associated with endometrial polyp after adjustment (OR, 2.742).

CONCLUSION

BPA exposure might be associated with DOR and infertility. Meanwhile, endometrial polyp is increased in women with high phthalate exposure. Therefore, the risk of exposures to EDCs for reproduction should be a matter of concern in reproductive-aged women.

Dietary factors associated with inflammatory laryngeal disease in South Korea

Laryngeal inflammation causes not only benign diseases of the larynx, such as laryngitis and granuloma, but also malignancy. Dietary factors are known to control or modulate the inflammatory reaction in the body. To date, the association between laryngeal inflammation and dietary factors has not been reported using nationwide population-based data. The aim of this study was to analyze the association between several dietary factors and inflammatory laryngeal disease in the Korean population. This study analyzed the data from Korean National Health and Nutrition Examination Surveys which is cross-sectional nationwide-population-based study. Association between the dietary nutrient intake and the prevalence of inflammatory laryngeal diseases was analyzed in 21,116 participants who underwent a laryngoscopy and filled in the dietary intake questionnaires. Of the 21,116 participants included in the analysis, 758 (3.59%) were diagnosed with inflammatory laryngeal disease. Prevalence of inflammatory laryngeal disease was higher in men (4.58%) than in women (2.84%). The mean age of patients was 53.77 years. When analyzing the risk using propensity score matching, ILD group tend to consume more coffee and to intake less fiber and iron than normal group. On Logistic regression analysis, an increased intake of carbohydrate, fiber, and iron was associated with lowered risk of having ILD in female. The association between inflammatory laryngeal disease and dietary factors was prominent in the group aged ≥50 years and female. Increased intake of fiber, iron, and vitamin A were associated with lower risk in the group aged ≥50 years. In female, increased intake of fiber, iron were associated with lower risk of having ILD. In the group aged ≤50 years, only an increased consumption of makgeolli, Korean traditional rice wine, was associated with a higher risk of ILD.

Association between prenatal exposure to PM2.5 and the increased risk of specified infant mortality in South Korea

BACKGROUND

Findings from previous studies on the association between exposure to fine particulate matter (PM_2.5) and the risk of infant mortality were inconsistent. Thus, two main objectives of our study were to examine the association between exposure to PM_2.5 and specified infant mortality and to identify critical trimesters.

METHODS

We retrospectively created a birth cohort of singleton full-term infants born in South Korea between 2010 and 2015 using national birth and infant mortality data. The specified causes of infant mortality were circulatory and respiratory diseases, perinatal conditions, congenital anomalies, and sudden infant death syndrome. We performed 1:10 propensity score matching for various exposure windows: each trimester, prenatal, and postnatal (up to age 1). Conditional logistic regression was applied to estimate odds ratios (ORs) and 95% confidence intervals (CIs), while accounting for gestational age, birth weight, maternal education level, season of birth, and regions (metropolitan areas/provinces). We also conducted sex-stratified analyses and used different matching ratios for sensitivity analyses.

RESULTS

A total of 2,501,836 births and 761 deaths (0.03%) were identified in the birth cohort. We found an increased risk of infant mortality per 10 µg/m³ increase in PM_2.5 exposure during the prenatal period (OR: 1.29, 95% CI: 1.07-1.55). Exposure in the 1st and 2nd trimesters was linked to an elevated risk (OR: 1.19, 95% CI: 1.02-1.37; OR: 1.21, 95% CI: 1.04-1.40). However, no association was shown in the third trimester. PM_2.5 exposure in the 1st and 2nd trimesters was associated with elevated male infant mortality, but did not reach statistical significance in female infants. The use of different matching ratios did not significantly affect the results.

CONCLUSION

The study findings suggest that exposure to PM_2.5 could affect infant mortality differently by the timing of exposure and sex, which suggests a relation to fetal development. However, further investigations are warranted.

Macrophage-derived progranulin promotes allergen-induced airway inflammation

BACKGROUND

Progranulin (PGRN), mainly produced by immune and epithelial cells, has been known to be involved in the development of various inflammatory diseases. However, the function of PGRN in allergic airway inflammation has not been clearly elucidated, and we investigated the role of PGRN in allergic airway inflammation.

METHODS

Production of PGRN and various type 2 cytokines was evaluated in mouse airways exposed to house dust mite allergen, and main cellular sources of these molecules were investigated using macrophage, airway epithelial cell, and NKT cell lines. We elucidated the role of PGRN in allergic airway inflammation in mouse models of asthma using macrophage-derived PGRN-deficient mice and NKT cell knockout mice by evaluating cytokine levels in bronchoalveolar lavage fluids and histopathology. We also supplemented recombinant PGRN in the mouse models to confirm the role of PGRN in allergic airway inflammation.

RESULTS

PGRN production preceded other cytokines, mainly from macrophages, in the airway exposed to allergen. PGRN induced IL-4 and IL-13 production in NKT cells and IL-33 and TSLP in airway epithelial cells. PGRN-induced Th2 cytokine production was abolished in NKT-deficient mice. Finally, allergic inflammation was significantly attenuated in allergen-exposed PGRN-deficient mice, but inflammation was restored when recombinant PGRN was supplemented during the allergen sensitization period.

CONCLUSION

The presence of macrophage-derived PGRN in airways in the early sensitization period may be critical for mounting a Th2 immune response and for following an allergic airway inflammation pathway via induction of type 2 cytokine production in NKT and airway epithelial cells.

Development of novel NLRP3-XOD dual inhibitors for the treatment of gout

Gout is a crystalline-related arthropathy caused by the deposition of monosodium urate (MSU). Acute gouty arthritis is the most common first symptom of gout. Studies have shown that NOD-like receptor protein 3 (NLRP3) inflammasome as pattern recognition receptors can be activated by uric acid crystallization, triggering immune inflammation and causing acute gouty arthritis symptoms. Currently, the treatment of gout mainly includes two basic methods: reducing uric acid and alleviating inflammation. In this paper, 22 novel benzoxazole and benzimidazole derivatives were synthesized from deoxybenzoin oxime derivatives. These compounds have good inhibitory effects on NLRP3 and XOD screened by our research group in the early stage. The inhibitory activities of XOD and NLRP3 and their derivatives were also screened. Notably, compound 9b is a multi-targeting inhibitor of NLRP3 and XOD with excellent potency in treating hyperuricemia and acute gouty arthritis.

MC4R and HNF4α promoter methylation at birth contribute to triglyceride levels in childhood: A prospective cohort study

Although the changes in DNA methylation are assumed to be due to the association between adverse intrauterine conditions and adult metabolic health, evidence from human studies is rare. Little is known about the changes in DNA methylation present at birth that affect metabolic profiles in childhood. Previous studies have shown that the melanocortin 4 receptor (MC4R) and hepatocyte nuclear factor 4 alpha (HNF4α) genes are associated with obesity and metabolic disorders. Thus, we investigated the associations of the DNA methylation statuses of MC4R and HNF4α in cord blood with metabolic profiles in childhood.We collected data from 90 children 7 to 9 years of age included in the Ewha Birth & Growth Cohort Study in Korea. DNA methylation was analyzed by pyrosequencing. The children were split into 2 groups according to the cutoff triglyceride (TG) levels (<110 and ≥110 mg/dL).The methylation statuses of MC4R and HNF4α at birth were significantly associated with the TG level in childhood (P < .05). It was interesting to note that the methylation statuses of MC4R and HNF4α in cord blood were significantly decreased, whereas childhood body mass index was significantly increased, in children with high TG levels compared with children with low TG levels (P < .05).Our findings show that the methylation statuses of MC4R and HNF4α at birth are associated with metabolic profiles in childhood. These epigenetic modifications occurring in early life may contribute to subsequent metabolic-related disorders. Thus, we suggest that DNA methylation status in cord blood may be predictive of the risk of developing metabolic syndrome.

Associations of phthalate exposure with lipid levels and insulin sensitivity index in children: A prospective cohort study

We performed repeated measurements of phthalate metabolite concentrations during childhood and investigated the association of phthalate exposure with lipid levels and insulin resistance. This study included 164 subjects from the Korean Ewha Birth and Growth Cohort Study who underwent follow-up examinations at 3-5 and 7-9 years of age. We measured nine urinary phthalate metabolites, as well as fasting blood glucose, triglyceride (TG), and high-density lipoprotein-cholesterol (HDL-c) levels and the homeostatic model assessment for insulin resistance (HOMA-IR) value. We found that phthalate levels were higher in children at 3-5 years than at 7-9 years of age. Some phthalate metabolites were associated with increased TG and HOMA-IR levels at both age ranges. Repeated measurements of phthalate metabolites were performed to identify long-term exposure patterns. An increased level of mono(2‑ethylhexyl) phthalate (MEHP) was significantly associated with an increased TG level, and increased levels of MEHP, mono(2‑ethyl‑5‑oxohexyl) phthalate (MEOHP), and monoisononyl phthalate (MiNP) were significantly associated with an increased HOMA-IR value, at both age ranges. An increased level of mono-benzyl phthalate was associated with a decreased level of HDL-c at both ages. Our findings suggest that phthalate exposure during childhood is association with effects in terms of insulin-sensitivity index.

Endothelial Sox17 promotes allergic airway inflammation

BACKGROUND

IL-33, levels of which are known to be increased in patients with eosinophilic asthma and which is suggested as a therapeutic target for it, activates endothelial cells in which Sry-related high-mobility-group box (Sox) 17, an endothelium-specific transcription factor, was upregulated.

OBJECTIVE

We investigated the relationship between Sox17 and IL-33 and the possible role of Sox17 in the pathogenesis of asthma using a mouse model of airway inflammation.

METHODS

We used ovalbumin (OVA) to induce airway inflammation in endothelium-specific Sox17 null mutant mice and used IL-33 neutralizing antibody to evaluate the interplay between IL-33 and Sox17. We evaluated airway inflammation and measured levels of various cytokines, chemokines, and adhesion molecules. We also carried out loss- or gain-of-function experiments for Sox17 in human endothelial cells.

RESULTS

Levels of IL-33 and Sox17 were significantly increased in the lungs of OVA-challenged mice. Anti-IL-33 neutralizing antibody treatment attenuated not only OVA-induced airway inflammation but also Sox17 expression in pulmonary endothelial cells. Importantly, endothelium-specific deletion of Sox17 resulted in significant alleviation of various clinical features of asthma, including airway inflammation, immune cell infiltration, cytokine/chemokine production, and airway hyperresponsiveness. Sox17 deletion also resulted in decreased densities of Ly6c^high monocytes and inflammatory dendritic cells in the lungs. In IL-33-stimulated human endothelial cells, Sox17 showed positive correlation with CCL2 and intercellular adhesion molecule 1 levels. Lastly, Sox17 promoted monocyte adhesion to endothelial cells and upregulated the extracellular signal-regulated kinase-signal transducer and activator of transcription 3 pathway.

CONCLUSION

Sox17 was regulated by IL-33, and its genetic ablation in endothelial cells resulted in alleviation of asthma-related pathophysiologic features. Sox17 might be a potential target for asthma management.

Dietary patterns related to exposure to persistent organic pollutants based on the Ewha Birth and Growth Cohort

Persistent organic pollutants (POPs) are endocrine disruptors that are typically ingested in food. Using data from the Ewha Birth and Growth Cohort study, we identified dietary patterns related to blood persistent organic pollutant (POP) levels in children. In total, 188 Korean children (95 boys and 93 girls) aged 7-9 years were included in this study. Daily food intake data derived from a semi-quantitative food-frequency questionnaire were grouped into 33 food groups. Dietary patterns were analyzed using the reduced rank regression method, with blood POP levels as dependent variables. The marker polychlorinated biphenyl (PCB) pattern showed more weighted loading factors in the intake of shellfish/salted seafood, cheese, nuts and seeds, and total PCBs showed similar results. The dioxin-like PCB pattern was characterized by a higher intake of yogurt, beverages, and fruit and a lower intake of grain, seaweeds, and processed meat. Additionally, the total organochlorine pesticide (OCP) pattern showed positive factor loading values in shrimp and beverages, and negative factor loading values in seaweeds and processed meat. Each dietary pattern accounted for 25.0% of total OCPs, 22.9% of dioxin-like PCBs, 21.6% of marker PCBs, and 21.3% of total PCBs in blood. Dietary pattern scores were linearly related to blood POP levels, and this association remained after adjusting for sex, age, follow-up survey year, maternal educational level, body mass index, and total energy. Dietary patterns differed slightly among the individual POPs. Further studies are needed to develop an intervention strategy for children.

Does exposure to PM10 decrease age at menarche?

BACKGROUND

There has been a consistent decrease in age at menarche in South Korea. A potential risk factor for early menarche is exposure to particulate matter (PM), because endocrine-disrupting compounds emitted into air from anthropogenic sources may be incorporated into PM. The objective of this study was to examine the association between pre-menarcheal exposure to PM ≤ 10 μm in diameter (PM₁₀) and age at menarche in adolescents of South Korea using Korea National Health and Nutrition Examination Survey (KNHANES) 2010-2012 data.

METHODS

We used self-reported age at menarche of 639 girls aged 13-17 years in this study. The cut-off age for early menarche was set to 12 years. Based on each subject's address, 1-year, 2-year, and 3-year averages of annual mean PM₁₀ concentrations (models 1-3) were linked to KNHANES. Models were adjusted for body mass index (BMI), city size, household income level, maternal age at menarche, and second-hand smoke exposure at home. SURVEYREG and SURVEYLOGISTIC procedures were used to address the complex survey design of KNHANES.

RESULTS

Overall analysis showed that exposure to PM₁₀ has a significant effect on decreasing age at menarche. Multiple linear regression results suggested that each 1 μg/m³ increase in 1-year, 2-year, 3-year averages of annual mean PM₁₀ concentrations accelerated age at menarche by 0.046 years (95% CI: -0.064, -0.027; p < .0001), 0.038 years (95% CI: -0.059, -0.018; p = 0.0003),and 0.031 years (95% CI: -0.047, -0.015; p = 0.0002), respectively. Adjusted ORs for a 1 μg/m³ increase in PM₁₀ concentration were 1.08 (95% CI: 1.04 -1.12) for model 1, 1.06 (95% CI: 1.02 -1.10) for model 2, and 1.05 (95% CI: 1.01 -1.09) for model 3.

CONCLUSION

Our findings suggest that elevated PM₁₀ concentration can decrease age at menarche. This is the first study that investigates the association between exposure to PM₁₀ and age at menarche using a nationally representative sample of Koreans.

Association between the DNA methylations of POMC, MC4R, and HNF4A and metabolic profiles in the blood of children aged 7-9 years

Background

Proopiomelanocortin (POMC), melanocortin 4 receptor (MC4R), and hepatocyte nuclear factor 4 alpha (HNF4A) are closely associated with weight gain and metabolic traits. In a previous study, we demonstrated associations between the methylations of POMC, MC4R, and HNF4A and metabolic profiles at birth. However, little is known about these associations in obese children. To evaluate the clinical utility of epigenetic biomarkers, we investigated to determine whether an association exists between the methylations of POMC, MC4R, and HNF4A and metabolic profiles in blood of normal weight and overweight and obese children.

Methods

We selected 79 normal weight children and 41 overweight and obese children aged 7–9 years in the Ewha Birth and Growth Cohort study. POMC methylation levels at exon 3, and MC4R and HNF4A methylation levels in promoter regions were measured by pyrosequencing. Serum glucose, total cholesterol (TC), triglyceride, high-density lipoprotein cholesterol (HDL–c), and insulin levels were analyzed using a biochemical analyzer and an immunoradiometric assay. Partial correlation and multiple regression analysis were used to assess relationships between POMC, MC4R, and HNF4A methylation levels and metabolic profiles.

Results

Significant correlations were found between POMC methylation and HDL–c levels, and between HNF4A methylation and both TC and HDL–c levels. Interestingly, associations were found between POMC methylation status and HDL–c levels, and between HNF4A methylation status and TC levels independent of body mass index.

Conclusions

These findings show that POMC, MC4R, and HNF4A methylation status in the blood of children are associated with metabolic profiles. Therefore, we suggest that the DNA methylation status might serve as a potential epigenetic biomarkers of metabolic syndrome.

A prospective cohort study of the association between bisphenol A exposure and the serum levels of liver enzymes in children

BACKGROUND

Bisphenol A (BPA) is an endocrine disrupter that acts in an estrogen-like manner. Few studies have investigated the association between urinary BPA concentrations and adverse liver function. Additionally, most studies were cross-sectional in nature and included only adults.

OBJECTIVES

We evaluated BPA exposure levels and prospectively explored the association between BPA exposure and liver function in children.

METHODS

Data were retrieved from the ongoing prospective Ewha Birth and Growth Cohort Study. Urinary BPA concentrations were measured in 164 children at 3-5 and 7-9 years of age. At each visit, fasting blood and urine samples were collected, and questionnaires were completed. The associations between the BPA concentrations at these ages and the serum levels of liver enzymes measured at 10-13 years of age were analyzed (n = 113). Multiple regression analysis was performed with adjustment for covariates. We also explored whether the BPA level exhibited dose-response relationships with liver enzyme levels.

RESULTS

The median urinary BPA concentrations were 0.76μg/g creatinine at 3-5 years and 0.61μg/g creatinine at 7-9 years of age. The urinary BPA concentrations at the two ages were correlated significantly (r = 0.23, p < 0.01). The urinary BPA concentrations at 7-9 years, but not that at 3-5 years, was associated significantly with the serum levels of liver enzymes at 10-13 years of age (p < 0.05). Those in the top tertile of urinary BPA concentration had higher levels of liver enzymes than did others. After adjustment for covariates, dose-response relationships of the BPA level with liver enzyme levels were evident at 7-9 years, but not at 3-5 years. Notably, the effect size was larger and the dose-response relationships were more evident in boys than in girls.

CONCLUSIONS

Exposure of children to even low doses of BPA may adversely affect later liver function.

Children's Environmental Health Indicators for Low- and Middle-Income Countries in Asia

BACKGROUND

Given that low- and middle-income countries (LMICs) in Asia still have high child mortality rates, improved monitoring using children's environmental health indicators (CEHI) may help reduce preventable deaths by creating healthy environments.

OBJECTIVES

Thus, the aim of this study is to build a set of targeted CEHI that can be applied in LMICs in Asia through the CEHI initiative using a common conceptual framework.

METHODS

A systematic review was conducted to identify the most frequently used framework for developing CEHI. Due to the limited number of eligible records, a hand search of the reference lists and an extended search of Google Scholar were also performed. Based on our findings, we designed a set of targeted CEHI to address the children's environmental health situation in LMICs in Asia. The Delphi method was then adopted to assess the relevance, appropriateness, and feasibility of the targeted CEHI.

FINDINGS

The systematic review indicated that the Driving-Pressure-State-Exposure-Effect-Action framework and the Multiple-Exposures-Multiple-Effects model were the most common conceptual frameworks for developing CEHI. The Multiple-Exposures-Multiple-Effects model was adopted, given that its population of interest is children and its emphasis on the many-to-many relationship. Our review also showed that most of the previous studies covered upper-middle- or high-income countries. The Delphi results validated the targeted CEHI. The targeted CEHI were further specified by age group, gender, and place of residence (urban/rural) to enhance measurability.

CONCLUSIONS

Improved monitoring systems of children's environmental health using the targeted CEHI may mitigate the data gap and enhance the quality of data in LMICs in Asia. Furthermore, critical information on the complex interaction between the environment and children's health using the CEHI will help establish a regional environmental children's health action plan, named "The Children's Environment and Health Action Plan for Asia."

hMSCs suppress neutrophil-dominant airway inflammation in a murine model of asthma

Although chronic eosinophilic inflammation is a common feature in patients with asthma, some patients have neutrophil-dominant inflammation, which is known to be associated with severe asthma.Human mesenchymal stem cells (hMSCs) have shown promise in treating various refractory immunological diseases. Thus, hMSCs may represent an alternative therapeutic option for asthma patients with neutrophil-dominant inflammation, in whom current treatments are ineffective. BALB/c mice exposed to ovalbumin and polyinosinic:polycytidylic acid (Poly I:C) to induce neutrophilic airway inflammation were systemically treated with hMSCs to examine whether the hMSCs can modulate neutrophilic airway inflammation. In addition, cytokine production was evaluated in co-cultures of hMSCs with either anti-CD3/CD28-stimulated peripheral blood mononuclear cells (PBMCs) obtained from asthmatic patients or cells of the human bronchial epithelial cell line BEAS-2B to assess the response to hMSC treatment. The total number of immune cells in bronchoalveolar lavage fluid (BALF) showed a dramatic decrease in hMSC-treated asthmatic mice, and, in particular, neutrophilic infiltration was significantly attenuated. This phenomenon was accompanied by reduced CXCL15 production in the BALF. BEAS-2B cells co-cultured with hMSCs showed reduced secretion of IL-8. Moreover, decreased secretion of IL-4, IL-13 and IFN-γ was observed when human PBMCs were cultured with hMSCs, whereas IL-10 production was greatly enhanced. Our data imply that hMSCs may have a role in reducing neutrophilic airway inflammation by downregulating neutrophil chemokine production and modulating T-cell responses.

DNA methylations of MC4R and HNF4α are associated with increased triglyceride levels in cord blood of preterm infants

The association of preterm birth with obesity and metabolic syndrome later in life is well established. Although the biological mechanism for this association is poorly understood, epigenetic alterations of metabolic-related genes in early life may have important roles in metabolic dysfunction. Thus, we investigated the associations of DNA methylations of melanocortin 4 receptor (MC4R) and hepatocyte nuclear factor 4 alpha (HNF4α) with metabolic profiles in cord blood of term and preterm infants.We measured metabolic profiles in cord blood samples of 85 term and 85 preterm infants. DNA methylation and mRNA expression levels of MC4R and HNF4α in cord blood cells were quantified using pyrosequencing and real-time PCR. Triglyceride (TG) levels were grouped by percentile as low (<10th percentile), mid (11th-89th percentiles), and high (>90th percentile). A multiple linear regression model was used to assess the differential effects of DNA methylation on metabolic indices in cord blood between term and preterm infants.The beta-coefficients for associations between TG levels and methylation statuses of MC4R-CpG3 and HNF4α-CpG2 in the P1 promoter differed significantly between term and preterm infants (P = 0.04 and P = 0.003, respectively). DNA methylation statuses of MC4R-CpG3 and HNF4α-CpG2 in the P1 promoter were significantly lower in preterm infants in the high-TG group compared with those in the mid- and low-TG groups (P = 0.01). Notably, preterm infants in the high-TG group had higher TG levels in cord blood than term infants in the high-TG group (60.49 vs 54.57 mg/dL). In addition, MC4R and HNF4α expression levels were higher in preterm infants than in term infants (P < 0.05).Epigenetic alterations of the newly identified genes MC4R and HNF4α in early life might contribute to metabolic profile changes, especially increased TG levels, in the cord blood of preterm infants.

The Effect of Exposure to Persistent Organic Pollutants on Metabolic Health among KOREAN Children during a 1-Year Follow-Up

Previous evidence suggests the potential for adverse effects of persistent organic pollutants (POPs) on metabolic health even at low-dose exposure levels common among the general population, but there is less evidence of these associations among children. Therefore, as part of a prospective cohort study, 214 children were measured for POPs exposure. After the 1-year follow-up, we assessed the effect of circulating POPs exposure among 158 children aged 7-9 years (at baseline) on the change of metabolic components of metabolic syndrome using multiple regression analysis. In addition, we calculated the continuous metabolic syndrome (cMetS) score and assessed the variation among individuals by POPs exposure. The concentrations of marker polychlorinated biphenyls (PCBs) were significantly associated with increased change in diastolic blood pressure (BP) and triglyceride levels during a 1-year follow-up, after controlling for sex, age, household income, and change in body mass index. Total PCBs also showed a marginal association with increasing cMetS score from the baseline. Of the metabolic components, change in diastolic BP over time showed a notable association with specific PCBs, but no association with organochlorine pesticides. Here, we found that low-dose exposures to PCBs among children in the general population could negatively influence metabolic health, particularly diastolic BP. Increased disease sensitivity during childhood can continue to adulthood, thus, these results support the need for continuous assessment of the health impact of POPs.

Combined effect of folate and adiposity on homocysteine in children at three years of age

BACKGROUND/OBJECTIVES

Cardiovascular diseases is a major cause of death and is responsible for 23.8% of deaths in Korea. Clinical symptoms manifest in adulthood, but susceptibility begins in utero. Elevated homocysteine levels and adiposity might be linked to a greater risk in children as well as adults. We hypothesized that those who have simultaneous risk for folate and adiposity would be affected with elevated homocysteine levels at 3 years of age.

SUBJECTS/METHODS

From the ongoing birth cohort at Ewha Womans University Mok-Dong Hospital, we compared adiposity parameters, serum homocysteine, and folate levels in 238 children (118 boys and 120 girls) at three years of age. The relationship between birth outcome, current weight and body mass index (BMI), postnatal growth, and homocysteine level were assessed using correlation and general linear model. Additionally, we assessed the combined effect between blood folate status and adiposity on current homocysteine levels.

RESULTS

Birth characteristics were not correlated with homocysteine. Current weight, BMI, upper-arm circumference, skinfold thickness, waist circumference, and hip circumference were positively correlated with homocysteine at three years of age (P < 0.05). Folate level was negatively correlated with homocysteine at three years of age (P < 0.0001). A relative high anthropometric measure which is compatible with adiposity and low folate level was associated with high homocysteine levels.

CONCLUSION

We found a combined effect of adiposity and folate levels with homocysteine levels at three years of age. This implicates the beneficial role of folate supplementation in the high-risk population at an early age.

Clusterin Modulates Allergic Airway Inflammation by Attenuating CCL20-Mediated Dendritic Cell Recruitment

Recruitment and activation of dendritic cells (DCs) in the lungs are critical for Th2 responses in asthma, and CCL20 secreted from bronchial epithelial cells (BECs) is known to influence the recruitment of DCs. Because asthma is a disease that is closely associated with oxidative stress, we hypothesized that clusterin, an oxidative stress regulatory molecule, may have a role in the development of allergic airway inflammation. The aim of this study was to examine whether clusterin regulates CCL20 production from the BECs and the subsequent DC recruitment in the lungs. To verify the idea, clusterin knockout (Clu(-/-)), clusterin heterogeneous (Clu(+/-)), and wild-type mice were exposed intranasally to house dust mite (HDM) extract to induce allergic airway inflammation. We found that the total number of immune cells in bronchoalveolar lavage fluid and the lung was increased in Clu(-/-) and Clu(+/-) mice. Of these immune cells, inflammatory DCs (CD11b(+)CD11c(+)) and Ly6C(high) monocyte populations in the lung were significantly increased, which was accompanied by increased levels of various chemokines, including CCL20 in bronchoalveolar lavage fluid, and increased oxidative stress markers in the lung. Moreover, HDM-stimulated human BECs with either up- or downregulated clusterin expression showed that CCL20 secretion was negatively associated with clusterin expression. Interestingly, clusterin also reduced the level of intracellular reactive oxygen species, which is related to induction of CCL20 expression after HDM stimulation. Thus, the antioxidant property of clusterin is suggested to regulate the expression of CCL20 in BECs and the subsequent recruitment of inflammatory DCs in the airway.

Relationship of serum 25-Hydroxyvitamin D (25[OH]D) levels and components of metabolic syndrome in prepubertal children

OBJECTIVE

The relationship between 25-hydroxyvitamin D (25[OH]D) levels and the lipid and metabolic levels of the prepubertal normal population is unclear. Our goals were to investigate the association of serum 25(OH)D concentrations with lipid and metabolic levels in Korean prepubertal children ages 7-9 y.

METHODS

We followed 205 children, ages 7-9 y in the Ewha Birth and Growth Cohort study, a prospective cohort sample established in 2001-2006, from July to August 2011. We studied the association of serum 25-hydroxyvitamin D (25[OH]D) levels with components of metabolic syndrome and insulin resistance indices using multivariate regression analysis adjusted for body mass index (BMI) z-scores.

RESULTS

The mean age of the 205 subjects was 7.89 ± 0.85 y, and the sample included 109 boys (53.2%). The average 25(OH)D levels of all participants was 25.0 ± 5.4 ng/mL. After adjustment for age and sex, triacylglycerol levels were significantly associated with 25(OH)D (β = -0.02, P = 0.02) concentrations even after adjustment for BMI z-scores (β = -0.02, P = 0.04). However, other metabolic components were not correlated with 25(OH)D status. Those with the lowest quartile of 25(OH)D levels had the highest serum triacylglycerol levels (P = 0.04, Ptrend = 0.01).

CONCLUSIONS

We found that serum 25(OH)D levels were negatively associated with serum triacylglycerol levels, even independently of adiposity, in prepubertal children. This study suggests that 25(OH)D insufficiency is related to metabolic syndrome via the derangement of triacylglycerol metabolism.

Can proopiomelanocortin methylation be used as an early predictor of metabolic syndrome?

OBJECTIVE

The objectives of this study were to compare early predictive marker of the metabolic syndrome with proopiomelanocortin (POMC) methylation status and to determine the association among birth weight, ponderal index, and cord blood methylation status.

RESEARCH DESIGN AND METHODS

We collected pregnancy outcome data from pregnant women, cord blood samples at delivery, and blood from children (7-9 years old; n = 90) through a prospective cohort study at Ewha Womans University, MokDong Hospital (Seoul, Korea), from 2003-2005. POMC methylation was assessed by pyrosequencing. We divided subjects into three groups according to cord blood POMC methylation: the low methylation (<10th percentile), mid-methylation, and high methylation (>90th percentile) groups. We analyzed the association of POMC methylation status at birth with adiposity and metabolic components using ANCOVA and multiple linear regression analysis.

RESULTS

Birth weights (P = 0.01) and ponderal indices (P = 0.01) in the high POMC methylation group were significantly lower than in the mid-POMC methylation group. In terms of metabolic components of childhood, blood triglycerides (57.97, 67.29 vs. 113.89 mg/dL; P = 0.03, 0.01) and insulin (7.10, 7.64 vs. 10.13 μIU/mL; P = 0.05, 0.02) at childhood were significantly higher in the high POMC methylation group than in the low and mid-POMC methylation group.

CONCLUSIONS

High POMC methylation in cord blood was associated with lower birth weight, and children with high POMC methylation in cord blood showed higher triglycerides and higher insulin concentrations in blood. Thus, POMC methylation status in cord blood may be an early predictive marker of future metabolic syndrome.

Mendelian randomization analysis of the effect of maternal homocysteine during pregnancy, as represented by maternal MTHFR C677T genotype, on birth weight

Background

We used Mendelian randomization analysis to investigate the causal relationship between maternal homocysteine level, as represented by maternal methylenetetrahydrofolate reductase (MTHFR) C677T genotype, with the birth weight of offspring.

Methods

We recruited women at 24 to 28 weeks’ gestation who visited Ewha Womans University Hospital for prenatal care during the period from August 2001 to December 2003. A total of 473 newborns with a gestational age of at least 37 weeks were analyzed in this study. We excluded twin births and children of women with a history of gestational diabetes, gestational hypertension, or chronic renal disease. The association of maternal homocysteine concentration with the birth weight of infants was analyzed using 2-stage regression.

Results

MTHFR C677T genotype showed a dose–response association with homocysteine concentration for each additional T allele (P_trend < 0.01). Birth weight decreased from 120 to 130 grams as maternal homocysteine level increased, while controlling for confounding factors; however, the association was of marginal significance (P = 0.06).

Conclusions

Our results suggest an adverse relationship between maternal homocysteine level and birth weight. A reduction in homocysteine levels might positively affect birth outcomes.

Association of vitamin D concentrations with adiposity indices among preadolescent children in Korea

BACKGROUND AND OBJECTIVE

We aimed to investigate the association between serum 25-hydroxyvitamin D (25(OH)D) and anthropometric indicators of adiposity among Korean preadolescent children aged 7-9 years.

SUBJECTS AND METHODS

Children aged 7 to 9 from the Ewha Birth & Growth Cohort were followed up from July to August 2011. Serum 25(OH)D concentration was measured using radio immunoassay. We assessed the magnitude of cross-sectional association with vitamin D concentrations and indicators of adiposity [body mass index (BMI), waist circumference (WC), mid-arm circumference (MAC), body fat mass (BFM), percent body fat (PBF), and triceps skinfold thickness (TSF)] using multiple linear and logistic regression analyses adjusted for sex, age, birth order, maternal education, and fruit/fruit juice intake.

RESULTS

Thirty-two (16%) out of a total of 205 children showed an optimal level of serum 25(OH)D, but most children did not reach a sufficient level (<30 ng/mL) even in summer. The level of 25(OH)D was inversely associated with BMI (β=-0.10, p<0.01), WC (β=-0.28, p<0.01), and BFM (β=-0.12, p=0.02) after adjusting for confounding factors and showed marginal boundary with PBF (β=-0.20, p=0.06) and TSF (β=-0.11, p=0.08). Regarding the risk of overweight, a 13% protective effect per 1 ng/mL increase of 25(OH)D was shown even after adjusting for relevant confounding factors (adjusted odds ratio=0.87, 95% confidence interval 0.78-0.98).

CONCLUSIONS

We found that the 25(OH)D concentrations were inversely associated with adiposity indices in preadolescent children. This study suggests that adequate vitamin D intake in growing children is crucial to maintain an optimal vitamin D level to prevent obesity and obesity-related health problems later in life.

Associations between genetic polymorphisms of beta-2 adrenergic receptor and preterm delivery in Korean women

PROBLEM

We investigated genetic polymorphisms to understand the etiology of preterm delivery, which involves inflammatory cytokines and uterine contraction. Maternal polymorphisms of ADRB2, iNOS, and eNOS were examined, and associations between these and the risk of preterm delivery were sought.

METHOD OF STUDY

This study was performed on 166 Korean women who underwent preterm delivery and 289 normal controls. Logistic regression analyses were carried out to identify single genes and haplotypes that affect the risk of preterm delivery.

RESULTS

The G/G haplotype of ADRB2-rs1042713 and -rs1042714 was found to be associated with the risk of preterm delivery (OR = 1.90, 95% CI = 1.08-3.33, P-value = 0.0252). The genotype frequency of G allele in ADRB2-rs1042714 was associated with increased the risk of preterm delivery. However, after the adjustment of multiple comparison corrections, the association with preterm delivery was not remained significantly.

CONCLUSION

These findings possibly aid our understanding of the pathogenesis of preterm delivery and suggest that a haplotype with variants in maternal genes involved in adrenergic activation may lead to the dysregulation of uterine contractility and increase the risk of preterm delivery.

A model for prediction of spontaneous preterm birth in asymptomatic women

BACKGROUND

Preterm birth is a complex health problem with social, environmental, behavioral, and genetic determinants of an individual's risk and remains a major challenge in obstetrics. Recent research has caused improvements in predicting preterm birth; however, there is still controversy about the prediction of preterm birth in asymptomatic women. The purpose of this study was to determine if Bayesian filtering can be used in a clinical setting to predict spontaneous preterm birth in asymptomatic women.

METHODS

A model of predicting spontaneous preterm birth using PopBayes based on a Bayesian filtering algorithm was developed using a previously collected dataset, then applied to a prospectively collected cohort of asymptomatic women who delivered singleton live newborns at or after 24 weeks of gestation. Cases complicated with major congenital malformations were excluded.

RESULTS

The proportion of patients with spontaneous preterm birth was 18.4% (96 of 522) at <37 weeks gestation, 5.4% (28 of 522) at <34 weeks gestation, and 2.7% (14 of 522) at <32 weeks gestation. The match rates with the combination of demographic, clinical, and genetic factors using a Bayesian filtering method (PopBayes) were higher than the match rates using demographic and clinical factors only, including maternal age, maternal body mass index (BMI), prior preterm birth, education, occupation, income, and active and passive smoking. The match rates in preterm delivery before 32 weeks of gestation were higher than the match rates in preterm delivery before 37 and 34 weeks of gestation (94.3% vs. 84.7% and 82.0%, respectively). The negative predictive values for demographic, clinical, and genetic factors in predicting preterm delivery using PopBayes were consistently >90%.

CONCLUSIONS

We suggest that Bayesian filtering (PopBayes) is a customizable and useful tool in establishing a model for the prediction of preterm birth.

The Associations between Social Support, Health-Related Behaviors, Socioeconomic Status and Depression in Medical Students

OBJECTIVES

The objective of this study was to estimate the prevalence of depression in medical students and to evaluate whether interpersonal social support, health-related behaviors, and socio-economic factors were associated with depression in medical students.

METHODS

The subjects in this study were 120 medical students in Seoul, Korea who were surveyed in September, 2008. The subjects were all women and over the age of 20. Their age, body mass index (BMI), quality of sleep, diet, household income, smoking, alcohol consumption, exercise levels, and self-reported health status were surveyed. The degree of perceived social support was measured using the interpersonal support evaluation list (ISEL). Depression was evaluated using the center for epidemiology studies depression scale (CES-D).

RESULTS

The mean CES-D score was 14.1±8.6 and 37.1% of the participants appeared to suffer from depression. Low levels of perceived interpersonal support increased the risk of depression by more than 10 times and having higher household income did not necessarily decrease the risk of depression.

CONCLUSION

Medical students have a relatively high level of depression. Efforts should be made to encourage social support in order to promote mental health in medical students.

Parental socioeconomic status and unintentional injury deaths in early childhood: consideration of injury mechanisms, age at death, and gender

The aim of this study was to determine whether the socioeconomic status (SES) of parents influences early childhood unintentional injury deaths for different injury mechanisms and the gender and age at death of the child. Study design is a population-based retrospective study. Death certificate data from 1995 to 2004 were linked to birth certificate data from 1995 to 1996 for each child who died when aged < or = 8 years. Parental age, birth order, marital status, residence area, educational level, and occupation were used as indices for SES. Cox proportional-hazards analysis was employed. Our results indicate that nonmetropolitan residence, low parental education level, and a father working in a nonadministrative job or as a farmer were associated with a higher risk of death from injury for both boys and girls. A mother aged younger than 20 years and parents working in manual jobs were associated with a higher risk in boys only. The risks of some socioeconomic factors (low parental education and a father working in a manual job or as a farmer) were evident for children aged 1-4 years. The risks of rural residency tended to increase in older children, and the risk of injury from having a mother aged younger than 20 years increased for younger children. The risks of childhood injury deaths from traffic accidents, falls, and fire/burns were associated with the SES of the parents. Younger parents were associated with higher risks of injury deaths from traffic accidents (hazard ratio [HR]: father, 7.9; mother, 1.9) and falls (HR: father, 2.0; mother, 2.5). A father working as a farmer was associated with a higher risk of childhood injury death from fire/burns (HR = 4.0). In conclusion, the parental SES risk profiles of childhood injury deaths varied with the age and gender of the child, and with the injury mechanism. Therefore, reducing excess injury deaths during early childhood requires preventive efforts targeted at high-risk parents, and based on injury mechanism and on the gender and age of the child.

Oxidative stress-related gene interactions with preterm delivery in Korean women

OBJECTIVE

We hypothesized that the cytochrome P450IA1 (CYP1A1), glutathione S-transferases mu 1 (GSTM1), and theta 1 (GSTT1) polymorphisms are associated with the risk for preterm delivery. This study was undertaken to identify gene-gene interactions and haplotypes that increase the risk of preterm delivery.

STUDY DESIGN

This case-control study was performed in Korea on 145 women with preterm birth and 120 normal controls. Logistic regression and multifactor dimensionality reduction analysis were used to explore single genes and gene-gene interactions, which have an impact on the risk of preterm delivery, respectively.

RESULTS

The GSTM1 null genotype and the interaction between the CYP1A1-I462V and GSTM1 null type conferred a risk of preterm birth. The association between preterm delivery and the CYP1A1-T6235C/I462V haplotype plus GSTM1 null type was verified.

CONCLUSION

The interaction between the CYP1A1-I462V and GSTM1 null genotype were found to increase the risk for preterm birth in Korean women. This finding provides evidence of a gene-gene interaction, which has an impact on preterm delivery.

Paraoxonase gene polymorphism, serum lipid, and oxidized low-density lipoprotein in preeclampsia

OBJECTIVES

Human paraoxonase-1 (PON-1) is thought to play a role in preeclampsia and atherosclerosis, mainly through a reduction in low-density lipoprotein oxidation. Oxidized low-density lipoprotein (LDL) is very important in endothelial dysfunction of preeclampsia. The aim of the present study was to investigate the association between PON1 gene polymorphism and preeclampsia and to determine concentrations of serum lipid in preeclampsia patients. We aimed also to evaluate serum oxidized LDL levels in normal and preeclampsia patients.

STUDY DESIGN

We performed the present study in 57 control women and 32 preeclampsia patients. PON-1 genotypes were determined by polymerase chain reaction amplification and restriction fragment length polymorphism. Serum triglyceride, cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol levels were measured. We also measured serum levels of oxidized LDL by ELISA method.

RESULTS

There was no significant difference in PON1 genotype frequencies between the control and preeclampsia patients. The levels of serum cholesterol and high-density lipoprotein were significantly lower in preeclampsia patients compared with that of the control women (p=0.05, and p<0.01, respectively). The serum levels of oxidized LDL in preeclampsia patients were significantly higher than those in the control women (p=0.001).

CONCLUSIONS

These findings support the importance of the atherogenic lipid profile and oxidized LDL that is enhanced in preeclampsia, and these findings may be significant contributors to endothelial dysfunction.

[Clustering of metabolic risk factors and its related risk factors in young schoolchildren]

OBJECTIVES

We wanted to determine the distribution of the clustering of the metabolic risk factors and we wanted to evaluate the related factors in young schoolchildren.

METHODS

A cross-sectional study of metabolic syndrome was conducted in an elementary school in Seoul, Korea. We evaluated fasting glucose, triglyceride, HDL cholesterol, blood pressures and the body mass index, and we used parent-reported questionnaires to assess the potential risk factors in 261 children (136 boys, 125 girls). We defined the metabolic risk factors as obesity or at risk for obesity (> or = 85th percentile for age and gender), a systolic or diastolic blood pressure at > or = 90th percentile for age and gender, fasting glucose at > or = 110 mg/dl, triglyceride at > or = 110 mg/dl and HDL cholesterol at < or = 40 mg/dl.

RESULTS

There were 15.7% of the subjects who showed clustering of two or more metabolic risk factors, 2.3% of the subjects who showed clustering for three or more risk factors, and 0.8% of the subjects who showed clustering for four or more risk factors. A multivariate analysis revealed that a father smoking more than 20 cigarettes per day, a mother with a body mass index of = 25 kg/m2, and the child eating precooked or frozen food more than once per day were associated with clustering of two or more components, with the odds ratios of 3.61 (95% CI = 1.24-10.48), 5.50 (95% CI=1.39-21.73) and 8.04 (95% CI = 1.67-38.81), respectively.

CONCLUSIONS

This study shows that clustering of the metabolic risk factors is present in young schoolchildren in Korea, with the clustering being associated with parental smoking and obesity as well as the child's eating behavior. These results suggest that evaluation of metabolic risk factors and intervention for lifestyle factors may be needed in both young Korean children and their parents.

[Public perceptions of the risk of Asian dust storms in Seoul and its metropolitan area]

OBJECTIVES

In spite of the recent increased concern for Asian dust storms, there are few studies concerning how dangerous the general public recognizes these dust storms to be. This study examined the public's perceptions of the risk of the Asian dust storms and also the source of the information concerning the risk.

METHODS

A telephone interview survey using a standardized questionnaire was done for the adults living in Seoul and its metropolitan area from May 15th, 2003 to May 16th, 2003. The contents of the questionnaire were the sociodemographic characteristics, the perceptions of risk to the Asian dust storms, and the coping strategy of the study participants.

RESULTS

The study participants get their information on Asian dust storms mainly from TV newscasts and they have a good knowledge of them. They regard it as one of the most dangerous health risks, along with dioxin. They think that it is associated with allergic rhinitis, conjunctivitis and bronchial asthma, etc. Of the 500 study participants, 201(40.2%) persons suffered bodily discomforts during the Asian dust storm period.

CONCLUSIONS

Although there are uncertainties about the health risks of Asian dust storms, the public thinks these dust storms are very dangerous to health in many ways. This negative perception will not disappear easily. To fill the gap of the public's perceptions of the risk and the objective evidence of its health effects, more studies about its health effects and the methods to reduce exposure are required.

Risk Factors for Preterm Birth in Korea

Preterm birth is a major determinant of neonatal morbidity and mortality and remains one of the most serious problems in obstetrics. The aim of this study was to investigate the risk factors for preterm birth in Korean pregnant women. A total of 2,645 women were evaluated between 20 and 42 weeks' gestation at 5 centers using a prospective study design. The patient population is limited to singleton gestations. Demographic factors, socioeconomic statuses, previous and current medical histories, complications of current gestation, and drug and alcohol abuse were evaluated, and univariate and multivariate logistic regression analyses performed. Among nulliparous women, the factors that showed a significant association with preterm delivery were as follows; vaginal bleeding during pregnancy (OR 2.6, CI 1.7-4.2), and below USD 1,000 average income (OR 5.1, CI 1.9-13.5). The factors that showed a significant association with preterm delivery among multiparous women were as follows; a history of spontaneous abortion (OR 2.4, CI 1.1-5.2), and a history of preterm delivery (OR 3.5, CI 1.02-11.8). In conclusion, vaginal bleeding during pregnancy, below USD 1,000 of average income, prior spontaneous abortion, and prior preterm delivery, were positively associated with preterm birth.

Reduced L-arginine level and decreased placental eNOS activity in preeclampsia

Nitric oxide is produced enzymatically by the nitric oxide synthase (NOS), which converts L-arginine in the presence of oxygen to L-citrulline and NO. Moreover, it has been reported that asymmetric dimethylarginine (ADMA) acts as is an endogenous inhibitor of endothelial NOS (eNOS) by competing with the enzyme for L-arginine. In this study, we measured L-arginine and ADMA in normal and preeclamptic women, and also investigated the association between the Glu298Asp eNOS gene polymorphism and preeclampsia. Finally, we assessed eNOS expression levels in the placentas of both normal and preeclamptic patients, using Western blot and immunohistochemistry. L-arginine levels were found to be significantly lower in the preeclamptic women than in the normal pregnant women (p=0.02) but there were no significant differences in ADMA levels between the normal and preeclamptic women. We also determined there to be no association between the Glu298Asp eNOS gene and preeclampsia. With regard to placental eNOS expression, we detected a lower degree of eNOS expression in the preeclamptic syncytiotrophoblasts than in the normal syncytiotrophoblasts. We suggest that reduced L-arginine levels, rather than increased ADMA levels, contribute to the development of preeclampsia, and also that decreased placental eNOS expression constitutes a characteristic finding in preeclamptic placentas.

[Correlates of self-rated fatigue in Korean employees]

OBJECTIVE

To elucidate the correlates of self-rated fatigue in Korean employees.

METHODS

The data for 10,176 (men, 7984; women, 2192; mean age, 34.2; SD: 8.8) employees recruited from a nation-wide sample were examined. A structured questionnaire was used to measure the participants' fatigue, sociodemographics (sex, age, education, and marital status), job-related characteristics (work duration, grade at work, work hours, shiftwork, employment type, and magnitude of workplace), and health-related habits (smoking, drinking, coffee intake, and exercise). Two types of measurement for fatigue were used to evaluate the magnitude of fatigue: self-rated question and a standardized measurement tool (Multidimensional Fatigue Scale: MFS).

RESULTS

According to the self-rated fatigue, 32% of employees reported that they felt fatigue for the past two weeks, and 9.6% of males and 8.7% of females had experienced excessive fatigue (6 months or more). Hierarchical multiple regression analysis showed that fatigue measured by MFS was more common in women, younger, college or more graduated, single, and employees who do not regularly exercise. Fatigue was also associated with long work hours, and the size of the workplace (< 1000 employees).

CONCLUSIONS

These results suggest that fatigue has been considered as a common complaint, and that it is affected by job-related factors like work hours and the workplace size as well as sociodemographics or health-related behaviors. Further research is needed to clarify the effects of fatigue on adverse health,outcomes, work performance, work disability, sick absence and medical utilization, and to examine the relationship of job characteristics (e.g.: work demand, decision latitude) to fatigue.

[Epidemiology of psychosocial distress in Korean employees]

OBJECTIVE

To estimate the magnitude of psychosocial distress and examine eligible factors associated with the development of psychosocial distress in Korean employees, using a nationwide sample.

METHODS

A total of 6977 workers were recruited from 245 companies. A structured questionnaire was used to assess sociodemographics, health-related behaviors, job characteristics, social support at work, personality traits (locus of control, type A behavior pattern), self-esteem, and psychosocial distress.

RESULTS

The results showed that 23% of workers were categorized as high stress, 73% as moderate, and 5% as normal. Hierarchical multiple regression analysis showed that psychosocial distress was more common in younger workers, both male and female. Regular exercise was negatively associated with increase of psychosocial distress. In job characteristics, as expected, low decision latitude, high job insecurity, and low social support at work were related to high psychosocial distress. Personality traits such as locus of control and type A behavior pattern, and self-esteem were more powerful predictors of psychosocial distress than general characteristics, health-related behavior, and job characteristics. There were some gender differences. While men who are less educated and single (unmarried, divorced, and separated) experienced higher levels of psychosocial distress than those who are educated and married, women who feel high job demand experienced higher levels of psychosocial distress than those who feel low job demand.

CONCLUSIONS

The proportion of the high stress group was higher than expected, and psychosocial factors like social support and personality characteristics (e.g. locus of control, type A behavior pattern and self-esteem) were more significant factors for psychosocial distress than other variables. This finding suggests that some psychosocial factors, especially inadequate social support, low self-esteem and lack of internal locus of control for the development of psychosocial distress, will also operate as an intervention strategy in the worksite stress reduction program. It is strongly required that worksite stress reduction programs should be established in at both occupational and level as well as in individual levels.

Prenatal Exposure to PM10 and Preterm Birth between 1998 and 2000 in Seoul, Korea

OBJECTIVES

The exposure to particulate air pollution during the pregnancy has reported to result in adverse pregnancy outcome such as low birth weight, preterm birth, still birth, and intrauterine growth retardation (IUGR). We aim to assess whether prenatal exposure of particulate matter less than 10 (m in diameter (PM10) is associated with preterm birth in Seoul, South Korea.

METHODS

We included 382, 100 women who delivered a singleton at 25-42 weeks of gestation between 1998 and 2000. We calculated the average PM10 exposures for each trimester period and month of pregnancy, from the first to the ninth months, based on the birth date and gestational age. We used three different models to evaluate the effect of air pollution on preterm birth; the logistic regression model, the generalized additive logistic regression model, and the proportional hazard model.

RESULTS

The monthly analysis using logistic regression model suggested that the risks of preterm birth increase with PM10 exposure between the sixth and ninth months of pregnancy and the highest risk was observed in the seventh month (adjusted odds ratio=1.07, 95% CI=1.01- 1.14). We also found the similar results using generalized additive model. In the proportional hazard model, the adjusted odds ratio for preterm births due to PM10 exposure of third trimester was 1.04 (95% CI=0.96-1.13) and PM10 exposure between the seventh month and ninth months of pregnancy was associated with the preterm births.

CONCLUSIONS

We found that there were consistent results when we applied the three different models. These findings suggest that air pollution exposure during the third trimester pregnancy has an adverse effect on preterm birth in South Korea.

Placental superoxide dismutase, genetic polymorphism, and neonatal birth weight

BACKGROUND

The roles of antioxidants in the placenta and genetic susceptibility to oxidant chemicals in relation to neonatal birth weight have not been elucidated. We determined whether the level of placental manganese superoxide dismutase (MnSOD) and its genetic polymorphism plays any role in oxidative stress and neonatal birth weight.

METHODS

We measured placental MnSOD and determined MnSOD genetic polymorphism among 108 pregnant women who were hospitalized for delivery and their singleton live births in Korea. Main outcome measurements are maternal urinary malondialdehyde (MDA) and birth weight.

RESULTS

Maternal urinary concentrations of MDA were significantly associated with neonatal birth weight (P=0.04). The enzyme level of placental MnSOD was also significantly associated with MDA concentration (P=0.04) and neonatal birth weight (P&lt; 0.01). We observed dose-response relationships between placental MnSOD and maternal urinary MDA, and neonatal birth weight after adjusting for maternal weight, height, age, and neonatal sex. After controlling for covariates, MnSOD variant genotype increased maternal urinary MDA concentrations (P&lt; 0.01) and reduced birth weight by 149 gm (P=0.08).

CONCLUSIONS

This study demonstrates that the placental level of MnSOD during pregnancy significantly affects fetal growth by reducing oxidative stress, and that genetic polymorphism of MnSOD probably modulate the effects of oxidants on fetal growth.

The risk of folate and vitamin B(12) deficiencies associated with hyperhomocysteinemia among pregnant women

The purpose of this study was to compare the folate and vitamin B (12) levels in pregnant and nonpregnant women to evaluate the risk for hyperhomocysteinemia and for folate and vitamin B (12) deficiencies during pregnancy. Healthy pregnant women (n = 92; 24 to 28 gestational weeks; 18 to 39 years old) and nonpregnant women (n = 176; 18 to 39 years old) were sampled for serum levels of folate, vitamin B (12), and homocysteine. Pregnant women were less likely to have folate deficiency (8.0% versus 12.0%) but much more likely to have vitamin B (12) deficiency (46.1% versus 0.6%) than nonpregnant women. Those with lower dietary vitamin intakes were more likely to have vitamin B (12) deficiency. Serum folate and vitamin B (12) were negatively correlated with homocysteine among pregnant women. Pregnant women with folate deficiency were more likely to have hyperhomocysteinemia than those without folate deficiency. The vitamin B (12) level associated with hyperhomocysteinemia was lower in pregnant subjects than in nonpregnant subjects in this study, indicating that pregnant women require vitamin B (12) supplementation.