Hye Ah Lee

The Effect of Eating Behavior on Being Overweight or Obese During Preadolescence

Objectives Being overweight or obese is central to metabolic syndrome, and these characteristics constitute dominant risk factors for chronic diseases. Although behavioral factors, including eating habits and sedentary lifestyles, are considered to be determinants of obesity, the specific childhood factors that contribute to this condition have not been clearly defined. Methods The subjects consisted of 261 children aged 7-9 years who were recruited from an elementary school during October 2003. Information was obtained from their parents using a questionnaire focused on eating behaviors and lifestyle factors, additional data were also collected via anthropometric measurements and biochemical examinations, including blood tests. Results A total of 48 (18.4%) of the 261 children were overweight, and 34 (70.8%) had at least one other component of metabolic syndrome. Eating behaviors emerged as significant lifestyle-related risk factors for being overweight or obese. Those who engaged in overeating more than twice per week had three times the risk of being overweight (odds ratio [OR], 3.10, 95% confidence interval [CI], 1.39 to 6.92), and those who ate rapidly had three times the risk of being overweight (OR, 3.28; 95% CI, 1.68 to 6.41). Those who had fewer family meals (fewer than 2-3/month) had a nine times higher risk of being overweight than those who had family meals more frequently (at least 1/day) (OR, 9.51; 95% CI, 1.21 to 74.82). Conclusions This study showed that being overweight or obese during preadolescence is associated with a higher risk of metabolic syndrome and is related to unhealthy eating behaviors. Thus, weight-control strategies and healthy eating behaviors should be developed early in life to reduce the risk for metabolic syndrome.

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.

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

Abstract 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.

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.

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 (Ptrend < 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.

The preventive effect of breast-feeding for longer than 6 months on early pubertal development among children aged 7–9 years in Korea

OBJECTIVE The present study was performed to investigate whether breast-feeding is associated with early pubertal development among children 7-9 years old in Korea. DESIGN Children were divided into those who did and did not receive breast-feeding for 6 months or longer in accordance with the recommendations of the WHO. Pubertal status was determined by clinical examination using Tanner staging. SETTING Prospective observational study. SUBJECTS We conducted a follow-up study of children aged 7-9 years in 2011 who had taken part in the Ewha Birth & Growth Cohort study. RESULTS Fifty (22.8%) of the total of 219 children were in early puberty, with the proportion being slightly higher for girls (24.1%) than boys (21.4%). Children who had entered early puberty were taller, weighed more and had a higher concentration of insulin-like growth factor 1. Moreover, the change in weight Z-score from birth to follow-up was significantly lower in children who were breast-fed than in those who were not (weight Z-score change: 0.32 (sd 1.59) v. 0.77 (sd 1.61), respectively, P=0.04). Comparison of breast-feeding by puberty status indicated a preventive association with early puberty in children who were breast-fed for 6 months or longer (OR=0.37; 95% CI 0.18, 0.74). This association remained significant after adjustment for relevant covariates. CONCLUSIONS These results demonstrate a beneficial association between breast-feeding and early pubertal development, especially in those breast-fed for 6 months or longer. The study suggests that interventions would need to start early in life to prevent early pubertal development.

Effect of Urinary Bisphenol A on Androgenic Hormones and Insulin Resistance in Preadolescent Girls: A Pilot Study from the Ewha Birth & Growth Cohort

To assess the effect of urinary bisphenol A (BPA) on repeated measurements of androgenic hormones and metabolic indices, we used multivariate analysis of variance (MANOVA) adjusted for potential confounders at baseline. During July to August 2011, 80 preadolescent girls enrolled in the Ewha Birth & Growth Cohort study participated in a follow-up study and then forty-eight of them (60.0%) came back one year later. Baseline levels of estradiol and androstenedione were higher in the BPA group than in the non-BPA group. One year later, girls in the high BPA exposure group showed higher levels of androstenedione, testosterone, estradiol, and insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) index, than those in the other groups (p < 0.05). In MANOVA, estradiol and androstenedione showed significant differences among groups, while dehydroepiandrosterone, insulin, and HOMA-IR showed marginally significant differences. Exposure to BPA may affect endocrine metabolism in preadolescents. However, further investigation is required to elucidate the mechanisms linking BPA with regulation of androgenic hormones.

Risks of Lung Cancer due to Radon Exposure among the Regions of Korea

Radon is likely the second most common cause of lung cancer after smoking. We estimated the lung cancer risk due to radon using common risk models. Based on national radon survey data, we estimated the population-attributable fraction (PAF) and the number of lung cancer deaths attributable to radon. The exposure-age duration (EAD) and exposure-age concentration (EAC) models were used. The regional average indoor radon concentration was 37.5 95 Bq/m3. The PAF for lung cancer was 8.3% (European Pooling Study model), 13.5% in males and 20.4% in females by EAD model, and 19.5% in males and 28.2% in females by EAC model. Due to differences in smoking by gender, the PAF of radon-induced lung cancer deaths was higher in females. In the Republic of Korea, the risk of radon is not widely recognized. Thus, information about radon health risks is important and efforts are needed to decrease the associated health problems. Graphical Abstract

Trends in Ischemic Heart Disease Mortality in Korea, 1985-2009: An Age-period-cohort Analysis

Objectives Economic growth and development of medical technology help to improve the average life expectancy, but the western diet and rapid conversions to poor lifestyles lead an increasing risk of major chronic diseases. Coronary heart disease mortality in Korea has been on the increase, while showing a steady decline in the other industrialized countries. An age-period-cohort analysis can help understand the trends in mortality and predict the near future. Methods We analyzed the time trends of ischemic heart disease mortality, which is on the increase, from 1985 to 2009 using an age-period-cohort model to characterize the effects of ischemic heart disease on changes in the mortality rate over time. Results All three effects on total ischemic heart disease mortality were statistically significant. Regarding the period effect, the mortality rate was decreased slightly in 2000 to 2004, after it had continuously increased since the late 1980s that trend was similar in both sexes. The expected age effect was noticeable, starting from the mid-60s. In addition, the age effect in women was more remarkable than that in men. Women born from the early 1900s to 1925 observed an increase in ischemic heart mortality. That cohort effect showed significance only in women. Conclusions The future cohort effect might have a lasting impact on the risk of ischemic heart disease in women with the increasing elderly population, and a national prevention policy is need to establish management of high risk by considering the age-period-cohort effect.

Elevated Metabolites of Steroidogenesis and Amino Acid Metabolism in Preadolescent Female Children With High Urinary Bisphenol A Levels: A High-Resolution Metabolomics Study

Health risks associated with bisphenol A (BPA) exposure are controversially highlighted by numerous studies. High-resolution metabolomics (HRM) can confirm these proposed associations and may provide a mechanistic insight into the connections between BPA exposure and metabolic perturbations. This study was aimed to identify the changes in metabolomics profile due to BPA exposure in urine and serum samples collected from female and male children (n = 18) aged 7-9. Urine was measured for BPA concentration, and the children were subsequently classified into high and low BPA groups. HRM, coupled with Liquid chromatography-mass spectrometry/MS, followed by multivariate statistical analysis using MetaboAnalyst 3.0, were performed on urine to discriminate metabolic profiles between high and low BPA children as well as males and females, followed by further validation of our findings in serum samples obtained from same population. Metabolic pathway analysis showed that biosynthesis of steroid hormones and 7 other pathways-amino acid and nucleotide biosynthesis, phenylalanine metabolism, tryptophan metabolism, tyrosine metabolism, lysine degradation, pyruvate metabolism, and arginine biosynthesis-were affected in high BPA children. Elevated levels of metabolites associated with these pathways in urine and serum were mainly observed in female children, while these changes were negligible in male children. Our results suggest that the steroidogenesis pathway and amino acid metabolism are the main targets of perturbation by BPA in preadolescent girls.