Domyung Paek

Cadmium in blood and hypertension

OBJECTIVES This study is to examine the effect of cadmium exposure on blood pressure in Korean general population. METHODS The study population consisted of 958 men and 944 women who participated in the 2005 Korean National Health and Nutrition Examination Survey (KNHANES), in which blood pressure and blood cadmium were measured from each participant. RESULTS The mean blood cadmium level was 1.67 microg/L (median level 1.55). The prevalence of hypertension was 26.2%. The blood cadmium level was significantly higher among those subjects with hypertension than those without (mean level 1.77 versus 1.64 microg/dL). After adjusting for covariates, the odds ratio of hypertension comparing the highest to the lowest tertile of cadmium in blood was 1.51 (95% confidence interval 1.13 to 2.05), and a dose-response relationship was observed. Systolic, diastolic, and mean arterial blood pressure were all positively associated with blood cadmium level, and this effect of cadmium on blood pressure was markedly stronger when the kidney function was reduced. CONCLUSIONS Cadmium exposures at the current level may have increased the blood pressure of Korean general population.

Blood levels of lead, cadmium, and mercury in the Korean population: Results from the Second Korean National Human Exposure and Bio-monitoring Examination

In Korea, there have been a number of efforts to measure levels of exposure to environmental pollutants among the population. This paper focuses on investigating the distribution of, extent of, and factors influencing the blood levels of lead, cadmium, and mercury in the Korean population, working from data obtained from the Second Korean National Human Exposure and Bio-monitoring Examination. To that end, blood metal concentrations were analyzed from a total of 2369 participants who were 18 years of age and older. The geometric mean concentrations and their 95% confidence intervals of metals in blood were found to be lead, 1.72 microg/dL (95% CI, 1.68-1.76); cadmium, 1.02 microg/L (95% CI, 1.00-1.05); and mercury, 3.80 microg/L (95% CI, 3.66-3.93). Regression analyses indicate that the levels of metals in the blood are mainly influenced by gender, age, and the education levels of the participants. Current smoking status is also found to be a significant factor for increasing both lead and cadmium levels. Although our study, as the first nationwide survey of exposure to environmental pollutants in Korea, has value on its own, it should be expanded and extended in order to provide information on environmental exposure pathways and to watch for changes in the level of exposure to environmental pollutants among the population.

Serum concentrations of major perfluorinated compounds among the general population in Korea: dietary sources and potential impact on thyroid hormones.

Perfluorinated compounds (PFCs) have been frequently detected in both the environment and biota, and have become a growing concern. However, information is limited on the potential sources and human health implications of such exposure. We evaluated the exposure levels of 13 major PFCs among a population (n=633, >12 years of age) in a mid-sized city of Korea, and investigated for their potential dietary sources and the impact on thyroid hormone concentrations. For this purpose, we collected blood samples from a general population in Siheung, Korea and measured for 13 PFCs, total thyroxine (T4), and thyroid stimulating hormone (TSH). In addition, a questionnaire survey on diet was conducted. Perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) were detected in relatively greater concentrations than the other 9 PFCs in the blood serum. Males tend to have greater concentrations than females for most PFCs, and the concentrations were elevated as age increased up to 50s. Body mass index (BMI) was also shown to influence the serum concentrations of several PFCs. After adjustment for age, sex, and BMI, the consumption of vegetable, potato, fish/shellfish, and popcorn was identified to be significantly related with concentrations of major PFCs in blood. Among the studied PFCs, the concentrations of perfluorotridecanoic acid (PFTrDA) were negatively correlated with total T4, and positively with TSH levels, especially among females. The result of this study will provide information useful for developing public health and safety management measures for PFCs.

Acute health effects of urban fine and ultrafine particles on children with atopic dermatitis

Although ambient particulate pollutants have been shown to exacerbate existing allergic symptoms of mucous membranes including rhinitis and asthma, the effects on skin such as atopic dermatitis in childhood deserve further study. We investigated the effects of urban particulate pollutants including ultrafine particles on atopic severity in children with atopic dermatitis. We included 41 schoolchildren, 8-12 years old, who had been diagnosed with atopic dermatitis. For 67 consecutive days, all of them measured their symptoms in a diary. To assess exposure, the daily ambient mass concentrations of particulate matter less than 10, 2.5 and 1 μm (PM(10), PM(2.5) and PM(1), respectively) and concentrations of submicron particles (0.01- 1 μm) were measured at a local school. The mean mass concentrations of PM(10), PM(2.5) and PM(1) were 74.0, 57.8 and 50.8 μg/m(3), respectively. The mean concentrations were 41,335/cm(3) ultrafine particles (UFPs) and 8577/cm(3) accumulation mode (0.1-1 μm) particles. Significant associations were found between the concentrations of ultrafine particles and the itchiness symptom in children with atopic dermatitis. An interquartile range (IQR) increase in previous day ultrafine particles concentration (IQR: 28-140/m(3)) was significantly associated with a 3.1% (95% confidence interval, 0.2-6.1) increase in the itch symptom score for children with atopic dermatitis. The results suggested that the concentration of ambient ultrafine particles may exacerbate skin symptoms in children with atopic dermatitis.

The association of metabolic syndrome with periodontal disease is confounded by age and smoking in a Korean population: the Shiwha–Banwol Environmental Health Study

AIM Because metabolic syndrome (MS) is pro-inflammatory and periodontitis is inflammatory, we issued the hypothesis that MS (the explanatory variable) is associated with periodontitis (the outcome variable). This study aimed to examine the link between MS and periodontitis among Koreans. MATERIALS AND METHODS From the Shiwha-Banwol Environmental Health Study, 1046 subjects aged 18 years or older were cross-sectionally surveyed. All participants underwent comprehensive dental and medical health examinations. The community periodontal index was used to assess periodontitis. Age, gender, monthly family income, smoking, drinking, frequency of daily teeth brushing, and physical activity were evaluated as confounders. RESULTS MS was strongly associated with periodontitis [odds ratio (OR): 1.7, 95% confidence interval (CI): 1.22-2.37], and MS with more components had a higher association. The association was higher for elders aged 65 years or more, males, and smokers. MS including both high glucose and hypertension had a higher association with the OR of 2.19 (95% CI: 1.23-3.90) comparing with other types of MS. CONCLUSIONS Our results suggested that MS might be associated with periodontitis and the association was confounded by age, gender, and smoking. MS with high glucose and hypertension showed the higher impact on this link.

Hair mercury concentrations of children and mothers in Korea: Implication for exposure and evaluation

BACKGROUND Mercury is a global pollutant that affects neurodevelopment of children. OBJECTIVE The objectives were to measure and evaluate mercury concentration of children and mothers, and its association with exposure. METHODS A cross-sectional assessment was done using questionnaires and hair mercury were analysed by Cold Vapor Atomic Absorption Spectrometry in the National Institute for Minamata Disease in Japan. RESULTS A total of 112 children and 111 mothers were included; mean age was 34 months and 32 years, respectively. 17.9% of children and 34.2% of mothers had concentrations greater than 1 parts per million (ppm) as reference level. Body weight at birth, feeding methods, maternal age, and maternal education level were significantly different in each group (p<.05). Mean maternal hair mercury level (0.91 ppm) was higher than children (0.74 ppm), and has a positive correlation between them (p<.05). 68.1% of children, 75% of pregnant period, 63.4% of lactating period, and 78.6% of last six months have been consuming fish. With multiple regression analysis, hair mercury levels in children aged less than 6 months had a linear relationship with body weight at birth, gestational weeks, feeding methods (breast- or bottle- feeding) and maternal educational level. While children aged over 6 months significantly differed with gender, frequency of fish servings per week, and frequency of maternal fish consumption in lactation period. And hair mercury levels had inverse linear relationship with maternal monthly income in this age group. Maternal mercury levels had linear relationship with maternal age. CONCLUSION Mercury levels in children may be affected by their mothers due to similar dietary patterns. Further long-term large-scale and follow-up studies are needed.

Low dose mercury and heart rate variability among community residents nearby to an industrial complex in Korea

BACKGROUND The effect of mercury on the cardiovascular system has been recently reported, but the mechanisms and its nature, especially in low dose ranges, still need to be confirmed. In this cross-sectional study, the hair mercury was analyzed in relation to the cardiac autonomic activity among community residents nearby to an industrial complex in Korea. METHODS A hair sample was obtained from the occiput and was analyzed using a DMA-80 (Milestone, Italy) mercury analyzer. We measured cardiovascular risk factors, including serum total cholesterol, serum triglyceride, HDL cholesterol, systolic and diastolic blood pressure, body mass index (BMI), past history of hypertension, diabetes, and dyslipidemia as potential confounders. As an end point, heart rate variability was assessed for 5 min, in time and frequency domains, using SA-3000P (Medi-core, Korea). For the time domain, standard deviation of the NN intervals (SDNN) was measured. For the frequency domains, very low frequency (VLF, <or=0.04 Hz), low frequency (LF, 0.04-0.15 Hz), high frequency (HF, 0.15-0.4 Hz), total power (TP, approximately <or=0.4 Hz), LF/HF ratio, LF norm (LF/LF+HF), and HF norm (HF/LF+HF) were measured. The association between hair mercury concentration and heart rate variability was assessed after controlling for covariates, including age, gender, socioeconomic status, and other relevant cardiovascular risk factors. RESULTS In total, 1589 subjects with a mean age of 33 years (range: 5-83) were included in the final analysis. Hair mercury concentration ranged from 0.01 to 13.36 ppm with a geometric mean of 0.83 microg/g. The hair mercury level was elevated for males, adults, and fish (especially sashimi) consumers, and higher household income group. When age was categorized into decades and analyzed separately, mercury significantly reduced HF measure in the second decade of age in Siwha area (beta=-0.193, p=0.0469) and in the first decade of age in Banwol area (beta=-0.520, p=0.0129). HF parameter decreased by 8.4% [95% confidence interval: 2.2-15.1%] with an 1 ppm increase in hair mercury concentration after adjusting for other selected variables in the multiple linear regression analysis. CONCLUSIONS The results suggest that mercury may affect the cardiac autonomic activity through parasympathetic dysfunction even at low exposure levels.

The Impact of the Components of Metabolic Syndrome on Heart Rate Variability: Using the NCEP‐ATP III and IDF Definitions

Background: This study examined the relationship between metabolic syndrome (MetS) and heart rate variability (HRV) in Korean adults.

Visceral fat area-defined obesity and periodontitis among Koreans.

AIM Although the association of periodontitis with body mass index (BMI)-defined obesity has been studied, it remains controversial. Hence, this study aims to determine whether the obesity is associated with periodontitis among Koreans and to determine the most significant indicator of the obesity on the link. MATERIALS AND METHODS From the Sihwa-Banwol Environmental Health Cohort, 1046 subjects 15 years of age or older were cross-sectionally surveyed. All participants underwent periodontal and medical health examinations. Age, gender, monthly family income, smoking, drinking, frequency of daily teeth brushing and physical activity were evaluated through interviews. The community periodontal index (CPI) was used to assess periodontitis. BMI, waist circumference (WC), waist hip ratio and visceral fat area (VFA) were used to assess obesity. Multivariate linear and logistic regression analyses were applied. RESULTS BMI, WC and VFA had a dose-effect relationship with the number of sextants with periodontitis. Although subgroup analysis revealed several significant associations between obesity and periodontitis (CPI 3-4), the greatest association between VFA and periodontitis was found in males, age 45-54 (odds ratio=3.30; 95% confidence interval: 1.53-7.09). CONCLUSIONS Obesity was associated with periodontitis. VFA was the most suitable indicator of obesity in relation to periodontitis. Obesity may be a substantial risk factor for periodontitis.

Fine particle air pollution and mortality: importance of specific sources and chemical species.

Background: While exposure to ambient fine particles <2.5 &mgr;m in aerodynamic diameter (PM2.5) has well-established health effects, there is limited quantitative evidence that links specific sources of PM2.5 with those effects. This study was designed to examine the risks of exposure to chemical species and source-specific PM2.5 mass on mortality in Seoul, Korea, a highly populated city. Methods: We compare daily mortality counts with PM2.5 chemical speciation data collected every 3 days, as well as nine sources of PM2.5 mass resolved by a positive matrix factorization receptor model, from March 2003 through November 2007. A Poisson generalized linear model incorporating natural splines was used to evaluate associations of PM2.5 chemical species and sources with mortality. Results: PM2.5 mass and several chemical species were associated with mortality. Organic carbon, elemental carbon, and lead were associated with mortality outcomes when using multipollutant models adjusted for other chemical species levels. Source-apportioned PM2.5 derived from mobile sources (ie, gasoline and diesel emissions) and biomass burning was associated with respiratory mortality and cardiovascular mortality, respectively. There were moderate associations of industry and of roadway emissions with cardiovascular mortality. Conclusions: Local combustion sources may be particularly important contributors to PM2.5, leading to adverse health effects.