BackgroundGlobal DNA methylation levels have been reported to be inversely associated with blood levels of persistent organic pollutants (POPs), xenobiotics that accumulate in adipose tissue. Whether these associations extend to a population with much lower concentrations of POPs is not known.ObjectivesThis study was performed to examine whether low-dose exposure to POPs was associated with global DNA hypomethylation in Koreans.MethodsThe amount of global DNA hypomethylation was estimated by the percent 5-methyl-cytosine (%5-mC) in Alu and LINE-1 assays in 86 apparently healthy Koreans. Among various POPs, organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenylethers (PBDEs) were measured.ResultsMost OC pesticides were inversely and significantly associated with %5-mC in the Alu assay, with correlation coefficients in the range −0.2 to −0.3 after adjusting for age, sex, body mass index, smoking, and alcohol. The strongest OC pesticide associations with %5-mC in the Alu assay were observed with oxychlordane, trans-nonachlor, and p,p′-dichlorodiphenyldichloroethylene. The correlation coefficient of age with %5-mC in the Alu assay was −0.24, similar to correlations of OC pesticides with %5-mC in the Alu assay. Most PCBs and PBDEs showed nonsignificant inverse trends with %5-mC in the Alu assay, but for some PCBs the U-shaped association was significant. On the other hand, POPs were not associated with %5-mC in the LINE-1 assay.ConclusionsWe found that low-dose exposure to POPs, in particular OC pesticides, was associated with global DNA hypomethylation in apparently healthy Koreans.

This study attempted to calculate and investigate the incidence of hospitalized acute myocardial infarction (AMI) and stroke in Korea. Using the National Health Insurance claim data, we investigated patients whose main diagnostic codes included AMI or stroke during 2006 to 2010. As a result, we found out that the number of AMI hospitalized patients had decreased since 2006 and amounted to 15,893 in 2010; and that the number of those with stroke had decreased since 2006 and amounted to 73,501 in 2010. The age-standardized incidence rate of hospitalized AMI, after adjustment for readmission, was 41.6 cases per 100,000-population in 2006, and had decreased to 29.4 cases in 2010 (for trend P < 0.001). In the case of stroke was estimated at 172.8 cases per 100,000-population in 2006, and had decreased to 135.1 cases in 2010 (for trend P < 0.001). In conclusion, the age-standardized incidence rates of both hospitalized AMI and stroke in Korea had decreased continuously during 2006 to 2010. We consider this decreasing trend due to the active use of pharmaceuticals, early vascular intervention, and the national cardio-cerebrovascular disease care project as the primary and secondary prevention efforts.

ObjectivesThis study was conducted to observe recent changes in adolescents' dietary behavior and indirectly evaluate the effects of the government's nutritional policies in Korea.MethodsWe analyzed the secular trends in seven dietary behaviors using the Korea Youth Risk Behavior Web-based Survey data from 2005 to 2009. Through literature review, we included the policies implemented for the improvement of adolescents'dietary behaviors during the same periods.ResultsThe significant linear trends were observed in all dietary behaviors (p<0.05). Overall, all behaviors except the fruit intake rate were desirably changed during five years but undesirable changes were observed between 2008 and 2009 in all behaviors. Within those periods, several policies were implemented including 'Ban on carbonated-beverages in school', 'Green Food Zone', etc. Despite confirmed evidence of their effects, the policies on individual behavior such as nutrition education didn't influence the prevalence of dietary behaviors because they were conducted to too limited persons. Polices on the school environmental improvement, such as ban on carbonated beverage in school, were more effective because they decreased the exposure of undesirable food environment. However, for effect of Green Food Zone improving community environment we couldn't come to a conclusion because of too short period after full implementation.ConclusionsAmong government nutrition policies conducted from 2005 to 2009, those on environmental improvement, especially in school, were more effective than those on individual behavior. Therefore, the development and implement of policies on school environmental improvement are needed in Korea.

ObjectivesUnderstanding recent trends in cigarette smoking among adolescents is important in order to develop strategies to prevent cigarette smoking. The aim of this study was to compare recent trends in cigarette smoking for adolescents living in rural areas, small towns and metropolitan cities in Korea.MethodsThe raw data from the Korea Youth Risk Behavior Web-based Survey (KYRBWS) from 2005 to 2009 were used. Data were analyzed by using the method of complex survey data analysis considering complex sampling design. Logistic regression models were used to evaluate significant linear time trends in cigarette smoking. The indicators of cigarette use behaviors were 'current smoking rate', 'frequent smoking rate', 'heavy smoking rate' and 'smoking experience rate before 13 years of age'. All analyses were conducted according to gender.ResultsStatistically significant increasing trends in current smoking rate and frequent smoking rate were observed and borderline significant increasing trends in heavy smoking rate were shown among rural boys. Among metropolitan city boys, statistically significant increasing trends were also seen for frequent smoking. Statistically significant decreasing trends in current smoking rate were observed among small town and metropolitan city girls. Smoking experience rate before 13 years of age for rural girls decreased significantly.ConclusionsCigarette smoking prevalence among adolescents in the rural areas has increased in the last five years especially among boys. Our findings suggest that anti-tobacco program for adolescents should be conducted primarily for those in rural areas.

Objectives: Cigarette smoking prevalence among adolescent males in rural areas of Korea has increased in recent years. The aim of this study was to explore the factors related to increasing trends in cigarette smoking among adolescent males living in rural areas. Methods:The raw data from the Korea Youth Risk Behavior Web-based Survey from 2006 to 2009 were used. Data were analyzed by using the method of complex survey data analysis considering complex sampling design. Multiple logistic regression models were used to explore the factors affecting cigarette smoking. We evaluated the linear time trends in the prevalence of factors that were related to current smoking status and the linear time trends in cigarette smoking in groups stratified by the exposure to each factor using logistic regression models. Finally, we examined the contributions of the factors to the time trends in cigarette smoking by adjusting for each of those factors in the baseline regression models and changes in the adjusted odds ratio by survey year. Results:A statistically significant increasing trend in smoking was observed after adjusting for the factors affecting cigarette smoking.Significant factors related to cigarette use were perceived stress, experience with depression, current alcohol drinking, exposure to secondhand smoke, and academic performance. The factor related to increasing trends in cigarette smoking was academic performance.Conclusions: Stress about academic performance is an important factor affecting the increase in cigarette smoking among adolescent males in a rural area of Korea.