Hye Yin Park

Air pollution and symptoms of depression in elderly adults.

Background: Although the effect of air pollution on various diseases has been extensively investigated, few studies have examined its effect on depression. Objectives: We investigated the effect of air pollution on symptoms of depression in an elderly population. Methods: We enrolled 537 participants in the study who regularly visited a community center for the elderly located in Seoul, Korea. The Korean version of the Geriatric Depression Scale-Short Form (SGDS-K) was used to evaluate depressive symptomatology during a 3-year follow-up study. We associated ambient air pollutants with SGDS-K results using generalized estimating equations (GEE). We also conducted a factor analysis with items on the SGDS-K to determine which symptoms were associated with air pollution. Results: SGDS-K scores were positively associated with interquartile range (IQR) increases in the 3-day moving average concentration of particulate matter with an aerodynamic diameter ≤ 10 μm (PM10) [17.0% increase in SGDS-K score, 95% confidence interval (CI): 4.9%, 30.5%], the 0–7 day moving average of nitrogen dioxide [NO2; 32.8% (95% CI: 12.6%, 56.6%)], and the 3-day moving average of ozone [O3; 43.7% (95% CI: 11.5%, 85.2%)]. For these three pollutants, factor analysis showed that air pollution was more strongly associated with emotional symptoms such as feeling happy and satisfied than with somatic or affective symptoms. Conclusions: Our study suggests that increases in PM10, NO2, and O3 may increase depressive symptoms among the elderly. Of the symptoms evaluated, ambient air pollution was most strongly associated with emotional symptoms.

Associations of Bisphenol A Exposure With Heart Rate Variability and Blood Pressure

Bisphenol A (BPA) is a high-volume production chemical that has been suspected to have adverse health effects. Recent studies have suggested that cardiovascular diseases are associated with the BPA exposure. The aim of present study was to investigate the associations of urinary BPA with heart rate variability and blood pressure. We recruited 560 noninstitutionalized elderly citizens from August 2008 to August 2010 in Seoul. All of the participants were ≥60 years old. The participants took medical examinations ⩽5 times. Urinary BPA concentration, heart rate variability, and blood pressure were measured at each time. A total of 1511 observations from 521 participants were included in the analyses. We observed that urinary BPA was associated negatively with the root mean square of successive differences for heart rate and positively with blood pressure. The odds ratio of showing hypertension (systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg) was 1.27 (95% CI, 0.85–1.88) in the fourth quartile compared with the first quartile of urinary BPA concentration. When the analyses were restricted to participants who did not report previous history of hypertension (n=258), the odds ratio was increased to 2.35 (95% CI, 1.33–4.17).

Diethylhexyl Phthalates Is Associated with Insulin Resistance via Oxidative Stress in the Elderly: A Panel Study

Background Insulin resistance (IR) is believed to be the underlying mechanism of metabolic syndrome and type 2 diabetes mellitus (DM). Recently, a few studies have demonstrated that phthalates could cause oxidative stress which would contribute to the development of IR. Therefore, we evaluated whether exposure to phthalates affects IR, and oxidative stress is involved in the phthalates-IR pathway. Methods We recruited 560 elderly participants, and obtained blood and urine samples during repeated medical examinations. For the determination of phthalate exposure, we measured urinary levels of mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) as metabolites of diethylhexyl phthalates (DEHP), and mono-n-butyl phthalate (MnBP) as a metabolite of di-butyl phthalate (DBP). Malondialdehyde (MDA), an oxidative stress biomarker, was also measured in urine samples. We measured serum levels of fasting glucose and insulin, and derived the homeostatic model assessment (HOMA) index to assess IR. A mixed-effect model and penalized regression spline were used to estimate the associations among phthalate metabolites, MDA, and IR. Results The molar sum of MEHHP and MEOHP (∑DEHP) were significantly associated with HOMA (β = 0.26, P = 0.040), and the association was apparent among participants with a history of DM (β = 0.88, P = 0.037) and among females (β = 0.30, P = 0.022). However, the relation between MnBP and HOMA was not found. When we evaluated whether oxidative stress is involved in increases of HOMA by ∑DEHP, MDA levels were significantly associated with increases of ∑DEHP (β = 0.11, P<0.001) and HOMA (β = 0.49, P = 0.049). Conclusions Our study results suggest that exposure to DEHP in the elderly population increases IR, which is related with oxidative stress, and that participants with a history of DM and females are more susceptible to DEHP exposure.

Socioeconomic Inequalities in Adolescent Depression in South Korea: A Multilevel Analysis

Background In recent years, South Korea has witnessed a sustained rise in the prevalence of adolescent depression. In the present study, we sought to investigate family and school environmental influences on adolescent depression. Methods and Findings Middle and high school students (N = 75,066) were randomly selected respondents to a web-based survey and answered questions on their academic and socioeconomic backgrounds, parental support, parental education level, physical activities, lifestyle habits and their experience of depression in the past one year. Two-level multilevel analysis was used to investigate the relationship between depression and individual (level 1) and school (level 2) factors. Girls reported having experienced depression in greater numbers than boys (43.96% vs. 32.03%). A significant association was found between adolescent depression experience and gender, grade, self-rated academic achievement, family affluence scale, parental support, parental education level, lifestyle habits, physical activity and sleep dissatisfaction. The students living with rich parents were more likely to be depressive, and maternal higher education was significantly associated with higher probability of boys’ depression experience. Low academic achievement was highly associated with the experience of depression. In school level contexts, girls were found to be less likely to be depressive in girls-only schools. Conclusion The adolescent depression experience is not only an individual phenomenon but is highly associated with other factors such as parents, peers, academic achievement, and even gender mix in the school. Thus, prevention measures on youth depression need to focus on emphasizing less pressure from parents on academic performance, and establishing healthy inter-gender relationships within co-education schools.

Influence of Genetic Polymorphisms on the Association between Phthalate Exposure and Pulmonary Function in the Elderly

BACKGROUND Phthalates are prevalent environmental exposure chemicals with rising concern on various health effects, including pulmonary function. Meanwhile, elderly people are more susceptible to environmental exposure, and their decreasing lung function is an important health issue. OBJECTIVES To investigate the association between urinary phthalate metabolite levels and indices for pulmonary function, and evaluate effect modification by genetic polymorphisms of oxidative-stress related genes, catalase (CAT), superoxide dismutase (SOD2), and myeloperoxidase (MPO) in elderly Koreans. METHODS We conducted a panel study on 418 individuals over 60 years old in Seoul, Korea, and repeatedly measured urinary phthalate metabolite levels and ran pulmonary function tests. Genetic polymorphisms of CAT (rs769218, rs769217), SOD2 (rs4880, rs2758331, rs5746136) and MPO (rs2071409, rs7208693) were determined. Mixed effect model was used to investigate association of phthalate levels with pulmonary function indices and to examine the effect of CAT, SOD2 and MPO polymorphisms on the association. RESULTS Inverse association was demonstrated between sum of mono-(2-ethyl-5-hydroxyhexyl) phthalate and mono-(2-ethyl-5-oxohexyl) phthalate (∑DEHP) levels and FEV1/FVC (β=-0.632, p=0.0275) or FEF25-75 (β=-0.077, p=0.025) after adjusting for age, months after previous measurements, sex, body mass index, cotinine, mean temperature and dew point. The effect of ∑DEHP on lung function was significant only in subjects with certain genotypes, and having all significant genotypes in three genes showed significant difference in the phthalate-pulmonary function association (FEV1/FVC: β=-2.169, p=0.0032; FEF25-75: β=-0.155, p=0.0103), while other combinations showed less estimate size without any significance. CONCLUSIONS Urinary phthalate metabolites levels are associated with decreasing pulmonary function in elderly Koreans, and effect modification of certain CAT, SOD2 and MPO polymorphisms on the association is suggested.

Interaction effect of serum 25-hydroxyvitamin D levels and CYP1A1, CYP1B1 polymorphisms on blood pressure in an elderly population.

Objective: Hypertension and vitamin D deficiency are prevalent worldwide, especially in the elderly. Considering the possibility of gene–environment contributions to disease development, we evaluated the influence of certain cytochrome P450 polymorphisms and vitamin D levels on blood pressure (BP). Methods: We measured serum 25-hydroxyvitamin D levels [25(OH)D] and BP in 535 individuals over 60 years old and identified single-nucleotide polymorphisms (SNPs) of CYP1A1 and CYP1B1 in lymphocyte DNA. Repeated measure analyses were used to determine the statistical association. Results: The relationship between 25(OH)D and SBP or DBP was inversely significant, and influence of several CYP1A1 and CYP1B1 SNPs on BP was found across different genotypes. Estimated effect of 25(OH)D levels on BP in the group with higher risky genotype scores of selected SNPs (rs4646421, rs2551188, and rs1056836) was greater (&bgr; = −2.841, P = 0.004 for SBP; &bgr; = −2.035, P = 0.001 for DBP) than the group with lower genotype score (&bgr; = −0.878, P = 0.347 for SBP; &bgr; = 0.037, P = 0.947 for DBP), and synergistic interaction between vitamin D levels and genotype variations was observed (P-interaction = 0.081 for SBP and 0.008 for DBP). When stratified by the hypertension medication status, interaction effect was found only in individuals taking medication (P-interaction = 0.004 for SBP and 0.001 for DBP). Conclusion: Genetic variations in CYP1A1 and CYP1B1 and the serum levels of 25(OH)D showed synergistic effect on BP, especially in individuals currently in treatment for hypertension.

PM10 Exposure and Non-accidental Mortality in Asian Populations: A Meta-analysis of Time-series and Case-crossover Studies

Objectives We investigated the association between particulate matter less than 10 µm in aerodynamic diameter (PM10) exposure and non-accidental mortality in Asian populations by meta-analysis, using both time-series and case-crossover analysis. Methods Among the 819 published studies searched from PubMed and EMBASE using key words related to PM10 exposure and non-accidental mortality in Asian countries, 8 time-series and 4 case-crossover studies were selected for meta-analysis after exclusion by selection criteria. We obtained the relative risk (RR) and 95% confidence intervals (CI) of non-accidental mortality per 10 µg/m3 increase of daily PM10 from each study. We used Q statistics to test the heterogeneity of the results among the different studies and evaluated for publication bias using Begg funnel plot and Egger test. Results Testing for heterogeneity showed significance (p<0.001); thus, we applied a random-effects model. RR (95% CI) per 10 µg/m3 increase of daily PM10 for both the time-series and case-crossover studies combined, time-series studies relative risk only, and case-crossover studies only, were 1.0047 (1.0033 to 1.0062), 1.0057 (1.0029 to 1.0086), and 1.0027 (1.0010 to 1.0043), respectively. The non-significant Egger test suggested that this analysis was not likely to have a publication bias. Conclusions We found a significant positive association between PM10 exposure and non-accidental mortality among Asian populations. Continued investigations are encouraged to contribute to the health impact assessment and public health management of air pollution in Asian countries.

Low-level Mercury Exposure and Risk of Asthma in School-age Children.

Background: Mercury (Hg) has been reported to have adverse effects on the immune system. However, the association between Hg exposure and asthma remains unclear. We hypothesized that blood Hg concentrations are associated with asthma and immune system blood profile changes in school-age children. Methods: Between 2005 and 2010, we evaluated 4,350 Korean children at 7–8 years of age with no previous asthma diagnosis. Follow-up surveys were conducted twice, each 2 years apart, until 11–12 years of age. For every survey, we evaluated asthma through a questionnaire and blood profile. We analyzed the association of Hg concentration with asthma by logistic and Cox regression models and the association with blood profile by generalized additive and linear mixed models. Results: Blood Hg concentrations at 7–8 years of age were associated with an increased risk of asthma (odds ratio [OR] = 1.3; 95% confidence interval [CI] = 1.0, 1.6) at ages up to 11–12 years (n = 191). Hg concentration was also associated with wheezing (OR = 1.2; 95% CI = 1.0, 1.3), asthma medication use (OR = 1.4; 95% CI = 0.97, 2.0), and airway hyperresponsiveness (OR = 1.2; 95% CI = 1.0, 1.3). Further adjustment for fish consumption did not change the results appreciably. Conclusions: Low-level Hg exposure was associated with asthma and blood profile changes in school-age children.

Benefit of Glycemic Control for Reducing the Effects of Air Pollution on Blood Pressure: A Panel Study

Objective: Diabetes mellitus (DM) is known to aggravate the association between air pollution and cardiovascular diseases, such as hypertension. However, the influence may differ based on the degree of glycemic control. Therefore, we hypothesized that the adverse effects of air pollutants on Blood Pressure (BP) in patients with controlled DM would be less than those in patients with uncontrolled DM. Methods: Data were analyzed from a panel study of 560 elderly participants, conducted between 2008 and 2010 in Seoul, Korea. Mixed effects models were used to assess the association of air pollutants [particulate matter with aerodynamic diameters<10 μm (PM10), PM2.5, PM10-2.5, nitrogen dioxide, ozone, sulfur dioxide, and carbon monoxide] with BP. We compared the magnitude of the effects among individuals with controlled and uncontrolled DM and those without DM. Results: Increases in the interquartile range levels of PM10 were significantly associated with 2.0 mmHg (95% CI, 0.7–41.7 mmHg) increases in systolic BP (SBP) and 2.0 mmHg (95% CI, 1.2–41.7 mmHg) increases in diastolic BP (DBP) when we analyzed all participants. Most of the other air pollutants, except ozone, were also associated with significant increases in BP. When we compared the BP changes among the three groups (non-DM, controlled DM, and uncontrolled DM), significant increases in SBP and DBP were observed in participants with uncontrolled DM and those without DM; significant BP increases were not observed in participants with controlled DM. Conclusion: Glycemic control provided benefits for alleviating BP changes associated with exposure to air pollutants.

Gaps in universal health coverage in South Korea: Association with depression onset in a community cohort

Background While controversies on limitation of coverage by the national health insurance and relatively high direct or “out-of-pocket” household payments by the national health insurance in South Korea still remain, potential unfavorable influence of the insufficiency of the universal health coverage on depression has not yet been evaluated. Methods and findings Baseline information were obtained from a community cohort (The Korean Genome and Epidemiology Study) of middle-aged subjects without depression at enrollment period (2001–2002). Subjects were followed-up biennially, and new onset depression was assessed using Becks Depression Inventory at 2nd round follow-up (2005–2006). Influence of direct medical expenditure on depression onset was investigated in all subjects and in stratified groups of different income level. Increasing risk of depression onset was observed for increased medical expenditure (OR [95% CI];1.44 [0.97–2.13], 1.90 [1.19–3.05], 1.71 [1.01–2.91] for spending <50000 KRW, 50000–100000 KRW, and ≥100000 KRW, respectively, vs. almost no expenditure per month; P for trend = 0.012), after adjusting for covariates such as monthly income and chronic disease history. Similar associations were observed in subjects less than or at average national income, but results were not significant in subgroup with monthly income above national average. Conclusions Even with the universal coverage, high co-payments and uninsured services in the Korean health insurance system yet possibly make the insured pay much for medical service utilization. This might have led to onset of an unfavorable health condition such as depression.