Sanghyuk Bae

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.

Exposures to Particulate Matter and Polycyclic Aromatic Hydrocarbons and Oxidative Stress in Schoolchildren

Background Air pollution is known to contribute to respiratory and cardiovascular mortality and morbidity. Oxidative stress has been suggested as one of the main mechanisms for these effects on health. Objective The aim of this study was to analyze the effects of exposure to particulate matter (PM) with aerodynamic diameters ≤ 10 μm (PM10) and ≤ 2.5 μm (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) on urinary malondialdehyde (MDA) levels in schoolchildren. Methods The study population consisted of 120 schoolchildren. The survey and measurements were conducted in four cities—two in China (Ala Shan and Beijing) and two in Korea (Jeju and Seoul)—between 4 and 9 June 2007. We measured daily ambient levels of PM and their metal components at the selected schools during the study period. We also measured urinary 1-hydroxypyrene (1-OHP) and 2-naphthol, to assess PAH exposure, and MDA, to assess oxidative stress. Measurements were conducted once a day for 5 consecutive days. We constructed a linear mixed model after adjusting for individual variables to estimate the effects of PM and PAH on oxidative stress. Results We found statistically significant increases in urinary MDA levels with ambient PM concentrations from the current day to the 2 previous days (p < 0.0001). Urinary 1-OHP level also showed a positive association with urinary MDA level, which was statistically significant with or without PM in the model (p < 0.05). Outdoor PM and urinary 1-OHP were synergistically associated with urinary MDA levels. Some metals bound to PM10 (aluminum, iron, strontium, magnesium, silicon, arsenic, barium, zinc, copper, and cadmium) and PM2.5 (magnesium, iron, strontium, arsenic, cadmium, zinc, aluminum, mercury, barium, and copper) also had significant associations with urinary MDA level. Conclusion Exposure to PM air pollution and PAHs was associated with oxidative stress in schoolchildren.

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.

Exposure to bisphenol A from drinking canned beverages increases blood pressure: randomized crossover trial.

Bisphenol A (BPA) is a chemical used in plastic bottles and inner coating of beverage cans, and its exposure is almost ubiquitous. BPA has been associated with hypertension and decreased heart rate variability in the previous studies. The aim of the present study was to determine whether increased BPA exposure from consumption of canned beverage actually affects blood pressure and heart rate variability. We conducted a randomized crossover trial with noninstitutionalized adults, who were aged ≥60 years and recruited from a local community center. A total of 60 participants visited the study site 3 times, and they were provided the same beverage in 2 glass bottles, 2 cans, or 1 can and 1 glass bottle at a time. The sequence of the beverage was randomized. We then measured urinary BPA concentration, blood pressure, and heart rate variability 2 hours after the consumption of each beverage. The paired t test and mixed model were used to compare the differences. The urinary BPA concentration increased after consuming canned beverages by >1600% compared with that after consuming glass bottled beverages. Systolic blood pressure adjusted for daily variance increased by ≈4.5 mm Hg after consuming 2 canned beverages compared with that after consuming 2 glass bottled beverages, and the difference was statistically significant. The parameters of the heart rate variability did not show statistically significant differences.The present study demonstrated that consuming canned beverage and consequent increase of BPA exposure increase blood pressure acutely.

Effect of diurnal temperature range on cardiovascular markers in the elderly in Seoul, Korea.

While diurnal temperature range (DTR) has been found to be a risk factor for mortality, evaluation of the underlying mechanisms involved in this association are lacking. To explain the association between DTR and health effects, we investigated how cardiovascular markers responded to DTR. Data was obtained from 560 participants who regularly attended a community elderly welfare center located in Seoul, Korea. Data collection was conducted a total of five times over a 3-year period beginning in August, 2008. We examined systolic and diastolic blood pressure (BP), heart rate (HR), and heart rate variability (HRV). Mixed-effects models and generalized additive mixed models were used to assess the relationship of DTR with BP, HR, and HRV. BP was not associated significantly with rapid temperature changes during the day. While HR was associated linearly with increments of DTR, the relationship between DTR and HRV showed nonlinear associations, or the presence of a cutoff around median DTR. At the cutoff level of DTR determined by an inflection point in the graph, standard deviation of normal-to-normal intervals (SDNN) and root mean square successive difference (RMSSD) were peaked, whereas the low frequency:high frequency (LF:HF) ratio was elevated with decreasing DTR below the cutoff level. The study demonstrated that HR increases with increasing temperature range during the day, and that HRV is reduced at small or large DTR, which suggests minimal cardiovascular stress around the median level of temperature range during the day.

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.

Urinary bisphenol A concentrations are associated with abnormal liver function in the elderly: a repeated panel study

Background Bisphenol A (4,40-isopropylidenediphenol, BPA) is known to adversely affect various organs. The liver is reported to be affected by BPA in animal studies. However, there are few studies in humans on the effects of BPA on the liver. Therefore, we evaluated the relationship between urinary BPA levels and liver function in elderly subjects using repeated measurements. Methods From 2008 to 2010, a total of 560 elderly subjects residing in Seoul were each evaluated up to three times. At the first visit, demographic data, environmental exposure and lifestyle information were obtained from a systemised questionnaire. At each visit, blood and urine samples were collected and stored for analysis. Linear mixed and GLIMMIX model analyses were performed after adjusting for age, sex, Body Mass Index, alcohol consumption, urinary cotinine concentrations, exercise frequency, and low-density lipoprotein cholesterol level. Results The mean urinary BPA concentration was 1.13 μg/g creatinine. Significant relationships were observed between urinary BPA and aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyl transferase after adjusting for potential confounders (p<0.05). When subjects were grouped according to urinary BPA concentrations divided by the median value, higher urinary BPA concentrations were associated with increased abnormal liver function (OR 2.66; 95% CI 1.15 to 5.90). Conclusions Community-level exposure to BPA was associated with abnormal liver function in the elderly, indicating that more stringent control of BPA is necessary to protect susceptible populations.

eNOS gene polymorphisms modify the association of PM10 with oxidative stress

Previous studies have suggested that air pollution increases various health outcomes through oxidative stress and oxidative stress-related genes modify the relationship between air pollution and health outcomes. Therefore, we evaluated the effect of PM(10) on the levels of malondialdehyde (MDA), oxidative stress biomarker, and the effect modification by genetic polymorphisms of eNOS, oxidative stress-related gene, in the 560 Korean elderly. We obtained urine samples repeatedly from participants during five medical examinations between 2008 and 2010 and all ambient air pollutant concentration data from the Korea National Institute of Environmental Research air quality monitoring system. We measured urinary levels of MDA to assess oxidative stress and genotyped eNOS (rs1799983, rs2853796, and rs7830). Mixed-effect model was used to estimate the effect of PM(10) on the level of oxidative stress biomarker and their modification by genotypes. PM(10) showed apparent positive effect on MDA level after adjusting for age, sex, BMI, cotinine level, temperature, dew point, levels of SO(2), O(3), NO(2), and CO, and season (p=0.0133). Moreover, the association of PM(10) with MDA was found only in participants with eNOS GG genotype for rs1799983 (p=0.0107), TT genotype for rs2853796 (p=0.0289), or GT genotype for rs7830 (p=0.0158) and in participants with a set of risky haplotypes (GTT, GTG, GGT, and TGT) (p=0.0093). Our results suggest that PM(10) affect oxidative stress in the elderly and eNOS genotype affect the oxidative stress level in regard of exposure to PM(10).

Health Impact Assessment of PM10 and PM2.5 in 27 Southeast and East Asian Cities.

Objective: We aimed to evaluate the annual health impacts of particulate matter (PM) less than 10 &mgr;m diameter (PM10) and less than 2.5-&mgr;m diameter (PM2.5) in 27 cities in Southeast and East Asian countries (Japan, the Philippines, the Republic of Korea, Singapore, and Vietnam) for the year 2009 (n = 50,756,699). Methods: We estimated the number of cases attributable to long-term exposure. We used a scenario that reduced the annual mean values for PM10 and PM2.5 to 20 and 10 &mgr;g/m3, respectively. Results: A reduction in long-term exposure to PM10 and PM2.5 would have postponed 8% to 9% of all-cause mortality or about 37,000 deaths. One third of them were associated with cardiopulmonary mortality and one ninth of them were associated with lung cancer mortality. Conclusions: Current air pollution levels in Southeast and East Asian countries have a nonnegligible public health impact.