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Objectives Previous epidemiological studies about oxidative stress and depression are limited by hospital-based case-control design, single-time measurements of oxidative stress biomarkers, and the small number of study participants. Therefore, in this study, we analyzed the association between biomarker of oxidative stress and depressive symptom scores using repeatedly measured panel data from a community-dwelling elderly population. Methods From 2008 to 2010, a total of 478 elderly participants residing in Seoul, Korea, were evaluated three times. Participants underwent the Korean version of the Short Form Generic Depression Scale (SGDS-K) test for screening depression, and urinary malondialdehyde (MDA) levels were measured as an oxidative stress biomarker. We used a generalized estimating equation with a compound symmetry covariance structure to estimate the effects of oxidative stress on depressive symptom scores. Results A two-fold increase in urinary MDA concentration was significantly associated with a 33.88% (95% confidence interval [CI], 21.59% to 47.42%) increase in total SGDS-K scores. In subgroup analyses by gender, a two-fold increase in urinary MDA concentration was significantly associated with increased SGDS-K scores in both men and women (men: 30.88%; 95% CI, 10.24% to 55.37%; women: 34.77%; 95% CI, 20.09% to 51.25%). In bivariate analysis after an SGDS-K score ≥8 was defined as depression, the third and the fourth urinary MDA quartiles showed a significantly increased odds ratio(OR) of depression compared to the lowest urinary MDA quartile (third quartile OR, 6.51; 95% CI, 1.77 to 24.00; fourth quartile OR, 7.11; 95% CI, 1.99 to 25.42). Conclusions Our study suggests a significant association between oxidative stress and depressive symptoms in the elderly population.

Desert dust is considered to be potentially toxic and its toxicity may change during long-range transportation. In Asian countries, the health effects of desert dust in different locations are not well understood. We therefore evaluated the city-combined and city-specific effects of Asian dust events on all-cause and cause-specific mortality in five populous cities in South Korea (Seoul) and Japan (Nagasaki, Matsue, Osaka and Tokyo). We obtained daily mean concentrations of Asian dust using light detection and ranging (lidar) between 2005 and 2011. We then evaluated city-specific and pooled associations of Asian dust with daily mortality for elderly residents (≥65 years old) using time-series analyses. Each 10 μg/m3 increase in the concentration of same-day (lag 0) or previous-day (lag 1) Asian dust was significantly associated with an elevated pooled risk of all-cause mortality (relative risk (RR): 1.003 [95% CI: 1.001–1.005] at lag 0 and 1.001 [95% CI: 1.000–1.003] at lag 1) and cerebrovascular disease (RR: 1.006 [95% CI: 1.000–1.011] at lag 1). This association was especially apparent in Seoul and western Japan (Nagasaki and Matsue). Conversely, no significant associations were observed in Tokyo, which is situated further from the origin of Asian dust and experiences low mean concentrations of Asian dust. Adverse health effects on all-cause and cerebrovascular disease mortality were observed in South Korea and Japan. However, the effects of Asian dust differed across the cities and adverse effects were more apparent in cities closer to Asian dust sources.

Previous animal studies have demonstrated that phthalate exposure is associated with depression-like behaviors. However, no human study has explored this relationship. We explored the association between urinary phthalate metabolite concentrations and depression in a nationally representative sample of the U.S. elderly population. We analyzed 2030 participants aged 60 years or older with available data on phthalates and depression from the 2005 to 2012 National Health and Nutrition Examination Survey (NHANES). We selected 10 urinary phthalate metabolites with a weighted detection rate >60%. Depression was defined as a 9-item Patient Health Questionnaire score ≥10. The models were adjusted for age, sex, race/ethnicity, education level, income-to-poverty ratio, health insurance coverage, marital status, smoking status, alcohol consumption, moderate physical activity, body mass index, comorbidity status, NHANEs cycle, and urinary creatinine levels. One-unit increases in log-transformed mono-(3-carboxypropyl) phthalate (MCPP) (odds ratio [OR]=1.24, 95% confidence interval [CI]=1.02-1.52) and mono(carboxynonyl) phthalate (MCNP) (OR=1.42, 95% CI=1.15-1.75) were positively associated with depression. When we stratified the urinary phthalate metabolites into quartiles, the highest quartiles (Q4) of MCNP (OR=2.57, 95% CI=1.25-5.27) and mono-n-butyl phthalate (MBP) (OR=2.40, 95% CI=1.10-5.22) were associated with depression compared with the lowest quartiles (Q1). Concentrations of urinary phthalate metabolites MCPP, MCNP, and MBP were positively associated with the risk of depression in a representative sample of the U.S. elderly population. However, the present cross-sectional study is hypothesis generating and the associations need to be investigated through further longitudinal studies.

Background To date, the association of the neurotoxic agent cadmium (Cd) with depression in elderly people has been poorly evaluated. By investigating the relationship between blood cadmium levels and scores on a depression screening test, we aimed to investigate the impact of cadmium exposure on elderly depression. Methods From 2008 to 2010, a total of 395 elderly participants residing in Seoul, Korea, were evaluated 3 times. Demographic data and lifestyle information were obtained via a systemised questionnaire, and blood samples were collected for analysis. Participants underwent the Korean Version of the Short Form Generic Depression Scale test (SGDS-K) for screening depression and associations were estimated using logistic regression models adjusted for potential confounders. Results Blood cadmium levels were associated with depressive symptoms in the first visit data analysis. By analysing the first visit data, the highest quartile blood cadmium group (Q4) showed increased risk for depressive symptoms compared to the lowest quartile group (Q1) (OR 3.50, 95% CI 1.22 to 10.00). However, the data of the second and third visits suggested that blood cadmium may be protective against depressive symptoms (second visit data, Q4 vs Q1, OR 0.78, 95% CI 0.19 to 3.14; third visit data, Q4 vs Q1, OR 0.58, 95% CI 0.04 to 8.77). Conclusions Owing to inconsistent results in analyses between blood cadmium levels and depressive symptoms, we cannot conclude any solid association between blood cadmium levels and depressive symptoms in the elderly population. To clarify the relationship, other prospective studies are needed in the future.

An adverse association between diurnal temperature range (DTR) and mortality has been suggested, but with variable relationships in different cities. Comprehensive approaches to understanding the health effects of DTR using multinational data are required. We investigated the association between DTR and cause-specific mortality in an age-specific population and assessed the dependency of the health effects of DTR on geographic and climatic factors. Poisson generalized linear regression analyses with allowances for over-dispersion were applied to daily DTR and cause-specific mortality data from 30 cities in China, Japan, Korea, and Taiwan between 1979 and 2010, adjusted for various climatic and environmental factors. City-specific effects of DTR were estimated and summarized for the overall effects using geographic and climatic determinants in a meta-analysis. For all-cause, circulatory, and respiratory mortality, the greatest city-specific effects per 1°C DTR were found in Tianjin, China (1.80%; 95% confidence interval [CI]: 0.48, 3.14); Tangshan, China (2.25%; 95% CI: 0.65, 3.87); and Incheon, Korea (2.84%; 95% CI: 0.04, 5.73), respectively, and overall effects across 30 cities were 0.58% (95% CI: 0.44, 0.72), 0.81% (95% CI: 0.60, 1.03), and 0.90% (95% CI: 0.63, 1.18), respectively. Using quartile cutoff values for climatic (DTR, and mean temperature) and geographic (latitude, and longitude) characteristics, we divided the 30 cities into 4 different groups and conducted a meta-analysis within the groups using either a random or fixed effects model. Adverse effects of DTR were more pronounced for those aged ≥65years and varied according to geographic, longitudinal (0.07%; 95% CI: 0.05, 0.10), and climatic characteristics and the scale of DTR (0.33%; 95% CI: 0.12, 0.55) for overall all-cause mortality. The DTR is a risk factor affecting human health, depending on geographic location and the temperature variation, with particular vulnerability in aged populations.

Few studies have examined how the precedence of abnormal temperatures in previous neighboring years affects the population's health. In the present study, we attempted to quantify the health effects of abnormal weather patterns by creating a metric called the temperature deviation index (TDI) and estimated the effects of TDI on mortality in Japan. We used data from 47 prefectures in Japan to compute the TDI on days between May and September from 1966 to 2010. The TDI is a summed product of an indicator of absence of high temperatures in the neighboring years, and more weights were assigned to the years closest to the current year. To estimate the TDI effects on elderly mortality, we used generalized linear modeling with a Poisson distribution after adjusting for apparent temperature, barometric pressure, day of the week, and time trend. For each prefecture, we estimated the TDI effects and pooled the estimates to yield a national average for 1991-2010 in Japan. The estimated effects of TDI in middle- or high-latitude prefectures were greater than in low-latitude prefectures. The estimated national average of TDI effects was a 0.5 % (95 % confidence intervals [CI], 0.1, 1.0) increase in elderly mortality per 1-unit (around 1 standard deviation) increase in the TDI. The significant pooled estimation of TDI effects was mainly due to the TDI effects on summer days with moderate temperature (25th-49th percentile, mean temperature 22.9 °C): a 1.9 % (95 % CI, 1.1, 2.6) increase in elderly mortality per 1-unit increase in the TDI. However, TDI effects were insignificant in other temperature ranges. These findings suggest that elderly deaths increased on moderate temperature days in the summer that differed substantially from days during that time window in the neighboring years. Therefore, not only high temperature itself but also temperature deviation compared to previous years could be considered to be a risk factor for elderly mortality in the summer.

Asian countries face frequent spikes in concentrations of particulate matter smaller than 2.5 μm (PM2.5), which may consist of domestic emissions, transported pollutants from neighboring countries, and secondary aerosol formation (SAF). We aimed to estimate the burden on health in South Korea due to PM2.5 exposure from source countries. We computed the health benefits of meeting air quality guidelines during high pollution periods or spike periods. We used daily mortality counts, PM2.5 concentrations, and primary and secondary contributions to pollutant levels in seven cities and nine provinces in South Korea during 2006–2016. Generalized additive mixed modeling with a Poisson distribution and random effects in 16 regions was used to examine the short-term effects of PM2.5 on mortality. We computed attributable burden due to PM2.5 exposure and the potential benefits of meeting the air quality guidelines set by the World Health Organization (WHO, 25 μg/m3) and the Korea Ministry of Environment (50 and 35 μg/m3 before and after 2015, respectively). A concentration–response curve showed a non-linear relationship between daily mortality counts and PM2.5 levels. The short-term health impacts of PM2.5 were suggested to be 1638 non-accidental deaths in 2016 in South Korea due to daily domestic emissions and pollutants transported from neighboring countries. Of these, 1509, 995, or 238 deaths could have been prevented if the daily mean PM2.5 concentration had been kept below 25, 35, or 50 μg/m3. After accounting for the contribution of SAF to PM2.5, primary sources of PM2.5 resulted in 258–860 and 26–88 deaths due to pollution transported from China and North Korea, respectively, and 162–538 deaths were due to domestic emissions. Meeting the air quality guidelines of the WHO could have prevented most of these deaths.

Background The linearity of concentration-response (C-R) curve between ambient ozone (O3) concentration and mortality has been controversial. The aim of the present analysis was to examine the C-R curve between O3 concentration and mortality with a causal framework approach. Methods We extracted data of hourly meteorology, hourly O3 concentration and daily non-accidental mortality in Seoul from 2001 to 2009. We divided the dataset into two, odd-number (training set) and even-number years (testing set). Using the training set, we constructed a prediction model from hourly O3 concentration with support vector regression estimating the daily variations of mean O3 concentration caused by sun irradiation, wind speed and direction, controlling temperature, barometric pressure and temporal trend. With this model we predicted variance of daily O3 from the testing set, thus creating an instrumental variable. We analyzed the association between the instrumental variable and daily mortality. We also analyzed the association according to the quartiles of daily mean O3 concentration to examine the linearity of the association. Results The instrumental variable was significantly and negatively associated with daily mortality in the linear model. In the stratified analysis, the negative slope was observed in the lowest quartile and the negative slope of the association diminished as the quartile increased, and the slope became positive over the 3rd quartile (O3 > 23.3 ppb). The interaction between quartiles and instrumental variable was significant (P = 0.0108). Conclusion We observed unequal effect of exposure to ambient O3 concentration on mortality according to the different ranges of daily mean O3 concentration with a causal framework approach.

Background: Exposure to bisphenol A (BPA) may impact obesity development, either in the exposed subjects or offspring.Objective: To investigate the association between prenatal and postnatal exposu...

Previous studies suggested evidence of an effect of exposure to ambient air pollutants on risk of certain congenital heart and structural defects. However, few studies have investigated the effects...

BACKGROUND:Prenatal environmental cadmium exposure in children may be associated with attention deficit hyperactivity disorder (ADHD) in children.OBJECTIVE:To examine the relationship between the h...

BackgroundPyrethroids, a class of ubiquitous insecticides, have been considered as endocrine-disrupting chemicals. The use of pesticides has increased over the past few decades, which raise concern...

Supplemental Digital Content is available in the text, Observational studies have shown that obesity is a major risk factor for hypertension, but unmeasured confounding factors may exist. We used Mendelian randomization (MR) to assess the causal effect of obesity on hypertension. The MR analysis was performed in a well-defined community cohort study of 8832 middle-aged (40–69 years) adults in Korea enrolled from 2001 to 2013. We used baseline hypertension and newly diagnosed hypertension during the 10-year follow-up period as the outcome variable. Genetic risk score associated with body mass index (BMI GRS) was used as the instrumental variable (IV) to measure the causal relationship between obesity and hypertension. The IV estimate of causal odds ratio (OR) was derived using the Wald ratio estimator and then exponentiation to express the result as an OR. In the multivariable model adjusting for age, sex, study area, education, smoking, and current alcohol consumption, each 1 kg/m2 increase in BMI was associated with a 19% (OR: 1.19, 95% confidence interval [CI]: 1.17–1.21) increase in hypertension risk. We selected 6 single-nucleotide polymorphisms (P

Background/Aim: Despite its clinical importance, the associations between phthalate exposure and thyroid-stimulating hormone (TSH) levels have not been sufficiently investigated yet. Methods: We us...

Background We aimed to evaluate the spatial and temporal trends of the health burden attributable to particulate matter less than 2.5 µm in diameter (PM2.5) in the metropolitan cities and provinces of the Korea. Methods We used modeled PM2.5 concentration data for the basic administrative levels, comprising the cities and the provinces of Korea, the corresponding annual population census data for each level, and the age and cause specific mortality data. We applied cause-specific integrated exposure-response functions to calculate the premature mortality attributable to ambient PM2.5 for four disease end points (ischemic heart disease [IHD], chronic obstructive pulmonary disease [COPD], lung cancer [LC], and cerebrovascular disease [stroke]) for the year 2015. Moreover, the temporal trends of the health burden from 2006 to 2015 were assessed. Results The annual average PM2.5 concentration for Korea was 24.4 μg/m3, and 11,924 premature deaths were attributable to PM2.5 exposure in 2015. By simulating the reduction in the annual mean values of PM2.5 to 10 µg/m3, about 8,539 premature deaths were preventable. There was spatial variation in mortality burden attributable to PM2.5 across the sub-national regions of Korea. In particular, the high burden was concentrated at Seoul and Gyeonggi province due to the high population density. However, decreasing trends were noted for most of the metropolitan cities and provinces of Korea since 2006. Conclusion Our findings show that further actions to improve air quality in Korea would substantially improve the health burden due to particulate matter., Graphical Abstract

Background We aimed to evaluate the spatial and temporal trends of the health burden attributable to particulate matter less than 2.5 µm in diameter (PM2.5) in the metropolitan cities and provinces of the Korea. Methods We used modeled PM2.5 concentration data for the basic administrative levels, comprising the cities and the provinces of Korea, the corresponding annual population census data for each level, and the age and cause specific mortality data. We applied cause-specific integrated exposure-response functions to calculate the premature mortality attributable to ambient PM2.5 for four disease end points (ischemic heart disease [IHD], chronic obstructive pulmonary disease [COPD], lung cancer [LC], and cerebrovascular disease [stroke]) for the year 2015. Moreover, the temporal trends of the health burden from 2006 to 2015 were assessed. Results The annual average PM2.5 concentration for Korea was 24.4 μg/m3, and 11,924 premature deaths were attributable to PM2.5 exposure in 2015. By simulating the reduction in the annual mean values of PM2.5 to 10 µg/m3, about 8,539 premature deaths were preventable. There was spatial variation in mortality burden attributable to PM2.5 across the sub-national regions of Korea. In particular, the high burden was concentrated at Seoul and Gyeonggi province due to the high population density. However, decreasing trends were noted for most of the metropolitan cities and provinces of Korea since 2006. Conclusion Our findings show that further actions to improve air quality in Korea would substantially improve the health burden due to particulate matter.

Background Animal studies have reported an association between phthalates and depression, although there is limited evidence from epidemiological studies. We investigated the association between phthalate exposure and symptoms of depression in an elderly population. Methods Repeated measures surveys up to three times were conducted during the study period (2012–2014) in the 535 elderly subjects. We measured the following urinary phthalate metabolite levels: mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono-n-butyl phthalate (MnBP), and mono-benzyl phthalate (MBzP). MEHHP, MEOHP, and MECPP are metabolites of diethylhexyl phthalates (DEHP). MnBP and MBzP are metabolites of dibutyl phthalate and butyl benzyl phthalate, respectively. The phthalate metabolite concentrations were evaluated to identify associations with the symptoms of depression using the Korean version of the Geriatric Depression Scale-Short Form (SGDS-K). After factor analysis of the components of SGDS-K, we evaluated the association between phthalate exposure and SGDS-K subgroups to determine which symptoms of depression were affected by phthalate exposure. Results Concentrations of DEHP metabolites were positively associated with the risk of depressive symptoms in the elderly population (Odds ratio (95% confidence interval); 1.92 (1.17–3.13) for sum of three DEHP metabolites), while we found no significant association between depressive symptoms and either MnBP or MBzP. When we evaluated the associations between phthalate metabolite concentrations and the SDGS-K subgroup, we found that affective and spiritual symptoms were significantly associated with DEHP metabolite concentrations. Conclusions Our study suggests that DEHP exposure is associated with depressive symptoms, particularly, the affective and spiritual symptoms, among the elderly population.

Substantial epidemiologic literature has demonstrated the effects of air pollution and temperature on mortality. However, there is inconsistent evidence regarding the temperature modification effect on acute mortality due to air pollution. Herein, we investigated the effects of temperature on the relationship between air pollution and mortality due to non-accidental, cardiovascular, and respiratory death in seven cities in South Korea. We applied stratified time-series models to the data sets in order to examine whether the effects of particulate matter10 μm (PM10) on mortality were modified by temperature. The effect of PM10 on daily mortality was first quantified within different ranges of temperatures at each location using a time-series model, and then the estimates were pooled through a random-effects meta-analysis using the maximum likelihood method. From all the data sets, 828,787 non-accidental deaths were registered from 2000-2009. The highest overall risk between PM10 and non-accidental or cardiovascular mortality was observed on extremely hot days (daily mean temperature:99th percentile) in individuals aged65 years. In those aged ≥65 years, the highest overall risk between PM10 and non-accidental or cardiovascular mortality was observed on very hot days and not on extremely hot days (daily mean temperature: 95-99th percentile). There were strong harmful effects from PM10 on non-accidental mortality with the highest temperature range (99th percentile) in men, with a very high temperature range (95-99th percentile) in women. Our findings showed that temperature can affect the relationship between the PM10 levels and cause-specific mortality. Moreover, the differences were apparent after considering the age and sex groups.

Objectives: The deleterious effects of air pollution on various health outcomes have been demonstrated. However, few studies have examined the effects of air pollution on liver enzyme levels. Methods: Blood samples were drawn up to three times between 2008 and 2010 from 545 elderly individuals who regularly visited a community welfare center in Seoul, Korea. Data regarding ambient air pollutants (particulate matter ≤2.5 μm [PM2.5], nitrogen dioxide [NO2], ozone [O3], carbon monoxide, and sulfur dioxide) from monitoring stations were used to estimate air pollution exposure. The effects of the air pollutants on the concentrations of three liver enzymes (aspartate aminotransferase [AST], alanine aminotransferase [ALT], and γ-glutamyltranspeptidase [γ-GTP)]) were evaluated using generalized additive and linear mixed models. Results: Interquartile range increases in the concentrations of the pollutants showed significant associations of PM2.5 with AST (3.0% increase, p=0.0052), ALT (3.2% increase, p=0.0313), and γ-GTP (5.0% increase, p=0.0051) levels; NO2 with AST (3.5% increase, p=0.0060) and ALT (3.8% increase, p=0.0179) levels; and O3 with γ-GTP (5.3% increase, p=0.0324) levels. Significant modification of these effects by exercise and alcohol consumption was found (p for interaction

In developed countries, low latitude and high temperature are positively associated with the population's ability to adapt to heat. However, few studies have examined the effect of economic status on the relationship between long-term exposure to high temperature and health. We compared heterogeneous temperature-related mortality effects relative to the average summer temperature in high-socioeconomic-status (SES) cities to temperature-related effects in low-SES cities. In the first stage of the research, we conducted a linear regression analysis to quantify the mortality effects of high temperature (at or above the 95th percentile) in 32 cities in Taiwan, China, Japan, and Korea. In the second stage, we used a meta-regression to examine the association between mortality risk with average summer temperature and gross domestic product (GDP) per capita. In cities with a low GDP per capita (less than 20,000 USD), the effects of temperature were detrimental to the population if the long-term average summer temperature was high. In contrast, in cities with a high GDP per capita, temperature-related mortality risk was not significantly related to average summer temperature. The relationship between long-term average summer temperature and the short-term effects of high temperatures differed based on the city-level economic status.

BACKGROUND: There are few data on the interaction between temperature and snow and rain precipitation, although they could interact in their effects on road traffic injuries. METHODS: The integrated database of the Korea Road Traffic Authority was used to calculate the daily frequency of road traffic injuries in Seoul. Weather data included rain and snow precipitation, temperature, pressure, and fog from May 2007 to December 2011. Precipitation of rain and snow were divided into nine and six temperature range categories, respectively. The interactive effects of temperature and rain and snow precipitation on road traffic injuries were analyzed using a generalized additive model with a Poisson distribution. RESULTS: The risk of road traffic injuries during snow increased when the temperature was below freezing. Road traffic injuries increased by 6.6% when it was snowing and above 0°C, whereas they increased by 15% when it was snowing and at or below 0°C. In terms of heavy rain precipitation, moderate temperatures were related to an increased prevalence of injuries. When the temperature was 0-20°C, we found a 12% increase in road traffic injuries, whereas it increased by 8.5% and 6.8% when it was 20°C, respectively. The interactive effect was consistent across the traffic accident subtypes. CONCLUSIONS: The effect of adverse weather conditions on road traffic injuries differed depending on the temperature. More road traffic injuries were related to rain precipitation when the temperature was moderate and to snow when it was below freezing. Language: en

BACKGROUND: The effects on postnatal growth of maternal exposure to low levels of lead during pregnancy have not been well established. In addition, information is limited regarding the protective effect of dietary calcium intake during pregnancy against the effect of lead for fetal and postnatal growth. We investigated the relationship between prenatal exposure to lead and growth at birth and 6, 12, and 24 months postnatal, and evaluated the role of calcium intake against the effect of lead. METHODS: A total of 1150 pregnant women, and their subsequent offspring, enrolled in a prospective birth cohort study (Mothers and Children's Environmental Health Study), were evaluated. Multivariable regression analysis was conducted to estimate the effects of prenatal maternal blood lead levels on growth at each follow-up. RESULTS: The blood lead levels of participating mothers were CONCLUSIONS: Prenatal lead exposure

Background Extreme temperatures and temperature changes are known indicators of climate change, and large temperature variations for several consecutive days may affect human health such as exacerbating respiratory symptoms. The objective of this study was to determine the association between outdoor temperature change and asthma-related emergency department visits. In particular, this study examined seasonality and identified susceptible populations, such as the elderly. Methods The health data for asthma-related emergency department visits were collected from July 1, 2007, to December 31, 2010 in Seoul, Korea, through the National Emergency Department Information System of the National Emergency Medical Center and we defined temperature change as the absolute difference of mean temperature between the current day and the previous day. We applied generalized linear models with an allowance of over-dispersion for quantifying the estimated effects of temperature change on asthma-related emergency department visits, adjusting for meteorological conditions, air pollution, and time trend. Results In general, temperature change was adversely associated with asthma-related emergency department visits, with a 1-unit increase of temperature change associated with a 3.5% (95% CI 0.7, 6.4%) increase in emergency department visits. In addition, seasonal variation after adjusting for mean temperature and diurnal temperature range had an adverse effect in spring, summer, and fall and a protective effect in winter. Patients aged ≥65 years experienced the most prominent effect during the fall, with a 17.9% (95% CI 4.1, 33.6%) increase in emergency department visits per 1-unit increase of temperature change, whereas the other seasons showed no statistically significant association. Conclusions Along with diurnal temperature range, temperature change may be an alternative indicator of climate change. Temperature change variables are well-known and easy to communicate with the public relative to the health effects of outdoor temperature fluctuations.

The association between temperature (cold or heat) and cardiovascular mortality has been well documented. However, few studies have investigated the underlying mechanism of the cold or heat effect. The main goal of this study was to examine the effect of temperature on dehydration markers and to explain the pathophysiological disturbances caused by changes of temperature. We investigated the relationship between outdoor temperature and dehydration markers (blood urea nitrogen (BUN)/creatinine ratio, urine specific gravity, plasma tonicity and haematocrit) in 43,549 adults from Seoul, South Korea, during 1995-2008. We used piece-wise linear regression to find the flexion point of apparent temperature and estimate the effects below or above the apparent temperature. Levels of dehydration markers decreased linearly with an increase in the apparent temperature until a point between 22 and 27 °C, which was regarded as the flexion point of apparent temperature, and then increased with apparent temperature. Because the associations between temperature and cardiovascular mortality are known to be U-shaped, our findings suggest that temperature-related changes in hydration status underlie the increased cardiovascular mortality and morbidity during high- or low-temperature conditions.

The relationship between the serum concentrations of perfluoroalkyl compounds (PFCs) and growth parameters was investigated in 2-year-old Korean children. The study included 361 children aged 2years (192 boys and 169 girls; 22-27months), born at term appropriate-for-gestational-age, who visited between 2012 and 2013. Growth parameters of height and weight, and serum samples were collected from 2-year-old children. Four PFCs (perfluorohexane sulfonic acid [PFHxS], perfluorooctane sulfonic acid [PFOS], perfluorooctanoic acid [PFOA], and perfluorononanoic acid [PFNA]), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), and perfluoroheptanoic acid (PFHpA) were detected in >99, 93.4, 89.8, and 74.2% of the serum samples, respectively. The duration of breastfeeding was positively associated with the serum concentrations of ln-transformed PFHxS, PFOS, PFHpA, PFOA, PFNA, PFDA, and PFUnDA (all P

BACKGROUND Being common, mild anemia is sometimes considered a mere consequence of aging; however, aging alone is unlikely to lead to anemia. Therefore, this study aimed to investigate the association between mild anemia and total mortality and cause-specific mortality in apparently healthy elderly subjects. METHODS A retrospective cohort study was conducted on 10,114 apparently healthy elderly individuals who underwent cancer screening and routine medical check-ups at one Health Promotion Center between May 1995 and December 2007. We defined mild anemia as a hemoglobin concentration between 10.0 g/dL and 11.9 g/dL in women and between 10.0 g/dL and 12.9 g/dL in men. We assessed the relationship between the overall, cardiovascular (CV), and cancer mortality and mild anemia using Cox proportional hazard models. RESULTS Mild anemia was present in 143 men (3.1%) and 246 women (6.1%). During an average follow-up of 7.6 years, 495 deaths occurred, including 121 CV and 225 cancer deaths. After adjustments, mild anemia was associated with a 128% increase in the risk of all-cause mortality hazard ratio (HR, 2.28; 95% confidence interval [CI], 1.54- 3.37) in men and cancer-related mortality (HR, 2.25; 95% CI, 1.22-4.13), particularly lung cancer (HR, 2.70; 95% CI, 1.03-7.08) in men, but not in women. In the subgroup analyses based on smoking status, obesity, and age, the associations were more prominent in never or former smoker groups and the older group. CONCLUSION The present study shows that overall and cancer-related mortality was associated with mild anemia in elderly men. Future prospective studies are needed to consolidate our findings.

Background Prenatal and postnatal exposure to bisphenol A (BPA) may affect early brain development. Rodent studies suggest that prenatal and postnatal neurodevelopmental toxicity from BPA exposure may manifest as social deficits in offspring. We investigated the association between prenatal and postnatal exposure to BPA and social impairments in a sample of 4-year-old children. Methods We recruited second-trimester pregnant women between 2008 and 2011, and measured their creatinine-adjusted prenatal urine BPA levels. In 2014-2015, a subset of 4-year-old children born to these women underwent neurobehavioral assessment and physical examination. We collected urine and blood from the children and assessed social impairments, including deficits in social interaction, social communication, and other behavior patterns using the Korean version of the Social Communication Questionnaire (K-SCQ) (n = 304). We examined social impairments associated with prenatal exposure at mid-term pregnancy and postnatal exposure to BPA at 4 years of age, using linear and piecewise linear regression models. Results The relationship between prenatal BPA exposure and social communication was non-linear and statistically significant at or above the flexion point for BPA levels of 3.0 μg/g creatinine in girls (58.4%, 95% confidence interval [CI], 6.5% to 135.8%). Each 2-fold increase in postnatal BPA exposure was significantly associated with an 11.8% (95% CI, 0.6% to 24.3%) increase in impairment in social communication in 4-year old girls, as indicated by the linear regression model. Conclusion Prenatal and postnatal BPA exposure is associated with social impairment at 4 years of age, particularly in girls. Electronic supplementary material The online version of this article (doi:10.1186/s12940-017-0289-2) contains supplementary material, which is available to authorized users.

Some studies have suggested that high ambient temperatures are a risk factor for kidney-related diseases. However, none have examined the association between ambient temperature and acute kidney injury (AKI). This study aimed to examine the association between daily mean temperature and AKI and identify high-risk subgroups in this association. We obtained health insurance claim data from the Health Insurance Review and Assessment Service (HIRA) for 24,800 admitted cases of AKI during the period 2007-2014 in Seoul, Korea. Using a time-series design and piecewise linear regression models, we estimated the percentage change in AKI admissions associated with daily mean temperature after controlling for relevant covariates. Daily mean temperature and AKI admissions displayed an inverse association in the cold season and a nonlinear relationship with a flexion point around 28.8°C in the warm season. AKI admissions increased by 23.3% (95% confidence interval [CI]: 14.3, 33.0) per 1°C increase in mean temperature above the 28.8°C flexion point in the warm season. The estimates were greatest among men with hypertension (55.1%; 95% CI: 25.1, 92.2). However, we did not observe significant increases in AKI admissions associated with ambient temperature in the cold season (0.4% [95% CI: -0.1, 0.9] per 1°C decrease in mean temperature). Our results suggest that hospital admissions for AKI increase in association with high temperature, particularly among men with hypertension in the warm season. Thus, early detection of AKI during heat wave periods is crucial. Our findings also provide evidence for the local government to target populations vulnerable to high ambient temperatures.

Prenatal exposure to volatile organic compounds may restrict fetal development and adversely influence infants' life. Therefore, we investigated the relationship between prenatal exposure to total volatile organic compounds (TVOC) and postnatal neurobehavioral development. A subsample of 383 pregnant participants was chosen from the prospective birth cohort study of Mother and Children's Environmental Health Study; MOCEH (N=1,751) from three regions of the Republic of Korea (Seoul, Cheon-an, and Ulsan). Participants were enrolled during their first trimester with informed consent. We investigated maternal characteristics including socio-economic and obstetrical history using questionnaires. An environmental hygienist measured participating mothers' personal TVOC exposure using passive samplers during pregnancy. Participants visited the research center at 6, 12, 24 and 36 months. At each visit, questionnaires about infantile environment and health conditions were answered and a neurobehavioral test (BSID-II) was conducted by certified investigators. We conducted multiple general linear and mixed model analyses to investigate the relationship between TVOC and infantile neurobehavioral development (SAS 9.3). Mean prenatal TVOC exposure was 284.2μg/m3. In longitudinal analyses on infantile neurobehavioral development, adjusted mean psychomotor development index and mental developmental index scores in high TVOC exposure group (cut off at Q3: 374.0 ug/m3) were 3 points lower than the low exposure group. Results suggested exposure to higher TVOC during the fetal period may adversely influence neurobehavioral development in the early life stage.

Although epidemiologic studies have shown an association between the total mass of particulate matter2.5μm in aerodynamic diameter (PMIn this longitudinal study, we investigated the relationship between PMBP, HR, and rMSSD were associated with concentration of total mass of PMOur results suggest an association between specific PM

Distribution of mercury at each visit and overall study. Table S2. Estimated association between log transformed liver enzymes and total blood mercury levels using generalized estimating equations model in non-drinkers. Figure S1. Flow chart for study participants. Figure S2. Generalized additive mixed model for total mercury concentrations and three liver enzymes. Additionally adjusted for sex, age, smoking status, drinking status, exercise, education, high-density lipoproteins cholesterol, overweight and calorie. (PDF 147Â kb)

Selection of study participants. Table S1. Characteristics of mothers included and excluded in the follow-up of the Birth cohort (N = 10,752). Table S2. Characteristics of participants included and excluded in the study. Table S3. Percentage change in scores on the K-SCQ associated with 2-fold increase in creatinine-unadjusted prenatal and postnatal BPA levels. Table S4. Percentage change in scores on the K-SCQ associated with 2-fold increase in creatinine-adjusted prenatal and postnatal BPA levels after controlling for covariates. Figure S2. Percentage change in scores on the K-SCQ associated with 2-fold increase at or above level of creatinine-adjusted prenatal Bisphenol A (3.0 μg/g creatinine) by sex. (DOCX 143 kb)

Asian dust storms (ADS) have affected several Asian countries and have been a major concern due to adverse effects on public health. The occurrence of ADS differs in each country based on geographical features and distance from the storms' origin. Many studies have reported significant associations between ADS and morbidity. However, regarding the association between ADS and mortality, only a few studies have found statistically significant ADS effects in Korea, Taiwan and Japan. Accordingly, this study aimed to examine the effects of ADS on daily mortality in three Asian cities (Seoul, South Korea; Taipei, Taiwan; and Kitakyushu, Japan) and to explore the differences in the extent of effects in each city. We performed time-series analyses using a generalized additive model (GAM) with Quasi-Poisson regressions. Deaths due to accidents or external causes were excluded. We used a dummy variable as an indicator of ADS and considered lag effects of ADS. Stratified analyses by disease and age and sensitivity analyses controlling for NO2, SO2, and PM10 were also conducted respectively. Additionally, influenza epidemics were adjusted for considering seasonal patterns, and a meta-analysis was performed. We reported results as excess mortality by percentage due to Asian dust storms. We found significant excess mortality in Seoul and Kitakyushu as follows. In Seoul, ADS showed adverse effects on mortality under 65 years old (lag 2: 4.44%, lag 3: 5%, lag 4: 4.39%). In Kitakyushu, ADS had adverse effects on respiratory mortality (lag 2: 18.82%). Contradictory to results in Seoul and Kitakyushu, ADS seemed to have a protective effect in Taipei: total non-accidental mortality (lag 0: −2.77%, lag 1: −3.24%), mortality over 65 years old (lag 0: −3.35%, lag 1: −3.29%) and respiratory mortality (lag 0: −10.62%, lag 1: −9.67%). Sensitivity analyses showed similar findings as the main results. Our findings suggest that ADS may affect mortality in several Asian cities, and that a dust storm warning system could help protect people from dust storms.

The primary purpose of this study was to investigate the effects of phthalate exposure on the intelligence and attentional performance of 6-year old children when adjusting each other as covariates. We also investigated the differential effects of phthalate exposure on the intelligence and attention according to exposure period (maternal or children). Urine concentrations of mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-n-butyl phthalate (MBP) were analyzed. Multivariable linear regression models were used to investigate the relationship between exposure to various phthalates with IQ scores and continuous performance test (CPT) variables. There were robust associations between child MEHHP and MEOHP levels with full scale IQ (FSIQ) even after adjusting for demographic variables and CPT scores (MEHHP -9.27, 95% CI: -17.25, -1.29; MEOHP -9.83, 95% CI: -17.44, -2.21). Child MEHHP and MEHOP levels negatively affected omission errors (MEHHP -20.36, 95% CI: -34.17, -6.55; MEOHP -18.93, 95% CI: -32.58, -5.28) and the response time variability (MEHHP -21.07, 95% CI: -39.04, -3.10; MEOHP -20.41, 95% CI -38.14, -2.69) of the CPT after adjusting for demographic variables and IQ. Maternal phthalate exposure had no effects on IQ or CPT variables. These results suggest that children phthalate exposure, but not maternal exposure, has an adverse effect on IQ and attentional performance, and these associations were found to be independent of each other.

Recent studies have revealed that the effect of temperature on mortality has changed over time. One of the major contributors to the changes is adaptation. We aimed to understand the relationship between elderly mortality and temperature anomaly using the temperature deviation index (TDI), which considers exposure history. Summertime (May to September) mortality data from 1996 to 2014 and meteorological data from 1971 to 2014 were obtained for 16 regions covering South Korea. The TDI was defined as the target day’s temperature abnormality compared to previous 25 years’ apparent temperature (AT). The relationship between the TDI and elderly mortality for each region was examined by generalized linear modeling with Poisson distribution. Pooled estimates were computed to yield a national effect estimate. Stratified analyses were performed using the percentiles of AT and TDI. Most regions showed positive linear associations, and the associations ranged from 0.4 to 4.3% increase per unit increase of the TDI. In the pooled analyses, a unit increase of the TDI was associated with a 1.4% increase (95% confidence interval [CI] 0.93–1.87) in elderly mortality. In the stratified analysis, the relationship between the TDI and elderly mortality was significant at or above the 75th percentile of AT (1.32% increase; 95% CI 0.47–2.22). We suggest a positive association between the TDI and elderly mortality in South Korea. The association observed particularly in the highest percentile of AT in the stratified analysis suggests independent effects of temperature anomaly in addition to those of absolute AT.

ObjectiveWe evaluated frequency and risk factors of delayed TSH elevation (dTSH) and investigated follow-up outcomes in the dTSH group with venous TSH (v-TSH) levels of 6-20 mU/L according to whether late preterm infants born at gestational age (GA) 35-36 weeks had risk factors.MethodsThe medical records of 810 neonates (414 boys) born at Seoul National University Hospital who had a normal neonatal screening test (NST) and underwent the first repeat venous blood test at 10-21 days post birth were reviewed.ResultsSeventy-three (9.0%) neonates showed dTSH, defined as a v-TSH level ≥6.0 mU/L, 12 of whom (1.5%) were started on levothyroxine medication. A multivariate-adjusted model indicated that a low birth weight (LBW ConclusionsdTSH was detected in 9.0% and levothyroxine was indicated in 1.5% of infants born at GA 35-36 weeks, particularly those with a LBW, a congenital anomaly, or history of ICM exposure. Either levothyroxine or retesting is indicated for late preterm neonates with TSH levels ≥10 mU/L regardless of risk factors. If healthy preterm neonates show v-TSH levels of 6-10 mU/L, a second repeat test may not be necessary; however, further studies are required to set a threshold for retesting.

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

Cardiovascular mortality has been shown to increase in the winter. However, it is unclear whether cold temperature affects indicators known as cardiovascular markers. We evaluated the association between ambient temperature and cardiovascular markers using data collected retrospectively from 55,567 adults who had visited a health check-up clinic between 1995 and 2008. Non-parametric smoothing regressions were fitted to determine the shapes of association between temperature and cardiovascular markers such as blood pressure, lipid profiles, platelet count, and high sensitivity C-reactive protein (hsCRP). Mixed effect model was used to investigate the significance of the relationship between temperature and cardiovascular markers. Decreased ambient temperature was associated with an increase in systolic and diastolic blood pressures, platelet count and serum low density lipoprotein-cholesterol concentration. In contrast, high density lipoprotein-cholesterol level declined with decreasing temperature. The hsCRP level increased with decreasing temperature in the minimum temperatures below 0°C, but revealed a reverse association above. Our study suggests that excess cardiovascular mortality in cold weather might be associated with temperature-related variations of cardiovascular markers.

Introduction : Chronic suppurative otitis media (CSOM) and hearing impairment are associated with oxidative stress, which could be induced by cadmium exposure. We evaluated the role of CSOM as a me...

Background: Blood pressure rises with a drop in external temperature 1-3, but the role of DNA methylation in such blood pressure modulation has not been studied in detail. Methods: We evaluated blo...