Implementation of a portable diffraction phase microscope for digital histopathology.

Quantitative phase imaging (QPI) has a significant advantage in histopathology as it helps in differentiating biological tissue structures and cells without the need for staining. To make this capability more accessible, it is crucial to develop compact and portable systems. In this study, we introduce a portable diffraction phase microscopy (DPM) system that allows the acquisition of phase map images from various organs in mice using a low-NA objective lens. Our findings indicate that the cell and tissue structures observed in portable DPM images are similar to those seen in conventional histology microscope images. We confirmed that the developed system's performance is comparable to the benchtop DPM system. Additionally, we investigate the potential utility of digital histopathology by applying deep learning technology to create virtual staining of DPM images.

Recent advances in microbial production of medium chain fatty acid from renewable carbon resources: A comprehensive review.

Microbial production of medium chain length fatty acids (MCFAs) from renewable resources is becoming increasingly important in establishing a sustainable and clean chemical industry. This review comprehensively summarizes current advances in microbial MCFA production from renewable resources. Detailed information is provided on two major MCFA production pathways using various renewable resources and other auxiliary pathways supporting MCFA production to help understand the fundamentals of bio-based MCFA production. In addition, conventional and well-studied MCFA producers are classified into two categories, natural and synthetic producers, and their characteristics on MCFA production are outlined. Moreover, various engineering strategies employed to achieve the highest MCFAs production up to date are showcased together with key enzymes suggested for MCFA overproduction. Finally, future challenges and perspectives are discussed towards more efficient production of bio-based MCFA production.

Quantitative Screening of Cervical Cancers for Low-Resource Settings: Pilot Study of Smartphone-Based Endoscopic Visual Inspection After Acetic Acid Using Machine Learning Techniques.

BACKGROUND: Approximately 90% of global cervical cancer (CC) is mostly found in low- and middle-income countries. In most cases, CC can be detected early through routine screening programs, including a cytology-based test. However, it is logistically difficult to offer this program in low-resource settings due to limited resources and infrastructure, and few trained experts. A visual inspection following the application of acetic acid (VIA) has been widely promoted and is routinely recommended as a viable form of CC screening in resource-constrained countries. Digital images of the cervix have been acquired during VIA procedure with better quality assurance and visualization, leading to higher diagnostic accuracy and reduction of the variability of detection rate. However, a colposcope is bulky, expensive, electricity-dependent, and needs routine maintenance, and to confirm the grade of abnormality through its images, a specialist must be present. Recently, smartphone-based imaging systems have made a significant impact on the practice of medicine by offering a cost-effective, rapid, and noninvasive method of evaluation. Furthermore, computer-aided analyses, including image processing-based methods and machine learning techniques, have also shown great potential for a high impact on medicinal evaluations. OBJECTIVE: In this study, we demonstrate a new quantitative CC screening technique and implement a machine learning algorithm for smartphone-based endoscopic VIA. We also evaluated the diagnostic performance and practicability of the approach based on the results compared to the gold standard and from physicians' interpretation. METHODS: A smartphone-based endoscope system was developed and applied to the VIA screening. A total of 20 patients were recruited for this study to evaluate the system. Overall, five were healthy, and 15 were patients who had shown a low to high grade of cervical intraepithelial neoplasia (CIN) from both colposcopy and cytology tests. Endoscopic VIA images were obtained before a loop electrosurgical excision procedure for patients with abnormal tissues, and their histology tissues were collected. Endoscopic VIA images were assessed by four expert physicians relative to the gold standard of histopathology. Also, VIA features were extracted from multiple steps of image processing techniques to find the differences between abnormal (CIN2+) and normal (≤CIN1). By using the extracted features, the performance of different machine learning classifiers, such as k-nearest neighbors (KNN), support vector machine, and decision tree (DT), were compared to find the best algorithm for VIA. After determining the best performing classifying model, it was used to evaluate the screening performance of VIA. RESULTS: An average accuracy of 78%, with a Cohen kappa of 0.571, was observed for the evaluation of the system by four physicians. Through image processing, 240 sliced images were obtained from the cervicogram at each clock position, and five features of VIA were extracted. Among the three models, KNN showed the best performance for finding VIA within holdout 10-fold cross-validation, with an accuracy of 78.3%, area under the curve of 0.807, a specificity of 80.3%, and a sensitivity of 75.0%, respectively. The trained model performed using an unprovided data set resulted in an accuracy of 80.8%, specificity of 84.1%, and sensitivity of 71.9%. Predictions were visualized with intuitive color labels, indicating the normal/abnormal tissue using a circular clock-type segmentation. Calculating the overlapped abnormal tissues between the gold standard and predicted value, the KNN model overperformed the average assessments of physicians for finding VIA. CONCLUSIONS: We explored the potential of the smartphone-based endoscopic VIA as an evaluation technique and used the cervicogram to evaluate normal/abnormal tissue using machine learning techniques. The results of this study demonstrate its potential as a screening tool in low-resource settings.

Association between Environmental Polycyclic Aromatic Hydrocarbons Exposure and Insulin Resistance: Using The Second Korean National Environmental Health Survey

Background@#A positive association between air pollution and insulin resistance has been shown in previous studies as a precursor state of type 2 diabetes, especially in older adults. This study was conducted to investigate the association between insulin resistance and environmental polycyclic aromatic hydrocarbon (PAH) exposure as ubiquitous outdoor and indoor air pollution components. @*Methods@#From the second Korean National Environmental Health Survey, 5,717 adults aged ≥19 years were included in this study. To identify the association between environmental PAH exposure (urinary 1-hydroxypyrene, 1-OHP) and insulin resistance, defined by the ratio of triglyceride to high-density lipoprotein cholesterol, we performed multiple stepwise regression analysis, adjusting for age, sex, education, physical activity, exposure to smoking and air pollution, body mass index, hypertension, and diabetes mellitus. @*Results@#Urinary 1-OHP concentration was significantly associated with the ratio of triglyceride to high-density lipoprotein cholesterol. @*Conclusion@#Environmental exposure to PAHs is associated with increased insulin resistance in adults.

Association Between Ambient Air Pollution Exposure and Spontaneous Pneumothorax Occurrence.

BACKGROUND: Spontaneous pneumothorax is hypothesized to be associated with air pollution exposure based on pathophysiological mechanisms involving airway inflammation. Therefore, we analyzed the association between daily concentrations of air pollutants [sulfur dioxide, nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), particulate matter (PM) less than 2.5 µm in diameter (PM2.5), PM less than 10 µm in diameter (PM10), and coarse PM (PM10-2.5)] and the number of spontaneous pneumothorax-related hospital visits. METHODS: We analyzed a subset of data from the National Health Insurance Service-National Sample Cohort, a nationally representative dynamic cohort based on health insurance claims data in Korea. Using time series analysis with the Poisson generalized additive model, we evaluated hospital visit data of over 100,000 male cohort members residing in Seoul from 2007 to 2010. RESULTS: We identified 516 hospital visits due to spontaneous pneumothorax. In a single-pollutant model, an interquartile range increase of PM and CO exposure at lag day 1 was associated with spontaneous pneumothorax hospital visits (relative risk, 95% confidence interval: PM2.5: 1.10 (1.01, 1.21); PM10: 1.09 (1.01, 1.18); PM10-2.5: 1.06 (1.00, 1.12); CO: 1.11 (1.01, 1.23)). For lag day 2, NO2 and PM exposure was associated with pneumothorax hospital visits (NO2: 1.15 (1.01, 1.32); PM10: 1.10 (1.02, 1.18); PM10-2.5: 1.07 (1.02, 1.13)). In a multipollutant model, the association was consistent for PM. CONCLUSION: The number of hospital visits due to spontaneous pneumothorax increased with air pollution exposure, especially with PM. Our finding suggests that air pollution is a possible predisposing factor for spontaneous pneumothorax.

Influence of Mineral Supplementation on the Results from Analysis of Flavonol Glycoside Content in Ginkgo biloba Dietary Supplements.

Flavonoids are a major component of Ginkgo biloba extract (GBE). Several studies have investigated chelate formation and the redox reaction between flavonoids and metal ions; however, the effect of mineral supplements on the results from the analysis of the flavonol glycoside content in products containing GBE dietary supplement remains unknown. In this study, the effects of commonly used mineral supplements on the recovery of quercetin from GBE-containing dietary supplements were investigated using conventional methods of flavonol glycoside determination. Mineral supplements containing Zn (II), Mn (II), and Fe (II) did not affect quercetin recovery, whereas Cu (II) and Fe (III) significantly reduced recovery (P<0.05). Quercetin oxidation was prevented by adding an antioxidant to the diluent (extraction solvent). Among the tested synthetic antioxidants, tert-butyl hydroquinone (TBHQ) promoted the greatest increase in quercetin recovery. The flavonol glycoside content of commercially available GBE-containing dietary supplements was analyzed using a conventional diluent or a diluent containing 20 mg/mL TBHQ. The amount of quercetin recovered from products containing Cu (II) was found to decrease with increasing hydrolysis duration and the duration in the final test solution state using the conventional diluent, while the TBHQ-containing diluent yielded consistent quercetin contents (P<0.05). These findings suggest that quercetin, a major aglycone of GBE flavonol glycosides, can be oxidized by Cu (II) and Fe (III) during the analytical process and, therefore, the total flavonol glycoside content may be underestimated. The addition of TBHQ to the diluent can improve the accuracy and reproducibility of flavonol glycoside content analysis in GBE-containing dietary products supplemented with minerals.

Emergence of a multidrug-resistant clinical isolate of Escherichia coli ST8499 strain producing NDM-13 carbapenemase in the Republic of Korea.

We described a carbapenem-resistant Escherichia coli ST8499 strain producing New Delhi metallo-ß-lactamase-13 (NDM-13) from patient in Korea. The isolate exhibited multidrug resistance, but remained susceptible to colistin and tigecycline. The blaNDM-13 gene was located on a 130-kb self-transmissible plasmid. This is the first report of NDM-13 carbapenemase in Korea.

Label-free optical projection tomography for quantitative three-dimensional anatomy of mouse embryo.

Recent progress in three-dimensional optical imaging techniques allows visualization of many comprehensive biological specimens. Optical clearing methods provide volumetric and quantitative information by overcoming the limited depth of light due to scattering. However, current imaging technologies mostly rely on the synthetic or genetic fluorescent labels, thus limits its application to whole-body visualization of generic mouse models. Here, we report a label-free optical projection tomography (LF-OPT) technique for quantitative whole mouse embryo imaging. LF-OPT is based on the attenuation contrast of light rather than fluorescence, and it utilizes projection imaging technique similar to computed tomography for visualizing the volumetric structure. We demonstrate this with a collection of mouse embryo morphologies in different stages using LF-OPT. Additionally, we extract quantitative organ information applicable toward high-throughput phenotype screening. Our results indicate that LF-OPT can provide multi-scale morphological information in various tissues including bone, which can be difficult in conventional optical imaging technique.

Mobile Text Messaging Interventions for Smoking Cessation: A Systematic Review

BACKGROUND: Smoking is one of the most serious health problems worldwide. The aim of this systematic review was to demonstrate the effect of text messaging-based interventions on smoking cessation.METHODS: Electronic databases were searched using specific key terms. The inclusion criteria were (1) articles that employed a randomized controlled trial and (2) articles that examined the effect of text messaging interventions on smoking cessation. However, studies employing multimedia messaging service and smartphone apps were excluded.RESULTS: In total, six randomized controlled trial studies with seven interventions were included in this systematic review. Of these six studies, almost all concluded that text-messaging interventions had no significant effect on smoking cessation. However, one study conducted in England revealed that text messaging intervention groups had a higher rate of six-month prolonged abstinence from smoking than did the control group.CONCLUSION: Text messaging interventions could be effective for those who want to quit smoking. We aimed to determine the effectiveness of using text messaging interventions for smoking cessation. However, there were only six studies that employed randomized controlled trials to determine such effectiveness. More studies on the effect of text messaging interventions for smoking cessation using subjects from various age groups and socioeconomic backgrounds are needed in the future.

Detection of Pathogenic Viruses in the Ambient Air in Seoul, Korea.

The possible transport of pathogenic microorganisms during Asian dust events could be an important concern for health workers; however, this is still uncertain owing to a lack of supporting evidence. The present study aimed to investigate the presence of pathogenic microorganisms in air samples collected during the Asian and non-Asian dust periods. Between March and September 2016, air samples were collected at three weather observation stations in Seoul using a high-volume air sampler. Multiplex PCR was performed using the Allplex™ respiratory and gastrointestinal panel assay kits to detect 46 microorganisms. RT-PCR was performed for klassevirus, Aichivirus, and human parechovirus (HPeV) detection. In total, 71 air samples were collected during the Asian (8 samples) and non-Asian (63 samples) dust events. During an Asian dust event, only one human rhinovirus (HRV)-positive air sample was collected on April 23. During the non-Asian dust period, HRV, HPeV, norovirus (NoV), enteroaggregative Escherichia coli (EAEC), enterotoxigenic E. coli (ETEC), and Blastocystis hominis were detected in four, two, one, one, one, and one air samples, respectively. Pathogenic viruses were mostly detected in ambient air samples during the non-Asian dust period, which suggests a possible air-borne transmission of viral pathogens; however, the role of Asian dust in epidemics caused by pathogenic viruses is unclear.

Concentrations of Bisphenols in Canned Foods and Their Risk Assessment in Korea.

The purpose of this study was to survey concentrations of bisphenols in canned foods using liquid chromatography-tandem mass spectrometry, to estimate the dietary exposure to bisphenols, and to assess the related risk for the Korean population from the intake of canned foods. The linearity of bisphenols in the range of 2.5 to 725 µg/L was satisfactory with correlation coefficients ( r2) of 0.999. The limit of detection was 0.14 to 5.85 µg/L, and the limit of quantitation was 0.44 to 17.73 µg/L. Sample recoveries were 70.56 to 113.6%, with relative standard deviations below 10% for spiking levels of 50 and 250 µg/kg (15 and 75 µg/kg for BPS). The bisphenol concentrations in 104 canned foods ranged from undetectable to 1,525 µg/kg. The estimated mean daily intake of bisphenols was 0.54 to 78.69 ng/kg of body weight per day, and the 95th percentile daily intake was 1.92 to 134 ng/kg of body weight per day. Therefore, the intake of bisphenols from canned foods for the population in Korea is unlikely to cause human health problems. The analytical methods used are suitable for regular monitoring and assessment of human exposure to bisphenols from foods.

Determination and identification of titanium dioxide nanoparticles in confectionery foods, marketed in South Korea, using inductively coupled plasma optical emission spectrometry and transmission electron microscopy.

Food-grade titanium dioxide (TiO2) is a common and widespread food additive in many processed foods, personal care products, and other industrial categories as it boosts the brightness and whiteness of colours. Although it is generally recognised as safe for humans, there is a growing interest in the health risks associated with its oral intake. This study quantified and identified TiO2 nanoparticles present in confectionery foods, which are children's favourite foods, with inductively coupled plasma optical emission spectrometry (ICP-OES) and transmission electron microscopy (TEM). A reliable digestion method using hot sulphuric acid and a digestion catalyst (K2SO4:CuSO4 = 9:1) was suggested for titanium analysis. Validations of the experimental method were quite acceptable in terms of linearity, recoveries, detection limits, and quantification limits. Of all the 88 analysed foods, TiO2 was detected in 19 products, all except three declared TiO2 in their labelling. The mean TiO2 content of candies, chewing gums, and chocolates were 0.36 mg g-1, 0.04 mg g-1, and 0.81 mg g-1, respectively. Whitish particles isolated from the confectionery foods were confirmed as TiO2 nanoparticles via TEM and energy dispersive X-ray spectroscopy (EDX), in which nanosized particles (<100 nm) were identified.

Association of High-Risk Drinking with Metabolic Syndrome and Its Components in Elderly Korean Men: The Korean National Health and Nutrition Examination Survey 2010–2012 / 가정의학회지

BACKGROUND: Previous studies have examined the association between alcohol consumption and metabolic syndrome (MetS) in adults, but studies in the elderly are lacking. We examined the relationship between high-risk alcohol consumption and MetS in elderly Korean men using the Alcohol Use Disorders Identification Test (AUDIT) questionnaire from the 2010–2012 Korean National Health and Nutrition Examination Survey. METHODS: Among 25,534 subjects, 2,807 were men >60 years of age; after exclusions, we included 2,088 men in the final analysis. We categorized the study participants into three groups according to AUDIT score: low risk (0–7), intermediate risk (8–14), and high risk (≥15 points). RESULTS: Among the study population, 17.0% of the men were high-risk drinkers, who had the highest mean waist circumference, systolic and diastolic blood pressure (BP), fasting plasma glucose (FPG), and triglyceride (TG) levels. The overall prevalence of MetS was 41.9% in the elderly men, and it was significantly higher in the group with high (48.3%) versus low (31.9%) AUDIT scores. The prevalence of MetS components (elevated BP, high FPG, high TG, and low high-density lipoprotein cholesterol) was associated with a high AUDIT score. The odds ratios (95% confidence interval) of the high-risk group for MetS, elevated BP, and high TG were 1.40 (1.03–1.89), 1.82 (1.28–2.60), and 1.77 (1.30–2.41) after adjustment for confounding variables. CONCLUSION: AUDIT score was correlated with most MetS components in elderly Korean men.

Lamellar keratoplasty using position-guided surgical needle and M-mode optical coherence tomography.

Deep anterior lamellar keratoplasty (DALK) is an emerging surgical technique for the restoration of corneal clarity and vision acuity. The big-bubble technique in DALK surgery is the most essential procedure that includes the air injection through a thin syringe needle to separate the dysfunctional region of the cornea. Even though DALK is a well-known transplant method, it is still challenged to manipulate the needle inside the cornea under the surgical microscope, which varies its surgical yield. Here, we introduce the DALK protocol based on the position-guided needle and M-mode optical coherence tomography (OCT). Depth-resolved 26-gage needle was specially designed, fabricated by the stepwise transitional core fiber, and integrated with the swept source OCT system. Since our device is feasible to provide both the position information inside the cornea as well as air injection, it enables the accurate management of bubble formation during DALK. Our results show that real-time feedback of needle end position was intuitionally visualized and fast enough to adjust the location of the needle. Through our research, we realized that position-guided needle combined with M-mode OCT is a very efficient and promising surgical tool, which also to enhance the accuracy and stability of DALK.

Smartphone-Based Endoscope System for Advanced Point-of-Care Diagnostics: Feasibility Study.

BACKGROUND: Endoscopic technique is often applied for the diagnosis of diseases affecting internal organs and image-guidance of surgical procedures. Although the endoscope has become an indispensable tool in the clinic, its utility has been limited to medical offices or operating rooms because of the large size of its ancillary devices. In addition, the basic design and imaging capability of the system have remained relatively unchanged for decades. OBJECTIVE: The objective of this study was to develop a smartphone-based endoscope system capable of advanced endoscopic functionalities in a compact size and at an affordable cost and to demonstrate its feasibility of point-of-care through human subject imaging. METHODS: We developed and designed to set up a smartphone-based endoscope system, incorporating a portable light source, relay-lens, custom adapter, and homebuilt Android app. We attached three different types of existing rigid or flexible endoscopic probes to our system and captured the endoscopic images using the homebuilt app. Both smartphone-based endoscope system and commercialized clinical endoscope system were utilized to compare the imaging quality and performance. Connecting the head-mounted display (HMD) wirelessly, the smartphone-based endoscope system could superimpose an endoscopic image to real-world view. RESULTS: A total of 15 volunteers who were accepted into our study were captured using our smartphone-based endoscope system, as well as the commercialized clinical endoscope system. It was found that the imaging performance of our device had acceptable quality compared with that of the conventional endoscope system in the clinical setting. In addition, images captured from the HMD used in the smartphone-based endoscope system improved eye-hand coordination between the manipulating site and the smartphone screen, which in turn reduced spatial disorientation. CONCLUSIONS: The performance of our endoscope system was evaluated against a commercial system in routine otolaryngology examinations. We also demonstrated and evaluated the feasibility of conducting endoscopic procedures through a custom HMD.

Monitoring heavy metals, residual agricultural chemicals and sulfites in traditional herbal decoctions.

BACKGROUND: Asian traditional herbal preparations are frequently considered for the contamination with undeclared toxic or hazardous substances. The aim of this study was to determine the toxic heavy metals, pesticides and sulfur dioxide in decoctions that is a common form of final utilization in Korea. METHODS: A total of 155 decoctions composed of multi-ingredient traditional herbs were randomly sampled from Seoul in Korea between 2013 and 2014. For each decoction, the concentrations of four heavy metals (arsenic, cadmium, lead and mercury), 33 pesticides and sulfur dioxide were analyzed using inductively coupled plasma mass spectrometry (ICP-MS), mercury analyzer, gas chromatography/nitrogen phosphorous detector (GC/NPD), gas chromatography/micro electron capture detector (GC/µECD), and Monier-Williams method respectively. RESULTS: One hundred fifty-two of One hundred fifty-five decoctions (98.1%) contained one of three heavy metals (96.1% for As, 97.4% for Cd, and 90.3% for Pb, 0.0% for Hg). Their average concentrations (77.0 ± 79.7 ug/kg for As, 20.4 ± 23.7 ug/kg for Cd, and 68.8 ± 76.5 ug/kg for Pb) were approximately 20% of the maximum allowable limits of vegetable or ginseng beverage described in the Korean Food Standard Codex while their 95th percentile concentrations were below than the guideline for them. None of 33 pesticides was detected in 155 decoction samples, and only one sample showed over limit of detection for residual sulfites. CONCLUSIONS: This study support that the contained status of toxic heavy metals, pesticides and sulfur dioxide in herbal decoctions are currently within safe level in Korea, and provide a reference data for the further studies focused on the safety herbal preparations.

Association between ambient particulate matter and disorders of vestibular function.

BACKGROUND: Exposure to environmental chemicals has been suggested to alter the physiologic state of the inner and middle ear. However, it is unknown if particulate matter exposure is associated with acute vestibular dysfunction. OBJECTIVES: To estimate the effects of particulate matter exposure on the number of hospital visits related to three major diseases of vestibular dysfunction, Meniere's disease (MD), benign paroxysmal positional vertigo (BPPV), and vestibular neuronitis (VN). METHODS: Our study subject is from Korean National Health Insurance Service-National Sample Cohort, which is dynamic cohort consist of 1 million participants representing the Korean population. Among total cohort participants, we used the hospital visit data of 210,000 individuals who resided in Seoul from 2007 to 2010. Time series analysis using the Poisson generalized additive model and case-crossover analysis using conditional logistic regression were used to investigate the association between daily particulate matter levels (PM2.5, particulate matter <2.5µg/m3; PM10, particulate matter <10µg/m3; PM10-2.5, PM10- PM2.5) and number of MD, BPPV, and VN hospital visits. RESULTS: Time series analysis showed that an interquartile range (IQR) increase in PM10 and PM10-2.5 on lag day 1 was associated with an increased risk of MD hospital visits [relative risk (RR), 95% confidence interval (CI), PM10: 1.09 (1.02-1.15); PM10-2.5: 1.06 (1.02-1.10)]. In addition, elderly individuals (≥60 years old) showed an increased risk of MD hospital visits after particulate matter exposure when compared to younger individuals. An IQR increase in particulate matter on lag day 1 was associated with a marginally significant increase in VN hospital visits [RR (95%CI), PM2.5: 1.11 (0.98-1.25); PM10: 1.07 (0.99-1.15); PM10-2.5: 1.04 (0.99-1.09)]. However, no association between particulate matter exposure and BPPV hospital visits was noted. Case-crossover analyses showed similar results to the time-series analysis across all three diseases. CONCLUSION: MD hospital visits were associated with ambient particulate matter exposure. Elderly individuals, in particular, were more susceptible to particulate matter exposure than younger individuals.

Monitoring of airborne particulate matter at mountainous urban sites.

Concentrations of various size fractions (TSP, PM10, PM2.5, and PM1.0) of particulate matter (PM) were measured at two mountainous sites, Buk Han (BH) and Gwan AK (GA), along with one ground reference site at Gwang Jin (GJ), located in Seoul, South Korea for the 4 years from 2010 to 2013. The daily average concentrations of TSP, PM10, PM2.5, and PM1.0 at BH were 47.9 ± 32.5, 37.0 ± 24.6, 20.6 ± 12.9, and 15.3 ± 9.53 µg m(-3), respectively. These values were slightly larger than those measured at GA while much lower than those measured at the reference site (GJ). Seasonal variations in PM concentrations were consistent across all locations with a relative increase in concentrations observed in spring and winter. Correlation analysis showed clear differences in PM concentrations between the mountainous sites and the reference site. Analysis of these PM concentrations indicated that the distribution of PM in the mountainous locations was affected by a number of manmade sources from nearby locations, including both traffic and industrial emissions.

Long-Term Fine Particulate Matter Exposure and Major Depressive Disorder in a Community-Based Urban Cohort.

BACKGROUND: Previous studies have associated short-term air pollution exposure with depression. Although an animal study showed an association between long-term exposure to particulate matter ≤ 2.5 µm (PM2.5) and depression, epidemiological studies assessing the long-term association are scarce. OBJECTIVE: We aimed to determine the association between long-term PM2.5 exposure and major depressive disorder (MDD). METHODS: A total of 27,270 participants 15-79 years of age who maintained an address within the same districts in Seoul, Republic of Korea, throughout the entire study period (between 2002 and 2010) and without a previous MDD diagnosis were analyzed. We used three district-specific exposure indices as measures of long-term PM2.5 exposure. Cox proportional hazards models adjusted for potential confounding factors and measured at district and individual levels were constructed. We further conducted stratified analyses according to underlying chronic diseases such as diabetes mellitus, cardiovascular disease, and chronic obstructive pulmonary disease. RESULTS: The risk of MDD during the follow-up period (2008-2010) increased with an increase of 10 µg/m3 in PM2.5 in 2007 [hazard ratio (HR) = 1.44; 95% CI: 1.17, 1.78], PM2.5 between 2007 and 2010 (HR = 1.59; 95% CI: 1.02, 2.49), and 12-month moving average of PM2.5 until an event or censor (HR = 1.47; 95% CI: 1.14, 1.90). The association between long-term PM2.5 exposure and MDD was greater in participants with underlying chronic diseases than in participants without these diseases. CONCLUSION: Long-term PM2.5 exposure increased the risk of MDD among the general population. Individuals with underlying chronic diseases are more vulnerable to long-term PM2.5 exposure. CITATION: Kim KN, Lim YH, Bae HJ, Kim M, Jung K, Hong YC. 2016. Long-term fine particulate matter exposure and major depressive disorder in a community-based urban cohort. Environ Health Perspect 124:1547-1553; http://dx.doi.org/10.1289/EHP192.

Associations of air pollution exposure with blood pressure and heart rate variability are modified by oxidative stress genes: A repeated-measures panel among elderly urban residents.

BACKGROUND: Oxidative stress has been suggested as a major cause of elevated blood pressure (BP) and reduced heart rate variability (HRV) due to air pollution. We hypothesized that the associations of air pollution exposure with BP and HRV are modified by oxidative stress gene polymorphisms. METHODS: Between 2008 and 2010, we conducted up to 5 surveys of 547 elderly participants, measured their BP and HRV, and genotyped 47 single nucleotide polymorphisms (SNPs) in 18 oxidative stress genes. Linear mixed models were constructed to evaluate the associations of particulate matter ≤10 µm, nitrogen dioxide, and sulfur dioxide with BP and HRV, as well as the modifications of these associations by the genotyped SNPs. RESULTS: Single-SNP analyses revealed interactions between air pollution and 15 SNPs (for BP) and 33 SNPs (for HRV) (all, P for interaction < 0.05). When we generated genetic risk scores for BP and HRV, using the SNPs with interactions in the single-SNP models, we found that associations of air pollution exposure with BP and HRV were modified by the genetic risk scores (P for interaction < 0.05). CONCLUSIONS: These results strongly suggest that the associations of air pollution with BP and HRV are mediated by oxidative stress pathways.