Association between urinary arsenic concentration and genetic polymorphisms in Korean adults.

Arsenic (As) is a human carcinogen widely distributed in the environment. This study evaluated the association between the urinary As concentration and single nucleotide polymorphisms (SNPs) in Korean adults to determine the genetic factors related to As concentration. The study included 496 participants for the genome-wide association study (GWAS) and 1483 participants for the candidate gene approach study. Participants were 19 years and older. The concentrations of total As (Tot As) and total As metabolites (Tmet As, the sum of inorganic As and their metabolites; arsenite, arsenate, monomethylarsonic, and dimethylarsinic acid) in the urine were analyzed. The GWAS identified four SNPs (rs1432523, rs3776006, rs11171747, and rs807573) associated with urinary Tot As and four SNPs (rs117605537, rs3776006, rs11171747, and rs148103384) significantly associated with urinary Tmet As concentration (P < 1 × 10-4). The candidate gene study identified two SNPs (PRDX2 rs10427027 and GLRX rs3822751) in genes related to the reduction reaction associated with urinary Tot As and Tmet As. This study suggests that genetic factors may play a role in regulating As metabolism in the human body, affecting both exposure levels and its potential health risks in the general Korean population, even at low exposure levels. Supplementary Information: The online version contains supplementary material available at 10.1007/s43188-023-00216-x.

Effectiveness of Robotic Arm-Assisted Total Knee Arthroplasty on Transfusion Rate in Staged Bilateral Surgery.

The transfusion rate in staged bilateral total knee arthroplasty (TKA) remains high despite the application of blood management techniques. The potential of robotic arm-assisted TKA (R-TKA) in reducing the transfusion rate in staged bilateral surgery has not yet been investigated. Therefore, we aimed to evaluate the effectiveness of R-TKA on transfusion reduction compared with conventional TKA (C-TKA) in staged bilateral surgery. This retrospective study involved two groups of patients who underwent 1-week interval staged bilateral TKA-the C-TKA group and the R-TKA group-using MAKO SmartRobotics (Stryker, Kalamazoo, MI, USA). Each group comprised 53 patients after propensity score matching and was compared in terms of nadir hemoglobin (Hb) level and transfusion rate after each stage of surgery. Both groups showed no significant differences in the propensity-matched variables of age, sex, body mass index, American Society of Anesthesiologists physical status score, and preoperative Hb level. The R-TKA group showed a significantly higher nadir Hb level than the C-TKA group after the second TKA (p = 0.002). The transfusion rate was not significantly different between the two groups after the first TKA (p = 0.558). However, the R-TKA group showed a significantly lower transfusion rate in the TKA (p = 0.030) and overall period (p = 0.023) than the C-TKA group. Patients who undergo staged bilateral R-TKA have lower transfusion rate than those who undergo C-TKA. R-TKA may be effective in minimizing unnecessary allogeneic transfusions in staged bilateral surgery.

Subchondral insufficiency fracture is a predictive factor of osteoarthritis progression and conversion to arthroplasty in non-surgically treated medial meniscus root tear.

PURPOSE: To investigate the radiographic and clinical outcomes of non-surgical treatment for medial meniscus posterior root tear (MMPRT), and prognostic factors for osteoarthritis (OA) progression and clinical failure. METHODS: A prospectively collected database was retrospectively reviewed for patients who were diagnosed with acute medial meniscus posterior root tear (MMPRT) between 2013 and 2021 and treated non-surgically for more than 2 years. Patient demographic characteristics and clinical outcomes including pain numeric rating scale (NRS), International Knee Documentation Committee (IKDC) subjective score, Lysholm score, and Tegner activity scale were evaluated. For radiographic evaluation, knee radiographs were obtained to assess the angle of knee alignment and Kellgren-Lawrence (K-L) grade during the first and annually follow-up visits. Baseline magnetic resonance (MR) images were reviewed for the presence of medial meniscus extrusion, bone marrow edema, subchondral insufficiency fracture of medial femoral condyle, and cartilage lesion. The OA progression group was defined as patients who experienced a worsening of one or more grades in the K-L classification system. Prognostic factors were evaluated for OA progression and conversion to total knee arthroplasty (TKA). RESULTS: Ninety-four patients (90 female and 4 male) with a mean age of 67.0 ± 7.3 years (range, 53-83 years) were followed for a mean of 46.1 ± 22.1 months (range, 24.1-170.5). During the follow-up period, no significant differences in clinical scores were observed, and there were also no significant differences between the groups with and without OA progression. Overall, 12 patients (13%) underwent TKA at a mean of 20.7 ± 16.5 months (range, 8-69 months) and 34 patients (36%) demonstrated OA progression at a mean time of 24 ± 15 months (range, 12-62). The subchondral insufficiency fracture was a prognostic factor for OA progression (p = 0.045 for knee radiograph and p = 0.019 for MR) and conversion to TKA (RR, 4.08 [95% CI 1.23-13.57]; p = 0.022). CONCLUSIONS: Non-surgical treatment for acute medial meniscus posterior root tear did not result in any significant change in clinical outcomes from the initial to the final follow-up. The rate of conversion to arthroplasty was 13%, and the rate of osteoarthritis progression was 36%. Furthermore, subchondral insufficiency fracture was found to be a concomitant prognostic factor correlated with OA progression and conversion to arthroplasty. This information can provide insights for physicians when discussing treatment options with patients, particularly regarding the use of non-surgical treatment and may contribute as a source for future studies of medial meniscus posterior root tear. LEVEL OF EVIDENCE: IV.

Effects of Environmental Cadmium Exposure on the Liver in Korean Adults: Cross-Sectional and Longitudinal Studies.

Cadmium (Cd) is a ubiquitous environmental pollutant with an exceptionally long biological half-life. The liver is a major organ for Cd metabolism, but the toxicity of Cd is unclear. This study sought to determine whether blood Cd (BCd) level (representing recent exposure [months] to Cd) was associated with liver function in Korean adults, both cross-sectionally and longitudinally. The baseline cross-sectional study involved 2,086 adults (male: 908, female: 1,178) in 2010 - 2011, and 503 of them (male: 207, female: 296) were followed up in 2014 - 2015. BCd was measured by graphite-furnace atomic absorption spectrometry, and liver function indices (aspartate aminotransferase [AST], alanine aminotransferase [ALT], and γ-glutamyltransferase [GGT]) were determined. Liver damage was defined as an abnormal elevation of more than one liver function index. The geometric mean of BCd (1.07 µg/L) was higher in females than in males (1.16 vs. 0.96 µg/L). Liver function indices increased significantly in a dose-dependent manner according to the BCd levels, except for ALT in males, and were higher in males than in females. BCd level was also associated with the risk of liver damage in both sexes. No significant changes in BCd were observed between baseline and follow-up. The liver function indices in 2014 - 2015 were comparable to those in 2010 - 2011 in males, while ALT and GGT were significantly increased in 2014 - 2015 compared to 2010 - 2011 in females with relatively high BCd. These findings suggest that even a low level of environmental Cd exposure, short- and long-term, may affect liver function, and females appear more susceptible than males.

Functional alignment with robotic­arm assisted total knee arthroplasty demonstrated better patient-reported outcomes than mechanical alignment with manual total knee arthroplasty.

PURPOSE: Given the improved accuracy of robot-assisted surgery, robotic-arm assisted functionally aligned total knee arthroplasty (RFA-TKA) aims to preserve the native pre-arthritic knee biomechanics, to achieve balanced flexion-extension gaps. The purpose of this study was to compare the accuracy of the implant position and short-term clinical outcomes of patients who underwent RFA-TKA vs. mechanically aligned total knee arthroplasty with manual technique (MA-TKA). METHODS: A prospectively collected database was reviewed retrospectively for patients who underwent primary TKA. Sixty patients who underwent RFA-TKA between February 2020 and July 2020 were included in the RFA-TKA group. Sixty patients who underwent MA-TKA were included via 1:1 matching for age, sex, and body mass index based on the RFA-TKA group. For radiological evaluation, knee X-rays were used to assess the functional knee phenotype and implant position accuracy by measuring the coronal and sagittal alignment, and these measurements were compared between the two groups. Patient demographic characteristics and patient-reported outcomes including Knee Society scores, Western Ontario and McMaster Universities Arthritis Index, and forgotten joint score-12 were compared between the groups. RESULTS: Statistically significant differences were observed in postoperative 2-year clinical outcomes in favor of RFA-TKA group which showed greater accuracy in the tibial component sagittal alignment than MA-TKA (1.0 ± 2.3 vs. 0.7 ± 1.6, respectively; P < 0.001). However, outliers in the component positions were more common in the MA-TKA group, which was statistically significant for the femoral coronal and tibial sagittal alignments (P = 0.017 and 0.015, respectively). CONCLUSIONS: Functional alignment in TKA could be accurately obtained with the assistance of a robotic arm, and the results showed greater 2 year postoperative patient-reported outcome and satisfaction than mechanically aligned TKA using manual instruments. LEVEL OF EVIDENCE: III.

Decision-making factors and their thresholds for total knee arthroplasty in lateral tibiofemoral osteoarthritis patients: a retrospective cohort study.

BACKGROUND: There has been no study examining lateral tibiofemoral (TF) osteoarthritis (OA) and objective decision-making factors affecting when patients decide to have total knee arthroplasty (TKA). The purpose of this study was to assess which factors and their thresholds cause patients with lateral TF OA to decide on TKA. METHODS: We conducted a retrospective cohort study and identified patients who had initially been diagnosed with isolated lateral TF OA from October 2004 to February 2021. We finally included 56 patients; patients who had chosen conservative treatment followed by in-depth interviews for the deliberation stage (n = 32), and the other patients who decided to undergo TKA for the decision-making stage (n = 24). Demographic, clinical, and radiographic characteristics were considered candidate predictive factors. Radiographic variables included the Ahlbäck grade, hip-knee-ankle (HKA) angle, joint line convergence angle (JLCA), and TF subluxation. Univariate and multivariate logistic regression analyses were performed. RESULTS: Clinically, the pain visual analog scale (VAS) score was significantly higher and the knee flexion angle was lower at the decision-making stage. Radiographic measurements showed that the Ahlbäck grade, HKA angle, JLCA, and TF subluxation measured at the center, in addition to the tibiotalar angle, differed statistically between the two stages. According to univariate analyses, two clinical characteristics and six radiographic variables on the ipsilateral side of the leg, and one radiographic variable on the contralateral side of the leg were included as factors influencing the patients' decision to undergo TKA. After making adjustments based on multivariate analysis, the ipsilateral knee pain VAS (OR = 1.61; 95% CI = 1.14-2.28, p = 0.007) and medial TF subluxation measured at the center (OR = 1.14, 95% CI = 1.01-1.32, p = 0.072) were found to be significant factors for choosing TKA. The area under the curve (AUC) for pain VAS was 0.757 and the cutoff value was 4.5. The AUC for TF subluxation measured at the center was 0.697 and the cutoff value was -4.10% of medial TF subluxation. CONCLUSION: Higher ipsilateral knee pain VAS and more severe medial TF subluxation measured at the center were independent factors affecting patient decisions to undergo TKA with lateral TF OA. Understanding the determining factors that may affect patient decision-making when considering TKA may be an essential aspect of evaluating the prognosis of patients with lateral TF OA. LEVEL OF EVIDENCE: III.

Exposure Levels and Contributing Factors of Various Arsenic Species and Their Health Effects on Korean Adults.

Arsenic is a human carcinogen. Data on urinary arsenic species analyses of Koreans are limited. This study evaluated the arsenic exposure level, contributing factors, and health effects in Korean adults. Dietary intake information and urine samples were obtained from 2044 participants. Arsenic exposure was assessed based on urinary concentrations of arsenic species, such as inorganic arsenic, As(III) and As(V), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and arsenobetaine (AsB), using high-performance liquid chromatography with inductively coupled plasma mass spectrometry, followed by determination of biomarkers, malondialdehyde and c-peptide. The geometric mean concentrations were 30.9 µg/L for the sum of inorganic arsenic and their metabolites, and 84.7 µg/L for the total sum of arsenic measured. Urinary concentrations of arsenic species were influenced by age, inhabitant area (inland or coastal), and seafood intake, which was positively correlated with inorganic arsenic, DMA, and AsB. Rice intake was positively correlated with inorganic arsenic and its metabolites but not with AsB. Additionally, malondialdehyde and c-peptide levels were significantly associated with urinary concentrations of various arsenic species. Seafood and rice are major sources of organic/inorganic arsenic exposure in Korean adults; however, it is necessary to evaluate whether their overconsumption could have a potentially detrimental effect on human health.

Patterns and Distribution of Deep Vein Thrombosis and Its Effects on Clinical Outcomes After Opening-Wedge High Tibial Osteotomy.

BACKGROUND: Although a few studies have reported the incidence of deep vein thrombosis (DVT) after opening-wedge high tibial osteotomy (OWHTO), previous studies focused only on symptomatic DVT. Information is lacking regarding the overall incidence of DVT after OWHTO, thrombus location, and the relationship between DVT and clinical outcome. PURPOSE: To determine the overall incidence of DVT and classify the location of DVT after OWHTO. We also determined whether significant differences in clinical improvement exist in patients with and without DVT at 6 months and at 2 years after OWHTO. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: This study included 46 patients (47 knees) who underwent OWHTO. All patients were instructed to perform knee range of motion exercises and partial weightbearing after drain removal. None of the patients received a chemoprophylaxis for DVT except intermittent pneumatic compression. DVT was diagnosed using 128-row multidetector computed tomography performed before discharge on the fourth postoperative day. The location was classified into 6 segments in the distal portion (muscular and axial veins) and proximal portion (popliteal, femoral, and common femoral veins and veins located above the iliac vein). International Knee Documentation Committee (IKDC) score was assessed preoperatively and postoperatively at 6 months, 1 year, and 2 years using a linear mixed model. RESULTS: Although the incidence of symptomatic DVT was 8.5% (n = 4), the overall incidence of early DVT was 44.7% (n = 21). All DVTs were located in the distal portion of the lower extremity vein, and 76.2% of the DVTs were located in an axial vein. The IKDC scores were 33.6 ± 7.2 and 35.3 ± 9.1 (P = .910) preoperatively, 38.1 ± 5.6 and 40.6 ± 8.4 (P = .531) at 6 months after surgery, and 44.8 ± 6.9 and 45.9 ± 11.4 (P = .786) at 2 years after surgery in patients without and those with DVT, respectively. CONCLUSION: The overall incidence of early DVT after OWHTO was 44.7%. DVT after OWHTO was found particularly around the osteotomy site (76.2%). Patients with DVT did not have inferior short-term clinical outcomes after surgery.

Mini-Screws-Only Fixation Method for Small Fragments of Medial Malleolus Fractures.

BACKGROUD: Open reduction and internal fixation is the standard treatment for a displaced medial malleolus fracture (MMFx), achieving ankle stability and bony union to prevent post-traumatic arthritis. Previous fixation techniques including tension band wiring and unicortical screw fixation are not optimal for fixation of small fragments in MMFx due to their small size and poor manipulability. Here, we describe a novel surgical method using mini-screws only for fixation of small fragments in MMFx. METHODS: We conducted a retrospective consecutive study of patients who underwent surgery using mini-screws for small fragment MMFx between April 2013 and March 2018. We reviewed the patients' clinical characteristics and assessed the fracture features radiographically. Clinical outcomes were assessed by measuring the range of motion of both ankle joints and investigating symptomatic implants. We reviewed the radiographic outcomes of the medial malleolus and the functional outcomes using the Foot and Ankle Outcome Score (FAOS) at the last follow-up. RESULTS: Nine patients were included in the study. The minimal follow-up period was 27 months. There was no incidental bone breakage during the procedure. All MMFx healed without reduction loss, nonunion, or implant failure at the last follow-up. Two patients had mild osteoarthritic changes of the ankle joint. The mean FAOS score of the patients was 80.99 (range, 65.44-98.42). No patients required removal of the hardware. CONCLUSIONS: Fixation of comminuted fractures of the medial malleolus using mini-screws for young adult patients is a straightforward and simple technique. Safe fixation of the anterior and posterior colliculi reduces the risk of implant irritation symptoms that necessitate implant removal.

Changes in the Occurrence of Gastrointestinal Infections after COVID-19 in Korea.

BACKGROUND: After the global epidemic of coronavirus disease 2019 (COVID-19), lifestyle changes to curb the spread of COVID-19 (e.g., wearing a mask, hand washing, and social distancing) have also affected the outbreak of other infectious diseases. However, few studies have been conducted on whether the incidence of gastrointestinal infections has changed over the past year with COVID-19. In this study, we examined how the incidence of gastrointestinal infections has changed since COVID-19 outbreak through open data. METHODS: We summarized the data on the several viruses and bacteria that cause gastrointestinal infections from the open data of the Korea Disease Control and Prevention Agency for 3 years from March 2018 to February 2021 (from Spring 2018 to Winter 2020). Moreover, we confirmed three most common legal gastrointestinal infectious pathogens from March 2016. RESULTS: From March 2020, when the COVID-19 epidemic was in full swing and social distancing and personal hygiene management were heavily emphasized, the incidence of infection from each virus was drastically decreased. The reduction rates compared to the averages of the last 2 years were as follows: total viruses 31.9%, norovirus 40.2%, group A rotavirus 31.8%, enteric adenovirus 13.4%, astrovirus 7.0%, and sapovirus 12.2%. Among bacterial pathogens, the infection rates of Campylobacter and Clostridium perfringens did not decrease but rather increased in some periods when compared to the average of the last two years. The incidence of nontyphoidal Salmonella, Staphylococcus aureus, or enteropathogenic Escherichia coli somewhat decreased but not significantly compared to the previous two years. CONCLUSION: The incidence of infection from gastrointestinal viruses, which are mainly caused by the fecal-to-oral route and require direct contact among people, was significantly reduced, whereas the incidence of bacterial pathogens, which have food-mediated transmission as the main cause of infection, did not decrease significantly.

Effects of Exposure to Lead and Cadmium on Health of Inhabitants of Abandoned Metal Mine Area in Korea.

People living near abandoned mines are at increased risk of exposure to toxic metals. We surveyed 4500 inhabitants with the mean age of 68.5 years old (male: 1768, female: 2732) living near 104 abandoned metal mines from 2013 to 2017 (the 2nd phase health survey in Korea). We conducted personal interviews, blood and urine sampling, and analyzed the concentrations of lead (Pb) and cadmium (Cd) in whole blood and Cd in urine using a graphite furnace atomic absorption spectrometer. The geometric means of blood Pb, blood Cd, and urine Cd were 2.27 µg/dL, 1.42 µg/L, and 1.66 µg/g creatinine, respectively. The level of metal exposure was lower than that reported from the first phase health survey in Korea (2008‒2011) but was higher than in the general population of Korea. Blood Pb was higher in males while blood Cd and urine Cd were significantly higher in females. Blood Pb was highest in the 40‒59 age group, while blood and urine Cd levels continuously increased until age 80 or older. The Cd levels in blood and urine were affected by consumption of locally produced rice and duration of residence near abandoned mines. Furthermore, negative correlations were observed between blood Pb and blood and urine Cd levels. Additionally, 252 of the 4500 subjects exceeded the thresholds of blood Cd or urine Cd levels. Together, these findings suggest that Cd has more sustainable and adverse health effects on the abandoned mine inhabitants, who are mostly aged. Therefore, continuous biomonitoring and risk assessment to environmental health risks are necessary for environmental pollution control and health promotion.

Copper-zinc imbalance induces kidney tubule damage and oxidative stress in a population exposed to chronic environmental cadmium.

PURPOSE: This cross-sectional study aimed to assess the effect of environmental cadmium (Cd) exposure and essential metal imbalance on renal tubular damage and oxidative stress in 979 adults living in a Cd-polluted area near an abandoned copper (Cu) refinery. METHODS: We analyzed urinary Cd concentrations, renal tubular damage and oxidative stress markers, such as beta-2 microglobulin (ß2-MG) and N-acetyl-ß-D-glucosaminidase (NAG) activity and urine malondialdehyde (MDA) levels. The serum copper-to-zinc ratio (CZR) was used as an essential metal imbalance indicator. We divided the subjects into two Cd exposure groups based on the reference level of urinary Cd for renal dysfunction (2 µg/g creatinine). RESULTS: The geometric mean concentration of urinary Cd in all subjects was 2.25 µg/g creatinine. In both low and high Cd exposure groups, urinary Cd levels were positively correlated with urinary NAG activity, but not with serum CZR. After multivariate adjustment, serum CZR was strongly associated with urinary ß2-MG levels in the low Cd exposure group (ß = 1.360, P = 0.019) and was significantly associated with urinary MDA levels, regardless of Cd exposure level. In addition, the risk of renal tubular damage was significantly associated with urinary Cd level, particularly in the lowest or highest CZR tertile groups. CONCLUSIONS: Essential metal imbalance may be a determinant of oxidative stress and renal tubular damage in a chronically Cd-exposed population, and proper zinc supplementation will be effective in preventing adverse health effects due to Cd exposure.

Derivation of occupational exposure limits for multi-walled carbon nanotubes and graphene using subchronic inhalation toxicity data and a multi-path particle dosimetry model.

In this study, we aimed to provide the recommended occupational exposure limits (OELs) for multi-walled carbon nanotubes (MWCNTs) and graphene nanomaterials based on data from a subchronic inhalation toxicity study using a lung dosimetry model. We used a no observed adverse effect level (NOAEL) of 0.98 mg m-3 and 3.02 mg m-3 in rats for MWCNTs and graphene, respectively. The NOAELs were obtained from a 13-week inhalation study in rats. The deposition fractions of MWCNTs and graphene in the respiratory tract of rats and humans were calculated by using the multi-path particle dosimetry model (MPPD model, v3.04). The deposition fraction in the alveolar region was 0.0527 and 0.0984 for MWCNTs and 0.0569 and 0.1043 for graphene in rats and human lungs, respectively. Then, the human equivalent exposure concentrations (HECs) of MWCNTs and graphene were calculated according to the method by the National Institute for Occupational Safety and Health (NIOSH). The HEC was estimated to be 0.17 mg m-3 for MWCNTs and to be 0.54 mg m-3 for graphene, which was relevant to the rat NOAEL of 0.98 mg m-3 and 3.02 mg m-3 for MWCNTs and graphene, respectively. Finally, we estimated the recommended OELs by applying uncertainty factors (UFs) to the HEC as follows: an UF of 3 for species differences (rats to humans), 2 for an experimental duration (subchronic to chronic), and 5 for inter-individual variations among workers. Thus, the OEL was estimated to be 6 µg m-3 for MWCNTs and 18 µg m-3 for graphene. These values could be useful in preventing the adverse health effects of nanoparticles in workers.

Lead, Mercury, and Cadmium Exposure in the Korean General Population.

BACKGROUND: Lead (Pb), mercury (Hg), and cadmium (Cd) are well-known environmental pollutants. They are unnecessary in the biological processes of humans. This study was performed to estimate the representative background exposure levels to the metals by measuring concentrations in whole blood of the Korean general population. METHODS: This population-based cross-sectional study included 4,000 subjects (1,886 males and 2,114 females) 0-83 years of age in 2010 and 2011. Adult subjects (≥ 19 years of age) were collected by sex- and age-stratified probability method, and preschool- and school-aged subjects were recruited by a cluster sampling method. Written consent was provided prior to blood sampling. Pb and Cd blood concentrations were determined by a flameless atomic absorption spectrophotometry, and blood Hg was analyzed by a direct Hg analyzer. RESULTS: The geometric mean, median and 95th percentile of blood Pb was 1.82 µg/dL, 1.83 µg/dL, and 3.78 µg/dL, respectively. The respective values were 2.92 µg/L, 2.87 µg/L, 9.12 µg/L for Hg, and 0.56 µg/L, 0.59 µg/L, 2.20 µg/L for Cd. Blood Pb and Hg were higher in males than in females, but no sex difference was observed, respectively, in subjects 0-4 years of age for Pb and in subjects less than 20 years for Hg. However, blood Cd was higher in females than in males and no sex difference was observed in subjects < 30 years of age. CONCLUSION: This study provides representative data of human exposure to Pb, Hg, and Cd covering whole age groups of the general population in Korea.

Low-Level Environmental Cadmium Exposure Induces Kidney Tubule Damage in the General Population of Korean Adults.

Cadmium (Cd) is the most potent nephrotoxic heavy metal and may affect bone; it also has a long biological half-life in the human body. This study was designed to assess the effect of environmental low-level Cd exposure on kidney function and bone in the general population. The subjects of this cross-sectional study were 1907 healthy Korean adults who had not been exposed to Cd occupationally. We analyzed the concentrations of Cd in the urine, markers of renal tubule damage, such as ß2-microglobulin (ß2-MG) and N-acetyl-ß-D-glucosaminidase (NAG) activity in the urine, calculated the estimated glomerular filtration rate (eGFR) using serum creatinine, and measured bone mineral density (BMD). Also, we analyzed malondialdehyde (MDA) levels in the urine. The geometric mean concentration of Cd in urine was higher in women (1.36 µg/g creatinine) than in men (0.82 µg/g creatinine). Urinary Cd was significantly positively correlated with urinary ß2-MG and NAG activity, whereas it was negatively correlated with eGFR and BMD. The risk of renal tubule damage was significantly associated with urine Cd level, and the association remained significant after controlling for various confounding variables. However, no association was observed between urinary Cd level and glomerular dysfunction or bone damage. The concentration of MDA was increased with urinary Cd level in a dose-dependent manner. These findings suggest that low-level environmental Cd exposure may cause microscopic damage to renal tubules through oxidative stress but might not impair kidney glomeruli or bones.

Exome-wide association study identifies genetic polymorphisms of C12orf51, MYL2, and ALDH2 associated with blood lead levels in the general Korean population.

BACKGROUND: Lead (Pb) is a ubiquitous toxic metal present in the environment that poses adverse health effects to humans. Inter-individual variation in blood Pb levels is affected by various factors, including genetic makeup. However, limited data are available on the association between genetic variation and blood Pb levels. The purpose of this study was to identify the genetic markers associated with blood Pb levels in the Korean population. METHODS: The study subjects consisted of 1,483 healthy adults with no history of occupational exposure to Pb. We measured blood Pb levels and calculated probable daily intake of Pb according to dietary data collected using 24-hour recall. We conducted exome-wide association screening using Illumina Human Exome-12v1.2 platform (n = 500) and a replication analysis using VeraCode Goldengate assay (n = 1,483). RESULTS: Among the 244,770 single nucleotide polymorphisms (SNPs) tested, 12 SNPs associated with blood Pb level were identified, with suggestive significance level (P < 1 × 10-4). In the Goldengate assay for replication, three SNPs (C12orf51 rs11066280, MYL2 rs12229654, and ALDH2 rs671) were associated with statistically suggestively significant differences in blood Pb levels. When stratified by drinking status, a potential association of C12orf51 rs11066280, MYL2 rs12229654, and ALDH2 rs671 with blood Pb level was observed only in drinkers. A marginally significant gene-environment interaction between ALDH2 rs671 and alcohol consumption was observed in relation to blood Pb levels. The effects of the three suggestively significant SNPs on blood Pb levels was dependent on daily calcium intake amounts. CONCLUSIONS: This exome-wide association study indicated that C12orf51 rs11066280, MYL2 rs12229654, and ALDH2 rs671 polymorphisms are linked to blood Pb levels in the Korean population. Our results suggest that these three SNPs are involved in the determination of Pb levels in Koreans via the regulation of alcohol drinking behavior, and that their negative effects may be compensated by appropriate calcium intake.

Rivastigmine patch reduces the incidence of postoperative delirium in older patients with cognitive impairment.

OBJECTIVE: To date, data regarding the efficacy of acetylcholinesterase inhibitors in preventing postoperative delirium (POD) are inconsistent and conflicting. Older individuals with cognitive dysfunction are thought to show POD more frequently. Our aim was to study the effectiveness of rivastigmine prophylaxis on the incidence, severity, and risk factors for POD in older patients with cognitive impairment undergoing hip fracture surgery. METHODS: Of 62 older patients with cognitive impairment about to undergo surgery after a hip fracture, 31 were randomly assigned to receive a rivastigmine patch from 3 days before to 7 days after the operation (Group I), and the other 31 did not receive a rivastigmine patch (Group II). The two groups were compared with regard to incidence and severity of delirium on postoperative days 2 or 3 and 7. Multivariate logistic regression analysis was performed to assess factors associated with POD. RESULTS: Postoperative delirium occurred in five Group I patients and 14 Group II patients (p = 0.013). The mean severity of delirium in the two groups as determined by the Delirium Rating Scale was 2.2 and 6.2 respectively (p = 0.033). The odds ratio for POD was 0.259 (95% CI: 0.074-0.905, p = 0.034) after adjusting for American Society of Anesthesiologists score (p = 0.058), age (p = 0.203), and gender (p = 0.560). There were no rivastigmine-related perioperative complications. CONCLUSION: Perioperative rivastigmine patch application could reduce the occurrence of POD in older patients with low cognitive status. Copyright © 2016 John Wiley & Sons, Ltd.

Urinary arsenic species concentration in residents living near abandoned metal mines in South Korea.

BACKGROUND: Arsenic is a carcinogenic heavy metal that has a species-dependent health effects and abandoned metal mines are a source of significant arsenic exposure. Therefore, the aims of this study were to analyze urinary arsenic species and their concentration in residents living near abandoned metal mines and to monitor the environmental health effects of abandoned metal mines in Korea. METHODS: This study was performed in 2014 to assess urinary arsenic excretion patterns of residents living near abandoned metal mines in South Korea. Demographic data such as gender, age, mine working history, period of residency, dietary patterns, smoking and alcohol use, and type of potable water consumed were obtaining using a questionnaire. Informed consent was also obtained from all study subjects (n = 119). Urinary arsenic species were quantified using high performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP/MS). RESULTS: The geometric mean of urinary arsenic (sum of dimethylarsinic acid, monomethylarsonic acid, As3+, and As5+) concentration was determined to be 131.98 µg/L (geometric mean; 95% CI, 116.72-149.23) while urinary inorganic arsenic (As3+ and As5+) concentration was 0.81 µg/L (95% CI, 0.53-1.23). 66.3% (n = 79) and 21.8% (n = 26) of these samples exceeded ATSDR reference values for urinary arsenic (>100 µg/L) and inorganic arsenic (>10 µg/L), respectively. Mean urinary arsenic concentrations (geometric mean, GM) were higher in women then in men, and increased with age. Of the five regions evaluated, while four regions had inorganic arsenic concentrations less than 0.40 µg/L, one region showed a significantly higher concentration (GM 15.48 µg/L; 95% CI, 7.51-31.91) which investigates further studies to identify etiological factors. CONCLUSION: We propose that the observed elevation in urinary arsenic concentration in residents living near abandoned metal mines may be due to environmental contamination from the abandoned metal mine. TRIAL REGISTRATION: Not Applicable (We do not have health care intervention on human participants).

Allele Frequencies of the Single Nucleotide Polymorphisms Related to the Body Burden of Heavy Metals in the Korean Population and Their Ethnic Differences.

This study was performed to select single nucleotide polymorphisms (SNPs) related to the body burden of heavy metals in Koreans, to provide Korean allele frequencies of selected SNPs, and to assess the difference in allele frequencies with other ethnicities. The candidate-gene approach method and genome-wide association screening were used to select SNPs related to the body burden of heavy metals. Genotyping analysis of the final 192 SNPs selected was performed on 1,483 subjects using the VeraCode Goldengate assay. Allele frequencies differences and genetic differentiations between the Korean population and Chinese (CHB), Japanese (JPT), Caucasian (CEU), and African (YIR) populations were tested by Fisher's exact test and fixation index (F ST), respectively. The Korean population was genetically similar to the CHB and JPT populations (F ST < 0.05, for all SNPs in both populations). However, a significant difference in the allele frequencies between the Korean and CEU and YIR populations were observed in 99 SNPs (60.7%) and 120 SNPs (73.6%), respectively. Ten (6.1%) and 26 (16.0%) SNPs had genetic differentiation (F ST > 0.05) among the Korean-CEU and Korean-YIR comparisons, respectively. The SNP with the largest F ST value between the Korean and African populations was cystathionine-ß-synthase rs234709 (F ST: KOR-YIR, 0.309; KOR-CEU, 0.064). Our study suggests that interethnic differences exist in SNPs associated with heavy metals of Koreans, and it should be considered in future studies that address ethnic differences in heavy-metal concentrations in the body and genetic susceptibility to the body burden of heavy metals.