Comparison of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorobutane sulfonate (PFBS) removal in a combined adsorption and electrochemical oxidation process

This study focused on three of the most studied PFAS molecules, namely perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorobutane sulfonate (PFBS). They were compared in terms of their adsorption capacity onto graphite intercalated compound (GIC), a low surface area, highly conductive and cheap adsorbent. The adsorption on GIC followed a pseudo second order kinetics and the maximum adsorption capacity using Langmuir was 53.9 μg/g for PFOS, 22.3 μg/g for PFOA and 0.985 μg/g for PFBS due to electrostatic attraction and hydrophobic interactions. GIC was added into an electrochemical oxidation reactor and >100 μg/L PFOS was found to be fully degraded (<10 ng/L) leaving degradation by-products such as PFHpS, PFHxS, PFPeS, PFBS, PFOA, PFHxA and PFBA below 100 ng/L after 5 cycles of adsorption onto GIC for 20 min followed by regeneration at 28 mA/cm2 for 10 min. PFBS was completely removed due to degradation by aqueous electrons on GIC flakes. Up to 98 % PFOA was removed by the process after 3 cycles of adsorption onto GIC for 20 min followed by regeneration at 25 mA/cm2 for 10 min. When PFBS was spiked individually, only 17 % was removed due to poor adsorption on GIC. There was a drop of 3-40 % by treating PFOS, PFOA and smaller sulfonates in a real water matrix under the same electrochemical conditions (20 mA/cm2), but PFOS and PFOA removal percentage were 95 and 68 % after 20 min at 20 mA/cm2.

History of Changes in the Protocol of Clinical Trial of Zinc Supplementation in Treatment of COVID-19 by Hydroxychloroquine

An article published in this journal used a randomized controlled trial to evaluate the efficacy of combining chloroquine/hydroxychloroquine (CQ/HCQ) and zinc in the treatment of COVID-19 patients. Findings from this study indicate that zinc supplements did not enhance the clinical efficacy of hydroxychloroquine in improving COVID-19 treatment. Although this finding is consistent with many previous studies, several concerns regarding study protocol and trial registration, including interventions and primary outcomes, have been raised in which the protocol has been changed after the completion of the recruitment.

Role of ABCB1 and ABCB4 in renal and biliary excretion of perfluorooctanoic acid in mice

BACKGROUND

Perfluorooctanoic acid (PFOA) is one of the major per- and polyfluoroalkyl substances. The role of ATP-binding cassette (ABC) transporters in PFOA toxicokinetics is unknown.

METHODS

In this study, two ABC transporters, ABCB1 and ABCB4, were examined in mice with single intravenous PFOA administration (3.13 µmol/kg). To identify candidate renal PFOA transporters, we used a microarray approach to evaluate changes in gene expression of various kidney transporters in Abcb4 null mice.

RESULTS

Biliary PFOA concentrations were lower in Abcb4 null mice (mean ± standard deviation: 0.25 ± 0.12 µg/mL) than in wild-type mice (0.87 ± 0.02 µg/mL). Immunohistochemically, ABCB4 expression was confirmed at the apical region of hepatocytes. However, renal clearance of PFOA was higher in Abcb4 null mice than in wild-type mice. Among 642 solute carrier and ABC transporters, 5 transporters showed significant differences in expression between wild-type and Abcb4 null mice. These candidates included two major xenobiotic transporters, multidrug resistance 1 (Abcb1) and organic anion transporter 3 (Slc22a8). Abcb1 mRNA levels were higher in Abcb4 null mice than in wild-type mice in kidney. In Abcb4 null mice, Abcb1b expression was enhanced in proximal tubules immunohistochemically, while that of Slc22a8 was not. Finally, in Abcb1a/b null mice, there was a significant decrease in the renal clearance of PFOA (0.69 ± 0.21 vs 1.1 mL ± 0.37/72 h in wild-type mice). A homology search of ABCB1 showed that several amino acids are mutated in humans compared with those in rodents and monkeys.

CONCLUSIONS

These findings suggest that, in the mouse, Abcb4 and Abcb1 are excretory transporters of PFOA into bile and urine, respectively.

Association between lignan polyphenol bioavailability and enterotypes of isoflavone metabolism: A cross-sectional analysis

Lignan polyphenols derived from plants are metabolized by bacteria in the gut to mammalian lignans, such as enterolactone (ENL) and enterodiol (END). Mammalian lignan intake has been reported to be associated with obesity and low blood glucose levels. However, the factors that are responsible for individual differences in the metabolic capacity for ENL and END are not well understood. In the present study, the effects of enterotypes of isoflavone metabolism, equol producers (EQP) and O-desmethylangolensin producers (O-DMAP), on lignan metabolism were examined. EQP was defined by urinary daidzein (DAI) and equol concentrations as log(equol/DAI) ≥ -1.42. O-DMAP was defined by urinary DAI and O-DMA concentrations as O-DMA/DAI > 0.018. Isoflavone and lignan concentrations in urine samples from 440 Japanese women were measured by gas chromatography-mass spectrometry. Metabolic enterotypes were determined from the urinary equol and O-DMA concentrations. Urinary END and ENL concentrations were compared in four groups, combinations of EQP (+/-) and O-DMAP (+/-). The urinary lignan concentration was significantly higher in the O-DMAP/EQP group (ENL: P<0.001, END: P<0.001), and this association remained significant after adjusting for several background variables (END: β = 0.138, P = 0.00607 for EQP and β = 0.147, P = 0.00328 for O-DMAP; ENL: β = 0.312, P<0.001 for EQP and β = 0.210, P<0.001 for O-DMAP). The ENL/END ratio was also highest in the O-DMAP/EQP group, indicating that equol and O-DMA metabolizing gut bacteria may be involved in lignan metabolism. In conclusion, urinary lignan concentrations were significantly higher in groups containing either EQP or O-DMAP than in the non-EQP/non-O-DMAP group. The variables and participants in this study were limited, which the possibility of confounding by other variables cannot be ruled out. However, there are no established determinants of lignan metabolism to date. Further research is needed to determine what factors should be considered, and to examine in different settings to confirm the external validity.

Formation and Degradability of Per- and Polyfluoroalkyl Substances in River Soils around a Fluoropolymer-Manufacturing Plant in Osaka, Japan

Our previous studies reported that perfluorooctanoic acid (PFOA) contamination decreased in well, tap, and surface water around a fluoropolymer plant in Osaka, Japan, between 2003 and 2016. In this study, we evaluated the degradability of PFOA and perfluorohexanoic acid in river soils to identify the influence of the degradation on the perfluorocarboxylic acids (PFCAs) in the Yodo River Basin. We also investigated the influence of abiotic oxidation on the formation of PFCAs in soils and measured the fluorotelomer alcohols (FTOHs) as precursors of PFCAs in the soil and air samples collected at Osaka and Kyoto. No major degradations were observed in soils contaminated with PFCA during the 24-week experimental period, while the PFOA levels increased only in the control group. The PFCA levels significantly increased after oxidation in this group. The dominant FTOH in soils was 10:2 FTOH, whereas 6:2 FTOH was dominant in the air samples. These findings suggest that PFOA was rapidly removed from water system but persist in soils. Moreover, the results indicate the need to evaluate not only the PFCAs, but also the FTOHs and other precursors for the accurate prediction of PFCA accumulation and fates in the environment.

Temporal trends in bisphenol exposures and associated health risk among Japanese women living in the Kyoto area from 1993 to 2016

BACKGROUND

Bisphenols, and especially bisphenol A, are widely used as components of epoxy resins and polycarbonate. Widespread detection and potential health risks have led to bisphenol A being replaced by other alternatives, including structurally similar bisphenol analogs. Several bisphenol analogs are suspected to have similar adverse health consequences. This study examined the temporal trends in bisphenol exposure among a group of Japanese women from 1993 to 2016, and assessed the associated health risks.

METHODS

We used archived single spot urine samples of healthy Japanese women living in the Kyoto area (n = 133) collected in 1993, 2000, 2003, 2009, 2011, and 2016. We measured the concentrations of 10 bisphenols in these samples.

RESULTS

A sharp increase in the detection rates of bisphenol F was observed after 2000. There was a distinct downward trend in urinary bisphenol A concentrations and an upward trend in bisphenol E concentrations after 2009. While the hazard index for all measured bisphenols was below 1 in all subjects, bisphenol F was determined as the most important risk driver after 2000, rather than bisphenol A.

DISCUSSION

Trends of decreasing bisphenol A and increasing bisphenol E exposure especially after 2011, along with no significant change in the sum of all bisphenol analogs in urine, provide clear evidence that bisphenol A has been replaced by other bisphenols in the study population. We found no significant change in the total exposure to bisphenols during the study period. Bisphenol F might become the most important bisphenol in terms of risk, while cumulative risks due to all bisphenol exposure were deemed insignificant. Considering the accumulating evidence indicating adverse effects at lower exposure levels, further studies are warranted to assess exposure and risk from bisphenol A analogs.

Association between serum concentrations of perfluoroalkyl substances and global DNA methylation levels in peripheral blood leukocytes of Japanese women: A cross-sectional study

Global DNA methylation levels in peripheral blood leukocytes can be a biomarker for cancer risk; however, levels can be changed by various factors such as environmental pollutants. We investigated the association between serum concentrations of perfluoroalkyl substances (PFASs) and global DNA methylation levels of leukocytes in a cross-sectional study using the control group of a Japanese breast cancer case-control study [397 women with a mean age of 54.1 (SD 10.1) years]. Importantly, our analysis distinguished branched PFAS isomers as different from linear isomers. The serum concentrations of 20 PFASs were measured by in-port arylation gas-chromatography negative chemical ionization mass spectrometry. Global DNA methylation levels in peripheral blood leukocytes were measured using a luminometric methylation assay. Associations between log₁₀-transformed serum PFAS concentrations and global DNA methylation levels were evaluated by regression coefficients in multivariable robust linear regression analyses. Serum concentrations of 13 PFASs were significantly associated with increased global DNA methylation levels in leukocytes. Global DNA methylation was significantly increased by 1.45 %-3.96 % per log₁₀-unit increase of serum PFAS concentration. Our results indicate that exposure to PFASs may increase global DNA methylation levels in peripheral blood leukocytes of Japanese women.

Plasma eicosapentaenoic acid, a biomarker of fish consumption, is associated with perfluoroalkyl carboxylic acid exposure in residents of Kyoto, Japan: a cross-sectional study

BACKGROUND

Per- and polyfluoroalkyl substances (PFASs) are highly fluorinated organic compounds that have been widely used in industry during the past few decades. The main exposure routes for PFASs are thought to be the diet, drinking water, and dust. In this study, we aimed to evaluate the relationship between perfluoroalkyl carboxylic acids (PFCAs, members of the PFAS family) and the plasma eicosapentaenoic acid-to-arachidonic acid ratio (EPA/AA), a biological indicator of seafood intake, to determine whether seafood intake may represent a means of exposure to PFASs in the Japanese population.

METHODS

We performed a cross-sectional study using 131 plasma samples collected from residents of Kyoto, Japan in 2013 and held in the Kyoto University biological sample bank. The concentrations of perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluoroundecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), perfluorotridecanoic acid (PFTrDA), EPA, and AA were quantified by gas chromatography-mass spectrometry, and multiple linear regression was used to analyze the results.

RESULTS

In multiple linear regression analyses with age and eGFR, PFOA showed a significant positive linear association with age (p = 0.0005); PFHpA showed a significant negative linear association with estimated glomerular filtration rate (eGFR; p = 0.0338); and PFHpA, PFOA, PFNA, PFUnDA, and PFDoDA exhibited significant positive linear associations with EPA/AA (p = 0.0358, 0.0056, 0.0242, <0.0001, and <0.0001, respectively). Because only PFHpA and PFOA were associated with smoking, their concentrations were examined again with smoking variable included and neither showed an association with smoking habit. PFOA showed a significant linear association with EPA/AA ratio (p = 0.0072), but PFHpA did not (p = 0.051).

CONCLUSIONS

The plasma concentrations of PFOA, PFNA, PFUnDA and PFDoDA significantly associated with the EPA/AA ratio in residents of Kyoto.

Chlorinated persistent organic pollutants in human breast milk in the Miyagi Prefecture disaster-affected area 1 year after the Great East Japan Earthquake of 2011

BACKGROUND

In the Great East Japan Earthquake of 11 March 2011, an earthquake and accompanying tsunami struck the Tohoku region of northeastern Japan. Buildings collapsed and the tsunami spread waste, including hazardous materials. This study aimed to determine the concentrations of persistent organic pollutants (POPs) in the breast milk of mothers living in the disaster-affected area of Sendai 1 year after the earthquake. Temporal trends in the POPs concentrations were evaluated by comparison with previous studies.

METHODS

One hundred breast milk samples were obtained from lactating mothers at a hospital in Sendai in 2012. The results were compared with those from other years to examine whether there were changes in the POPs concentrations after the earthquake. We measured polychlorinated biphenyls (PCBs) and organochlorine pesticides, such as chlordanes, using gas chromatography-mass spectrometer (GC-MS) with negative chemical ionization, and dichlorodiphenyl trichloroethane (DDT) and its metabolites using GC-MS with electron impact ionization.

RESULTS

The mean total PCBs (11 congeners), total chlordane, and total DDT concentrations were 76.2 ng/g lipid, 39.8 ng/g lipid, and 73.5 ng/g lipid, respectively. For the samples collected in 2012, the concentrations of POPs in breast milk showed minimal changes compared with results from previous years for samples collected at the same hospital in Sendai.

CONCLUSIONS

Our study demonstrates that 1 year after the earthquake and tsunami, the concentrations of chlorinated POPs in breast milk had not changed substantially.

Profiles and determinants of dicofol, endosulfans, mirex, and toxaphenes in breast milk samples from 10 prefectures in Japan

Human exposure to persistent organic pollutants (POPs) is reflected by POP concentrations in breast milk. Many studies of POPs in breast milk have been performed in Japan, but insufficient information is available about some legacy POPs (e.g., mirex and toxaphenes, included in the Stockholm Convention in 2001) and novel POPs (e.g., dicofol and endosulfans, included in the Stockholm Convention in 2019 and 2011, respectively). In this study, dicofol, endosulfan, mirex, and toxaphene concentrations in breast milk from 10 prefectures in Japan were determined. The samples were collected between 2005 and 2010, before Stockholm Convention restrictions on endosulfans and mirex were implemented. Common POPs (e.g., polychlorinated biphenyls) were also analyzed to allow the contamination statuses to be compared. The α-endosulfan and β-endosulfan concentrations were 0.26-13 and 0.012-0.82 ng/g lipid, respectively. The toxaphene #26 and #50 concentrations were <0.08-5.6 and < 0.1-8.5 ng/g lipid, respectively. The dicofol concentrations were <0.01-4.8 ng/g lipid. The mirex concentrations were <0.2-3.5 ng/g lipid. The α- and β-endosulfan concentrations on a lipid weight basis negatively correlated with the lipid contents of the milk samples (ρ = -0.65, p < 0.01 for α-endosulfan; ρ = -0.58, p < 0.01 for β-endosulfan). The toxaphene concentrations positively correlated with the lipid contents. The mirex concentrations positively correlated with the maternal age but negatively correlated with the maternal body mass index. No correlations between the dicofol concentrations and the factors were found. Principal component analysis divided the data into four groups, (1) chlordanes, dichlorodiphenyltrichloroethanes and related compounds, hexachlorobenzene, hexachlorocyclohexanes, hexachloroethane, and polychlorinated biphenyls, (2) endosulfans, (3) dicofol, dieldrin, and toxaphenes, and (4) bromodiphenyl ether 47. This indicated that bromodiphenyl ether 47, dicofol, endosulfans, and toxaphenes have different exposure routes or different kinetics to the other legacy POPs.

Association between urinary zinc excretion and isoflavone-metabolizing enterotypes among Japanese females: a cross-sectional study

BACKGROUND

Zinc absorption and competition among gut bacteria have been reported in animal studies. Thus, gut bacteria may modify zinc availability in humans. Metabolism of intestinal bacteria is known to be necessary for the activation of several phytoconstituents in the body. For example, equol, a typical substance of soybean isoflavone, is produced by intestinal bacteria metabolizing daidzein and the enterotype is one of distinct ones among Japanese population. The difference in the intestinal microflora can modify the bioavailability of zinc. In this study, we examined urinary zinc concentrations in adult female equol producers (EQPs).

METHODS

Urine samples from women participating in health examinations in Miyagi, Okinawa, Kyoto, Kochi, and Hokkaido prefectures were used; from total 17,484 samples, approximately 25 samples were randomly selected for each age group from 30 to 60 years per region (subsample: n = 520), and 520 samples with available urinary zinc concentration (determined by flame atomic absorption analysis) and enterobacterial type were analyzed. EQP was defined as log(equol/daidzein) ≥ -1.42, and urinary concentrations were corrected for creatinine concentration. Urinary zinc concentrations were compared by Student's t-test and multiple regression analyses.

RESULTS

The geometric mean urinary zinc concentration (µg/g-Cr) was lower in EQP than in non-EQP (p = 0.0136 by t-test after logarithm transformation). On the other hand, there was no correlation between urinary zinc concentration with daidzein (r = -0.0495, P = 0.436) and equol concentrations (r = -0.0721, P = 0.256). There was a significant negative association between urinary zinc concentration and EQP (β = -0.392, P = 0.0311) after adjusting with other potential confounding variables, such as daidzein intake.

CONCLUSIONS

The results suggest that gut bacteria that produce equol are involved in the metabolism of zinc. Based on previous studies, the bacteria that affect the metabolism of both substances are thought to be Enterococcus. Future studies are expected to identify specific intestinal bacteria for zinc availability and understand individual differences in the effects of micronutrients.

Efficacy of personal protective equipment to prevent environmental infection of COVID-19 among healthcare workers: a systematic review

BACKGROUND

Healthcare workers (HCWs) employed personal protective equipment (PPE) during the COVID-19 pandemic, crucial to protecting themselves from infection. To highlight the efficacy of PPE in preventing environmental infection among HCWs, a systematic review was conducted in line with PRISMA guidance.

METHODS

A search of the PubMed and Web of Science databases was conducted from January 2019 to April 2021 using pre-defined search terms. Articles were screened by three researchers. The approved papers were read in full and included in this review if relevance was mutually agreed upon. Data were extracted by study design and types of PPEs.

RESULTS

47 of 108 identified studies met the inclusion criteria, with seven reviews and meta-analyses, seven cohort, nine case-control, fifteen cross-sectional studies, four before and after, four case series, and one modeling studies. Wearing PPE offered COVID-19 protection in HCWs but required adequate training. Wearing surgical masks provided improved protection over cloth masks, while the benefit of powered air-purifying respirators is less clear, as are individual gowns, gloves, and/or face shields.

CONCLUSIONS

Wearing PPE, especially facial masks, is necessary among HCWs, while training in proper use of PPE is also important to prevent COVID-19 infection.

Diabetes Mellitus May Exacerbate Liver Injury in Patients with COVID-19: A Single-Center, Observational, Retrospective Study

INTRODUCTION

The spread of coronavirus disease 2019 (COVID-19) is having a profound effect on global health. In this study, we investigated early predictors of severe prognosis from the perspective of liver injury and risk factors for severe liver injury in patients with COVID-19.

METHODS

We examined prognostic markers and risk factors for severe liver injury by analyzing clinical data measured throughout the course of the illness and the disease severity of 273 patients hospitalized for COVID-19. We assessed liver injury on the basis of aminotransferase concentrations and fibrosis-4 (FIB-4) index on admission, peak aminotransferase concentration during hospitalization, aminotransferase peak-to-average ratio, and albumin and total bilirubin concentrations. Furthermore, we analyzed age, aspartate aminotransferase (AST) concentrations, FIB-4 index on admission, hypertension, diabetes mellitus (DM), dyslipidemia, cerebral infarction, myocardial infarction, and body mass index as mortality risk factors.

RESULTS

We identified advanced age as a risk factor. Among biochemical variables, AST concentration and FIB-4 index on admission were associated with high mortality. AST on admission and peak AST during hospitalization were significantly higher in the non-surviving (n = 45) than the discharged group (n = 228). Multivariable Cox hazards analyses for mortality showed significant hazard ratios for age, peak AST, and FIB-4 index on admission (p = 0.0001 and 0.0108, respectively), but not in a model including AST and FIB-4 index on admission. Furthermore, the AST peak was significantly higher among non-surviving patients with DM than in those without DM.

CONCLUSIONS

We found that advanced age, high AST, and FIB-4 index on admission and a higher peak AST during hospitalization are risk factors for poor COVID-19 prognosis. Furthermore, DM was a risk factor for exacerbation of liver injury among non-surviving patients. The AST concentration and FIB-4 index should be assessed periodically throughout hospitalization, especially in patients with high AST values on admission and those with DM.

Hantavirus infection as a risk factor for chronic kidney disease of unknown aetiology (CKDu) and its prevalence in endemic areas of Sri Lanka since 2010 according to a retrospective serological analysis

Background. Chronic kidney disease of unknown aetiology (CKDu) is a major public health problem in Sri Lanka, especially among agrarian communities. Although the cause of CKDu is still unknown, hantavirus infection has been proposed as a risk factor.Methods. This study was performed using serological samples collected from two CKDu-endemic areas, Anuradhapura (2010) and Badulla districts (2010 and 2016), and a non-endemic area, Matale (2016) district. The presence of anti-Thailand orthohantavirus IgG antibodies was investigated in serum samples. Hantavirus seroprevalence and demographic data were epidemiologically analysed.Results. Seroprevalence was higher in CKDu patients (40.6-60.0 %) and healthy individuals in CKDu-endemic areas (17.6-25.5 %) than in healthy individuals in non-endemic areas (3.0 %). Statistically significant odds ratios (ORs) for hantavirus infection in CKDu patients were detected in CKDu-endemic areas [ORs: 3.2 and 3.1; 95 % confidence interval (CI): 1.8-5.5 and 1.8-5.2 in Anuradhapura and Badulla districts in 2010; and OR: 4.4, 95 % CI: 2.3-8.5 in 2016 in Badulla district). Furthermore, the OR for hantavirus infection in Badulla district has increased in the last decade from 3.1 (95 % CI: 1.8-5.3) to 4.4 (95 % CI: 2.3-8.5).Conclusion. Hantavirus infection has been prevalent in two distant CKDu-endemic areas since 2010. The observed significant association of hantavirus seropositivity with CKDu indicates a possible role of hantavirus infection in CKDu pathogenesis.

Use of Nonprescription and Prescription Drugs and Drug Information Sources among Breastfeeding Women in Japan: A Cross-Sectional Study

Breastfeeding women may experience various health issues that require medication. This survey aimed to gain insights into the use of nonprescription and prescription drugs by breastfeeding women in Japan. A cross-sectional study involving women with children aged under two years was conducted in Fukuoka, Japan. Nonprescription drugs were used by 26% of participants in the breastfed-only group, 41% in the breastfed more than half the time group, 55% in the formula-fed more than half the time group, and 82% in the formula-fed-only group. We found that when breastfeeding rates decreased, the use of nonprescription drugs increased (p < 0.05, Cochran-Armitage test for trend). There were significant differences in the use of nonprescription cold medicines and oral analgesics between the formula-fed and breastfed groups, but a nonsignificant difference in prescription drugs use between the groups. These results indicated breastfeeding had a significant influence on use of nonprescription drugs, which was not observed with prescription drugs. Breastfeeding women commonly used the Internet to obtain information on both nonprescription and prescription drugs; however, this did not influence medication use.

Conflict-related environmental damages on health: lessons learned from the past wars and ongoing Russian invasion of Ukraine

On 24 February 2022, Russian military forces invaded Ukraine. The fighting has already caused unimaginable conditions and millions of people were forced to flee their homes. For decades, conflicts have been linked to environmental pollution, exposure to radioactivity and heavy metals as well as infectious diseases. The invasion may cause specific environmental risks, like the release of radioactive substances from nuclear power plants and contaminated soils. Because international collaboration is one of the most effective ways to address environmental problems, it is critical to establish scientific bodies within a global framework to identify concrete actions and tangible measures to provide immediate assistance to citizens. This commentary discusses the above issues from lessons learned from the past wars and the way forward in the Russian invasion of Ukraine.

Exposure to phthalate esters in Japanese females in Kyoto, Japan from 1993 to 2016: Temporal trends and associated health risks

Phthalates are used as plasticizers in many products used in daily life worldwide. Due to industrial and economic developments, exposure among general population to phthalates may vary geographically and temporally. However, studies are lacking for investigating temporal changes in phthalate exposure in the Japanese population. In the present study, the temporal trends in exposure to various phthalates were assessed among a group of Japanese adult female population over 1993-2016 and derived associated risks. For this purpose, urine samples of healthy Japanese females in Kyoto, Japan (N = 132) collected in 1993, 2000, 2003, 2009, 2011, and 2016, were employed and measured for the concentrations of 18 phthalate metabolites. Over this period, the detection rates of mono(3-carboxypropyl) phthalate (MCPP) and monoisobutyl phthalate (MiBP) decreased, and the geometric means of the urinary concentrations of mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) showed a significant decreasing trend. Cumulative risk due to exposure to dibutyl phthalate (DBP), diisobutyl phthalate (DiBP), butyl benzyl phthalate (BBP), and di-2-ethylhexyl phthalate (DEHP) showed a dramatic decrease only between 1993 and 2000. The maximum hazard quotient (HQ_M) was attributed to DEHP in most subjects regardless of sampling year. This study showed the temporal trend of the exposure of Japanese females to several phthalate esters over two decades. As of the late 2010's, DEHP was still the predominant component of phthalate ester exposure in the population. The HI value, however, indicates that direct risk due to phthalate exposure was unlikely among the studied population.

Identifying low-PM2.5 exposure commuting routes for cyclists through modeling with the random forest algorithm based on low-cost sensor measurements in three Asian cities

Cyclists can be easily exposed to traffic-related pollutants due to riding on or close to the road during commuting in cities. PM_2.5 has been identified as one of the major pollutants emitted by vehicles and associated with cardiopulmonary and respiratory diseases. As routing has been suggested to reduce the exposures for cyclists, in this study, PM_2.5 was monitored with low-cost sensors during commuting periods to develop models for identifying low exposure routes in three Asian cities: Taipei, Osaka, and Seoul. The models for mapping the PM_2.5 in the cities were developed by employing the random forest algorithm in a two-stage modeling approach. The land use features to explain spatial variation of PM_2.5 were obtained from the open-source land use database, OpenStreetMap. The total length of the monitoring routes ranged from 101.36 to 148.22 km and the average PM_2.5 ranged from 13.51 to 15.40 μg/m³ among the cities. The two-stage models had the standard k-fold cross-validation (CV) R² of 0.93, 0.74, and 0.84 in Taipei, Osaka, and Seoul, respectively. To address spatial autocorrelation, a spatial cross-validation approach applying a distance restriction of 100 m between the model training and testing data was employed. The over-optimistic estimates on the predictions were thus prevented, showing model CV-R² of 0.91, 0.67, and 0.78 respectively in Taipei, Osaka, and Seoul. The comparisons between the shortest-distance and lowest-exposure routes showed that the largest percentage of reduced averaged PM_2.5 exposure could reach 32.1% with the distance increases by 37.8%. Given the findings in this study, routing behavior should be encouraged. With the daily commuting trips expanded, the cumulative effect may become significant on the chronic exposures over time. Therefore, a route planning tool for reducing the exposures shall be developed and promoted to the public.

Levels of urinary metabolites of benzene compounds, trichloroethylene, and polycyclic aromatic hydrocarbons and their correlations with socioeconomic, demographic, dietary factors among pregnant women in six cities of China

Maternal exposure to benzene and related compounds, trichloroethylene, and polycyclic aromatic hydrocarbons has been suggested as risk factors for reproductive and developmental problem. In different countries and groups, there are differences in socioeconomic circumstances, consumer products, dietary habits, lifestyles, and so on, resulting in different exposure risks from these chemicals. This study investigated the correlation between their metabolite concentrations and socioeconomic, demographic, and dietary factors to explore the possible exposure source of the concerned pollutants in pregnant women. We conducted biological monitoring to assess the exposure of these chemicals using urine samples from 590 to 639 pregnant women during 2nd or 3rd trimester of pregnancy in six cities of China. Socioeconomic and demographic characteristics and dietary habits were collected from questionnaires. The detection rate was over 74% of the urine samples for all metabolites. Compared with the Fourth National Report on Human Exposure to Environmental Chemical concentrations for females (FNRHEEC, the US Centers for Disease Control and Prevention), the metabolite concentrations of benzene compounds and trichloroethylene, excluding MA reported here, were higher. Principal component analysis results showed that SBMA and MHA could be proxy of the principal sources of metabolites for benzene compounds. The concentrations of SBMA and MA were higher in Fuzhou and Wuhan, respectively. The concentration of DCVMA was higher in Shenzhen, Xi'an, and Nanning, and the concentration of PGA was higher in Fuzhou, Wuhan, and Xi'an. Also, the 1-OHPG concentration in Wuhan is higher than that in Fuzhou and Shenzhen. Unhealthy dietary habits, using cosmetics and indoor exposure, contacting chemical solvent during pregnancy were associated with increased benzene compounds, trichloroethylene, and PAH exposure. There were significant positive associations between 1-OHPG level and maternal BMI, low education status, and cooking without a range hood. Pregnant women in China may be at a greater risk of exposure to most of the target compounds than US females, and their exposure levels varied in different regions. Some adverse environmental and behavioral factors may increase the exposure of environmental toxins, which can urge people to take measures to reduce the health risk to pregnant women during pregnancy.

Serum perfluoroalkyl substances and breast cancer risk in Japanese women: A case-control study

BACKGROUND

Perfluoroalkyl substances (PFASs) may contribute to causing breast cancer; however, associations between exposure to PFASs and risk of breast cancer are controversial.

OBJECTIVES

In the present study, we newly distinguished branched isomers of PFASs from their linear isomers and aimed to investigate the association between serum PFAS concentrations and breast cancer risk in Japanese women.

METHODS

We used a case-control design to study 405 eligible matched pairs attending four hospitals in Nagano Prefecture, Japan from May 2001 to September 2005. We used in-port arylation gas-chromatography mass spectrometry with negative chemical ionization to measure serum concentrations of 20 PFAS congeners. We calculated multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of breast cancer and its hormone-receptor subtypes by quartiles or tertiles of serum PFASs.

RESULTS

After multivariable adjustment for breast cancer risk factors, we found that serum concentrations of 20 PFAS congeners were significantly inversely associated with risk of breast cancer. Comparing the extreme quartiles of linear isomers of perfluorooctane sulfonate or perfluorooctanoic acid, ORs were 0.15 (95% CI: 0.07, 0.33 P for trend <0.0001) and 0.21 95% CI: 0.10, 0.44 P for trend <0.0001). Among postmenopausal women, whereas we found the linear isomer of perfluorotridecanoic acid to be inversely associated with breast cancer risk, a medium degree of exposure to the branched isomer of perfluorotridecanoic acid was associated with a marginally increased risk of breast cancer (OR [95% CI] = 1.74 [0.98, 3.09]).

DISCUSSION

In our case-control study, we found overall no association between serum PFAS concentrations and increased risk of breast cancer. Many inverse associations between serum PFAS concentrations and breast cancer risk were found.

Urinary equol levels are positively associated with urinary estradiol excretion in women

Isoflavones found in soy products are a promising class of nutrients that may have a positive effect on human health. In particular, the phytoestrogen metabolite equol is associated with a reduced risk of developing female hormone-related diseases. However, the effect of equol on estrogen remains unclear. Equol can modify blood and urinary estradiol (E2) levels. The aim of this cross-sectional study was to examine the associations between urinary estrogen levels, equol levels, and equol production status in Japanese women. We analyzed urine samples from 520 women by gas chromatography-mass spectrometry. Urinary E2 and 4-hydroxylated E2 levels were higher in equol producers (EQP) than in non-EQPs (P < 0.0001 and P=0.00112, respectively). After adjusting for age and tobacco use by analysis of covariance, the association remained significant (β = 0.299, P < 0.0001). Analysis of covariance demonstrated that equol levels in urine were also positively associated with urinary E2 (β = 0.597, P < 0.0001). The log equol concentration showed a significant, but moderate, negative association with the serum E2 concentration (β = − 0.0225, P = 0.0462). Our findings suggest that equol may promote urinary E2 excretion and modify blood E2 levels in women.

Deletion of 2 amino acids in IHH in a Japanese family with brachydactyly type A1

BACKGROUND

Brachydactyly type A1 (BDA1) is an autosomal dominant disorder characterized by uniform shortening of the middle phalanges in all digits. It is associated with variants in the Indian Hedgehog (IHH) gene, which plays a key role in endochondral ossification. To date, heterozygous pathogenic IHH variants involving several codons, which are restricted to a specific region of the N-terminal active fragment of IHH, have been reported. The purpose of this study was to identify the pathogenic variant in a Japanese family with BDA1 and to evaluate its pathogenesis with regard to previous reports.

METHODS

The proband, a 9-year-old boy, his siblings, and his father had shortened digits and a short stature of variable severity. Based on physical examinations, radiographic findings and family history, they were diagnosed with BDA1. This family is the first case of an isolated malformation in Japan. Sanger sequencing of IHH was performed on these individuals and on the proband's unaffected mother. The significance of the variants was assessed using three-dimensional analysis methods.

RESULTS

Sanger sequencing showed a novel IHH heterozygous variant, NM_002181.4:c.544_549delTCAAAG(p.Ser182Lys183del) [NC_000002.12:g.219057461_219057466del].. These two residues are located outside the cluster region considered a hotspot of pathogenic variants. Three-dimensional modelling showed that S182 and K183 are located on the same surface as other residues associated with BDA1. Analysis of residue interactions across the interface between IHH and its interacting receptor protein revealed the presence of hydrogen bonds between them.

CONCLUSIONS

We report a novel variant, NM_002181.4:c.544_549delTCAAAG (p.Ser182Lys183del) [NC_000002.12:g.219057461_219057466del] in a Japanese family with BDA1. Indeed, neither variations in codons 182 or 183 nor with such two-amino-acid deletions in IHH have been reported previously. Although these two residues are located outside the cluster region considered a hotspot of pathogenic variants, we speculate that this variant causes BDA1 through impaired interactions between IHH and target receptor proteins in the same manner as other pathogenic variants located in the cluster region. This report expands the genetic spectrum of BDA1.