Mortality after exposure to polychlorinated biphenyls and dibenzofurans: 30 years after the "Yucheng accident"

Polychlorinated biphenyls and incident coronary heart disease-related outcomes in Great Lakes fish consumers

BACKGROUND

Exposure to polychlorinated biphenyls (PCBs) has been linked to risk factors for cardiovascular disease such as increased inflammation, accelerated atherosclerosis, diabetes, and sex hormone dysregulation. Furthermore, there is increasing evidence suggesting associations between internal dose of PCBs and cardiovascular outcomes.

OBJECTIVES

The purpose of this study is to investigate longitudinal associations of PCBs with coronary heart disease (CHD)-related outcomes in a cohort of Great Lakes sport fish consumers.

METHODS

The Great Lakes Sport Fish Consumer cohort was established in the early 1990's. Eight hundred nineteen participants were followed from 1993 to 2017. Serum PCBs were measured in 1994/1995 (baseline), in 2001, and in 2004, while health history questionnaires were administered in 1996, 2003, 2010, and 2017. Cox models were used to prospectively investigate associations of total PCBs and PCB groupings, based on aryl hydrocarbon receptor activity, with incident self-reported physician diagnosis of coronary heart disease (CHD), myocardial infarction (MI), and angina pectoris.

RESULTS

A 2-fold increase in phenobarbital-type PCBs was associated with a 72% increase in likelihood of self-reported incident diagnosis of CHD (HR=1.72, 95% CI: 1.06-2.81; p=0.0294). Similar results were observed for total PCBs (HR=1.68, 95% CI: 1.05-2.69; p=0.0306) and mixed methacholine/phenobarbital type (mixed-type) PCBs (HR=1.60, 95% CI: 1.02-2.52; p=0.0427), but not methacholine-type PCBs. PCBs were not strongly associated with risk of MI or angina.

CONCLUSIONS

This study presents evidence that exposure to PCBs increases the risk of developing coronary heart disease. Given the large number of risk factors and causal pathways for CHD, future research is required to better understand biological mechanisms of action for PCBs on CHD.

Microbiological quality of edible vegetable oils produced and marketed in Gondar City, Northwest Ethiopia

Edible oils are imported and produced in Ethiopia, notably in Gondar, and their production has expanded considerably in recent years. The expansion of locally produced edible vegetable oils with severe quality control, substandard edible oil production, and quality deterioration may contribute to the contamination of microbes, which may cause public health problems. This study determines the microbiological quality of edible vegetable oils being produced and marketed in Gondar City, Northwest Ethiopia, in 2021. A laboratory-based cross-sectional study design was conducted from May to July 2021 in Gondar City. A simple random sampling technique was used to collect 17 edible vegetable oil samples. Aseptically collected samples were analyzed in the microbiology lab room. The microbiological quality of vegetable oil was assessed using standard microbiological procedures and techniques. The collected data were entered into a Microsoft Excel 2016 spreadsheet and Stata Version 14. A non-parametric Kruskal-Wallis test was used to assess significant variation. Seventeen edible vegetable oil samples were examined and found to contain a varying number of bacteria, yeast, and molds. Staphylococcus aureus, Klebsiella Pneumoniae, and Pseudomonas aeruginosa were the identified bacteria, whereas Saccharomyces cerevisiae, Aspergillus niger, Aspergillus flavus, and Aspergillus fumigatus were the identified fungi. Total coliform and fecal coliform isolates were also identified in the oil samples. A level of microbial contamination that has public health importance was observed in some of the oil samples analyzed, and the isolated microorganisms indicate unhygienic handling, processing, and storage practices in the oil production and market sites. The introduction of strict rules, regulations, and updated manufacturing technologies and processes to ensure food safety and quality is needed.

Polychlorinated biphenyls and risk of metabolic syndrome and comparison with the risk of diabetes: A systematic review and meta-analysis

With the increasing incidence of metabolic syndrome (MetS) worldwide and no consistent results on PCBs and MetS. A meta-analysis to explore their relationship was conducted. Given the high correlation and overlap of MetS with diabetes, analysis of diabetes risk, was used as a supplement to compare with MetS. Seven studies included MetS, 15 studies for diabetes, and one study included both outcomes. It was found that PCBs may not be a risk factor for MetS, but their high heterogeneity indicates that they are under-represented. In addition, our results showed that total PCBs might be a protective factor against diabetes. In the whole blood subgroup, which can reflect the accumulation of more than one body load, heterogeneity was reduced, and its OR value suggested that PCBs increased the risk of MetS in the whole blood biomaterial. DL-PCBs were positively associated with MetS and diabetes, while NDL-PCBs were negatively associated with diabetes. In the subgroup analysis of PCBs homologs, DL-PCB-126 and DL-PCB-118 were risk factors for MetS and diabetes, respectively. In addition, PCB-153 and 180 showed a dose-response relationship between them and diabetes mellitus, respectively. The results of total analysis of MetS and diabetes mellitus and subgroup analysis of PCBs were mixed, and this reason might be attributed to the different mechanisms of action and effect sizes of different PCBs, so based on subgroup results and in vivo and in vitro experiments, we considered PCBs to be a risk factor for MetS and diabetes. Due to various reasons, there are still many shortcomings in the evaluation of PCBs impact on human health, and more high-quality research are needed to further explore the role of PCBs of different species and congeners in MetS and diabetes.

Endocrine-disrupting chemicals and autoimmune diseases

Endocrine-disrupting chemicals (EDCs) widely exist in people's production and life which have great potential to damage human and animal health. Over the past few decades, growing attention has been paid to the impact of EDCs on human health, as well as immune system. So far, researchers have proved that EDCs (such as bisphenol A (BPA), phthalate, tetrachlorodibenzodioxin (TCDD), etc.) affect human immune function and promotes the occurrence and development of autoimmune diseases (ADs). Therefore, in order to better understand how EDCs affect ADs, we summarized the current knowledge about the impact of EDCs on ADs, and elaborated the potential mechanism of the impact of EDCs on ADs in this review.

Detection of Persistent Organic Pollutants in Omental Adipose Tissue from Patients with Diffuse-Gastric Cancer: A Pilot Study

Simple Summary

This pilot study reported the observation that great omentum could be analyzed to detect persistent organic pollutants (POPs). Diffuse gastric cancer is an increasing disease that could be associated with pollutants’ exposition. Here, we report a specific POP profile regarding a patient not affected by cancer, nor by diffuse gastric cancer or other abdominal cancers. The widespread presence of a substantial list of POPs (PCDDs/Fs, PCBs, and brominated flame retardants) was found in the omentum from patients with diffuse gastric cancer with minor presence of some organochlorine pesticides.

Abstract

The greater omentum represents a specific adipose tissue resected with gastric surgery for cancer. Diffuse gastric adenocarcinoma (diffuse-GC) is of major relevance among gastric cancers due to its unknown origin, aggressiveness, and metastasis in the peritoneal cavity. We postulated that persistent organic pollutants (POPs) could be detected in the greater omentum. Great omentum from patients with (i) diffuse-GC, or (ii) with other peritoneal metastatic cancer, and (iii) control group without cancer disease were analyzed for the distribution of a large panel of 96 POPs. POPs include polychlorinated dioxins/furans (PCDD/Fs), polychlorobiphenyls (PCBs), polybrominated diphenyl ethers (PBDE), polybrominated biphenyls (PBB), hexabromocyclododecanes, organochlorine pesticides, and polycyclic aromatic hydrocarbons (PAHs). The widespread presence of a substantial list of POPs (PCDDs/Fs, PCBs, and brominated flame retardants) was found in the omentum from patients with aggressive diffuse-GC, with minor presence of some organochlorine pesticides and PAHs at the low analyzed levels. Some chemicals appeared in larger concentrations in diffuse-GC or other cancer groups, including some PCDDs, PCB105, 123, 138, PBDE209, and PBB153. Overall, the present pilot study provides novel information regarding POPs levels in the omental fat, which is an understudied fat depot in terms of POPs load, and diffuse-GC association.

Cancer- and noncancer-specific cumulative incidence of death after exposure to polychlorinated biphenyls and dioxins: A competing risk analysis among Yusho patients

BACKGROUND

In competing risks settings, the cause-specific cumulative incidence function is of great interest since it quantifies cumulative risk in the presence of other causes. To date, however, long-term cancer- and noncancer-specific mortality in Yusho patients exposed to polychlorinated biphenyls (PCBs) and dioxin-related compounds has not been estimated.

METHODS

We identified vital status and cause of death for Yusho patients between 1968 and 2017. Risk of cancer- and noncancer-specific mortality was estimated using a flexible hazards-based regression model, with accounting for competing events.

RESULTS

In total, 1664 Yusho patients with 63,566 person-years of follow-up were included in the analysis. 50-year cumulative incidence of cancer mortality was 12.4% (95% confidence interval [CI], 10.5-14.7) in males and 4.7% (95% CI, 3.5-6.4) in females (difference, 7.7 percentage points [95% CI, 5.2-10.2]; adjusted hazard ratio for males, 2.61 [95% CI, 1.93-3.52]). For noncancer, the 50-year cumulative incidence of mortality was 35.4% (95% CI, 32.8-38.3) in males and 35.6% (95% CI, 33.3-38.1) in females (difference, -0.2 percentage points [95% CI, -3.5 to 3.1]; adjusted hazard ratio for males, 1.51 [95% CI, 1.26-1.82]).

CONCLUSIONS

These findings confirm that male Yusho patients have a significantly higher risk of cumulative incidence of cancer-specific mortality than female Yusho patients. Our findings might be useful in providing Yusho patients with more accurate information on cancer prognosis and survivorship and help determine more appropriate disease management.

Aryl Hydrocarbon Receptor and Dioxin-Related Health Hazards-Lessons from Yusho

Poisoning by high concentrations of dioxin and its related compounds manifests variable toxic symptoms such as general malaise, chloracne, hyperpigmentation, sputum and cough, paresthesia or numbness of the extremities, hypertriglyceridemia, perinatal abnormalities, and elevated risks of cancer-related mortality. Such health hazards are observed in patients with Yusho (oil disease in Japanese) who had consumed rice bran oil highly contaminated with 2,3,4,7,8-pentachlorodibenzofuran, polychlorinated biphenyls, and polychlorinated quaterphenyls in 1968. The blood concentrations of these congeners in patients with Yusho remain extremely elevated 50 years after onset. Dioxins exert their toxicity via aryl hydrocarbon receptor (AHR) through the generation of reactive oxygen species (ROS). In this review article, we discuss the pathogenic implication of AHR in dioxin-induced health hazards. We also mention the potential therapeutic use of herbal drugs targeting AHR and ROS in patients with Yusho.

Mortality in Yusho patients exposed to polychlorinated biphenyls and polychlorinated dibenzofurans: a 50-year retrospective cohort study

BACKGROUND

In 1968, the Yusho incident resulted in accidental exposure to polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), and related compounds in Japan. This study updated the risk of mortality in Yusho patients.

METHODS

We obtained updated cohort data for all Yusho patients for the period 1968-2017. We calculated standardized mortality ratios (SMRs) for all-cause and cause-specific mortality over a 50-year follow-up period compared with the general population in Japan.

RESULTS

A total of 1664 Yusho patients with 63,566 person-years of follow up were included in the analysis. Among males, excess mortality was observed for all cancers (SMR: 1.22, 95% confidence interval [CI]: 1.02 to 1.45) and lung cancer (SMR: 1.59, 95% CI: 1.12 to 2.19). Among females, increased mortality was observed for liver cancer (SMR: 2.05, 95% CI: 1.02 to 3.67). No significant increase was seen in non-cancer-related mortality compared with the general population.

CONCLUSIONS

Carcinogenic risk in humans after exposure to PCBs and PCDFs remains higher among Yusho patients. Our findings suggest the importance of care engagement and optimum management to deal with the burden of Yusho disease.

Characterization of 9 Gas Chromatography Columns by Linear and Lee Retention Indices for Polychlorinated Biphenyls and Polychlorinated Naphthalenes

Polychlorinated biphenyls (PCBs) and naphthalenes (PCNs) are ubiquitous environmental contaminants with varying degrees of toxicity. There are hundreds of possible congeners with similar chemical characteristics, which make these compounds difficult to isolate in environmental samples. Historically, PCBs and PCNs were identified by using an Aroclor or Halowax mixture instead of the individual compounds, which was impractical because of limited numbers of individual standards. A retention index database was developed with all 209 PCBs and 36 PCNs to help identify these chemicals in environmental and biological matrixes. This study uses linear and Lee retention indices to identify all 209 PCBs and 36 PCNs on nine gas chromatography columns. The most toxic congeners, the 12 dioxin-like PCBs, were compared across all columns to determine which stationary phases gave the best selectivity for those compounds. Column selectivity was also examined to determine columns for confirmatory analyses and GC×GC separations. The Rxi-17SilMS demonstrated the most drastic difference in PCB selectivity and, to a lesser extent, PCNs when compared with the other eight columns and could work as a confirmatory column or as a 2nd dimension column for GC×GC separations.

Applying a social-ecological framework to Yucheng: 40 years after exposure to polychlorinated biphenyls and dibenzofurans

Although many epidemiological studies have been conducted on Yucheng cohorts, this incident has rarely been examined from social-ecological perspectives. This study adopted a social-ecological model as a framework to provide a more complete description of Yucheng in order to understand its effects on affected individuals, communities, and society. At first, recent studies on Yucheng victim's health effects  was updated. Long-term follow-up studies of Yucheng cohort have revealed the adverse health effects exerted on victims and their children. Subsequently, this study uses the disaster ecology model as a conceptual framework to review Yucheng. The movements of Yucheng victims and their supporters have constituted a primary actor for promoting the personal and legal rights of Yucheng victims. Finally, this study discusses how to improve future studies to effectively assist victims in their recovery from this incident.

Serum levels of polychlorinated biphenyls and risk of non-Hodgkin lymphoma: A hospital-based case-control study

Polychlorinated biphenyls (PCB) have been classified by the International Agency for Research on Cancer (IARC) in Group 1 as carcinogenic to human, based on sufficient evidence in humans of an increased risk of cutaneous malignant melanoma and limited evidence for non-Hodgkin lymphoma (NHL). However present findings on the association of PCB exposure and NHL are still controversial. This study examined the relationship between PCB serum levels and risk of NHL in a Northern Italy area (Brescia province), where a chemical factory produced PCBs from 1938 to 1984, causing human contamination. A case-control study of 215 NHL patients and 215 control subjects was conducted. Cases and controls were assayed for serum levels of 33 PCB congeners. No associations were found between risk of NHL and serum levels of total PCBs (OR = 0.51; 95% CI: 0.25-1.04 for highest vs lowest quartile) or specific PCB congeners. The study confirmed a strong association of NHL with HCV infection (OR = 3.60; 95% CI: 1.30-10.02). This case-control study does not support the hypothesis of an association between current serum levels of PCBs and NHL development in the general population.

Mechanisms of Environmental Contributions to Fatty Liver Disease

PURPOSE

Fatty liver disease (FLD) affects over 25% of the global population and may lead to liver-related mortality due to cirrhosis and liver cancer. FLD caused by occupational and environmental chemical exposures is termed "toxicant-associated steatohepatitis" (TASH). The current review addresses the scientific progress made in the mechanistic understanding of TASH since its initial description in 2010.

RECENT FINDINGS

Recently discovered modes of actions for volatile organic compounds and persistent organic pollutants include the following: (i) the endocrine-, metabolism-, and signaling-disrupting chemical hypotheses; (ii) chemical-nutrient interactions and the "two-hit" hypothesis. These key hypotheses were then reviewed in the context of the steatosis adverse outcome pathway (AOP) proposed by the US Environmental Protection Agency. The conceptual understanding of the contribution of environmental exposures to FLD has progressed significantly. However, because this is a new research area, more studies including mechanistic human data are required to address current knowledge gaps.

A retrospective investigation into the occurrence and human exposure to polychlorinated naphthalenes (PCNs), dibenzo-p-dioxins and furans (PCDD/Fs) and PCBs through cod liver products (1972-2017)

A retrospective analysis of a number of historical medicinal grade cod liver oil samples produced in Northern Europe revealed relatively high contamination levels of PCNs, PCDD/Fs and PCBs. The total toxic equivalence (TEQ) associated with PCDD/Fs, dl-PCBs and PCNs was in the range 95-427 pg g^-1 for Baltic cod liver oils and from 70 to 148 pg g^-1 for oils sourced from the North Atlantic. The corresponding range for canned cod liver products (Baltic Sea) sampled in 2017 ranged from 52 to 104 pg g^-1 fat (33-34 pg g^-1 ww). The contribution from PCBs to the overall TEQ toxicity was around 3-6-fold higher than from PCDD/Fs and ranged from 24 to 318 pg TEQ g^-1ww. The estimated summed TEQ intakes of PCDD/Fs, dl-PCBs and dl-PCNs resulting from the consumption of the daily recommended doses was highest for the Baltic cod liver oils ranging from 16 to 293 pg kg^-1 body mass (bm) day^-1 for an adult, 20-183 pg kg^-1 bm day^-1 for a teenager and 15-131 pg kg^-1 bm day^-1 for a child. The contribution to daily adult TEQ intake from PCNs alone, although relatively small is estimated to contribute up to 5-fold above the recent EFSA proposed TWI of 2 pg kg^-1 bm. The results indicate that although currently produced fish oils may undergo rigorous purification procedures and show low contaminant levels, cod livers sourced from the Baltic and consumed locally, continue to contribute substantially to the dietary intake of these contaminants.

Factors associated with plasma concentrations of polychlorinated biphenyls (PCBs) and dichlorodiphenyldichloroethylene (p,p'-DDE) in the Canadian population

This study describes blood plasma concentrations of PCBs and p,p'-DDE in the Canadian population aged 20-79 years. PCBs and p,p'-DDE were measured in 1668 participants in the Canadian Health Measures Survey, Cycle 1 (2007-2009). We investigated how concentrations vary by sociodemographic, anthropometric, and lifestyle variables, identified factors associated with exposures, and evaluated concentrations against health-based guidance values. Congeners of PCB most commonly detected were PCB-138, PCB-153, and PCB-180. p,p'-DDE was detectable in > 99% of the samples. Factors associated with ∑PCBs were age, region of birth, frequency of fish consumption, and liver intake (R² = 58.1%). For p,p'-DDE, significant factors were sex, age, region of birth, household education, and ethnic origin (R² = 47.0%). PCB concentrations in Canadians were similar to those in the United States, and lower than those reported in Europe. A small percentage equalled or exceeded the Human Biomonitoring value of 3.5 µg/L for PCBs. Few exceedances of the p,p'-DDE biomonitoring equivalent were observed.

Risk for animal and human health related to the presence of dioxins and dioxin-like PCBs in feed and food

The European Commission asked EFSA for a scientific opinion on the risks for animal and human health related to the presence of dioxins (PCDD/Fs) and DL-PCBs in feed and food. The data from experimental animal and epidemiological studies were reviewed and it was decided to base the human risk assessment on effects observed in humans and to use animal data as supportive evidence. The critical effect was on semen quality, following pre- and postnatal exposure. The critical study showed a NOAEL of 7.0 pg WHO2005-TEQ/g fat in blood sampled at age 9 years based on PCDD/F-TEQs. No association was observed when including DL-PCB-TEQs. Using toxicokinetic modelling and taking into account the exposure from breastfeeding and a twofold higher intake during childhood, it was estimated that daily exposure in adolescents and adults should be below 0.25 pg TEQ/kg bw/day. The CONTAM Panel established a TWI of 2 pg TEQ/kg bw/week. With occurrence and consumption data from European countries, the mean and P95 intake of total TEQ by Adolescents, Adults, Elderly and Very Elderly varied between, respectively, 2.1 to 10.5, and 5.3 to 30.4 pg TEQ/kg bw/week, implying a considerable exceedance of the TWI. Toddlers and Other Children showed a higher exposure than older age groups, but this was accounted for when deriving the TWI. Exposure to PCDD/F-TEQ only was on average 2.4- and 2.7-fold lower for mean and P95 exposure than for total TEQ. PCDD/Fs and DL-PCBs are transferred to milk and eggs, and accumulate in fatty tissues and liver. Transfer rates and bioconcentration factors were identified for various species. The CONTAM Panel was not able to identify reference values in most farm and companion animals with the exception of NOAELs for mink, chicken and some fish species. The estimated exposure from feed for these species does not imply a risk.

The environmental pollutant, polychlorinated biphenyls, and cardiovascular disease: a potential target for antioxidant nanotherapeutics

Despite production having stopped in the 1970s, polychlorinated biphenyls (PCBs) represent persistent organic pollutants that continue to pose a serious human health risk. Exposure to PCBs has been linked to chronic inflammatory diseases, such as cardiovascular disease, type 2 diabetes, obesity, as well as hepatic disorders, endocrine dysfunction, neurological deficits, and many others. This is further complicated by the PCB's strong hydrophobicity, resulting in their ability to accumulate up the food chain and to be stored in fat deposits. This means that completely avoiding exposure is not possible, thus requiring the need to develop intervention strategies that can mitigate disease risks associated with exposure to PCBs. Currently, there is excitement in the use of nutritional compounds as a way of inhibiting the inflammation associated with PCBs, yet the suboptimal delivery and pharmacology of these compounds may not be sufficient in more acute exposures. In this review, we discuss the current state of knowledge of PCB toxicity and some of the antioxidant and anti-inflammatory nanocarrier systems that may be useful as an enhanced treatment modality for reducing PCB toxicity.

Food safety in the 21st century

Food is essential to life, hence food safety is a basic human right. Billons of people in the world are at risk of unsafe food. Many millions become sick while hundreds of thousand die yearly. The food chain starts from farm to fork/plate while challenges include microbial, chemical, personal and environmental hygiene. Historically, documented human tragedies and economic disasters due to consuming contaminated food occurred as a result of intentional or unintentional personal conduct and governmental failure to safeguard food quality and safety. While earlier incidents were mainly chemical contaminants, more recent outbreaks have been due to microbial agents. The Disability Adjusted Life Years (DALYs) attributed to these agents are most devastating to children younger than 5 years of age, the elderly and the sick. To ensure food safety and to prevent unnecessary foodborne illnesses, rapid and accurate detection of pathogenic agents is essential. Culture-based tests are being substituted by faster and sensitive culture independent diagnostics including antigen-based assays and polymerase chain reaction (PCR) panels. Innovative technology such as Nuclear Magnetic Resonance (NMR) coupled with nanoparticles can detect multiple target microbial pathogens' DNA or proteins using nucleic acids, antibodies and other biomarkers assays analysis. The food producers, distributors, handlers and vendors bear primary responsibility while consumers must remain vigilant and literate. Government agencies must enforce food safety laws to safeguard public and individual health. Medical providers must remain passionate to prevent foodborne illnesses and may consider treating diseases with safe diet therapy under proper medical supervision. The intimate collaboration between all the stakeholders will ultimately ensure food safety in the 21st century.

Persistent organic pollutants and mortality in the United States, NHANES 1999-2011

BACKGROUND

Persistent organic pollutants (POPs) are environmentally and biologically persistent chemicals that include polybrominated diphenyl ethers (PBDEs), per- and polyfluoroalkyl substances (PFASs), polychlorinated biphenyls (PCBs), and organochlorine (OC) pesticides. Currently, data on the associations between exposure to POPs and the risk of mortality in the U.S. population is limited. Our objective was to determine if higher exposure to POPs is associated with greater risk of all-cause, cancer, heart/cerebrovascular disease, or other-cause mortality.

METHODS

Analyses included participants aged 60 years and older from the 1999-2006 National Health and Nutrition Examination Surveys (NHANES). We included 483 participants for analyses of PBDEs, 1043 for PFASs, and 461 for PCBs, and 1428 for OC pesticides. Exposures to POPs were estimated using biomarkers measured in serum. Mortality status through December 31, 2011 was obtained from public-use, linked mortality files. We used Cox proportional hazard models to quantify the associations of interest. Where we observed an association, we explored effect modification by sex, body mass index, smoking status, and albuminuria. We also explored the combined effect of PBDEs and OC pesticides in the subsample of participants with measures of both analytes.

RESULTS

Serum measurements of PBDEs, PFASs, and PCBs were not clearly associated with increased all-cause or cause-specific mortality in older Americans. Beta-hexachlorocyclohexane was associated with an increased risk of all-cause mortality [HR per 1 SD increase =1.18, 95% CI = 1.01, 1.38]. Oxychlordane [HR = 1.15 95% CI 1.06, 1.25], p,p'-DDE [HR = 1.12, 95% CI = 1.02, 1.23], trans-nonachlor [HR = 1.11, 95% CI = 1.04, 1.18], and beta-hexachlorocyclohexane [HR = 1.25, 95% CI = 1.03, 1.52] were associated with increased risk of other-cause mortality. Exploratory analyses suggested associations between OC pesticides and other-cause mortality were modified by sex. Exploratory analyses also suggested that the combination of high PBDE and high OC pesticide exposure had a stronger than expected adverse effect on all-cause mortality.

CONCLUSION

Higher exposure to beta-hexachlorocyclohexane, an OC pesticide, is associated with increased all-cause mortality and higher exposure to four OC pesticides is associated with increased non-cancer, non-heart/cerebrovascular disease mortality in U.S. adults 60 years or older. These associations may be modified by sex or exposure to other POPs.

Do polychlorinated biphenyls cause cancer? A systematic review and meta-analysis of epidemiological studies on risk of cutaneous melanoma and non-Hodgkin lymphoma

In 2015 a IARC Working Group upgraded the classification of PCBs to Group 1 "Carcinogenic to humans", also on the basis of evidence from epidemiological studies showing an excess risk for melanoma. Increased risks for non-Hodgkin lymphoma (NHL) and breast cancer were also reported though the evidence was limited. However, some recent reviews of studies on PCB exposure and risk of cancer provided discrepant findings. Therefore, we re-evaluated the association between exposure to PCBs and risk of melanoma and NHL by a systematic review and meta-analysis. We retrieved 11 independent cohort studies on occupationally exposed workers. About half of them showed increased standardized mortality or incidence ratios (SMRs or SIRs) for melanoma and none for NHL. The pooled SMRs were 1.32 (95% CI: 1.05-1.64) for melanoma and 0.94 (0.73-1.23) for NHL. Among population-based cohort and case-control studies with individual measures of PCB exposure, one only study was carried out on PCB exposure and melanoma, showing an odds ratio (OR) of 6.0 (2.0-18.2) for the highest compared to lowest quartile of PCB distribution. 13 cohort and case-control studies evaluated the association between NHL and PCB concentration in blood or subcutaneous fat, with summary OR = 1.5 (1.1-1.7) for the highest vs lowest quantile of PCB distribution. However, two cohort studies on people intoxicated by rice oil containing PCBs found no excess of deaths for skin cancer and inconsistent results for NHL. In conclusion, these findings do not provide a strong evidence that PCB exposure can increase the risk of melanoma and NHL in humans.

Polychlorinated biphenyls disrupt hepatic epidermal growth factor receptor signaling

1. Polychlorinated biphenyls (PCBs) are persistent environmental pollutants that disrupt hepatic xenobiotic and intermediary metabolism, leading to metabolic syndrome and nonalcoholic steatohepatitis (NASH). 2. Since phenobarbital indirectly activates Constitutive Androstane Receptor (CAR) by antagonizing growth factor binding to the epidermal growth factor receptor (EGFR), we hypothesized that PCBs may also diminish EGFR signaling. 3. The effects of the PCB mixture Aroclor 1260 on the protein phosphorylation cascade triggered by EGFR activation were determined in murine (in vitro and in vivo) and human models (in vitro). EGFR tyrosine residue phosphorylation was decreased by PCBs in all models tested. 4. The IC₅₀ values for Aroclor 1260 concentrations that decreased Y1173 phosphorylation of EGFR were similar in murine AML-12 and human HepG2 cells (∼2-4 μg/mL). Both dioxin and non-dioxin-like PCB congeners decreased EGFR phosphorylation in cell culture. 5. PCB treatment reduced phosphorylation of downstream EGFR effectors including Akt and mTOR, as well as other phosphoprotein targets including STAT3 and c-RAF in vivo. 6. PCBs diminish EGFR signaling in human and murine hepatocyte models and may dysregulate critical phosphoprotein regulators of energy metabolism and nutrition, providing a new mechanism of action in environmental diseases.

Polychlorinated biphenyls and dibenzofurans increased abnormal sperm morphology without alterations in aneuploidy: The Yucheng study

In 1979, more than 2000 persons ingested rice oil contaminated with polychlorinated biphenyls and polychlorinated dibenzofurans; this event was called the "Yucheng accident." An increased percentage of oligospermia, reduced ability of sperm to penetrate oocytes, and reduced percentage of male offspring were reported in Yucheng men. This study examined whether the sperm sex ratio and chromosome aneuploidy are responsible for our observed findings in Yucheng men. In 1999-2000, Yucheng men and their neighborhood referents aged 37-50 years were recruited for physical examination, followed by semen analysis. The semen samples were analyzed for chromosomal aneuploidy through fluorescent in situ hybridization according to an established procedure in our laboratory. A total of 50 Yucheng men and 34 neighborhood referents volunteered to participate in the study. Although abnormal morphology was mildly increased, no differences were observed in sperm percentages, with normal numbers of chromosomes X, Y, and 8 in the two groups. The percentage of sperm with aneuploidy of the sex chromosomes or chromosome 8 and of that with diploidy did not vary between both groups. The normal X/Y sperm ratio was not different between the groups. However, among Yucheng men, 8% had a normal X/Y sperm ratio of >1.4, and no neighborhood referent showed such an elevated X/Y ratio. Chromosomal aneuploidy was not elevated in Yucheng men. The mechanisms underlying the reduced sperm capability of oocyte penetration and changed offspring sex ratio in Yucheng men remain undetermined.

Regulating chemicals: law, science, and the unbearable burdens of regulation

The challenges of regulating industrial chemicals remain unresolved in the United States. The Toxic Substances Control Act (TSCA) of 1976 was the first legislation to extend coverage to the regulation of industrial chemicals, both existing and newly registered. However, decisions related to both law and science that were made in passing this law inevitably rendered it ineffectual. Attempts to fix these shortcomings have not been successful. In light of the European Union's passage of innovative principles and requirements for chemical regulation, it is no longer possible to deny the opportunity and need for reform in US law and practice.

Increased deaths from gastric cancer in communities living close to waste landfills

BACKGROUND

Municipal waste landfills (MWLs) have been linked with some malignancies, but data about gastric cancer (GC) are still uncertain.

METHODS

Number of deaths from GC, death rates, and odds ratios (ORs) were calculated considering all residents in the 258 towns in the Apulia Region (4,099,547 subjects, years 2006-2009), living within 3 km from each of the 16 regional MWLs (n = 716,404) or in control areas (n = 3,383,143).

RESULTS

Males living close to MWLs showed a higher death rate for GC, a twofold higher mean number of GC deaths and higher adjusted ORs of GC, compared with controls areas.

CONCLUSIONS

In a large population and over a wide time period, an increased risk of death from GC has been shown in males living in communities close to MWLs. Primary prevention policies acting through more sustainable waste management might probably partially reduce deaths from GC in areas with MWLs.

Yusho and its latest findings-A review in studies conducted by the Yusho Group

The Yusho incident is an unprecedented mass food poisoning that occurred in Japan in 1968. It was caused by the ingestion of rice bran oil contaminated with polychlorinated biphenyls (PCBs) and various dioxins and dioxin-like compounds, such as polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The victims of Yusho have suffered from characteristic skin manifestations associated with systemic, ophthalmological, and mucosal symptoms for a long period of time. The Study Group of Yusho (the Yusho Group) has been conducting annual medical check-ups on Yusho victims for more than 45years. Since 2002, when concentrations of dioxins in the blood of Yusho patients started to be measured, the pharmacokinetics of dioxins, relationship between blood levels of dioxins and symptoms/signs in patients directly exposed to dioxins, and the adverse effects on the next generation have become dramatically clear. Herein we review recent findings of studies conducted by the Yusho Group to evaluate chronic dioxin-induced toxicity to the next generation as well as Yusho patients in comparison with a similar food mass poisoning, the Yucheng incident. Additionally, we summarized basic studies carried out by the Yusho Group to re-evaluate the mechanisms of dioxin toxicities in experimental models and various functions of the aryl hydrocarbon receptor (AhR), known as the dioxin receptor, pathway.

Mortality after exposure to polychlorinated biphenyls and polychlorinated dibenzofurans: a meta-analysis of two highly exposed cohorts

Both Yucheng and Yusho were events of accidental exposure to highly doses of polychlorinated biphenyls and dibenzofurans in Asian people. Mortality experiences caused by various diseases were reported in both cohorts with similar and dissimilar findings. We thus conducted a meta-analysis of two cohorts to reevaluate the effects of PCBs and PCDFs on major causes of mortalities. Two recently updated Yucheng and Yusho mortality studies were included. For selected diseases, standardized mortality ratios (SMR) and 95% confidence intervals (95% CI) were extracted. Meta-analyses were conducted using a random-effects model only when heterogeneity (I(2)  > 50% and/or p value <0.10 by the Q test) was not found. A total of 1,803 Yucheng subjects (male, N = 830; female, N = 973) with 48,751 person-years of follow-up and 1,664 Yusho subjects (male, N = 860; female, N = 804) with 50,773 person-years are included. An increase in all-cause mortality (pooled SMR=1.2, 95% CI: 1.1-1.3, I(2)  = 0.0%), all cancers (pooled SMR=1.3, 95% CI: 1.1-1.6, I(2)  = 0.0%), lung cancer (pooled SMR=1.7, 95% CI: 1.2-2.3, I(2) =0.0%), heart disease (pooled SMR=1.3, 95% CI: 1.0-1.7, I(2)  = 43.4%) and hepatic disease (pooled SMR=1.9, 95% CI: 1.3-2.8, I(2)  = 0.0%) were found in pooled males. Significant elevation from liver cancer was found in pooled females (pooled SMR=2.0, 95% CI: 1.1-3.6, I(2)  = 0.0%). This meta-analysis of Yucheng and Yusho cohorts showed similar elevation from all cancer, lung cancer, heart disease and hepatic disease mortalities in exposed men. Furthermore, a new finding of elevated liver cancer mortality in exposed women was identified.

Health related quality of life and polychlorinated biphenyls and dibenzofurans exposure: 30 years follow-up of Yucheng cohort

BACKGROUND

Quality of life (QOL) can be affected by diseases, disasters, and exposure events to environmental factors. However, whether health-related QOL (HRQOL) might be adversely affected by exposure to dioxin-like chemicals 30 years ago is unknown.

METHODS

We studied people who were poisoned to polychlorinated biphenyls (PCBs) and dibebenzofurans (PCDFs) due to ingestion of contaminated rice oil in 1979 in central Taiwan, and were called Yucheng (oil-disease in Chinese) people. In 2008, we conducted a survey in 1305 exposed people by mailed questionnaire, which included HRQOL by World Health Organization (WHO) quality of life-BREF (WHOQOL-BREF) Taiwanese version. A total of 240 Yucheng subjects aged 18-65 years satisfactorily completed the Questionnaire. For comparison, we obtained information from the database of 2001 National Health Survey conducted by the National Health Research Institute and Bureau of Health Promotion, Department of Health, Taiwan. Data from age-, sex-, and county-matched background individuals were extracted using 1:3 match. HRQOL among Yucheng people with/without skin manifestation and unexposed referents were compared, while adjusting for other factors by multiple regression analyzes.

RESULTS

The Yucheng people had significantly reduced scores in the physical, psychological, social, and environmental domains as compared to the referents. Those with skin manifestations were more severely affected than those with no skin manifestations, suggesting a dose-related effect on QOL in exposed people.

CONCLUSION

We show for the very first time that poisoning due to persistent organic pollutants PCBs and PCDFs can affect QOL 30 years after the exposure, especially among those most severely poisoned.

Net survival after exposure to polychlorinated biphenyls and dioxins: the Yusho study

BACKGROUND

Net survival is an important measure of the overall outcome of disease management. This net survival is the most appropriate for international comparisons of disease impact between countries or time periods with different patterns of all-cause mortality because it is not influenced by other causes of death. However, little information is available on net survival among Yusho patients, who were accidentally exposed to PCBs and other dioxin-related compounds.

METHODS

We estimated the net survival of 1664 Yusho patients (860 males, 804 females) as Yusho cohort subjects using the unbiased Pohar-Perme method.

RESULTS

Among males, 1-, 5-, 10-, and 15-year net survival were 99.5% (95% confidence interval (CI): 97.9, 99.9), 99.1% (CI: 95.0, 99.9), 97.4% (CI: 86.5, 99.5), and 97.4% (CI: 84.2, 99.6), respectively. Among females, net survival remained almost constant. 1-, 5-, 10-, and 15-year net survival were generally higher in females than in males.

CONCLUSIONS

This study provides the first unbiased estimations of net survival among Yusho patients. We confirmed that older male Yusho patients have experienced a significant decrease in net survival. Our results suggest that the excess hazard of PCBs and dioxins must be taken into account when evaluating unbiased estimates of net survival.

Cancer and non-cancer excess mortality resulting from mixed exposure to polychlorinated biphenyls and polychlorinated dibenzofurans from contaminated rice oil: "Yusho"

PURPOSE

In 1968, rice oil contaminated with polychlorinated biphenyls and polychlorinated dibenzofurans caused a severe outbreak of food poisoning in Japan and was termed locally as "Yusho" (oil disease). In our previous study, we found that area-based standardized mortality ratios (SMRs) of some diseases were elevated shortly after the incident. This previous study, however, was unable to determine whether these elevated SMRs were a result of other area-specific factors. To overcome this limitation, we obtained mortality data from the 5 years before the incident and conducted an area-based study using vital statistics records dating from 1963 to 2002.

METHODS

The population of Nagasaki Prefecture was set as the reference population for calculating SMRs. We also included data on cause-specific mortality attributable to cancer and expanded the population to encompass two severely exposed areas where contaminated rice oil was distributed (namely Tamanoura and Naru). We also calculated SMRs in the remainder of the Shimo-Goto region, excluding the exposed area, which was used as a comparison area.

RESULTS

Even after considering the time trends in mortality before the incident, mortality due to diabetes mellitus and heart disease, as well as all-cause mortality, was found to be elevated shortly afterward. Additionally, mortalities due to uterine cancer in Tamanoura and leukemia were also elevated at 30-34 and 10-59 years after the event in both exposed areas, respectively. SMRs for leukemia in Tamanoura were as high as 3.0 (95% confidence interval 1.4-6.2) and 2.4 (1.2-4.8) 10-19 years later. In this period, SMRs for leukemia in the comparison area were not elevated.

CONCLUSIONS

Further epidemiological studies are needed regarding this rice-oil, "Yusho" outbreak, especially with regard to cancer and non-cancer mortality.