Occupational exposure to pesticides and other biocides and risk of thyroid cancer

Dietary Exposure to Pesticide and Veterinary Drug Residues and Their Effects on Human Fertility and Embryo Development: A Global Overview

Drug residues that contaminate food and water represent a serious concern for human health. The major concerns regard the possible irrational use of these contaminants, since this might increase the amplitude of exposure. Multiple sources contribute to the overall exposure to contaminants, including agriculture, domestic use, personal, public and veterinary healthcare, increasing the possible origin of contamination. In this review, we focus on crop pesticides and veterinary drug residues because of their extensive use in modern agriculture and farming, which ensures food production and security for the ever-growing population around the world. We discuss crop pesticides and veterinary drug residues with respect to their worldwide distribution and impacts, with special attention on their harmful effects on human reproduction and embryo development, as well as their link to epigenetic alterations, leading to intergenerational and transgenerational diseases. Among the contaminants, the most commonly implicated in causing such disorders are organophosphates, glyphosate and antibiotics, with tetracyclines being the most frequently reported. This review highlights the importance of finding new management strategies for pesticides and veterinary drugs. Moreover, due to the still limited knowledge on inter- and transgenerational effects of these contaminants, we underlie the need to strengthen research in this field, so as to better clarify the specific effects of each contaminant and their long-term impact.

Potential health risks to disinfection workers from exposure to active substances in COVID-19 biocidal products

The importance of disinfection has recently been emphasized due to the increasing risk of the spread of infections such as coronavirus disease-2019 (COVID-19). In addition, disinfection for preventing the spread of COVID-19 is highly recommended. The increased use of biocidal products raises concerns regarding the potential health risks from exposure among disinfection workers. This study aimed to assess these exposure and health risks using questionnaires targeting disinfection workers who were exposed to the active substances in biocidal products used for disinfection during the COVID-19 pandemic. A follow-up survey was conducted among 271 disinfection workers for 10 working days within two weeks, and exposure factors with reference to disinfection were evaluated through interview-administered questionnaires. An exposure algorithm was used to evaluate the exposure of disinfection workers during disinfection. The hazard index (HI) was calculated by dividing the inhalation concentration obtained using the exposure algorithm and the dermal dose according to occupational exposure limits (OEL). A sensitivity analysis was conducted to identify the exposure factors with the greatest impact on the inhalation and dermal exposure algorithms. A logistic regression analysis was performed to verify the relationship with health effects and sociodemographic and exposure characteristics. The average number of disinfections performed during 10 working days was 17.5 ± 12.3 times. The type of disinfection work was divided into 2806 cases of COVID-19 prevention and disinfection and 1956 cases of regular pesticide application to prevent and remove any pests. The HI was ≥1, indicating a potential health risk, with the use of ethanol (6.50E+00), quaternary ammonium compounds (QACs; 1.49E+01), and benzalkonium chloride (BKC; 1.73E+00). Dermal exposure was more hazardous than inhalation exposure for 6 of the 11 active substances in biocidal products. The weight fraction and exposure time were the factors that most significantly influenced the inhalation and dermal exposure algorithms in the sensitivity analysis. Higher exposure concentrations were more likely to affect health (AOR: 3.239, 95% CI: 1.155-9.082). This study provides valuable information regarding the exposure and risk of disinfection workers to 11 biocidal active substances included in common disinfectants. Our results suggest that the use of ethanol, BKC, and QACs has potential health risks to disinfection workers, with a higher possibility of negative health impacts with increasing exposure concentration.

Chemical contaminants in blood and their implications in chronic diseases

Artificial chemical products are widely used and ubiquitous worldwide and pose a threat to the environment and human health. Accumulating epidemiological and toxicological evidence has elucidated the contributions of environmental chemical contaminants to the incidence and development of chronic diseases that have a negative impact on quality of life or may be life-threatening. However, the pathways of exposure to these chemicals and their involvements in chronic diseases remain unclear. We comprehensively reviewed the research progress on the exposure risks of humans to environmental contaminants, their body burden as indicated by blood monitoring, and the correlation of blood chemical contaminants with chronic diseases. After entering the human body through various routes of exposure, environmental contaminants are transported to target organs through blood circulation. The application of the modern analytical techniques based on human plasma or serum specimens is promising for determining the body burden of environmental contaminants, including legacy persistent organic pollutants, emerging pollutants, and inorganic elements. Furthermore, their body burden, as indicated by blood monitoring correlates with the incidence and development of metabolic syndromes, cancers, chronic nervous system diseases, cardiovascular diseases, and reproductive disorders. On this basis, we highlight the urgent need for further research on environmental pollution causing health problems in humans.

Risk of papillary thyroid carcinoma and nodular goiter associated with exposure to semi-volatile organic compounds: A multi-pollutant assessment based on machine learning algorithms

BACKGROUND

Exposure to semi-volatile organic compounds (SVOCs) may link to thyroid nodule risk, but studies of mixed-SVOCs exposure effects are lacking. Traditional analytical methods are inadequate for dealing with mixed exposures, while machine learning (ML) seems to be a good way to fill the gaps in the field of environmental epidemiology research.

OBJECTIVES

Different ML algorithms were used to explore the relationship between mixed-SVOCs exposure and thyroid nodule.

METHODS

A 1:1:1 age- and gender-matched case-control study was conducted in which 96 serum SVOCs were measured in 50 papillary thyroid carcinoma (PTC), 50 nodular goiters (NG), and 50 controls. Different ML techniques such as Random Forest, AdaBoost were selected based on their predictive power, and variables were selected based on their weights in the models. Weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were used to assess the mixed effects of the SVOCs exposure on thyroid nodule.

RESULTS

Forty-three of 96 SVOCs with detection rate >80 % were included in the analysis. ML algorithms showed a consistent selection of SVOCs associated with thyroid nodule. Fluazifop-butyl and fenpropathrin are positively associated with PTC and NG in single compound models (all P < 0.05). WQS model shows that exposure to mixed-SVOCs was associated with an increased risk of PTC and NG, with the mixture dominated by fenpropathrin, followed by fluazifop-butyl and propham. In the BKMR model, mixtures showed a significant positive association with thyroid nodule risk at high exposure levels, and fluazifop-butyl showed positive effects associated with PTC and NG.

CONCLUSION

This study confirms the feasibility of ML methods for variable selection in high-dimensional complex data and showed that mixed exposure to SVOCs was associated with increased risk of PTC and NG. The observed association was primarily driven by fluazifop-butyl and fenpropathrin. The findings warranted further investigation.

Organochlorine pesticides induce thyroid tumors through oxidative stress; an in vivo and in silico study

Thyroid disease is one of the most common endocrine problems around the world. Among the numerous factors, exposure to environmental elements such as pesticides is associated with an increase in the incidence of thyroid disorders. The aim of the present study was to investigate the role of organochlorine pesticides (OCPs) in induction of oxidative stress (OS) and development of thyroid tumors. This case-control study was conducted on 61 patients with papillary thyroid carcinoma (PTC), 70 patients with benign thyroid nodules (BTN), and 73 healthy individuals as control. Seven derived OCPs residues measured by gas chromatography (GC), and enzyme activities of acetylcholinesterase (AChE), superoxide dismutase3 (SOD3), catalase (CAT), glutathione peroxidase3 (GPx3) and paraoxonase1 (PON1) and also, non-enzymatic antioxidant including; malondialdehyde (MDA), total antioxidant capacity (TAC), protein carbonyl (PC), and nitric oxide (NO) biomarkers in all participants were investigated. Furthermore, all of the above enzymes were docked against measured OCPs. The results revealed that β-HCH, γ-HCH, 2,4 DDE, 4,4 DDE, 2,4-DDT, and 4,4-DDT levels along with MDA, NO, and PC levels were elevated, while AChE, SOD3, GPx3, CAT, and PON1 activities and TAC levels were decreased in the PTC and BTN groups compared with the control group. Therefore, OCPs might play a role in the development of thyroid tumors through several mechanisms including generation of OS. Importantly, in silico analysis confirmed the in vivo findings.

Exposures to pesticides and risk of cancer: Evaluation of recent epidemiological evidence in humans and paths forward

Knowledge of the role in cancer etiology of environmental exposures as pesticides is a prerequisite for primary prevention. We review 63 epidemiological studies on exposure to pesticides and cancer risk in humans published from 2017 to 2021, with emphasis on new findings, methodological approaches, and gaps in the existing literature. While much of the recent evidence suggests causal relationships between pesticide exposure and cancer, the strongest evidence exists for acute myeloid leukemia (AML) and colorectal cancer (CRC), diseases in which the observed associations were consistent across several studies, including high-quality prospective studies and those using biomarkers for exposure assessment, with some observing dose-response relationships. Though high-quality studies have been published since the IARC monograph on organophosphate insecticides in 2017, there are still gaps in the literature on carcinogenic evidence in humans for a large number of pesticides. To further knowledge, we suggest leveraging new techniques and methods to increase sensitivity and precision of exposure assessment, incorporate multi-omics data, and investigate more thoroughly exposure to chemical mixtures. There is also a strong need for better and larger population-based cohort studies that include younger and nonoccupationally exposed individuals, particularly during developmental periods of susceptibility. Though the existing evidence has limitations, as always in science, there is sufficient evidence to implement policies and regulatory action that limit pesticide exposure in humans and, hence, further prevent a significant burden of cancers.

Thyroid Carcinoma: A Review for 25 Years of Environmental Risk Factors Studies

Environmental factors are established contributors to thyroid carcinomas. Due to their known ability to cause cancer, exposure to several organic and inorganic chemical toxicants and radiation from nuclear weapons, fallout, or medical radiation poses a threat to global public health. Halogenated substances like organochlorines and pesticides can interfere with thyroid function. Like phthalates and bisphenolates, polychlorinated biphenyls and their metabolites, along with polybrominated diethyl ethers, impact thyroid hormones biosynthesis, transport, binding to target organs, and impair thyroid function. A deeper understanding of environmental exposure is crucial for managing and preventing thyroid cancer. This review aims to investigate the relationship between environmental factors and the development of thyroid cancer.

Time for Re-Evaluating the Human Carcinogenicity of Ethylenedithiocarbamate Fungicides? A Systematic Review

BACKGROUND

In January 2021, the European Union ended the license of Mancozeb, the bestselling ethylenedithiocarbamate (EBDC) fungicide, because of some properties typical of human carcinogens. This decision contrasts the IARC classification of EBDC fungicides (Group 3, not classifiable as to human carcinogenicity). A systematic review of the scientific literature was conducted to explore the current evidence.

METHODS

Human and experimental studies of cancer and exposure to EBDC fungicides (Mancozeb, Maneb, Zineb, and others) and ethylene thiourea (ETU), their major metabolite, published in English as of December 2021, were retrieved using PubMed, the list of references of the relevant reports, and grey literature.

RESULTS

The epidemiological evidence of EBDC carcinogenicity is inadequate, with two studies each suggesting an association with melanoma and brain cancer and inconsistent findings for thyroid cancer. Experimental animal studies point at thyroid cancer in rats and liver cancer in mice, while multiple organs were affected following the long-term oral administration of Mancozeb. The mechanism of thyroid carcinogenesis in rats has also been shown to occur in humans. Genotoxic effects have been reported.

CONCLUSIONS

The results of this systematic review suggest inadequate evidence for the carcinogenicity of EBDC fungicides from human studies and sufficient evidence from animal studies, with positive results on three out of ten key characteristics of carcinogens applying to humans as well. An IARC re-evaluation of the human carcinogenicity of EBDC fungicides is warranted.

Agrotóxicos, desfechos em saúde e agroecologia no Brasil: uma revisão de escopo

RESUMO A presente revisão de escopo objetivou evidenciar o perfil das pesquisas brasileiras que investigam os desfechos em saúde ocasionados pela exposição a agrotóxicos, procurando entender os principais achados, tais como metodologia empregada, tipo de substância, desfechos em saúde, locais investigados, sugestões de ações e diálogo com a agroecologia. Foi utilizada a metodologia ‘scoping review’, seguindo o modelo Prisma-ScR. Entre os 83 artigos encontrados, 61 estudaram os/as agricultores/as e 22 estudaram outros grupos populacionais. Houve predomínio de estudos primários e quantitativos, seguidos por revisões sistemáticas. Do total, 79 encontraram desfechos, com destaque aos danos hematológicos e genéticos, em sua maior parte causados pela intoxicação por mais de 1 agrotóxico. O maior número de estudos foi realizado na região Sul, seguida das regiões Sudeste, Nordeste, Centro-Oeste e Norte. Apenas uma pesquisa sugeriu a transição agroecológica enquanto solução para a problemática. Conclui-se que, perante um cenário de crescimento do uso de agrotóxicos, fazem-se urgentes proposições de ações intersetoriais e que não envolvam somente educação em saúde ou o setor saúde de forma isolada, como sugere a maioria dos artigos, sendo necessária a articulação entre setores ligados à agricultura, abastecimento, educação, saúde e meio-ambiente.

Farmers' Knowledge, Attitudes, and Perceptions Regarding Carcinogenic Pesticides in Fez Meknes Region (Morocco)

Pesticides play an important role in the improvement of agricultural production, but their use may result in adverse effects on the environment, consumers, and farmers' health. As there are limited data focusing on the factors influencing safety behavior toward pesticide use in Morocco, we conducted a cross-sectional survey in 15 rural communities of Morocco's Fes Meknes region to assess the attitudes, knowledge, and practices regarding pesticide use. A structured questionnaire was completed, containing the data of the interviewed farmers, their behavior towards safety measures, the type of active ingredient used, as well as the perception of risks to their own health following exposure to pesticides by the existence of chronic, self-perceived symptoms. Non-probability (empirical) sampling with the quota method was carried out, which consists of constructing the sample. Results showed that most respondents have not been trained in the application of pesticides, with almost half of the farmers using a category of pesticides which are classified by the International Agency for Research on Cancer as probable human carcinogenic (i.e., Glyphosate, Malathion). In terms of pesticide storage, 40% of farmers said that they did not store pesticides in a separate room after purchasing or using them. The empty containers were buried or burnt by half of the responders, while the remainder were thrown at the edge of fields or in public dumps. Although the participants were aware of the negative effects on their own health and on the environment caused by the application of pesticides in use, the protection measures by individual equipment were insufficient. A canonical analysis indicates that these behaviors were influenced by the farming experience, the benefit of the agricultural council services, the follow-up of training, and the education level. These variables are important factors in explaining and understanding the dangers to both the environment and health caused by pesticides. The most recorded likely consequences of pesticide exposure were visual impairment (46%), followed by dizziness (44.3%), headache (39.4%), and excessive sweating (34.4%), and 30.2% of participants identified consequent respiratory problems. Extension services targeted at safety and protection measures should be developed and accompanied by educational programs to put farmers' perceptions into practice and encourage them to adopt healthy and environmentally friendly behaviors.

Cancer incidence in World Trade Center-exposed and non-exposed male firefighters, as compared with the US adult male population: 2001-2016

OBJECTIVE

To compare cancer incidence in Fire Department of the City of New York (FDNY) firefighters who worked at the World Trade Center (WTC) site to incidence in a population of non-WTC-exposed firefighters, the Career Firefighter Health Study (CFHS) cohort, and to compare rates from each firefighter cohort to rates in demographically similar US males.

METHODS

FDNY (N=10 786) and CFHS (N=8813) cohorts included male firefighters who were active on 11 September 2001 (9/11) and were followed until death or 31 December 2016. Cases were identified from 15 state cancer registries. Poisson regression models assessed cancers in each group (FDNY and CFHS) versus US males, and associations between group and cancer rates; these models estimated standardised incidence ratios (SIRs) and adjusted relative rates (RRs), respectively. Secondary analyses assessed surveillance bias and smoking history.

RESULTS

We identified 915 cancer cases in 841 FDNY firefighters and 1002 cases in 909 CFHS firefighters. FDNY had: higher rates for all cancers (RR=1.13; 95% CI 1.02 to 1.25), prostate (RR=1.39; 95% CI 1.19 to 1.63) and thyroid cancer (RR=2.53; 95% CI 1.37 to 4.70); younger median ages at diagnosis (55.6 vs 59.4; p<0.001, all cancers); and more cases with localised disease when compared with CFHS. Compared with US males, both firefighter cohorts had elevated SIRs for prostate cancer and melanoma. Control for surveillance bias in FDNY reduced most differences.

CONCLUSIONS

Excess cancers occurred in WTC-exposed firefighters relative to each comparison group, which may partially be explained by heightened surveillance. Two decades post-9/11, clearer understanding of WTC-related risk requires extended follow-up and modelling studies (laboratory or animal based) to identify workplace exposures in all firefighters.

Changing incidence and projections of thyroid cancer in mainland China, 1983-2032: evidence from Cancer Incidence in Five Continents

PURPOSE

An increasing incidence of thyroid cancer has been seen in China during the past several decades. The aim of this study was to analyze potential age, period, and cohort effects on the incidence of thyroid cancer in mainland China and to predict new cases up to 2032.

METHODS

We calculated age-adjusted and age-specific incidence rates of thyroid cancer, conducted an age-period-cohort analysis of 35,037 thyroid cancer incidence cases reported to Cancer Incidence in Five Continents from 1983 to 2012 in mainland China, and predicted incidence up to 2032 using the Bayesian age-period-cohort method.

RESULTS

The age-adjusted overall incidence rate of thyroid cancer increased from 1.93/100,000 in 1983-1987 to 12.18/100,000 in 2008-2012 among females and from 0.77/100,000 in 1983-1987 to 3.89/100,000 in 2008-2012 among males, with a female-to-male ratio of approximately 3.0 during the three decades. Strong birth cohort and period effects on the incidence of thyroid cancer were observed for both sexes, and such an increasing trend is predicted to continue for at least the next 20 years. More than 3.7 million new cases are projected in the 2028-2032 period.

CONCLUSION

The increasing trend of thyroid cancer in mainland China will cause a great burden in the future. In addition to the potential impact of improvement in medical diagnostics, potential exposure to risk factors have played a role in the observed rising trend. Further population-based epidemiologic studies are required to identify risk factors to aid in thyroid cancer prevention and control.

The use of pesticides in Polish agriculture after integrated pest management (IPM) implementation

The aim of the conducted study was to characterize the attitudes and practices of Polish farmers in the area of performing chemical plant protection treatments. A particular attention was paid to identifying the relationship between the direction of changes in the volume of chemical plant protection product consumption and selected attributes of farms. The main time range of the analyses covered the period of 2013-2017. Statistical data and results of representative surveys carried out on a sample of 1101 farms in Poland were used in the research process. Due to the large number of variants of the analysed variables, a multiple correspondence analysis was used, which made it possible to determine the correlation between the examined features (direction of changes in pesticide use relative to the farm area, economic size of the farm and location of the farm). Statistical analysis showed the existence of strong relationships between the physical (1) and economic (2) size of farms and the direction of changes in pesticide consumption ((1) φ2 = 0.0907; (2) φ2 = 0.1141)). According to empirical studies, the reduction of pesticide consumption took place mainly on the smallest farms. The implementation of the integrated plant protection directive has not resulted in significant changes in the form of reduced pesticide use in large-scale field crops. This raises the need to modify the strategy and model of crop protection in large-scale field crops in Poland.

Endocrine-Disrupting Chemicals and Infectious Diseases: From Endocrine Disruption to Immunosuppression

Endocrine-disrupting chemicals (EDCs) are hormonally active compounds in the environment that interfere with the body's endocrine system and consequently produce adverse health effects. Despite persistent public health concerns, EDCs remain important components of common consumer products, thus representing ubiquitous contaminants to humans. While scientific evidence confirmed their contribution to the severity of Influenza A virus (H1N1) in the animal model, their roles in susceptibility and clinical outcome of the coronavirus disease (COVID-19) cannot be underestimated. Since its emergence in late 2019, clinical reports on COVID-19 have confirmed that severe disease and death occur in persons aged ≥65 years and those with underlying comorbidities. Major comorbidities of COVID-19 include diabetes, obesity, cardiovascular disease, hypertension, cancer, and kidney and liver diseases. Meanwhile, long-term exposure to EDCs contributes significantly to the onset and progression of these comorbid diseases. Besides, EDCs play vital roles in the disruption of the body's immune system. Here, we review the recent literature on the roles of EDCs in comorbidities contributing to COVID-19 mortality, impacts of EDCs on the immune system, and recent articles linking EDCs to COVID-19 risks. We also recommend methodologies that could be adopted to comprehensively study the role of EDCs in COVID-19 risk.

Circular Economy in Conjunction with Treatment Methodologies in the Biomedical and Dental Waste Sectors

In this review, life cycle assessment (LCA) principles are coupled with circular economy (CE) in order to address LCA examples in the biomedical sector worldwide. The objectives were (1) to explore the application of LCA in the medical, pharmaceutical, and dental fields; (2) to describe the ways of biomedical waste management; (3) to emphasize on the problem of dental waste in private and public dental sectors; and (4) to propose ways of “green circulation” of the dental waste. A literature search was performed using the Google Scholar, PubMed, and Scopus search engines covering the period from January 2000 until May 2020, corresponding to articles investigating the LCA and circular economy principles and legislation for biomedical and dental waste, their management options, and modern ways of recycling. The results showed that incineration seems to be the best management way option involved despite the mentioned drawbacks in this technology. Different adopted models are well defined for the dental field based on the 3Rs’ module (reduce, reuse, recycle). Replacing disposable products with reusable ones seems to be a good way to tackle the problem of waste in medical and dental sectors. Interventions on the selection and better biomedical and dental waste management will ensure eco-medicine and eco-dentistry of the future. These new terms should be the new philosophies that will change the way these fields operate in the future for the benefit of the professionals/patients and the community.

Endocrine Disrupting Chemicals and Thyroid Cancer: An Overview

Endocrine disruptive chemicals (EDC) are known to alter thyroid function and have been associated with increased risk of certain cancers. The present study aims to provide a comprehensive overview of available studies on the association between EDC exposure and thyroid cancer. Relevant studies were identified via a literature search in the National Library of Medicine and National Institutes of Health PubMed as well as a review of reference lists of all retrieved articles and of previously published relevant reviews. Overall, the current literature suggests that exposure to certain congeners of flame retardants, polychlorinated biphenyls (PCBs), and phthalates as well as certain pesticides may potentially be associated with an increased risk of thyroid cancer. However, future research is urgently needed to evaluate the different EDCs and their potential carcinogenic effect on the thyroid gland in humans as most EDCs have been studied sporadically and results are not consistent.

The pesticides use and the risk for head and neck cancer: A review of case-control studies

BACKGROUND

Tobacco, alcohol consumption, and HPV infection are the most common risk factors for head and neck cancer (HNC). Despite of this, recent evidences are growing on the association between long-term exposure to pesticides and the risk of chronic diseases, including different types of cancer. The present review evaluated in current literature evidence of an association between exposure to pesticides and the occurrence of HNCs.

MATERIAL AND METHODS

A literature search of the case-control studies was conducted in the PubMed, Web of science and Cochrane databases. Methodological quality of each study was rated with the Scottish Intercollegiate Guidelines Network (SIGN 50) checklist.

RESULTS

One thousand and thirty-five studies were identified and twelve met all criteria and, therefore, considered for quality assessment and data extraction. According to SIGN 50 criteria, six studies received an overall high-quality. All the studies considered of high quality found a positive association between exposure to pesticides and different HNC sites, including larynx, pharynx and nasal cavity. In addition, the increased risk was associated with the frequency of exposure.

CONCLUSIONS

Finally, improving pesticide users' awareness of their risks and proper handling, as well as adopting protective measures such as the use of personal protective equipment, appear to be effective in reducing human health damage.

Pesticide exposure and incident thyroid cancer among male pesticide applicators in agricultural health study

BACKGROUND

Many pesticides are known to have thyroid-disrupting properties. However, few studies have evaluated the association between specific pesticide ingredients and risk of thyroid cancer. We investigated self-reported pesticide use and incident thyroid cancer in the Agricultural Health Study (AHS), a large cohort of occupationally-exposed male pesticide applicators.

METHODS

The AHS is a prospective cohort of licensed pesticide applicators in Iowa and North Carolina. At enrollment (1993-1997) and follow-up (1999-2005), participants reported use of 50 pesticides. We characterized exposure as ever use (44 pesticides with ≥5 exposed cases) and by cumulative intensity-weighted lifetime days (22 pesticides with ≥10 exposed cases), a metric that accounts for factors that influence exposure. We estimated hazard ratios (HR) and 95% confidence intervals (CI) using Cox regression for incident thyroid (n = 85 cases) cancer among male participants using follow-up through 2014/2015.

RESULTS

Use of the fungicide metalaxyl (HR = 2.03, CI:1.16-3.52) and the organochlorine insecticide lindane (HR = 1.74, CI:1.06-2.84) was associated with increased risk of thyroid cancer. The herbicide chlorimuron-ethyl was inversely associated with risk when we restricted to papillary thyroid cancer, the most common subtype (HR = 0.52, CI:0.28-0.96). High use of the insecticide carbaryl (>median intensity-weighted days) was inversely associated with thyroid cancer (HR = 0.20, CI:0.08-0.53, p_trend = 0.001).

CONCLUSIONS

In this large cohort study, we observed increased risk of thyroid cancer associated with use of metalaxyl and lindane, and an inverse association with carbaryl. More work is needed to understand the potential role of these chemicals in thyroid carcinogenesis.

Agrochemicals with estrogenic endocrine disrupting properties: Lessons Learned?

Many agrochemicals have endocrine disrupting properties. A subset of these chemicals is characterized as "estrogenic". In this review, we describe several distinct ways that chemicals used in crop production can affect estrogen signaling. Using three agrochemicals as examples (DDT, endosulfan, and atrazine), we illustrate how screening tests such as the US EPA's EDSP Tier 1 assays can be used as a first-pass approach to evaluate agrochemicals for endocrine activity. We then apply the "Key Characteristics" approach to illustrate how chemicals like DDT can be evaluated, together with the World Health Organization's definition of an endocrine disruptor, to identify data gaps. We conclude by describing important issues that must be addressed in the evaluation and regulation of hormonally active agrochemicals including mixture effects, efforts to reduce vertebrate animal use, chemical prioritization, and improvements in hazard, exposure, and risk assessments.

A Study of Artificial Sweeteners and Thyroid Cancer Risk

Background

In recent decades, data from certain observational studies have stirred controversy over artificial sweeteners by linking them with certain malignancies. As the incidences of artificial sweetener consumption and thyroid cancer are both increasing, our study aimed to determine any possible association between them.

Methods

This retrospective observational study enrolled 50 patients (group 1) with proven diagnosis of well-differentiated thyroid cancer (WDTC) and 50 control subjects (group 2) diagnosed as having benign thyroid nodule by fine-needle aspiration. The survey questionnaire included the total amount and duration of intake of artificial sweeteners.

Results

Increased consumption of artificial sweeteners was noted in group 1 as compared to group 2, which was statistically significant (76% vs. 24%, P < 0.01). This study suggested that the use of an average of four packets (4 g) per day of artificial sweetener for an average duration of 5 years is associated with WDTC.

Conclusions

Our study emphasizes the significance of artificial sweetener consumption as a potential risk factor for WDTC and increase in public awareness regarding this association if other studies in future report similar findings.

Evaluation of Medical Surveillance and Incidence of Post-September 11, 2001, Thyroid Cancer in World Trade Center-Exposed Firefighters and Emergency Medical Service Workers

IMPORTANCE

Elevated incidence rates of thyroid cancer among World Trade Center (WTC)-exposed individuals may be associated with the identification of asymptomatic cancers during medical surveillance.

OBJECTIVE

To examine the association between WTC exposure and thyroid cancer among Fire Department of the City of New York (hereafter, Fire Department) rescue/recovery workers as well as the association with medical surveillance.

DESIGN, SETTING, AND PARTICIPANTS

This closed-cohort study classified the method of detection (asymptomatic and symptomatic) of thyroid cancers in 14 987 men monitored through the Fire Department-WTC Health Program diagnosed from September 12, 2001, to December 31, 2018. Age-, sex-, and histologic-specific Fire Department incidence rates were calculated and compared with demographically similar men in Olmsted County, Minnesota, from the Rochester Epidemiology Project using age-standardized rates, relative rates (RRs), and 95% CIs. The secondary analysis was restricted to papillary carcinomas.

EXPOSURES

World Trade Center exposure was defined as rescue/recovery work at the WTC site from September 11, 2001, to July 25, 2002.

MAIN OUTCOMES AND MEASURES

The outcomes evaluated comprised (1) number of incident thyroid cancers and their detection method categorizations in the Fire Department and Rochester Epidemiology Project cohorts; (2) Fire Department, Rochester Epidemiology Project, and Surveillance, Epidemiology, and End Results-21 age-standardized incidence rates of thyroid cancer; and (3) RRs comparing Fire Department and Rochester Epidemiology Project overall and by detection method categorization.

RESULTS

Seventy-two post-9/11 Fire Department cases of thyroid cancer were identified. Among the 65 cases (90.3%) with a categorized detection method, 53 cases (81.5%) were asymptomatic and 12 cases (18.5%) were symptomatic. Median (interquartile range) age at diagnosis was 50.2 (44.0-58.6) vs 46.6 (43.9-52.9) years for asymptomatic vs symptomatic cases. Associated primarily with asymptomatic cancers, the overall age-standardized incidence of Fire Department thyroid cancers (24.7; 95% CI, 17.4-52.3) was significantly higher than the Rochester Epidemiology Project (10.4; 95% CI, 8.5-12.7) and Surveillance, Epidemiology, and End Results-21 (9.1; 95% CI, 9.0-9.1) per 100 000 person-years. Furthermore, the RR of thyroid cancer among symptomatic men in Fire Department cases was not significantly different from that of men in the Rochester Epidemiology Project (0.8; 95% CI, 0.4-1.5); however, the rate of asymptomatic cancers was more than 3-fold that of the Rochester Epidemiology Project rate (RR, 3.1; 95% CI, 2.1-4.7).

CONCLUSIONS AND RELEVANCE

Excess asymptomatic thyroid cancer in Fire Department WTC-exposed rescue/recovery workers is apparently attributable to the identification of occult lesions during medical surveillance. Among WTC-exposed cohorts and the general population, these findings appear to have important implications for how thyroid cancer incidence rates are interpreted and how diagnoses should be managed.

Endocrine disrupting chemicals: exposure, effects on human health, mechanism of action, models for testing and strategies for prevention

Endocrine Disrupting Chemicals (EDCs) are a global problem for environmental and human health. They are defined as "an exogenous chemical, or mixture of chemicals, that can interfere with any aspect of hormone action". It is estimated that there are about 1000 chemicals with endocrine-acting properties. EDCs comprise pesticides, fungicides, industrial chemicals, plasticizers, nonylphenols, metals, pharmaceutical agents and phytoestrogens. Human exposure to EDCs mainly occurs by ingestion and to some extent by inhalation and dermal uptake. Most EDCs are lipophilic and bioaccumulate in the adipose tissue, thus they have a very long half-life in the body. It is difficult to assess the full impact of human exposure to EDCs because adverse effects develop latently and manifest at later ages, and in some people do not present. Timing of exposure is of importance. Developing fetus and neonates are the most vulnerable to endocrine disruption. EDCs may interfere with synthesis, action and metabolism of sex steroid hormones that in turn cause developmental and fertility problems, infertility and hormone-sensitive cancers in women and men. Some EDCs exert obesogenic effects that result in disturbance in energy homeostasis. Interference with hypothalamo-pituitary-thyroid and adrenal axes has also been reported. In this review, potential EDCs, their effects and mechanisms of action, epidemiological studies to analyze their effects on human health, bio-detection and chemical identification methods, difficulties in extrapolating experimental findings and studying endocrine disruptors in humans and recommendations for endocrinologists, individuals and policy makers will be discussed in view of the relevant literature.

Bayesian Hierarchical Modelling of Individual Expert Assessments in the Development of a General-Population Job-Exposure Matrix

The CANJEM job-exposure matrix compiles expert evaluations of 31 673 jobs from four population-based case-control studies conducted in Montreal. For each job, experts had derived indices of intensity, frequency, and probability of exposure to 258 agents. CANJEM summarizes the exposures assigned to jobs into cells defined by occupation/industry, agent, and period. Some cells may, however, be less populated than others, resulting in uncertain estimates. We developed a modelling framework to refine the estimates of sparse cells by drawing on information available in adjacent cells. Bayesian hierarchical logistic and linear models were used to estimate the probability of exposure and the geometric mean (GM) of frequency-weighted intensity (FWI) of cells, respectively. The hierarchy followed the Canadian Classification and Dictionary of Occupations (CCDO) classification structure, allowing for exposure estimates to be provided across occupations (seven-digit code), unit groups (four-digit code), and minor groups (three-digit code). The models were applied to metallic dust, formaldehyde, wood dust, silica, and benzene, and four periods, adjusting for the study from which jobs were evaluated. The models provided estimates of probability and FWI for all cells that pulled the sparsely populated cells towards the average of the higher-level group. In comparisons stratified by cell sample size, shrinkage of the estimates towards the group mean was marked below 5 jobs/cell, moderate from 5 to 9 jobs/cell, and negligible at ≥10 jobs/cell. The modelled probability of three-digit cells were slightly smaller than their descriptive estimates. No systematic trend in between-study differences in exposure emerged. Overall, the modelling framework for FWI appears to be a suitable approach to refine CANJEM estimates. For probability, the models could be improved by methods better adapted to the large number of cells with no exposure.

The importance of understanding the distribution of GSTM1 and GSTT1 genotypes and haplotypes in a region with intense agriculture activity

Brazil is one of the largest pesticide consumers in the world, mainly due to its intense agricultural activity. The State of Goias, situated in Central Brazil, is a region recognized as an essential producer of soy, corn, beans, sorghum, sugar cane, and cotton. In this study, we evaluated 602 unrelated individuals, distributed in central and southern regions in Goias, presenting combined frequencies (haplotypes) of the GSTT1 and GSTM1 genes. In all municipalities, the frequency of the GSTT1 null genotype was 38.2% and of the GSTM1 null genotype was 50.3%. Goiania, the capital of Goias, presented the highest frequencies of GSTT1 and GSTM1 null genotypes, probably due to a founder effect of non-representative colonizing ancestors. So, the ancestral population adapted to the environment, with the frequencies observed in Goiania. However, nowadays, as there is excessive use of pesticides, the community becomes susceptible to the harmful effects of xenobiotics exposure, mainly due to the high frequency of GSTT1 and GSTM1 null genotypes. As in Goias, the consumption of pesticides has shown considerable growth, haplotypes with null alleles are of high risk for the population. Our results indicated that it is essential to understand the frequencies of the GSTT1 and GSTM1 genes for the monitoring of risk groups, like farmers, who have contact with pesticides, directly or indirectly, as well as assisting in the development of preventive medicine practices.

Phytoestrogens and Thyroid Cancer Risk: A Population-Based Case-Control Study in Connecticut

BACKGROUND

Very few previous studies have examined the relationship between thyroid cancer risk and intake of phytoestrogens (PE); furthermore, these studies have reached inconsistent results.

METHODS

We analyzed data from a population-based case-control study in Connecticut from 2010 to 2011, including 387 histologically confirmed thyroid cancer cases and 433 population-based controls, with compound data available concerning specific PEs. Multivariate unconditional logistic regression models were used to estimate the associations between specific PEs and the risk of thyroid cancer, adjusting for potential confounders.

RESULTS

An elevated risk of thyroid cancer was associated with moderate to high levels of coumestrol intake [OR = 2.48, 95% confidence interval (CI), 1.39-4.43 for 40-80 μg/day; OR = 2.41, 95% CI, 1.32-4.40 for 80-130 μg/day; and OR = 2.38, 95% CI, 1.26-4.50 for >200 μg/day compared with <40 μg/day], and the main elevation in risk appeared among microcarcinomas (≤1 cm). A decreased risk of papillary macrocarcinomas (>1 cm; OR = 0.26, 95% CI, 0.08-0.85 for 1,860-3,110 μg/day compared with <760 μg/day) was associated with moderate genistein intake among women.

CONCLUSIONS

Our study suggests that high coumestrol intake increases the risk of thyroid cancer, especially microcarcinomas, whereas moderate amounts of genistein intake appear to be protective for females with thyroid macrocarcinomas.

IMPACT

The study highlights the importance of distinguishing between microcarcinomas and macrocarcinomas in future research on the etiology of thyroid cancer.

Thyroid Cancer Incidence Rates in North Dakota are Associated with Land and Water Use

Objective: The increasing rate of thyroid cancer diagnoses in the U.S. reflects the increasing use of ultrasonography and of specialist medical care. North Dakota is a rural state with limited access to specialist care, yet its incidence of thyroid cancer is significantly greater than that of the U.S. overall. We sought to identify factors responsible for the high incidence of thyroid cancer in North Dakota. Methods: We examined county-specific incidence rates for thyroid cancer in North Dakota in relation to demographic and geographic factors, including median household income, percent of land fertilized, cattle density per capita, and source of drinking water (city or well water), using structural equation modeling. We included county level data on residential radon levels and estimates of radioactive iodine in milk following nuclear weapons testing in the 1950s. Results: Thyroid cancer incidence rates were significantly associated with median income (p < 0.05); percent of land fertilized (p < 0.05); the use of city water (p < 0.01), and cattle density per capita (p < 0.001). Conclusions: The risk of thyroid cancer in North Dakota is positively associated with income and with factors related to land and water use. Our finding that thyroid cancer incidence rates are associated with the use of city water was unexpected and merits examination in other locations with a mix of city and well water use.

A Toxicogenomic Approach Reveals a Novel Gene Regulatory Network Active in In Vitro and In Vivo Models of Thyroid Carcinogenesis

Epidemiological and experimental studies emphasize the link between environmental chemicals exposure and thyroid cancer. However, this association is strongly debated and the mechanisms of action of environmental thyroid carcinogens still need to be identified. The analysis of in vitro transcriptomic data developed to investigate the effects of chlorpyrifos on immortalized thyrocytes highlighted the impaired expression of genes involved in endodermal carcinogenesis. This endodermal carcinogenic gene-network (ECGN, including Zfp36l2, Dmbt1, Ddit4), was validated in cellular and mouse models of thyroid carcinogenesis, characterized by the constitutive activation of the mitogen-activated protein kinase (MAPK) pathway and in immortalized thyrocytes exposed to tetrachlorodibenzo-p-dioxin (TCDD) and chlorpyrifos (CPF). The mRNA levels of Zfp36l2, Dmbt1 and Ddit4 were increased in models characterized by MAPK activation or following TCDD exposure, whereas they were inhibited by CPF exposure. Overall, the ECGN transcripts identify a novel gene-regulatory network associated with thyroid carcinogenesis promoted by genetic mutation or by environmental carcinogens. The latter have opposite effects on the modulation of the ECGN transcripts according to their mechanisms of action in promoting carcinogenesis. Therefore, the analyses of ECGN might be helpful in discriminating compounds that promote cellular survival associated or not to proliferation of thyrocytes.

Endocrine Disrupting Chemicals: Effects on Endocrine Glands

In recent years, endocrine disrupting chemicals have gained interest in human physiopathology and more and more studies aimed to explain how these chemicals compounds affect endocrine system. In human populations, the majority of the studies point toward an association between exposure to endocrine disrupting chemicals and the disorders affecting endocrine axis. A great number of endocrine disrupting chemicals seem to be able to interfere with the physiology of hypothalamus-pituitary-gonadal axis; however, every endocrine axis may be a target for each EDCs and their action is not limited to a single axis or organ. Several compounds may also have a negative impact on energy metabolic homeostasis altering adipose tissue and promoting obesity, metabolic syndrome, and diabetes. Different mechanism have been proposed to explain these associations but their complexity together with the degree of occupational or environmental exposure, the low standardization of the studies, and the presence of confounding factors have prevented to establish causal relationship between the endocrine disorders and exposure to specific toxicants so far. This manuscript aims to review the state of art of scientific literature regarding the effects of endocrine-disrupting chemicals (EDCs) on endocrine system.

Building Evidence for Health: Green Buildings, Current Science, and Future Challenges

Civilizational challenges have questioned the status quo of energy and material consumption by humans. From the built environment perspective, a response to these challenges was the creation of green buildings. Although the revolutionary capacity of the green building movement has elevated the expectations of new commercial construction, its rate of implementation has secluded the majority of the population from its benefits. Beyond reductions in energy usage and increases in market value, the main strength of green buildings may be the procurement of healthier building environments. Further pursuing the right to healthy indoor environments could help the green building movement to attain its full potential as a transformational public health tool. On the basis of 40 years of research on indoor environmental quality, we present a summary of nine environment elements that are foundational to human health. We posit the role of green buildings as a critical research platform within a novel sustainability framework based on social-environmental capital assets.

Evaluation of genotoxic effects in Brazilian agricultural workers exposed to pesticides and cigarette smoke using machine-learning algorithms

Monitoring exposure to xenobiotics by biomarker analyses, such as a micronucleus assay, is extremely important for the precocious detection and prevention of diseases, such as oral cancer. The aim of this study was to evaluate genotoxic effects in rural workers who were exposed to cigarette smoke and/or pesticides and to identify possible classification patterns in the exposure groups. The sample included 120 participants of both sexes aged between 18 and 39, who were divided into the following four groups: control group (CG), smoking group (SG), pesticide group (PG), and smoking + pesticide group (SPG). Their oral mucosa cells were stained with Giemsa for cytogenetic analysis. The total numbers of nuclear abnormalities (CG = 27.16 ± 14.32, SG = 118.23 ± 74.78, PG = 184.23 ± 52.31, and SPG = 191.53 ± 66.94) and micronuclei (CG = 1.46 ± 1.40, SG = 12.20 ± 10.79, PG = 21.60 ± 8.24, and SPG = 20.26 ± 12.76) were higher (p < 0.05) in the three exposed groups compared to the GC. In this study, we considered several different classification algorithms (the artificial neural network, K-nearest neighbors, support vector machine, and optimum path forest). All of the algorithms displayed good classification (accuracy > 80%) when using dataset2 (without the redundant exposure type SPG). It is clear that the data form a robust pattern and that classifiers could be successfully trained on small datasets from the exposure groups. In conclusion, exposing agricultural workers to pesticides and/or tobacco had genotoxic potential, but concomitant exposure to xenobiotics did not lead to additive or potentiating effects.

The cost of reproduction in women: Reproductive effort and oxidative stress in premenopausal and postmenopausal American women

OBJECTIVES

Life history theory predicts a trade-off between female investment in reproduction and somatic maintenance, which can result in accelerated senescence. Oxidative stress has been shown to be a causal physiological mechanism for accelerated aging and a possible contributor to this trade-off. We aimed to test the hypothesis for the existence of significant associations between measures of reproductive effort and the level of oxidative stress biomarkers in premenopausal and postmenopausal American women.

METHODS

Serum samples and questionnaire data were collected from 63 premenopausal and postmenopausal women (mean age 53.4 years), controls in the Connecticut Thyroid Health Study, between May 2010 and December 2013. Samples were analyzed for levels of 8-OHdG and Cu/Zn-SOD using immunoassay method.

RESULTS

Levels of oxidative damage (8-OHdG) but not oxidative defense (Cu/Zn-SOD) were negatively associated with parity and number of sons in premenopausal women (r = -0.52 for parity, r = -0.52 for number of sons, P < .01). Together, measures of reproductive effort, women's BMI, age, and menopausal status explained around 15% of variance in level of 8-OHdG. No association between reproductive effort characteristics and oxidative damage was found for postmenopausal women.

CONCLUSIONS

We found no evidence of a trade-off between somatic maintenance as measured by 8-OHdG and reproductive effort in women from this American population. On the contrary, higher gravidity and parity in premenopausal women was associated with lower damage to cellular DNA caused by oxidative stress. These results highlight the importance of population variation and environmental conditions when testing the occurrence of life-history trade-offs.