Exposure to endocrine disruptors and alterations in mineralized tissues: a narrative review / Exposición a disruptores endocrinos y alteraciones en tejidos mineralizados: revisión narrativa

Background: Endocrine Disrupting Chemicals (EDCs) would cause alterations in organs/systems of exposed individuals or their progeny. Objetive: To identify and analyze the main published findings on the effects of exposure to EDCs on teeth, cartilage, and bone. Material and Methods: Two databases were analyzed: Medline and Web of Science. Only observational studies analyzing the effect of EDCs on mineralized tissues published since 2006 were included in the study. Results: 25 articles were selected, most of them involving EDCs pesticides, plasticizers, or personal care products, highlighting organochlorine compounds, bisphenols, phthalates, dioxins, parabens, and perfluoroalkyls. Thirty-six per cent of the studies reported an accumulation of EDCs in teeth or bones, while 64% reported alterations in their development or morphology, mainly at the bone level, primarily affecting their mineral density and size, as well as that of the bones of exposed individuals or their progeny. The type of effect observed was related to the EDCs analyzed, and it seemed to depend on variables such as age, sex, ethnicity/race, and even the metabolic status of the individuals in the different species analyzed. No evidence associated with effects on cartilage was found. Conclusion: EDCs in the environment, at work, or at home, under different exposure routes, are capable of accumulating in teeth and bone, particularly affecting the latter. It is necessary to study the effect of EDCs on mineralized tissues in agro-industrial areas, especially on teeth.

Antecedentes: Los Químicos Disruptores Endocrinos (EDCs) causarían alteraciones en órganos/sistemas de individuos expuestos, o su progenie. Objetivo: Identificar y analizar los principales hallazgos publicados sobre el efecto de la exposición a EDCs en dientes, cartílago y hueso. Material y Métodos: Se analizaron dos bases de datos: Medline y Web of Science, incluyendo solo estudios observacionales publicados desde el 2006, analizando el efecto de los EDCs sobre tejidos mineralizados. Resultados:25 artículos fueron seleccionados, siendo la mayoría de los EDCs pesticidas, plastificantes o productos de cuidado personal, destacando los compuestos Organo-clorados, Bisfenoles, Ftalatos, Dioxinas, Parabenos y los Perfluoroalquilos. Un 36% de los estudios reportaron un acúmulo de EDCs en dientes o huesos, mientras que un 64% informaron de alteraciones en su desarrollo o morfología, particularmente a nivel de huesos, afectando principalmente su densidad mineral y su tamaño, así como el de los individuos expuestos o su progenie. El tipo de efecto observado tuvo relación con el EDCs analizado, pareciendo depender de variables tales como edad, sexo, etnia/raza e incluso el estado metabólico de los individuos, en las diferentes especies analizadas. No se encontraron evidencias asociadas a efectos en el cartílago. Conclusión: Los EDCs en el medio ambiente, ámbito laboral o doméstico, bajo distintas rutas de exposición, son capaces de acumularse en diente y hueso, afectando particularmente a este último. Es necesario estudiar el efecto de los EDCs en los tejidos mineralizados en zonas agroindustriales, particularmente a nivel de dientes.

The effect of Endocrine disrupting chemicals on myocardial fibrosis and related mechanism / 中华劳动卫生职业病杂志

Endocrine-disrupting chemicals (EDCs) an exogenous agent that interferes with the synthesis, secretion, transport, binding, action, or can mimic the occurrence of natural hormones that damage for the balance of homeostasis. Exposure to EDCs results in damage to human health that may persist in the long term. In recent years, accumulative evidence has demonstrated that EDCs also play a pivotal role in the onset and development of myocardial fibrosis, including heart failure, hypertension and vascular stiffening. Studies indicate that EDCs plays the negative effects of the cardiovascular system, however, EDCs-induced toxicity on heart remains unclear. This review summarized EDCs-induced myocardial fibrosis, and discuss the possible mechanisms of myocardial fibrosis induced by EDCs. This paper could provide further understandings for prevention, diagnosis and treatment of myocardial fibrosis.

Disruptores endócrinos: interações com o meio ambiente e puberdade / Endocrine disruptors: interactions with the environment and puberty

Este estudo tem como objetivo apresentar substâncias conhecidas como disruptores endócrinos e suas possíveis interferências no desenvolvimento puberal das meninas. Trata-se de uma revisão da literatura feita a partir do levantamento e análise de 37 referências bibliográficas nas quais os autores chamam a atenção para as diversas formas de absorção de produtos ricos em componentes desequilibradores hormonais que, por ação conjunta e prolongada, interferem no sistema endócrino, promovendo antecipação no desenvolvimento dos caracteres sexuais secundários. Concluiu-se que a exposição a inúmeros agentes disruptores presentes no dia a dia das meninas, por ação prolongada e acumulativa, pode promover uma antecipação na maturação dos caracteres sexuais secundários.(AU)

This study aims to present substances known as endocrine disruptors and theirpossible interference in girls puberal development. This is a systematic review of the literaturebased on the survey and analysis of 37 bibliographical references in which the authors drawattention to the multiple ways of absorption of products rich in hormonal imbalancecomponents that by combined and prolonged action, interfere in the endocrine system, promoting anticipation in the development of secondary sexual characteristics. In conclusion, the exposure to numerous disrupting agents present in the daily lives of girls, by prolonged andcumulative action, can promote an anticipation in the maturation of secondary sexual characteristics.(AU)

Chronic exposure of bisphenol S (BPS) affect hypothalamic-pituitary-testicular activities in adult male rats: possible in estrogenic mode of action

BACKGROUND@#The industrial revolution has resulted in increased synthesis and the introduction of a variety of compounds into the environment and their potentially hazardous effects have been observed in the biota. The present study was aimed to evaluate the potential endocrine-disrupting effects of chronic exposure to the low concentrations of bisphenol S (BPS) in male rats.@*METHODS@#Weaning male Sprague-Dawley rats (22 days old) were either exposed to water containing 0.1% ethanol for control or different concentrations of BPS (0.5, 5, and 50 μg/L) in drinking water for 48 weeks in the chronic exposure study. After completion of the experimental period, animals were dissected and different parameters (hormone concentrations, histology of testis and epididymis, oxidative stress and level of antioxidant enzymes in the testis, daily sperm production (DSP), and sperm parameters) were determined.@*RESULTS@#Results of the present study showed a significant alteration in the gonadosomatic index (GSI) and relative reproductive organ weights. Oxidative stress in the testis was significantly elevated while sperm motility, daily sperm production, and the number of sperm in epididymis were reduced. Plasma testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) concentrations were reduced and estradiol levels were high in the 50 μg/L-exposed group. Histological observations involved a significant reduction in the epithelial height of the testis along with disrupted spermatogenesis, an empty lumen of the seminiferous tubules, and the caput region of the epididymis.@*CONCLUSION@#These results suggest that exposure to 5 and 50 μg/L of BPS for the chronic duration started from an early age can induce structural changes in testicular tissue architecture and endocrine alterations in the male reproductive system which may lead to infertility in males.

Challenges to regulate products containing bisphenol A: Implications for policy / Desafíos para regular los productos que contienen bisfenol A: implicaciones para la política

Abstract: Bisphenol A (BPA), found in plastics and epoxy resins, is one of the most studied chemicals. BPA is regarded as an endocrine disruptor and has been related to adverse health effects in humans. However, some regulatory agencies around the world have concluded that BPA is safe at current human exposure levels. As the scientific community attempts to settle the debate on BPA's health effects, regulatory agencies have been put into a challenging public health policy situation. The United States has implemented no regulatory actions due to safety concerns, while Europe has used the precautionary principle to guide its regulation in the face of scientific uncertainty. In this paper, we explore the debate surrounding BPA regulation and the possibility for countries to introduce guidelines, using Mexico as an example. Policy change determinants analysis suggest that countries can and should impose regulations on BPA.

Resumen: El bisfenol A (BPA), presente en plásticos y resinas epoxi, es uno de los químicos más estudiados. Se considera un disruptor endocrino y se ha relacionado con efectos adversos para la salud humana. Algunas agencias regulatorias en el mundo han concluido que el BPA es seguro a los niveles de exposición humana actuales. Mientas la comunidad científica intenta resolver el debate sobre dichos efectos, las agencias regulatorias enfrentan una difícil situación de política pública. Los Estados Unidos de América no han implementado acciones reglamentarias por razones precautorias, mientras que Europa ha utilizado el principio precautorio para guiar su regulación ante la incertidumbre científica. En este documento exploramos el debate que rodea la regulación del BPA y la posibilidad de que los países introduzcan directrices, usando a México como ejemplo. El análisis de los determinantes del cambio de políticas sugiere que los países pueden y deben regular el BPA.

Impacto na saúde humana de disruptores endócrinos presentes em corpos hídricos: existe associação com a obesidade? / Impact on human health of endocrine disruptors present in environmental water bodies: is there an association with obesity?

Resumo Há evidências crescentes de que os desreguladores endócrinos (DE) podem afetar negativamente os seres humanos. Águas superficiais e subterrâneas são as principais fontes de obter a sua potabilidade, no entanto, podem ser contaminadas por DE, que não são totalmente removidos pelos processos convencionais de tratamento de água e esgoto. Alguns problemas de saúde estão relacionados à exposição dos seres humanos aos DE, sendo a obesidade um deles. Atualmente vive-se um aumento da prevalência da obesidade em todo o mundo, fato considerado preocupante, tendo em vista seu potencial impacto no sistema de saúde, pois, as principais doenças crônicas como diabetes e doenças cardiovasculares, têm a obesidade como grande fator de risco. Por meio de revisão de literatura, este artigo buscou reunir publicações científicas relacionando a exposição aos DE com a obesidade, com o objetivo de verificar a importância de sua remoção dos corpos hídricos, preservando a saúde da população e da biota aquática. A maioria dos estudos selecionados sugere associação entre DE e obesidade em humanos.

Abstract There is growing evidence that endocrine disruptors (ED) may adversely affect humans. Surface and underground water are the main sources for obtaining potable water, however they can be contaminated with ED, which are not completely removed by conventional water and sewage treatment processes. Some health problems are related to the exposure of humans to ED, obesity being one of them. There is currently an increase in the prevalence of obesity worldwide, a fact that is considered a concern in view of its potential impact on the health care system, since obesity is the major risk factor of the leading chronic diseases including diabetes and cardiovascular disease. By means of a review of the literature, this paper sought to gather scientific publications linking exposure to ED with obesity, in order to verify the importance of removal of ED from water bodies, thereby preserving the population’s health and aquatic biota. Most of the selected studies suggest an association between ED and obesity in humans.

El organofosforado clorpirifos como disruptor estrogénico y factor de riesgo para el cáncer de mama / The organophosphorus chlorpyrifos as endocrine disruptor and breast cancer factor risk

El clorpirifos (CPF) es un insecticida de amplio espectro que se utiliza en Argentina y en otros países de Latinoamérica. Se emplea para el control de plagas en la producción de frutas, hortalizas, cereales y plantas ornamentales. El principal mecanismo de acción descripto para este insecticida es la inhibición de la acetilcolinesterasa. Sin embargo, reportes más recientes sugieren múltiples efectos del plaguicida independientes de la inhibición de esa enzima. El objetivo de este trabajo es transmitir a la comunidad los resultados de nuestras investigaciones obtenidos utilizando diferentes dosis de CPF en distintos modelos experimentales, tanto in vitro como in vivo. En relación a esto, hemos evidenciado una acción del CPF sobre el sistema redox celular que conduce al incremento de especies reactivas del oxígeno y consecuentemente a la activación de diferentes vías de señalización. Además, hemos determinado que el insecticida CPF puede comportarse como un disruptor endócrino modulando la acción de los estrógenos y alterando la normal estructura del tejido mamario. Nuestros resultados alertan sobre el impacto que este compuesto podría tener sobre la salud, sugiriendo la necesidad de revisar su uso dado que manifiesta acciones a dosis encontradas en el ambiente.

Chlorpyrifos (CPF) is a broad spectrum insecticide used in Argentina and other Latin American countries. It is commonly used for pest control in the production of fruits, vegetables, cereals and ornamental plants. The main mechanism of action described for this insecticide is the inhibition of acetylcholinesterase activity. However, more recent reports suggest multiple effects for this pesticide in an independent way from the inhibition of this enzyme. The objective of this work is to convey to the community the results of our investigations obtained using different doses of CPF in various experimental models, both in vitro and in vivo. In this connection, we have shown a CPF action on the cellular redox system which leads to increased reactive oxygen species and the consequent activation of different signaling pathways. In addition, we have determined that the insecticide CPF acts as an endocrine disruptor modulating the action of estrogen and altering the normal structure of breast tissue. Our findings warn about the impact that this compound might have on health, suggesting the need to review its use since adverse actions were found at environmentally relevant doses.

Effects of endocrine disruptors in the development of the female reproductive tract / Efeitos dos desreguladores endócrinos no desenvolvimento do trato reprodutivo feminino

Environmental agencies have identified a growing number of environmental contaminants that have endocrine disrupting activity, and these can become a major public health problem. It is suggested that endocrine disruptors could account for the higher-than-expected increase in the prevalence of some non-communicable diseases, such as obesity, diabetes, thyroid diseases, and some cancers. Several endocrine Disrupting Chemicals (EDCs), such as pesticides, bisphenol A, phthalates, dioxins, and phytoestrogens, can interact with the female reproductive system and lead to endocrine disruption. Initially, it was assumed that EDCs exert their effects by binding to hormone receptors and transcription factors, but it is currently known that they may also alter the expression of enzymes involved in the synthesis or catabolism of steroids. Biomonitoring studies have identified these compounds in adults, children, pregnant women, and fetuses. Among the diseases of the female reproductive tract associated with EDCs exposure are the following: precocious puberty, polycystic ovary syndrome, and premature ovarian failure. The different populations of the world are exposed to a great number of chemicals through different routes of infection; despite the various available studies, there is still much doubt regarding the additive effect of a mixture of EDCs with similar mechanisms of action.

As diversas agências de controle ambiental têm identificado um crescente número de contaminantes ambientais que apresentam atividade de desregulador endócrino e estes poderão se tornar um dos maiores problemas de saúde pública. Sugere-se que os Desreguladores Endócrinos (EDCs) poderiam justificar o aumento na prevalência de algumas doenças não transmissíveis acima do esperado, como, por exemplo, obesidade, diabetes, doenças tireoidianas e alguns tipos de cânceres. Vários EDCs, como pesticidas, bisfenol A, ftalatos, dioxinas e fitoestrógenos, podem interagir com o sistema reprodutivo feminino e levar à desregulação endócrina. Inicialmente, supunha-se que os EDCs exercessem seus efeitos através da ligação com receptores hormonais e fatores de transcrição, mas, atualmente, sabe-se que também podem alterar a expressão de enzimas envolvidas na síntese ou no catabolismo dos esteroides. Estudos de biomonitoramento têm identificado esses compostos em adultos, crianças, gestantes e em fetos. Entre as patologias do trato reprodutor feminino associadas à exposição aos EDCs, destacam-se: puberdade precoce, síndrome dos ovários policísticos e falência ovariana prematura. As diversas populações estão expostas a um grande número de substâncias químicas, através de diferentes vias de contaminação. Apesar dos diferentes estudos disponíveis, ainda permanece uma grande dúvida sobre o efeito aditivo de uma mistura de EDCs com similar mecanismo de ação.

Disruption of reproductive development in male rat offspring following gestational and lactational exposure to di-(2-ethylhexyl) phthalate and genistein

Studies of developmental effects of mixtures of endocrine disrupters on the male reproductive system are of great concern. In this study, the reproductive effects of the co-administration of di-2-(ethylhexyl) phthalate (DEHP) and genistein (GEN) during pregnancy and lactation were studied in male rat offspring. Pregnant Sprague-Dawley rats were gavaged from gestation day 3 to postnatal day 21 with vehicle control, DEHP 250 mg/kg body weight (bwyday, GEN 50 mg/kg bwday, GEN 400 mg/kg bwday, and two combinations of the two compounds (DEHP 250 mg/kg bwday + GEN 50 mg/kg bwday, DEHP 250 mg/kg bwday + GEN 400 mg/kg bwday). The outcomes studied were general morphometry (weight, AGD), testicular histology, testosterone levels, and expression at the mRNA level of genes involved in steroidogenesis. Organ coefficient, AGD / body weight1/3 י, serum testosterone concentration and genes involved in steroidogenic pathway expression when exposed to DEHP (250mg/kg bwday), GEN(50mg/kg bwday) or GEN(400mg/kg bwday) alone were not significantly different from the control group. When exposed to (DEHP 250mg/kg bwday +GEN 50mg/kg bwday) together during pregnancy and lactation, serum testosterone concentration, epididymis coefficient and Cypal17a1,Scarb1 m RNA expression significantly decreased compared to the control and GEN(50mg/kg bwday). When exposed to (DEHP 250mg/kg bwday +GEN 400mg/kg bwday) together during pregnancy and lactation, AGD / body weight1/3 י, serum testosterone concentration, testis and epididymis coefficient and Star, Cypal17a1 mRNA expression appeared significantly decreased compared to the control and DEHP/GEN single exposure, together with developmental impairment of seminiferous tubules and seminiferous epithelium. Overall, co-administration of DEHP and GEN during gestation and lactation seem to acts in a cumulative manner to induce the most significant alterations in the neonate, especially with GEN at high dose, although the effect of the DEHP-GEN mixture on adult offspring should be observed further.

Contribution of environmental pollutants to male infertily: A working model of germ cell apoptosis induced by plasticizers

Bisphenol A [2,2-bis(4-hydroxyphenyl)propane] (BPA), 4-nonylphenol (NP) and di(2-ethylhexyl)phthalate (DEHP), and its metabolite mono-2-ethylhexyl phthalate (MEHP) are chemicals found in plastics, which act as endocrine disruptors (EDs) in animals, including human. EDs act like hormones in the endocrine system, and disrupt the physiologic function of endogenous hormones. Most people are exposed to different endocrine disruptors and concern has been raised about their true effect on reproductive organs. In the testis, they seem to preferentially attack developing testis during puberty rather than adult organs. However, the lack of information about the molecular mechanism, and the apparently controversial effect observed in different models has hampered the understanding of their effects on mammalian spermatogenesis. In this review, we critically discuss the available information regarding the effect of BPA, NP and DEHP/ MEHP upon mammalian spermatogenesis, a major target of EDs. Germ cell sloughing, disruption of the blood-testis-barrier and germ cell apoptosis are the most common effects reported in the available literature. We propose a model at the molecular level to explain the effects at the cellular level, mainly focused on germ cell apoptosis.

Contaminantes ambientais e os interferentes endócrinos / Environmental contaminants and endocrine disruptors

A toxicidade de diversos poluentes ambientais em seres humanos e demais espécies tem sido habitualmente investigada quanto aos seus efeitos teratogênicos e cancerígenos. Nas últimas décadas, muitos contaminantes têm demonstrado efeitos adversos sobre o sistema endócrino. Atualmente, cerca de onze milhões de substâncias químicas são conhecidas em todo mundo, sendo três mil delas produzidas em larga escala. Numerosos compostos químicos de uso doméstico, industrial e agrícola possuem comprovada atividade hormonal. Entre os produtos químicos com atividade estrogênica, destacam-se hormônios presentes em cosméticos, anabolizantes utilizados em rações animais, fitoestrógenos e poluentes orgânicos persistentes (POPs). Esses agentes que estão presentes nos efluentes industriais, residenciais e das estações de tratamento de água e esgoto representam uma importante fonte de contaminação ambiental. O Programa Internacional de Segurança Química (International Programme on Chemical Safety - IPCS) define como interferente endócrino substâncias ou misturas presentes no ambiente capazes de interferir nas funções do sistema endócrino, causando efeitos adversos em um organismo intacto ou na sua prole. No presente artigo, os autores apresentam uma revisão da literatura atual sobre o papel desses elementos nas doenças endócrinas e metabólicas, os prováveis mecanismos de ação envolvidos, discutindo-se perspectivas futuras em termos de investigação e estratégias para prevenção e redução dos seus possíveis danos.

The toxicity of various pollutants has been routinely investigated according to their teratogenic and carcinogenic effects. In the last few decades, however, many of such pollutants have been shown to adversely affect the endocrine system of human beings and other species. Currently, more than eleven million chemical substances are known in the world, and approximately 3,000 are produced on a large scale. Numerous chemical composites of domestic, industrial and agricultural use have been shown to influence hormonal activity. Examples of such chemical products with estrogenic activity are substances used in cosmetics, anabolizing substances for animal feeding, phytoestrogens and persistent organic pollutants (POPs). These agents are seen in residential, industrial and urban sewerage system effluents and represent an important source of environmental contamination. The International Programme on Chemical Safety (IPCS) defines as endocrine disruptors substances or mixtures seen in the environment capable of interfering with endocrine system functions resulting in adverse effects in an intact organism or its offspring. In this article the authors present a current literature review about the role of these pollutants in endocrine and metabolic diseases, probable mechanisms of action, and suggest paths of investigation and possible strategies for prevention and reduction of its possible damages.

[ effects of trifluralin on LH, FSH, and testosterone levels and testis histological changes in adult rats]

Trifluralin is a dinitroaniline herbicide and is used for controlling of annual grasses and broadleaf weeds in agriculture. It enters into the plants through developing roots and stops plant cells from dividing and elongation [meristemic inhibitor]. According to entrance of this herbicide into the body via fresh vegetables, in this research the effects of trifluralin on reproductive parameters of the male wistar rats including serum LH, FSH, testosterone, and changes in testicular tissue and body weight were investigated. In this experimental study, forty male wistar rats with weight of 250 +/- 5g were randomly divided in 5 groups, including control, sham [received normal saline as a solvent], and three experimental groups receiving 500, 1000 and 2000 mg/kg oral trifluralin, respectively. It was administered orally once a day for 16 days. After 16 days, body and testis weight were measured and blood samples were taken from heart and used for measurement of LH, FSH and testosterone levels. To evaluate histological changes, testes were removed and weighed and, after obtaining tissue section, stained by Hematoxilin-Eosine. Serum testosterone, FSH, and LH levels showed significant decrease in experimental groups [p<0.001, p<0.05]. There was significant decrease in the number of germinal and somatic cells in testis in experimental groups [p<0.05]. There was also a significant decrease in body and testis weight, and concentration of sperms in experimental groups [p<0.05]. Oral administration of trifluralin could decrease gonadotropins and testosterone levels and impair steroidogenesis and spermatogenesis by oxidative stress and production of free radicals

Consumo de agrotóxicos e distribuição temporal da proporção de nascimentos masculinos no Estado do Paraná, Brasil / Agricultural toxic use and temporal distribution of male birth rate in the state of Paraná, Brazil

OBJETIVO: Investigar a tendência temporal da proporção de nascimentos masculinos para o Estado do Paraná no período entre 1994 e 2004 e a correlação dessa tendência com o volume de vendas de agrotóxicos no Estado em 1985. MÉTODO: No presente estudo ecológico, foram empregados como fontes de dados o Instituto Brasileiro de Geografia e Estatística (volume de vendas de agrotóxicos) e o banco DATASUS (nascidos vivos segundo o sexo). Foram analisados 308 municípios, divididos em quartis conforme o consumo de agrotóxicos, resultando em quatro estratos contendo 77 municípios cada um, sendo o quarto quartil o de maior consumo. A proporção de nascimentos masculinos foi obtida ano a ano para cada município e, ao final do período (1994 a 2004), um valor mediano foi calculado para cada uma das localidades. Foi realizada uma análise bivariada e calculados os coeficientes de Pearson para cada quartil de municípios. Uma análise exploratória e comparativa dos quartis foi realizada, na qual se calculou o consumo médio per capita para os mesmos. Posteriormente, foram selecionados e analisados individualmente 10 municípios com intensa atividade agropecuária quanto ao perfil agrícola e à tendência da proporção de nascimentos masculinos ao longo do período de estudo. RESULTADOS: Foi observada uma discreta tendência de declínio na proporção de nascidos vivos do sexo masculino para o Estado como um todo. A magnitude desse declínio foi visivelmente maior quando se analisou individualmente o grupo de 10 municípios, cujos valores observados ao final da série mostraram-se muito abaixo daqueles normalmente descritos na literatura (proporção de nascimentos masculinos < 50 por cento). Em relação aos quartis, todos apresentaram correlação negativa, ainda que sem significância estatística. CONCLUSÕES: A tendência de declínio estatisticamente significativa na proporção de nascimentos masculinos em alguns municípios paranaenses sugere que o fenômeno possa ser decorrente da alta exposição ambiental aos agrotóxicos nessas localidades. Sendo assim, recomendam-se estudos futuros que visem a esclarecer e a dimensionar a força do impacto da contaminação ambiental por agrotóxicos na saúde reprodutiva, representada aqui pela razão de sexos ao nascimento.

OBJECTIVE: To determine the trend in male birth rates from 1994-2004 in the state of Paraná, Brazil, and whether a correlation exists between this trend and the state's agricultural toxic sales in 1985. METHOD: This ecological study employed data from the Brazilian Institute for Geography and Statistics (agricultural toxic sales) and the Unified Health System's data-base "DATASUS" (sex ratio at birth). Three hundred and eight (308) municipalities were analyzed, divided into quartiles by pesticide usage. Each of the four resulting quartiles included 77 municipalities, with the fourth quartile representing the highest consumption. The male birth rate was obtained for each year for each municipality. Then the median rate was calculated for the entire period (1994-2004) for each municipality. A bivariate analysis was carried out. Pearson coefficients were calculated for each quartile. An exploratory and comparative analysis of quartiles was performed, and the mean per capita consumption was calculated for each quartile. Ten municipalities with intense agricultural activity were then selected and analyzed individually in terms of their agricultural profile and male birth rate trend during the study period. RESULTS: A discrete decline was observed in the rate of live male births for the entire state. The magnitude of this decline was more evident when the group of 10 municipalities was analyzed: in this group, the rates observed at the end of the study period were much lower than those usually described in the literature (male birth rate < 50 percent). Pearson's correlation was negative for all quartiles, although without statistical significance. CONCLUSIONS: The statistically significant trend towards a decline in male births in some of the Paraná municipalities suggests that this phenomenon may be a result of a high level of environmental exposure to pesticides. Future studies should confirm and measure the impact of environmental pesticide contamination on reproductive health, expressed in this study as sex ratio at birth.