RESUMEN

The ability of organophosphate pesticides to disturb immune function has been demonstrated by in vivo and in vitro studies, but evidence of such effects on humans remains scarce. To assess the association between organophosphate pesticides exposure and cytokine levels in Mexican flower workers, a cross-sectional study was carried out. A questionnaire was provided to 121 male flower workers, and urine and blood samples were collected. Using gas chromatography, urinary concentrations of dialkylphosphate metabolites were determined. The serum cytokine levels, IL-4, IL-5, IL-6, IL-8, and IL-10, were measured using multiplex analysis, and levels of INF-γ and TNF-α by ELISA. We found that a higher dialkylphosphate concentration decreased the pro-inflammatory cytokines INF-γ (ß = -0.63; 95 % CI: -1.22, -0.05), TNF-α (ß= -1.18; 95 % CI: -2.38, 0.02), and IL-6 (ß= -0.59; 95 % CI: -1.29, 0.12), and increased IL-10 (ß=0.56; 95 % CI: 0.02, 1.09), the main anti-inflammatory cytokine, suggesting an imbalance of the immune response in flower workers.

Asunto(s)

Citocinas , Exposición Profesional , Plaguicidas , Humanos , México , Masculino , Exposición Profesional/análisis , Adulto , Citocinas/sangre , Plaguicidas/orina , Plaguicidas/sangre , Plaguicidas/toxicidad , Persona de Mediana Edad , Estudios Transversales , Flores , Adulto Joven , Compuestos Organofosforados/orina , Organofosfatos/orina , Organofosfatos/sangre

RESUMEN

OBJECTIVE: Occupational exposure to pesticides is a known risk for disrupting cellular immune response in flower workers due to their use of multiple chemical products, poor work conditions, and inadequate protection. Recently, the analysis of pesticide use patterns has emerged as an alternative to studying exposure to mixtures of these products. This study aimed to evaluate the association between exposure to different patterns of pesticide use and the cytokine profile of flower workers in the State of Mexico and Morelos, Mexico. METHODS: A cross-sectional study was carried out on a population of 108 flower workers. Serum levels of IL-4, IL-5, IL-6, IL-8, IL-10 cytokines were analyzed by means of multiplex analysis, and TNF-α and IFN-γ using an ELISA test. Pesticide use patterns were generated by principal components analysis. RESULTS: The analysis revealed that certain patterns of pesticide use, combining insecticides and fungicides, were associated with higher levels of pro-inflammatory cytokines, particularly IL-6 and IFN-γ. CONCLUSION: These findings indicate that pesticides may possess immunotoxic properties, contributing to increased inflammatory response. However, further comprehensive epidemiological studies are needed to establish a causal relationship.

Asunto(s)

Exposición Profesional , Plaguicidas , Humanos , Plaguicidas/toxicidad , Citocinas , Estudios Transversales , México/epidemiología , Interleucina-6 , Exposición Profesional/efectos adversos , Exposición Profesional/análisis , Flores/química

RESUMEN

MTHFR is a key enzyme in folate metabolism. Some genetic polymorphisms code for a less efficient enzyme, increasing serum concentrations of homocysteine. This has been associated with inadequate feto-maternal circulation and increased risk of spontaneous abortion. Paroxonase 1 (PON1) is a multifunctional enzyme that can detoxify homocysteine through its homocysteine thiolactonase activity. We evaluate the association between MTHFR 677 C>T polymorphisms and non-recurrent spontaneous abortion and its interaction with PON1 polymorphisms involved in homocysteine metabolism in women living in floricultural areas in Mexico. Sociodemographic, reproductive history, folic acid consumption during pregnancy and environmental exposure data of 264 women who had been pregnant sometime during the 10 years prior to study enrolment were collected. MTHFR 677 C>T, PON1 192Q>R and PON1 55L>M genotypes were determined by PCR amplification. Information on pregnancy outcome and maternal genotypes was obtained for 484 pregnancies: 34 non-recurrent spontaneous abortions (gestational age < 20 weeks) and 450 controls. GEE models were used to evaluate the association between MTHFR polymorphism and non-recurrent spontaneous abortion, and its interaction with PON1 polymorphisms. After adjusting for potential confounders, no significant association was found between the MTHFR 677 C>T maternal polymorphism and non-recurrent spontaneous abortion (OR CT vs CC= 0.39, 95% CI: 0.14-1.05; OR TT vs CC = 0.63, 95% CI: 1.22-1.80). No interactions with PON1 192Q>R or PON1 55L>M polymorphisms were identified (p for interaction = 0.88 and 0.41, respectively). PON1 55L>M maternal polymorphism was associated with higher risk of spontaneous abortion (OR LM/MM vs LL = 4.14, 95% CI: 1.49-11.54). Our results do not demonstrate an interaction between the MTHFR 677 C>T and PON1 192Q>R or PON1 55L>M maternal polymorphisms neither an independent association of MTHFR 677 C>T polymorphism with non-recurrent spontaneous abortion, whereas PON1 55LM/MM maternal genotype increase the odds of this event.

Asunto(s)

Aborto Espontáneo/genética , Arildialquilfosfatasa/genética , Metilenotetrahidrofolato Reductasa (NADPH2)/genética , Polimorfismo de Nucleótido Simple , Aborto Espontáneo/epidemiología , Adolescente , Adulto , Estudios de Casos y Controles , Estudios Transversales , Femenino , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Humanos , México/epidemiología , Embarazo , Adulto Joven

RESUMEN

Background Flower growers have high potential for exposures to pesticides. Occupational factors, such as tasks performed, the production method (organic or conventional), the use of personal protective equipment (PPE), and workplace characteristics influence the intensity of pesticide exposure. Objective To evaluate occupational characteristics affecting urinary concentration of dialkylphosphate (DAP) metabolites of organophosphate pesticides among a group of Mexican floricultural workers. Methods A questionnaire was administered to 117 workers who also provided a first morning urine sample. According to tasks performed and the production methods, pesticide contact was defined as low, medium, or high. PPE use was categorized as acceptable, fairly acceptable, and unacceptable. Urinary concentration of DAP metabolites were determined using gas-liquid chromatography. Association between occupational characteristics and DAP urinary concentrations was assessed by means of linear regression models. Results After adjusting for potential confounders, the workers in the medium and high contact categories had significantly higher DAP concentrations than those in the low contact category (ß: 0.3, CI 95%: 0.1-0.5). Greenhouse workers had greater DAP concentrations than outdoors workers (ß: 0.3, CI 95%: 0.1-0.5). Compared with non-acceptable use of PPE, acceptable use of PPE was associated with lower DAP concentrations (ß: -0.4, CI 95% -0.6 to -0.1). Conclusion Improved safety training is needed for correct PPE usage, especially among flower growers who use conventional pest control methods and who work in a greenhouse environment.

Asunto(s)

Agricultura , Exposición Profesional , Organofosfatos/orina , Adulto , Estudios Transversales , Flores/crecimiento & desarrollo , Humanos , Masculino , México , Persona de Mediana Edad , Factores Socioeconómicos , Adulto Joven

RESUMEN

Several studies have suggested that exposure to DDT may be related to changes in thyroid hormone levels in animals and humans, even though results across studies are inconsistent. The aim of this study was to assess the association between exposure to p,p'-DDE (a stable metabolite of DDT) and serum levels of thyroid hormones in floriculture workers. A longitudinal study was conducted on 136 male subjects from the States of Mexico and Morelos, Mexico, who were occupationally exposed to pesticides, during agricultural periods of high (rainy season) and low (dry season) levels of pesticide application. Using a structured questionnaire, a survey was carried out on socio-demographic characteristics, anthropometry, clinical history, alcohol and tobacco consumption, residential chemical exposure, and occupational history. Blood and urine samples were collected to determine serum levels of TSH, total T3, total T4, and p,p'-DDE, and metabolites of organophosphate pesticides (OP), respectively. The analysis of the associations between p,p'-DDE levels and thyroid hormone profile adjusting by potential confounding variables including urinary OP metabolites was carried out using multivariate generalized estimating equation (GEE) models. Our results showed that the geometric means of p,p'-DDE levels were 6.17 ng/ml and 4.71 ng/ml in the rainy and dry seasons, respectively. We observed positive associations between the serum levels of p,p'-DDE and those of total T3 (ß=0.01, 95% CI: -0.009, 0.03), and total T4 (ß=0.08, 95% CI:0.03, 0.14) and negative but no significant changes in TSH in male floricultural workers, supporting the hypothesis that acts as thyroid disruptor in humans.

Asunto(s)

Disruptores Endocrinos/sangre , Contaminantes Ambientales/sangre , Hidrocarburos Clorados/sangre , Plaguicidas/sangre , Hormonas Tiroideas/sangre , Adulto , Agricultura , Contaminantes Ambientales/orina , Flores , Humanos , Hidrocarburos Clorados/orina , Masculino , México , Persona de Mediana Edad , Exposición Profesional , Organofosfatos , Plaguicidas/orina , Adulto Joven

RESUMEN

BACKGROUND: Placental oxidative stress has been involved in the pathogenesis of certain reproductive adverse effects, including miscarriage. Paraxonase 1 (PON1) is a high-density lipoprotein(HDL)-linked enzyme that prevents oxidation of low-density lipoproteins (LDL) and is involved in detoxification from organophosphate pesticides. OBJECTIVE: To assess the association between maternal PON1 polymorphisms (PON1192Q/R, PON155 L/M y PON1-108C/T) and the risk of miscarriage in women chronically exposed to organophosphate pesticides in Mexico. METHODS: In a cross-sectional study, socio-demographic data, reproductive history data, environmental exposures, and other variables of concern were collected by means of a questionnaire from 264 women (floriculturists and wives of floriculturists) who had been pregnant sometime during the 10 years preceding the study. Blood samples were also collected from them. PON1192 and PON155 genotypes were determined by PCR amplification, and PON1-108 genotypes, by a TaqMan real-time polymerase chain reaction assay. Complete information regarding the results of pregnancy and maternal genotype tests was obtained for 514 pregnancies (35 miscarriages and 479 controls). The association between PON1 genotypes and miscarriage was evaluate through GEE models. RESULTS: The risk of miscarriage by mothers with PON1192RR genotype was 2.2 higher than by mothers with PON1192QR/PON1192QQ genotype (95% CI 0.93-5.17). The risk was close to 4 times higher in mothers with PON155MM/PON155LM genotype than in mothers with PON155LL genotype (OR=3.9; 95% CI 1.38-11.0). No significant differences were found in risk of miscarriage based on the maternal PON1-108C/T genotype. No evidence was found of an interaction between the various PON1 genotypes and the mothers' floricultural activity during pregnancy. CONCLUSIONS: This study suggests that there is an effect of genetic maternal PON1 polymorphisms on miscarriage and provides additional evidence that combines with the growing information about the ways in which certain PON1 genotypes can affect the development of the fetus in utero.

Asunto(s)

Aborto Espontáneo , Arildialquilfosfatasa/genética , Plaguicidas/toxicidad , Polimorfismo Genético , Femenino , Humanos , México

RESUMEN

The knowledge about the effect of cigarette smoking on the male reproductive function is still limited. The objective of this study was to evaluate the association between active exposure to tobacco smoke and the male reproductive hormone profile in a group of 136 Mexican flower growers. Serum levels of FSH, LH, prolactin, total testosterone, Inhibin B and estradiol were measured using enzyme-linked immunoabsorbent assay. Weight and height were also measured and a structured questionnaire was applied to get information on sociodemographic characteristics, clinical and work history and alcohol and tobacco consumption (current smoking habit and number of cigarettes smoked per day). Based on this information tobacco consumption was divided into four categories: never-smokers, ex-smokers, current smokers under five cigarettes/day and current smokers over or equal to five cigarettes/day. Using the group of never-smokers as reference and after adjusting for potential confounders, current smokers of five or more cigarettes/day showed significantly higher levels of LH (ß=0.33, p=0.01), prolactin (ß=0.18, p=0.03) and testosterone (ß=0.21, p=0.02). Current smokers of less than five cigarettes/day also showed higher levels of prolactin (ß=0.12, p=0.03) and testosterone (ß=0.18, p<0.01). Hormone levels of ex-smokers were similar to those of never-smokers. Our results are compatible with the hypothesis that tobacco consumption may act as an endocrine disruptor on the male hormone profile.

Asunto(s)

Fumar/efectos adversos , Adulto , Ensayo de Inmunoadsorción Enzimática , Estradiol/sangre , Hormona Folículo Estimulante/sangre , Humanos , Inhibinas/sangre , Hormona Luteinizante/sangre , Masculino , México , Prolactina/sangre , Fumar/sangre , Fumar/epidemiología , Testosterona/sangre , Adulto Joven

RESUMEN

OBJECTIVE: To evaluate the effects on anencephaly risk of the interaction between the maternal profile of folate, vitamin B12 and homocysteine and the 677C→T polymorphism in the gene encoding methylenetetrahydrofolate reductase (MTHFR). DESIGN: Case-control study paired (1:1) on maternity clinic, date of birth and state of residence. Cases of anencephaly were identified using the Registry of the Mexican Neural Tube Defect Epidemiological Surveillance System. Case and control mothers were selected from the same maternity departments. All mothers completed a structured questionnaire and blood samples were obtained to determine the MTHFR 677C→T polymorphism and biochemical profile. SETTING: Mexico, Puebla and Guerrero states, Mexico. SUBJECTS: A total of 151 mothers of cases and controls were enrolled from March 2000 to February 2001. We had complete information on biochemical profile and MTHFR C677T polymorphism for ninety-eight mothers of cases and ninety-one mothers of controls. RESULTS: The adjusted models show that the risk of anencephaly in mothers with 677TT genotype was reduced by 18 % (OR = 0·82; 95 % CI 0·72, 0·94) for each 1 ng/ml increment in serum folate. In terms of tertiles, mothers with 677TT genotype with serum folate levels in the upper tertile (>14·1 ng/ml) had a 95 % lower risk to have a child with anencephaly than mothers with serum folate levels in the first and second tertiles (P trend = 0·012). CONCLUSIONS: Our data agree with the hypothesis of a gene-nutrient interaction between MTHFR 677C→T polymorphism and folate status. We observed a protective effect on anencephaly risk only in mothers with 677TT genotype as serum folate levels increased.

Asunto(s)

Anencefalia/genética , Ácido Fólico/sangre , Homocisteína/sangre , Metilenotetrahidrofolato Reductasa (NADPH2)/genética , Polimorfismo Genético , Vitamina B 12/sangre , Adulto , Anencefalia/epidemiología , Estudios de Casos y Controles , Femenino , Genotipo , Humanos , Lactante , Metilenotetrahidrofolato Reductasa (NADPH2)/metabolismo , México/epidemiología , Embarazo , Factores de Riesgo , Encuestas y Cuestionarios , Complejo Vitamínico B/sangre

RESUMEN

OBJECTIVES: p,p'-Dichlorodiphenyldichloroethene (p,p'-DDE) acts as an androgen receptor antagonist, however data regarding its hormonal effects in men are limited. The objective of this study was to evaluate the association between serum levels of p,p'-DDE and reproductive hormone profile in Mexican male flower growers. METHODS: A longitudinal study was carried out in a population of men working in the production of flowers and ornamental plants in two Mexican states during July-October 2004 (rainy season) and December 2004-May 2005 (dry season). A questionnaire including information on socioeconomic characteristics, tobacco and alcohol use, presence of chronic and acute diseases, occupational history and anthropometry was used and blood and urine samples were obtained. Serum levels of p,p'-DDE were analysed by gas chromatography; FSH, LH, testosterone, oestradiol, inhibin B and prolactin levels were measured by enzymatic immunoassay. Urinary levels of dialkylphosphates (DAPs) were analysed by gas chromatography. Associations between serum levels of p,p'-DDE and male reproductive hormones (both transformed to their natural logarithm) were evaluated using multivariate generalised estimating equation (GEE) models. RESULTS: Median p,p'-DDE levels were 677.2 ng/g lipid (range 9.4-12 696.5) during the rainy season and 626.7 ng/g lipid (range 9.4-13 668.1) during the dry season. After adjusting for potential confounders (age, body mass index, state of residence and DAPs), p,p'-DDE levels were negatively associated with prolactin (ß=-0.04; 95% CI -0.07 to -0.008) and testosterone (ß=0.04; 95% CI -0.08 to 0.005) and positively with inhibin B (ß=0.11; 95% CI 0.02 to 0.21). CONCLUSION: These results indicate that p,p'-DDE can affect hypothalamic-pituitary-gonadal axis function in humans.

Asunto(s)

Agricultura , Diclorodifenil Dicloroetileno/sangre , Exposición a Riesgos Ambientales , Contaminantes Ambientales/sangre , Flores , Hormonas Gonadales/sangre , Gonadotropinas Hipofisarias/sangre , Insecticidas/sangre , Adulto , Análisis de Varianza , Humanos , Estudios Longitudinales , Masculino , México , Estaciones del Año

RESUMEN

Organophosphate pesticides are widely used in agricultural purposes. Recently, a few studies have demonstrated the ability of these chemicals to alter the function of the thyroid gland in human. Moreover, the paraoxonase-1 enzyme (PON1) plays an important role in the toxicity of some organophosphate pesticides, with low PON1 activity being associated with higher pesticide sensitivity. This study evaluates the interaction between exposure to organophosphate compounds and PON1 enzyme activity on serum levels of TSH and thyroid hormones in a population of workers occupationally exposed to pesticides. A longitudinal study was conducted on a population of floriculture workers from Mexico, during two periods of high and low-intensity levels of pesticide application. A structured questionnaire was completed by workers containing questions on sociodemographic characteristics and other variables of interest. Urine and blood samples were taken, and biomarkers of exposure (dialkylphosphates), susceptibility (PON1 polymorphisms and activity) and effect (thyroid hormone levels) were determined. Interaction between dialkylphosphates and PON1 polymorphisms or PON1 activity on hormone levels was evaluated by generalized estimating equation (GEE) models. A significant interaction was found between serum diazoxonase activity and total dialkylphosphates (ΣDAP) on TSH levels. Thus, when PON1 activity was increased we observed a decrease in the percentage of variation of TSH level for each increment in one logarithmic unit of the ΣDAP levels. This interaction was also observed with the PON1(192)RR genotype. These results suggest a stronger association between organophosphate pesticides and thyroid function in individuals with lower PON1 activity.

Asunto(s)

Agricultura , Arildialquilfosfatasa/metabolismo , Exposición Profesional , Compuestos Organofosforados/metabolismo , Plaguicidas/metabolismo , Glándula Tiroides/fisiología , Adulto , Arildialquilfosfatasa/genética , Biomarcadores/sangre , Biomarcadores/orina , Activación Enzimática/efectos de los fármacos , Activación Enzimática/fisiología , Femenino , Humanos , Estudios Longitudinales , Masculino , México/epidemiología , Exposición Profesional/efectos adversos , Compuestos Organofosforados/sangre , Compuestos Organofosforados/orina , Plaguicidas/sangre , Plaguicidas/orina , Pruebas de Función de la Tiroides , Glándula Tiroides/enzimología , Tirotropina/sangre , Tirotropina/orina , Adulto Joven

RESUMEN

BACKGROUND: Studies on experimental animals have found that organophosphate (OP) pesticides may act as endocrine disruptors; however, their effects on the human hormonal profile have not yet been adequately characterized. We evaluate the association between exposure to OP pesticides, measured through dialkyl phosphate (DAP) metabolites urinary levels, and the male hormone profile. METHODS: A cross-sectional study was performed in 104 floriculturists of Morelos, Mexico. A structured questionnaire was applied to get information on sociodemographic characteristics, anthropometry, clinical history, alcohol and tobacco consumption, and work history. DAP metabolites [dimethylphosphate (DMP), dimethylthiophosphate, dimethyldithiophosphate, diethylphosphate (DEP), diethylthiophosphate (DETP) and diethyldithiophosphate] were determined using gas-liquid chromatography. Serum levels of FSH, LH, prolactin, testosterone, inhibin B and estradiol were determined using enzyme-linked immunosorbent assay. Multiple linear regression was used to study the association between DAP metabolite levels and male hormonal profile. Data were adjusted by p,p'-dichlorodiphenyldichloroethene serum levels and other potential confounders. RESULTS: There was a negative association between inhibin B and urinary levels of DMP, DEP, DETP and total DAP metabolites. DEP levels were negatively associated with serum FSH concentrations, but marginally and positively associated with those of testosterone. DETP was marginally associated with lower LH serum levels. There were no other significant associations among OP metabolites and serum hormone levels. CONCLUSIONS: Inhibin B and FSH vary according to levels of DAP metabolites in men occupationally exposed to OP pesticides. These results suggest that OP pesticides could act as endocrine disruptors in humans; however, most hormonal values fell within the wide normal range and associations were small. There is, therefore, a need for further investigation to elucidate their biological and clinical relevance.

Asunto(s)

Hormonas Gonadales/sangre , Exposición Profesional/análisis , Organofosfatos/toxicidad , Plaguicidas/toxicidad , Hormonas Hipofisarias/sangre , Adolescente , Adulto , Creatinina/orina , Estradiol/sangre , Hormona Folículo Estimulante/sangre , Humanos , Inhibinas/sangre , Hormona Luteinizante/sangre , Masculino , México , Persona de Mediana Edad , Organofosfatos/orina , Exposición Paterna , Plaguicidas/orina , Prolactina/sangre , Testosterona/sangre

RESUMEN

OBJECTIVES: Exposure assessment to a single pesticide does not capture the complexity of the occupational exposure. Recently, pesticide use patterns analysis has emerged as an alternative to study these exposures. The aim of this study is to identify the pesticide use pattern among flower growers in Mexico participating in the study on the endocrine and reproductive effects associated with pesticide exposure. METHODS: A cross-sectional study was carried out to gather retrospective information on pesticide use applying a questionnaire to the person in charge of the participating flower growing farms. Information about seasonal frequency of pesticide use (rainy and dry) for the years 2004 and 2005 was obtained. Principal components analysis was performed. RESULTS: Complete information was obtained for 88 farms and 23 pesticides were included in the analysis. Six principal components were selected, which explained more than 70% of the data variability. The identified pesticide use patterns during both years were: 1. fungicides benomyl, carbendazim, thiophanate and metalaxyl (both seasons), including triadimephon during the rainy season, chlorotalonyl and insecticide permethrin during the dry season; 2. insecticides oxamyl, biphenthrin and fungicide iprodione (both seasons), including insecticide methomyl during the dry season; 3. fungicide mancozeb and herbicide glyphosate (only during the rainy season); 4. insecticides metamidophos and parathion (both seasons); 5. insecticides omethoate and methomyl (only rainy season); and 6. insecticides abamectin and carbofuran (only dry season). Some pesticides do not show a clear pattern of seasonal use during the studied years. CONCLUSIONS: The principal component analysis is useful to summarise a large set of exposure variables into smaller groups of exposure patterns, identifying the mixtures of pesticides in the occupational environment that may have an interactive effect on a particular health effect.

Asunto(s)

Enfermedades de los Trabajadores Agrícolas/epidemiología , Agricultura , Exposición Profesional/efectos adversos , Plaguicidas/toxicidad , Enfermedades de los Trabajadores Agrícolas/inducido químicamente , Estudios Transversales , Humanos , México/epidemiología , Análisis de Componente Principal

RESUMEN

En este trabajao se discute la problemática de la contaminación del aire en tres megaciudades de América Latina (Ciudad de México, Sao Paulo y Santiago); en particular se revisan los programas de control de la contaminación atmosférica que han puesto en marcha los gobiernos de esas ciudades y la evolución de los niveles de contaminantes durante el periodo 1988-1995 en Santiago de Chile y Sao Paulo, y hasta 1997 en la Ciudad de México, con el objeto de evaluar el impacto de esos programas. En las tres megaciudades se observó un descenso en las concentraciones de PTS, PM10, SO2, NO2, CO y O3 durante el periodo mencionado, aun que la mayoría de los contaminantes siguen rebasando la norma de calidad del aire. Cabe destacar que el mayor impacto de los programas ha sido sobre los niveles de SO2. Se recomienda el desarrollo de políticas de transporte sostenible; en ese sentido, en la Conferencia Europea de Ministros del Transporte la Organización para la Cooperación y el Desarrollo Económico (OCDE) propuso distintas estrategias. Por otra parte, la participación ciudadana es importante al tomar decisiones relacionadas con las políticas de transporte

Asunto(s)

Salud Urbana , Contaminación del Aire/estadística & datos numéricos , Contaminación del Aire/prevención & control , Brasil , Chile , México , Evaluación de Programas y Proyectos de Salud