Pesticide use patterns and their association with cytokine levels in Mexican flower workers.

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.

Renal tubular dysfunction in greenhouse farmers exposed to pesticides unveiled by a panel of molecular biomarkers of kidney injury.

Growing evidence suggests that chronic exposure to pesticides may cause adverse effects on the health of the exposed population leading to organ-specific toxicity, including kidney damage. Traditional markers used to assess renal function (glomerular filtration rate (GFR), and serum creatinine and cystatin C -Cys-C-) are inadequate to evaluate a potential subclinical renal impairment linked to occupational exposure to pesticides, since levels above the upper limit of normal only occur when renal damage is very extensive. The use of more sensitive biomarkers is therefore needed. This study investigated novel urinary biomarkers of kidney function (microalbuminuria, osteopontin (OPN), trefoil factor 3 (TFF3), ß-2-microglobulin, neutrophil gelatinase-associated lipocalin (NGAL), and Cys-C), together with the aforementioned traditional serum biomarkers, to assess potential kidney damage in farmers exposed to pesticides in an intensive agriculture setting. The study population consisted of 175 greenhouse workers and 91 healthy control subjects from Almeria (Southeastern Spain), a major hub of greenhouse agriculture. Data were collected at two different time-points of the same crop season: a period with greater pesticide use (high exposure period) and another with lower pesticide use (low exposure period). Significantly higher urinary levels of OPN and TFF3 were found in greenhouse workers than in controls, and in the high pesticide exposure period compared to that of low exposure. These changes suggest a subclinical tubular damage linked to pesticide exposure. In contrast, microalbuminuria, GFR, serum creatinine and Cys-C failed to be associated with pesticide exposure, suggesting that glomerular function was spared. Increased OPN and TFF3 levels over time may suggest a gradual progression from tubular dysfunction to chronic kidney disease in the exposed population.

Effect of prenatal exposure to organophosphates and pyrethroid pesticides on neonatal anthropometric measures and gestational age.

Several studies have examined the association between prenatal exposure to organophosphate and pyrethroid pesticides and their impact on foetal growth and newborn anthropometry; however, the available evidence is limited and inconclusive. This study examined whether prenatal organophosphate and pyrethroid pesticide exposure was associated with anthropometric measures at birth (weight, length, head circumference), ponderal index, gestational age, and prematurity in 537 mother-child pairs. These were randomly selected from the 800 pairs participating in the prospective birth cohort GENEIDA (Genetics, early life environmental exposures and infant development in Andalusia). Six non-specific organophosphate metabolites (dialkylphosphates, DAPs), one metabolite relatively specific to chlorpyrifos (3,5,6-trichloro-2-pyridinol, TCPy) and a common metabolite to several pyrethroids (3-phenoxybenzoic acid, 3-PBA) were measured in maternal urine from the 1st and 3rd pregnancy trimesters. Information on anthropometric measures at birth, gestational age and prematurity was retrieved from medical records. The sum on a molar basis of DAPs with methyl (Æ©DMs) and ethyl (Æ©DEs) moieties and the sum of the 6 DAPs metabolites (Æ©DAPs) was calculated for both trimesters of pregnancy. High urinary levels of dimethyl phosphate (DMP) during the 3rd trimester were associated with a decrease in birth weight (ß = -0.24; 95% CI: 0.41; -0.06) and birth length (ß = -0.20; 95% CI: 0.41; 0.02). Likewise, ΣDMs during 3rd trimester were near-significantly associated with decreased birth weight (ß = -0.18; 95% CI: 0.37; 0.01). In turn, increased urinary TCPy during 1st trimester was associated with a decreased head circumference (ß = -0.31; 95% CI: 0.57; -0.06). Finally, an increase in 3-PBA in the 1st trimester was associated with a decreased gestational age (ß = -0.36 95% CI: 0.65-0.08), whereas increased 3-PBA at 1st and 3rd trimester was associated with prematurity. These results indicate that prenatal exposure to organophosphate and pyrethroid insecticides could affect normal foetal growth, shorten gestational age and alter anthropometric measures at birth.

Biomarkers of oxidative stress in blood of workers exposed to non-cholinesterase inhibiting pesticides.

In occupational settings workers are often exposed to pesticides at relatively high doses compared to environmental exposures. Long-term exposure to pesticides has been associated with numerous adverse health effects in epidemiological studies, and oxidative stress is often claimed as one of the underlying mechanisms. In fact, different pesticides have been reported to induce oxidative stress due to the generation of free radicals and/or alteration in antioxidant defense enzymes. The present study examined greenhouse workers regularly exposed to diverse pesticides under integrated production system, and a group of controls of the same geographic area without any chemical exposure. Two different periods of the same crop season were assessed, one of high exposure (with greater use of pesticides) and other of low exposure (in which a less use of these compounds was made). Non-specific biomarkers of oxidative stress, e.g. thiobarbituric acid reactive substances (TBARS), ferric reducing ability of serum (FRAS), total thiol groups (SHT), gamma-glutamyl transpeptidase (GGT) and paraoxonase-1 (PON1) were measured in serum samples from all study subjects, alongside erythrocyte acetylcholinesterase (AChE). Results are suggestive of a mild increase in oxidative stress associated with pesticide exposure, which was compensated by an adaptive response to raise the antioxidant defenses and thus counter the detrimental effects of sustained oxidative stress. This response led to significantly increased levels of FRAS, SHT and PON1 in greenhouse workers relative to controls. Furthermore, AChE was decreased likely as a result of oxidative stress as workers did not use organophosphate insecticides.

Toxicological interactions of pesticide mixtures: an update.

Pesticides can interact with each other in various ways according to the compound itself and its chemical family, the dose and the targeted organs, leading to various effects. The term interaction means situations where some or all individual components of a mixture influence each other's toxicity and the joint effects may deviate from the additive predictions. The various mixture effects can be greatly determined by toxicokinetic and toxicodynamic factors involving metabolic pathways and cellular or molecular targets of individual pesticides, respectively. However, the complexity of toxicological interactions can lead to unpredictable effects of pesticide mixtures. Interactions on metabolic processes affecting the biotransformation of pesticides seem to be by far the most common mechanism of synergism. Moreover, the identification of pesticides responsible for synergistic interactions is an important issue for cumulative risk assessment. Cholinesterase inhibiting insecticides (organophosphates and N-methylcarbamates), triazole fungicides, triazine herbicides, and pyrethroid insecticides are overrepresented in the synergistic mixtures identified so far. Since the limited available empirical evidence suggests that synergisms at dietary exposure levels are rather rare, and experimentally occurred at unrealistic high concentrations, synergism cannot be predicted quantitatively on the basis of the toxicity of mixture components. The prediction of biological responses elicited by interaction of pesticides with each other (or with other chemicals) will benefit from using a systems toxicology approach. The identification of core features of pesticide mixtures at molecular level, such as gene expression profiles, could be helpful to assess or predict the occurrence of interactive effects giving rise to unpredicted responses.

Expression of placental regulatory genes is associated with fetal growth.

The placenta is the principal organ regulating respiratory, nutritional, endocrine and metabolic functions on behalf of the developing fetus. Changes in gene expression patterns of placenta-specific genes may influence fetal growth. We profiled the expression of 17 genes related to placenta functioning in term placentas (n=677) to identify genes differentially expressed across birth weight categories [small (SGA), appropriate (AGA) and large (LGA) for gestational age]. ABCG2, CEBPB, CRH, GCM1, GPC3, INSL4, PGF and PLAC1 were inversely associated with LGA status, with odds ratios (ORs) and 95% confidence intervals (CI) ranging from GCM1 (OR=0.44, 95% CI: 0.29, 0.70) to CRH (OR=0.73, 95% CI: 0.61, 0.88). NR3C1 was positively associated with LGA status (OR=2.33, 95% CI: 1.43, 3.78). PLAC1 (OR=0.66, 95% CI: 0.47, 0.92) and ABCG2 (OR=0.63, 95% CI: 0.44, 0.91) were additionally inversely associated with SGA status, and PGF was positively associated with SGA status (OR=1.59, 95% CI=1.08, 2.35). General trends were confirmed in an independent cohort (n=306). Given that aberrant fetal growth may have long-lasting effects, our results suggest the potential utility of placental gene expression profiles as potential early markers of disease onset later in life.

Association between organochlorine pesticide exposure and thyroid hormones in floriculture workers.

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.

Cadmium exposure and neuropsychological development in school children in southwestern Spain.

This study assessed the association between cadmium exposure and neuropsychological development in children from a region with high industrial and mining activities in southwestern Spain. We conducted a cross-sectional study with 261 children aged 6-9 years between January and March 2012. Cadmium exposure was measured in urine and hair of children, and neuropsychological development was assessed with the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) and with three computerized tests from the Behavioral Assessment and Research System (BARS): Reaction Time Test (RTT), Continuous Performance Test (CPT) and Selective Attention Test (SAT). Multivariate linear regression models, adjusted for potential confounders, were used to estimate the association between neuropsychological development and cadmium exposure measured in urine and hair samples. Geometric means of urine and hair cadmium levels were 0.75 µg/g creatinine and 0.01 µg/g, respectively. We observed that doubling of levels of cadmium in urine was associated with a reduction of two points (95% CI: -3.8 to -0.4) in the Full-Scale intelligence quotient (IQ) in boys. By domains, association was statistically significant for Verbal Comprehension (ß=-2.0; p=0.04) and close to the significance level for Perceptual Reasoning (ß=-1.8; p=0.06). Among girls, only Verbal Comprehension showed suggestive associations with cadmium exposure (ß=-1.7; p=0.06). Cadmium exposure is associated with cognitive delays in boys in our region. Our results provide additional evidence of the neurotoxic effect of low-level postnatal cadmium exposure among children, and support the hypothesis of differences between sexes in the neurotoxic effect of metals on children.

A Th2-type immune response and low-grade systemic inflammatory reaction as potential immunotoxic effects in intensive agriculture farmers exposed to pesticides.

Pesticides are chemicals widely used in agriculture to keep crops healthy and prevent them from being destroyed by pests, thus contributing to a sustainable food and feed production. However, long-term exposure to these compounds may be harmful to human health as they can affect the function of various organs systems, including the immune system. There is growing evidence that pesticides may increase the risk of developing immune-based diseases and inflammation. This study assessed whether greenhouse farmers occupationally exposed to pesticides presented alterations in immunoregulatory proteins, used as surrogate biomarkers of immune function. The study population consisted of 175 greenhouse workers occupationally exposed to pesticides and 91 non-exposed controls. Serum levels of 27 cytokines, chemokines and growth factors were measured using a magnetic bead-based immunoassay in a subpopulation of 111 greenhouse workers and 79 non-exposed controls. Since analytical determinations were performed in two periods of the same crop season with different use of pesticides (period of high and low pesticide exposure), linear mixed models for repeated measures were used to optimize statistical inference. The increase in IL-13, IL-4 and IL-6 observed in greenhouse workers compared to controls, and in the period of high exposure to pesticides relative to that of low exposure, suggest an altered Th1/Th2 balance towards the Th2 response. This finding points to a type-2 inflammation commonly presented as allergic inflammation, which has often been reported in farm-workers and in which pesticide exposure is considered a risk factor. Furthermore, the increase in IL-1ß and VEGF, mediators of inflammation and angiogenesis, may suggest a low-grade systemic inflammation that might underlie chronic pathological conditions linked to pesticide exposure.

Urban environment and health: a cross-sectional multiregional project based on population health surveys in Spain (DAS-EP project) - study protocol.

INTRODUCTION: The European Environment Agency estimates that 75% of the European population lives in cities. Despite the many advantages of city life, the risks and challenges to health arising from urbanisation need to be addressed in order to tackle the growing burden of disease and health inequalities in cities. This study, Urban environment and health: a cross-sectional multiregional project based on population health surveys in Spain (DAS-EP project), aims to investigate the complex association between the urban environmental exposures (UrbEEs) and health. METHODS AND ANALYSIS: DAS-EP is a Spanish multiregional cross-sectional project that combines population health surveys (PHS) and geographical information systems (GIS) allowing to collect rich individual-level data from 17 000 adult citizens participating in the PHS conducted in the autonomous regions of the Basque Country, Andalusia, and the Valencian Community, and the city of Barcelona in the years 2021-2023. This study focuses on the population living in cities or metropolitan areas with more than 100 000 inhabitants. UrbEEs are described by objective estimates at participants' home addresses by GIS, and subjective indicators present in PHS. The health outcomes included in the PHS and selected for this study are self-perceived health (general and mental), prevalence of chronic mental disorders, health-related quality of life, consumption of medication for common mental disorders and sleep quality. We aim to further understand the direct and indirect effects between UrbEEs and health, as well as to estimate the impact at the population level, taking respondents' sociodemographic and socioeconomic characteristics, and lifestyle into consideration. ETHICS AND DISSEMINATION: The study was approved by the regional Research Ethics Committee of the Basque Country (Ethics Committee for Research Involving Medicinal Products in the Basque Country; PI2022138), Andalusia (Biomedical Research Ethics Committee of the Province of Granada; 2078-N-22), Barcelona (CEIC-PSMar; 2022/10667) and the Valencian Community (Ethics Committee for Clinical Research of the Directorate General of Public Health and Center for Advanced Research in Public Health; 20221125/04). The results will be communicated to the general population, health professionals, and institutions through conferences, reports and scientific articles.

Chronic burden of near-roadway traffic pollution in 10 European cities (APHEKOM network).

Recent epidemiological research suggests that near road traffic-related pollution may cause chronic disease, as well as exacerbation of related pathologies, implying that the entire "chronic disease progression" should be attributed to air pollution, no matter what the proximate cause was. We estimated the burden of childhood asthma attributable to air pollution in 10 European cities by calculating the number of cases of 1) asthma caused by near road traffic-related pollution, and 2) acute asthma events related to urban air pollution levels. We then expanded our approach to include coronary heart diseases in adults. Derivation of attributable cases required combining concentration-response function between exposures and the respective health outcome of interest (obtained from published literature), an estimate of the distribution of selected exposures in the target population, and information about the frequency of the assessed morbidities. Exposure to roads with high vehicle traffic, a proxy for near road traffic-related pollution, accounted for 14% of all asthma cases. When a causal relationship between near road traffic-related pollution and asthma is assumed, 15% of all episodes of asthma symptoms were attributable to air pollution. Without this assumption, only 2% of asthma symptoms were attributable to air pollution. Similar patterns were found for coronary heart diseases in older adults. Pollutants along busy roads are responsible for a large and preventable share of chronic disease and related acute exacerbations in European urban areas.

[Climate change and vector-borne diseases. From knowledge to action]. / Cambio climático y enfermedades transmitidas por vectores. Convertir el conocimiento en acción.

Andalusia is particularly sensitive to climate change, not only because of extreme weather events, but also because of the impact on the population dynamics of vectors, pathogens, reservoirs and hosts, which has led to a change in the epidemiological patterns of vector-borne diseases. In order to achieve an integrated vector management for disease control, public action is necessary. This study describes the design of the initial phase of a strategy for knowledge translation about climate change and vector-borne diseases to the public, using transdisciplinary co-creation and the World Café participatory method with three discussion rounds to address strategies for three age groups (adults, adolescents and schoolchildren). The aim is to drive knowledge into action and for this purpose the underlying messages for action (strategic and instrumental) have been identified, as well as the formats of the knowledge products and the potential implementers of the strategies.

A step towards harmonising human biomonitoring study setup on European level: Materials provided and lessons learnt in HBM4EU.

Internal exposure of the human body to potentially harmful chemical substances can be assessed by Human Biomonitoring (HBM). HBM can be used to generate conclusive data that may provide an overview of exposure levels in entire or specific population groups. This knowledge can promote the understanding of potential risks of the substances of interest or help monitoring the success of regulatory measures taken on the political level. Study planning and design are key elements of any epidemiologic study to generate reliable data. In the field of HBM, this has been done using differing approaches on various levels of population coverage so far. Comparison and combined usage of the resulting data would contribute to understanding exposure and its factors on a larger scale, however, the differences between studies make this a challenging and somewhat limited endeavour. This article presents templates for documents that are required to set up an HBM study, thus facilitating the generation of harmonised HBM data as a step towards standardisation of HBM in Europe. They are designed to be modular and adaptable to the specific needs of a single study while emphasising minimum requirements to ensure comparability. It further elaborates on the challenges encountered during the process of creating these documents during the runtime of the European Joint Programme HBM4EU in a multi-national expert team and draws up lessons learnt in the context of knowledge management.

Implementation of effect biomarkers in human biomonitoring studies: A systematic approach synergizing toxicological and epidemiological knowledge.

Human biomonitoring (HBM) studies have highlighted widespread daily exposure to environmental chemicals. Some of these are suspected to contribute to adverse health outcomes such as reproductive, neurological, and metabolic disorders, among other developmental and chronic impairments. One of the objectives of the H2020 European Human Biomonitoring Initiative (HBM4EU) was the development of informative effect biomarkers for application in a more systematic and harmonized way in large-scale European HBM studies. The inclusion of effect biomarkers would complement exposure data with mechanistically-based information on early and late adverse effects. For this purpose, a stepwise strategy was developed to identify and implement a panel of validated effect biomarkers in European HBM studies. This work offers an overview of the complete procedure followed, from comprehensive literature search strategies, selection of criteria for effect biomarkers and their classification and prioritization, based on toxicological data and adverse outcomes, to pilot studies for their analytical, physiological, and epidemiological validation. We present the example of one study that demonstrated the mediating role of the effect biomarker status of brain-derived neurotrophic factor BDNF in the longitudinal association between infant bisphenol A (BPA) exposure and behavioral function in adolescence. A panel of effect biomarkers has been implemented in the HBM4EU Aligned Studies as main outcomes, including traditional oxidative stress, reproductive, and thyroid hormone biomarkers. Novel biomarkers of effect, such as DNA methylation status of BDNF and kisspeptin (KISS) genes were also evaluated as molecular markers of neurological and reproductive health, respectively. A panel of effect biomarkers has also been applied in HBM4EU occupational studies, such as micronucleus analysis in lymphocytes and reticulocytes, whole blood comet assay, and malondialdehyde, 8-oxo-2'-deoxyguanosine and untargeted metabolomic profile in urine, to investigate, for example, biological changes in response to hexavalent chromium Cr(VI) exposure. The use of effect biomarkers in HBM4EU has demonstrated their ability to detect early biological effects of chemical exposure and to identify subgroups that are at higher risk. The roadmap developed in HBM4EU confirms the utility of effect biomarkers, and support one of the main objectives of HBM research, which is to link exposure biomarkers to mechanistically validated effect and susceptibility biomarkers in order to better understand the public health implications of human exposure to environmental chemicals.

HBM4EU-MOM: Prenatal methylmercury-exposure control in five countries through suitable dietary advice for pregnancy - Study design and characteristics of participants.

BACKGROUND: Seafood is a major source of vital nutrients for optimal fetal growth, but at the same time is the main source of exposure to methylmercury (MeHg), an established neurodevelopmental toxicant. Pregnant women must be provided with dietary advice so as to include safely fish in their diet for nutrition and mercury control. The aim of this work is to present the design of a multicentre randomized control trial (RCT), which combines human biomonitoring (HBM) with dietary interventions using seafood consumption advice to pregnant women for MeHg control, and to collect information about other possible sources of exposure to mercury. It also presents the materials developed for the implementation of the study and the characteristics of the study participants, which were self-reported in the first trimester of pregnancy. METHODS: The "HBM4EU-MOM" RCT was performed in the frame of the European Human Biomonitoring Initiative (HBM4EU) in five coastal, high fish-consuming European countries (Cyprus, Greece, Spain, Portugal and Iceland). According to the study design, pregnant women (≥120/country, ≤20 weeks gestational age) provided a hair sample for total mercury assessment (THg) and personal information relevant to the study (e.g., lifestyle, pregnancy status, diet before and during the pregnancy, information on seafood and factors related to possible non-dietary exposures to mercury) during the first trimester of pregnancy. After sampling, participants were randomly assigned to "control" (habitual practices) or "intervention" (received the harmonized HBM4EU-MOM dietary advice for fish consumption during the pregnancy and were encouraged to follow it). Around child delivery, participants provided a second hair sample and completed another tailored questionnaire. RESULTS: A total of 654 women aged 18-45 years were recruited in 2021 in the five countries, primarily through their health-care providers. The pre-pregnancy BMI of the participants ranged from underweight to obese, but was on average within the healthy range. For 73% of the women, the pregnancy was planned. 26% of the women were active smokers before the pregnancy and 8% continued to smoke during the pregnancy, while 33% were passive smokers before pregnancy and 23% remained passively exposed during the pregnancy. 53% of the women self-reported making dietary changes for their pregnancy, with 74% of these women reporting making the changes upon learning of their pregnancy. Of the 43% who did not change their diet for the pregnancy, 74% reported that their diet was already balanced, 6% found it difficult to make changes and 2% were unsure of what changes to make. Seafood consumption did not change significantly before and during the first trimester of pregnancy (overall average ∼8 times per month), with the highest frequency reported in Portugal (≥15 times per month), followed by Spain (≥7 times per month). During the first-trimester of pregnancy, 89% of the Portuguese women, 85% of the Spanish women and <50% of Greek, Cypriot and Icelandic women reported that they had consumed big oily fish. Relevant to non-dietary exposure sources, most participants (>90%) were unaware of safe procedures for handling spillage from broken thermometers and energy-saving lamps, though >22% experienced such an incident (>1 year ago). 26% of the women had dental amalgams. ∼1% had amalgams placed and ∼2% had amalgams removed during peri-pregnancy. 28% had their hair dyed in the past 3 months and 40% had body tattoos. 8% engaged with gardening involving fertilizers/pesticides and 19% with hobbies involving paints/pigments/dyes. CONCLUSIONS: The study design materials were fit for the purposes of harmonization and quality-assurance. The harmonized information collected from pregnant women suggests that it is important to raise the awareness of women of reproductive age and pregnant women about how to safely include fish in their diet and to empower them to make proper decisions for nutrition and control of MeHg, as well as other chemical exposures.

Effect of exposure to p,p'-DDE on male hormone profile in Mexican flower growers.

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.

Effect on risk of anencephaly of gene-nutrient interactions between methylenetetrahydrofolate reductase C677T polymorphism and maternal folate, vitamin B12 and homocysteine profile.

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.

The questionnaire design process in the European Human Biomonitoring Initiative (HBM4EU).

BACKGROUND: Designing questionnaires is a key point of epidemiological studies assessing human exposure to chemicals. The lack of validated questionnaires can lead to the use of previously developed and sub-optimally adapted questionnaires, which may result in information biases that affect the study's validity. On this ground, a multidisciplinary group of researchers developed a series of tools to support data collection within the HBM4EU initiative. The objective of this paper is to share the process of developing HBM4EU questionnaires, as well as to provide researchers with harmonized procedures that could help them to design future questionnaires to assess environmental exposures. METHODS: In the frame of the work package on survey design and fieldwork of the HBM4EU, researchers carried out procedures necessary for the development of quality questionnaires and related data collection tools. These procedures consisted of a systematic search to identify questionnaires used in previous human biomonitoring (HBM) studies, as well as the development of a checklist and evaluation sheet to assess the questionnaires identified. The results of these evaluations were taken into consideration for the development of the final questionnaires. RESULTS: The main points covered by each of the sections included in HBM4EU questionnaires are described and discussed in detail. Additional tools developed for data collection in the HBM4EU (e.g. non-responder questionnaire, satisfaction questionnaire, matrix-specific questionnaire) are also addressed. Special attention is paid to the limitations faced and hurdles overcome during the process of questionnaire development. CONCLUSIONS: Designing questionnaires for use in HBM studies requires substantial effort by a multidisciplinary team to guarantee that the quality of the information collected meets the study's objectives. The process of questionnaire development described herein will contribute to improve the harmonization of HBM studies within the social and environmental context of the EU countries.

A meta-analysis of pre-pregnancy maternal body mass index and placental DNA methylation identifies 27 CpG sites with implications for mother-child health.

Higher maternal pre-pregnancy body mass index (ppBMI) is associated with increased neonatal morbidity, as well as with pregnancy complications and metabolic outcomes in offspring later in life. The placenta is a key organ in fetal development and has been proposed to act as a mediator between the mother and different health outcomes in children. The overall aim of the present work is to investigate the association of ppBMI with epigenome-wide placental DNA methylation (DNAm) in 10 studies from the PACE consortium, amounting to 2631 mother-child pairs. We identify 27 CpG sites at which we observe placental DNAm variations of up to 2.0% per 10 ppBMI-unit. The CpGs that are differentially methylated in placenta do not overlap with CpGs identified in previous studies in cord blood DNAm related to ppBMI. Many of the identified CpGs are located in open sea regions, are often close to obesity-related genes such as GPX1 and LGR4 and altogether, are enriched in cancer and oxidative stress pathways. Our findings suggest that placental DNAm could be one of the mechanisms by which maternal obesity is associated with metabolic health outcomes in newborns and children, although further studies will be needed in order to corroborate these findings.

Evaluation of conventional and non-conventional biomarkers of liver toxicity in greenhouse workers occupationally exposed to pesticides.

The liver plays a prominent role in maintenance of homeostasis and is the major organ for xenobiotic metabolism, including pesticides. Conventional liver function tests are widely used to assess hepatocellular and biliary system dysfunction by measuring serum levels of aminotransferases (ALT, AST) and cholestasis enzymes (alkaline phosphatase -ALP- and γ-glutamyl transferase -GGT-), respectively. Although these tests are not entirely specific for liver damage, their specificity increases when measured concurrently, but still have limited usefulness to predict early liver dysfunction. Hence, non-conventional biomarkers may have a better performance for the early detection of biochemical hepatotoxicity with a greater specificity and sensitivity. A cross-sectional study with a follow-up component was conducted on 175 greenhouse workers regularly exposed to pesticides under integrated production system, and 91 controls living in the same geographical area. All individuals were evaluated for conventional (ALT, AST, ALP, GGT) and non-conventional biomarkers of hepatotoxicity (ornithine transcarbamylase (-OTC-), Arginase-1 -ARG1- and glutathione S-transferase alpha -GSTα-) over two periods of the same crop season, one of high pesticide exposure and other of low exposure. A slight increase in AST was observed in greenhouse workers relative to controls, suggestive of subtle hepatocellular toxicity. Although ALP, ARG1 and GST-α levels were decreased in greenhouse workers, this might be related to a potential homeostatic mechanism that regulates their expression. Altogether, these findings do not represent unambiguous evidence of liver dysfunction (e.g., hepatocellular or biliary system impairment) but may be the result of the low-toxicity pesticides used by greenhouse workers.