Prevalence of adverse reproductive outcomes in a population occupationally exposed to pesticides in Colombia

Health of greenspace workers: Morbidity and mortality data from the AGRICAN cohort

INTRODUCTION

Knowledge on the health of greenspace workers is scarce, even though they are exposed to many occupational hazards. The aim of this study was to analyze mortality by cause, prevalence of some non-cancer diseases, and incidence of the main cancers among greenspace workers.

METHODS

A sub-cohort of greenspace workers was formed within the AGRICAN cohort. Demographic information, health characteristics and self-reported diseases at enrollment were described separately in terms of frequencies (%), median and Interquartile Range (IQR) for greenspace workers, farmers, and other non-agricultural workers. Causes of death and cancer incidence were identified through linkage with cancer registries from enrollment (2005-2007) to 2015. Hazard ratio (HR) and 95% Confidence Intervals [95% CI] were estimated using Cox proportional hazard regression with age as the underlying timescale.

RESULTS

The sub-cohort included 6247 greenspace workers who were higher proportion men, younger and more frequently smokers than farmers and non-agricultural workers. Male and female greenspace workers reported more history of allergic diseases; and males, more history of depression. Compared to other workers male greenspace workers showed a non-significant higher mortality from ischemic cardiological diseases (HR = 1.14 [0.81-1.60]). Incidence was higher in male greenspace workers than farmers for overall cancer (HR = 1.15 [1.04-1.27]), cancer of the prostate (HR = 1.21 [1.02-1.44]), thyroid (HR = 2.84 [1.26-6.41]), testis (HR = 3.98 [1.50-10.58]) and skin melanoma (HR = 2.15 [1.33-3.47]). Non-significant increased risks were also found for sarcomas, larynx and breast. In women, risk of breast cancer was higher in greenspace workers than in farmers (HR = 1.71 [1.17-2.50]).

CONCLUSIONS

Whereas greenspace workers have often been included with other pesticide applicators in epidemiological studies, our analyses highlighted the differences between these two populations. They demonstrate the need to study them separately and to investigate more thoroughly the role of specific occupational exposures such as pesticides as well as the effect on women.

The Possibility of Sustainable Urban Horticulture Based on Nature Therapy

Population growth and increased stress caused by urbanization have led to social problems that are predicted to intensify in the future. In these conditions, the recently established ”nature therapy” has revealed that an environment rich in various plant life significantly contributes to the relief of physical and mental stress. Meanwhile, from the perspective of reduction in the energy required for transportation and the retention of plant freshness, urban horticulture, in which plant life exists harmoniously with the city, has attracted considerable attention. Interactions between humans and plants in urban horticulture are considered to contribute to the good health and wellbeing of people. Therefore, we incorporate human-centered thinking based on nature therapy into horticultural produce-centered thinking based on conventional urban horticulture. By introducing a pioneering urban horticulture plant factory as an example, we propose the possibility of sustainable urban horticulture based on nature therapy.

Prenatal toxicity of the environmental pollutants on neuronal and cardiac development derived from embryonic stem cells

Pesticides, antibiotics, and industrial excipients are widely used in agriculture, medicine, and chemical industry, respectively. They often end up in the environment, not only being not easily decomposed but also being accumulated. Moreover, they may cause serious toxic problems such as reproductive and developmental defects, immunological toxicity, and carcinogenesis. Hence, they are called environmental pollutants. It is known that the environmental pollutants easily enter the body through various channels such as respiration, ingestion of food, and skin contact etc. in everyday life. If they enter the mother through the placenta, they can cause the disturbance in embryo development as well as malfunction of organs after birth because early prenatal developmental process is highly sensitive to toxic chemicals and stress. Embryonic stem cells (ESCs) that consist of inner cell mass of blastocyst differentiate into distinct cell lineages via three germ layers such as the ectoderm, mesoderm, and endoderm due to their pluripotency. The differentiation process initiated from ESCs reflects dynamic nature of embryonic development. Therefore, ESCs have been used as a useful tool to investigate early developmental toxicities of a variety of stress. Based on relatively recent scientific results, this review would address toxicity of a few chemical substances that have been widely used as pesticide, antibiotics, and industrial excipient on ESCs based-prenatal developmental process. This review further suggests how they act on the viability of ESCs and/or early stages of cardiac and neuronal development derived from ESCs as well as on expression of pluripotency and/or differentiation markers through diverse mechanisms.

Contaminated land in Colombia: A critical review of current status and future approach for the management of contaminated sites

Environmental contaminants can have negative effects on human health and land, air and water resources. Consequently, there have been significant advances in regulation for protecting the environment in developed countries including the development of remediation frameworks and guidelines. On the other hand, fewer studies have been reported on the risks and health effects of contaminants in developing regions and there is scarce information regarding contaminated land assessment and environmental remediation. Colombia is an important emerging economy and has started to take the first steps towards the development of a framework for the management of contaminated sites and there are opportunities for the country to learn from countries with well-established frameworks such as the United States (US) and the United Kingdom (UK) and for international collaboration with organisations such as CRC for Contamination Assessment and Remediation of the Environment (CARE). We review main pollution issues, current status of contaminated land management in Colombia to identify the gaps in policy and regulation. We also review the UK and US contaminated land policies and regulations to identify the elements of those experiences that could support progress in the country. Finally, we propose recommendations (e.g. risk based approach, soil screening criteria, clean-up funding, liability) for Colombia that could support further development and implementation of a more effective contaminated land management framework.

Risk Assessment of Florists Exposed to Pesticide Residues through Handling of Flowers and Preparing Bouquets

Flowers are frequently treated with pesticides and, as a result, florists handling daily a large number of flowers can be exposed to pesticide residues. A study was conducted among twenty volunteer florists located in Namur Province and in the Brussels Capital Region of Belgium in order to assess their potential dermal exposure to dislodgeable pesticide residues transferred from flowers to hands. Two pairs of cotton gloves were worn during two consecutive half days while handling flowers and preparing bouquets (from min 2 h to max 3 h/day). The residual pesticide deposits on the glove samples were extracted with a multi-residue Quick Easy Cheap Effective Rugged Safe (QuEChERS) method and analyzed by a combination of gas and liquid chromatography tandem mass spectrometry (GC-MS/MS and LC-MS/MS) by an accredited laboratory. A total of 111 active substances (mainly insecticides and fungicides) were detected, with an average of 37 active substances per sample and a total concentration per glove sample of 22.22 mg/kg. Several predictive levels of contamination were considered to assess the risk. The potential dermal exposures (PDE) of florists were estimated at the average, for different percentiles, and at the maximum concentration of residues in samples. At the PDE P90 and at the PDEMAX (or worst case) values, three and five active substances respectively exceed the Acceptable Operator Exposure Level (AOEL), indicating risk situations. For the systemic exposure (SE), one active substance (clofentezine) exceeds the AOEL at the P90 predictive level. In the worst case, SEMAX (at the maximum concentrations), four active substances (clofentezine, famoxadone, methiocarb, and pyridaben) exceed their respective AOEL values. Among the 14 most frequently detected active substances, two have SEMAX values exceeding the AOEL. Exposure could be particularly critical for clofentezine with an SEMAX value four times higher than the AOEL (393%). The exposure of florists appeared to be an example of a unique professional situation in which workers are exposed regularly to both a very high number of toxic chemicals and rather high concentration levels. Therefore the priority should be to raise the level of awareness among the florists who must change their habits and practices if they want to minimize their exposure.

Pesticide Residues on Three Cut Flower Species and Potential Exposure of Florists in Belgium

In order to assess the prevalence of pesticide contamination and the risk of florists' exposure when handling cut flowers, sampling and analysis of 90 bouquets of the most commonly sold cut flowers in Belgium (50 bouquets of roses; 20 of gerberas, and 20 of chrysanthemums) were carried out. The bouquets were collected from 50 florists located in the seven largest cities of Belgium (Antwerp, Brussels, Charleroi, Ghent, Leuven, Liege, and Namur) and from five supermarkets located in the different regions. To have a better understanding of the route of exposure and professional practices a questionnaire was also addressed to a group of 25 florists who volunteered to take part in the survey. All florists were interviewed individually when collecting the questionnaire. The residual pesticide deposit values on cut flowers were determined in an accredited laboratory using a multi-residue (QuEChERS Quick Easy Cheap Effective Rugged Safe) method and a combination of gas chromatography (GC) and liquid chormatograhphy (LC) analysis. A total of 107 active substances were detected from all samples; i.e., an average of about 10 active substances per bouquet. The most severely contaminated bouquet accumulated a total concentration of residues up to 97 mg/kg. Results show that roses are the most contaminated cut flowers; with an average of 14 substances detected per sample and a total concentration per rose sample of 26 mg/kg. Some active substances present an acute toxicity (acephate, methiocarb, monocrotophos, methomyl, deltamethrin, etc.) and exposure can generate a direct effect on the nervous system of florists. Nevertheless, fungicides (dodemorph, propamocarb, and procymidone) were the most frequently detected in samples and had the highest maximum concentrations out of all the active substances analysed. Dodemorph was the most frequently detected substance with the highest maximum concentration (41.9 mg/kg) measured in the rose samples. It appears from the survey that, despite being exposed to high deposits of residues, florists usually do not protect themselves from contact with residues even if they spend several hours handling cut flowers and preparing bouquets (from 2 to 6 h/day, depending on the time of year and/or selling periods) daily. Bad habits (eating, drinking, or smoking at work) and absence of personal protective equipment of most florists also increase the risk of contact with pesticide residues.

Environmental, parental and gestational factors that influence the occurrence of hypospadias in male patients

OBJECTIVE

Hypospadias is a congenital defect, which affects normal development of the male urogenital external tract. In this malformation, the urethral orifice of the penis is positioned ventrally, thus interfering with normal urination and creating, in some adults, problems during sexual intercourse. Heritability of hypospadias has been shown in some reports, and the abnormality has been associated with the presence of mutations in one of the genes involved in urogenital development. However, even for patients who were born in families with a higher incidence rate of this defect, no evident genetic alteration could be identified in known genes, indicating that the list of loci involved is still incomplete. To further complicate matters, recent reports also underline that epigenetic changes, without any identifiable gene sequence mutation, may be involved in gene function impairment. Therefore, the inheritance of most hypospadias cases is not evident, suggesting that the genetic background is not the only cause of this malformation; indeed, the majority of hypospadias cases are classified as sporadic and idiopathic.

MATERIALS AND METHODS

Evidence has accumulated highlighting the role of the environment and of its relationships with the genome in the etiology of this abnormality. In particular, the interaction between some chemicals, which are able to mimic endogenous molecules such as sexual hormones--for this reason called endocrine disrupting compounds (EDC)--and specific receptors has been extensively investigated during the pregnancy. Additionally, several articles have shown that parental and gestational factors play a significant role too. Indeed, physiological alterations, such as body weight of the mother and/or of the newborn, mother's diabetes, impaired father fertility, and exposure of one parent to job-related pollutants, show in many cases a direct correlation with hypospadias incidence. The overall prevalence of this condition has been studied in many countries, suggesting that at least in some periods and/or in specific populations there are detectable fluctuations, probably mirroring the different natural environments. However, many articles present data that do not agree with these findings and, consequently, most causes of hypospadias are still highly debated.

RESULTS

In this review, we summarize the developmental steps involved in urogenital tract formation, with a particular emphasis on the genes that most frequently are associated with this condition, or that are subject to environmental stress, or that may be the targets of hormone-like, exogenous molecules. Then, we make an overview of the identified factors able to impair the function of important genes, even in the absence of their mutations, including those for which contradictory reports have been published. Finally, we propose an explanation of sporadic cases of hypospadias that reconciles these contradictions and suggest some steps for moving forward in the research focused on this condition.

CONCLUSION

We hypothesize that most patients develop hypospadias because of gene-environment interactions acting on polymorphic genes that, in the absence of environmental stimuli, would otherwise cause no developmental anomaly during urogenital development.

Self-reported parental exposure to pesticide during pregnancy and birth outcomes: the MecoExpo cohort study

The MecoExpo study was performed in the Picardy region of northern France, in order to investigate the putative relationship between parental exposures to pesticides (as reported by the mother) on one hand and neonatal parameters on the other. The cohort comprised 993 mother-newborn pairs. Each mother completed a questionnaire that probed occupational, domestic, environmental and dietary sources of parental exposure to pesticides during her pregnancy. Multivariate regression analyses were then used to test for associations between the characteristics of parental pesticide exposure during pregnancy and the corresponding birth outcomes. Maternal occupational exposure was associated with an elevated risk of low birth weight (odds ratio (OR) [95% confidence interval]: 4.2 [1.2, 15.4]). Paternal occupational exposure to pesticides was associated with a lower than average gestational age at birth (-0.7 weeks; p = 0.0002) and an elevated risk of prematurity (OR: 3.7 [1.4, 9.7]). Levels of domestic exposure to veterinary antiparasitics and to pesticides for indoor plants were both associated with a low birth weight (-70 g; p = 0.02 and -160 g; p = 0.005, respectively). Babies born to women living in urban areas had a lower birth length and a higher risk of low birth length (-0.4 cm, p = 0.006 and OR: 2.9 [1.5, 5.5], respectively). The present study results mainly demonstrate a negative correlation between fetal development on one hand and parental occupational and domestic exposure to pesticides on the other. Our study highlights the need to perform a global and detailed screening of all potential physiological effects when assessing in utero exposure to pesticides.

External birth defects in Southern Vietnam: a population-based study at the grassroots level of health care in Binh Thuan Province

BACKGROUND

There currently exists no data on birth defects from population-based studies in Vietnam. Our study's aim was to assess external birth defect (EBD) prevalence among live newborns in Binh Thuan Province in Vietnam with the help of health workers at all levels of the health system.

METHODS

A 2-month training session for 452 health professionals (HP) practicing delivery care in 127 Commune Health Stations (CHS) and in 12 provincial or district hospitals (DH) was setup in 2006. After a successful 6-month pilot study, a one-year registry of EBDs was established in 2008. All live newborns were screened for EBDs within 24 hours after birth in all DH obstetric departments and in all CHSs. Trained local HPs collected information by filling out a predesigned form and by photographing the affected newborn. EBDs were coded using the International Classification of Diseases system-10, Clinical Modification. The study was repeated in 2010.

RESULTS

Throughout 2010, out of a total of 13,954 newborns, 84 cases with one or more EBDs were reported, representing an overall prevalence rate of 60.2 per 10,000 live births. The most common groups of EBDs were limbs (27.2/10,000), orofacial clefts (20.1/10,000) and the central nervous system (7.9/10,000).

CONCLUSIONS

This first population-based study in Vietnam, which required coordination efforts at the local level, provides baseline prevalences of external birth defects. Data on EBDs from this study in southern Vietnam may be useful for setting up a regional population-based registry of birth defects in Vietnam.

Pesticide flow analysis to assess human exposure in greenhouse flower production in Colombia

Human exposure assessment tools represent a means for understanding human exposure to pesticides in agricultural activities and managing possible health risks. This paper presents a pesticide flow analysis modeling approach developed to assess human exposure to pesticide use in greenhouse flower crops in Colombia, focusing on dermal and inhalation exposure. This approach is based on the material flow analysis methodology. The transfer coefficients were obtained using the whole body dosimetry method for dermal exposure and the button personal inhalable aerosol sampler for inhalation exposure, using the tracer uranine as a pesticide surrogate. The case study was a greenhouse rose farm in the Bogota Plateau in Colombia. The approach was applied to estimate the exposure to pesticides such as mancozeb, carbendazim, propamocarb hydrochloride, fosetyl, carboxin, thiram, dimethomorph and mandipropamide. We found dermal absorption estimations close to the AOEL reference values for the pesticides carbendazim, mancozeb, thiram and mandipropamide during the study period. In addition, high values of dermal exposure were found on the forearms, hands, chest and legs of study participants, indicating weaknesses in the overlapping areas of the personal protective equipment parts. These results show how the material flow analysis methodology can be applied in the field of human exposure for early recognition of the dispersion of pesticides and support the development of measures to improve operational safety during pesticide management. Furthermore, the model makes it possible to identify the status quo of the health risk faced by workers in the study area.

Pesticide exposure in children

Pesticides are a collective term for a wide array of chemicals intended to kill unwanted insects, plants, molds, and rodents. Food, water, and treatment in the home, yard, and school are all potential sources of children's exposure. Exposures to pesticides may be overt or subacute, and effects range from acute to chronic toxicity. In 2008, pesticides were the ninth most common substance reported to poison control centers, and approximately 45% of all reports of pesticide poisoning were for children. Organophosphate and carbamate poisoning are perhaps the most widely known acute poisoning syndromes, can be diagnosed by depressed red blood cell cholinesterase levels, and have available antidotal therapy. However, numerous other pesticides that may cause acute toxicity, such as pyrethroid and neonicotinoid insecticides, herbicides, fungicides, and rodenticides, also have specific toxic effects; recognition of these effects may help identify acute exposures. Evidence is increasingly emerging about chronic health implications from both acute and chronic exposure. A growing body of epidemiological evidence demonstrates associations between parental use of pesticides, particularly insecticides, with acute lymphocytic leukemia and brain tumors. Prenatal, household, and occupational exposures (maternal and paternal) appear to be the largest risks. Prospective cohort studies link early-life exposure to organophosphates and organochlorine pesticides (primarily DDT) with adverse effects on neurodevelopment and behavior. Among the findings associated with increased pesticide levels are poorer mental development by using the Bayley index and increased scores on measures assessing pervasive developmental disorder, inattention, and attention-deficit/hyperactivity disorder. Related animal toxicology studies provide supportive biological plausibility for these findings. Additional data suggest that there may also be an association between parental pesticide use and adverse birth outcomes including physical birth defects, low birth weight, and fetal death, although the data are less robust than for cancer and neurodevelopmental effects. Children's exposures to pesticides should be limited as much as possible.

Organophosphate pesticide exposure and perinatal outcomes in Shanghai, China

Although pesticide use is widespread in China, little is known about levels of exposure to organophosphate pesticides in the population and its potential adverse health effects. We investigated levels of organophosphate exposure in pregnant women and the association between organophosphate exposure and perinatal outcomes in Shanghai, China, by enrolling 187 healthy pregnant women between September 2006 and January 2007. Pesticide exposure was assessed by a questionnaire administered to the mothers in the hospital after delivery as well as by analyses of maternal urinary nonspecific metabolites of organophosphate pesticides (dimethyl and diethyl phosphates). Information on birth weight and length was collected from medical records. Geometric means of metabolites were 25.75 μg/L for dimethylphosphate (DMP); 11.99 μg/L for dimethylthiophosphate (DMTP); 9.03 μg/L for diethylphosphate (DEP); and 9.45 μg/L for diethyldithiophosphate (DETP). We found that a log unit increase in urinary DEP was associated with a decrease in gestational duration in girls by 1.79 weeks. [ß(adjusted)=-1.79 weeks per log(10) unit increase; 95% confidence interval (CI), -2.82 to -0.76; p=0.001]. These data suggest that high pesticide level might adversely affect duration of gestation although this association was not present among boys. No associations for any of the organophosphate exposure measures were present for birth weight and length, suggesting that organophosphate pesticides may have no effects on fetal growth. Given that maternal urine pesticide levels in Shanghai were much higher than those reported in developed countries, more studies on the effects of in utero organophosphate exposure on fetal growth and child neurodevelopment are warranted.

Employment in the Ecuadorian cut-flower industry and the risk of spontaneous abortion

BACKGROUND

Research on the potentially adverse effects of occupational pesticide exposure on risk of spontaneous abortion (SAB) is limited, particularly among female agricultural workers residing in developing countries.

METHODS

Reproductive histories were obtained from 217 Ecuadorian mothers participating in a study focusing on occupational pesticide exposure and children's neurobehavioral development. Only women with 2+ pregnancies were included in this study (n = 153). Gravidity, parity and frequency of SAB were compared between women with and without a history of working in the cut-flower industry in the previous 6 years. Logistic regression analysis was conducted to assess the relation between SAB and employment in the flower industry adjusting for maternal age.

RESULTS

In comparison to women not working in the flower industry, women working in the flower industry were significantly younger (27 versus 32 years) and of lower gravidity (3.3 versus 4.5) and reported more pregnancy losses. A 2.6 (95% CI: 1.03-6.7) fold increase in the odds of pregnancy loss among exposed women was observed after adjusting for age. Odds of reporting an SAB increased with duration of flower employment, increasing to 3.4 (95% CI: 1.3, 8.8) among women working 4 to 6 years in the flower industry compared to women who did not work in the flower industry.

CONCLUSION

This exploratory analysis suggests a potential adverse association between employment in the cut-flower industry and SAB. Study limitations include the absence of a temporal relation between exposure and SAB, no quantification of specific pesticides, and residual confounding such as physical stressors (i.e., standing). Considering that approximately half of the Ecuadorian flower laborers are women, our results emphasize the need for an evaluating the reproductive health effects of employment in the flower industry on reproductive health in this population.

Oral exposure of mice to formulations of organophosphorous pesticides: gestational and litter outcomes

The purpose of this study was to examine gestational and litter outcomes in mice models from oral exposure to a mixture of formulations of organophosphorous pesticides used in local vegetable production. Male and female mice were exposed to premating and preconception, respectively, to a mixture of organophosphorous pesticide formulations for a period of 7 weeks. The pregnant dams were monitored during gestation and delivered by Caesarean section pre-partum. The percentages of resorptions and the resorptions/implantations ratios, in all the exposed groups, were significantly higher than the reference and the control groups. Percentages of litters with one or more lost embryos were observed in all the exposed groups and were significantly higher than the comparison groups. Fetal weights were significantly lower and the maternal weight gains per live fetus were significantly higher in the medium-dose-exposed groups than the control group. Percentages of fetuses with intra-uterine growth retardation at one standard deviation were significantly higher in all the exposed groups than the comparison groups.

Is hypospadias a genetic, endocrine or environmental disease, or still an unexplained malformation?

Hypospadias is one of the most frequent genital malformations in the male newborn and results from an abnormal penile and urethral development. This process requires a correct genetic programme, time- and space-adapted cellular differentiation, complex tissue interactions, and hormonal mediation through enzymatic activities and hormonal transduction signals. Any disturbance in these regulations may induce a defect in the virilization of the external genitalia and hypospadias. This malformation thus appears to be at the crossroads of various mechanisms implicating genetic and environmental factors. The genes of penile development (HOX, FGF, Shh) and testicular determination (WT1, SRY) and those regulating the synthesis [luteinizing hormone (LH) receptor] and action of androgen (5alpha reductase, androgen receptor) can cause hypospadias if altered. Several chromosomal abnormalities and malformative syndromes include hypospadias, from anterior to penoscrotal forms. More recently, CXorf6 and ATF3 have been reported to be involved. Besides these genomic and hormonal factors, multiple substances found in the environment can also potentially interfere with male genital development because of their similarity to hormones. The proportion of hypospadias cases for which an aetiology is detected varies with the authors but it nevertheless remains low, especially for less severe cases. An interaction between genetic background and environment is likely.

Epidemiologic evidence of relationships between reproductive and child health outcomes and environmental chemical contaminants

This review summarizes the level of epidemiologic evidence for relationships between prenatal and/or early life exposure to environmental chemical contaminants and fetal, child, and adult health. Discussion focuses on fetal loss, intrauterine growth restriction, preterm birth, birth defects, respiratory and other childhood diseases, neuropsychological deficits, premature or delayed sexual maturation, and certain adult cancers linked to fetal or childhood exposures. Environmental exposures considered here include chemical toxicants in air, water, soil/house dust and foods (including human breast milk), and consumer products. Reports reviewed here included original epidemiologic studies (with at least basic descriptions of methods and results), literature reviews, expert group reports, meta-analyses, and pooled analyses. Levels of evidence for causal relationships were categorized as sufficient, limited, or inadequate according to predefined criteria. There was sufficient epidemiological evidence for causal relationships between several adverse pregnancy or child health outcomes and prenatal or childhood exposure to environmental chemical contaminants. These included prenatal high-level methylmercury (CH(3)Hg) exposure (delayed developmental milestones and cognitive, motor, auditory, and visual deficits), high-level prenatal exposure to polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), and related toxicants (neonatal tooth abnormalities, cognitive and motor deficits), maternal active smoking (delayed conception, preterm birth, fetal growth deficit [FGD] and sudden infant death syndrome [SIDS]) and prenatal environmental tobacco smoke (ETS) exposure (preterm birth), low-level childhood lead exposure (cognitive deficits and renal tubular damage), high-level childhood CH(3)Hg exposure (visual deficits), high-level childhood exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (chloracne), childhood ETS exposure (SIDS, new-onset asthma, increased asthma severity, lung and middle ear infections, and adult breast and lung cancer), childhood exposure to biomass smoke (lung infections), and childhood exposure to outdoor air pollutants (increased asthma severity). Evidence for some proven relationships came from investigation of relatively small numbers of children with high-dose prenatal or early childhood exposures, e.g., CH(3)Hg poisoning episodes in Japan and Iraq. In contrast, consensus on a causal relationship between incident asthma and ETS exposure came only recently after many studies and prolonged debate. There were many relationships supported by limited epidemiologic evidence, ranging from several studies with fairly consistent findings and evidence of dose-response relationships to those where 20 or more studies provided inconsistent or otherwise less than convincing evidence of an association. The latter included childhood cancer and parental or childhood exposures to pesticides. In most cases, relationships supported by inadequate epidemiologic evidence reflect scarcity of evidence as opposed to strong evidence of no effect. This summary points to three main needs: (1) Where relationships between child health and environmental exposures are supported by sufficient evidence of causal relationships, there is a need for (a) policies and programs to minimize population exposures and (b) population-based biomonitoring to track exposure levels, i.e., through ongoing or periodic surveys with measurements of contaminant levels in blood, urine and other samples. (2) For relationships supported by limited evidence, there is a need for targeted research and policy options ranging from ongoing evaluation of evidence to proactive actions. (3) There is a great need for population-based, multidisciplinary and collaborative research on the many relationships supported by inadequate evidence, as these represent major knowledge gaps. Expert groups faced with evaluating epidemiologic evidence of potential causal relationships repeatedly encounter problems in summarizing the available data. A major driver for undertaking such summaries is the need to compensate for the limited sample sizes of individual epidemiologic studies. Sample size limitations are major obstacles to exploration of prenatal, paternal, and childhood exposures during specific time windows, exposure intensity, exposure-exposure or exposure-gene interactions, and relatively rare health outcomes such as childhood cancer. Such research needs call for investments in research infrastructure, including human resources and methods development (standardized protocols, biomarker research, validated exposure metrics, reference analytic laboratories). These are needed to generate research findings that can be compared and subjected to pooled analyses aimed at knowledge synthesis.

Spontaneous abortion and maternal work in greenhouses

BACKGROUND

A positive association between maternal occupational exposure to pesticide and spontaneous abortion has been reported in some studies. Work in greenhouses may imply exposure of pregnant women to pesticides continuously and at elevated level.

METHODS

A total of 717 women working in greenhouses provided information on 973 pregnancies, including 110 spontaneous abortions. These pregnancies were classified as exposed or not exposed according to maternal occupation, re-entry activities and application of pesticides in greenhouses during at least 1 month in the first trimester of pregnancy. The ORs for spontaneous abortion were estimated through a generalised estimate equations model for all orders of pregnancy together, and through a logistic regression model limited to first pregnancies.

RESULTS

Increased risks of spontaneous abortion were found for maternal re-entry activities within 24 hr after pesticides were applied (all orders of pregnancy: OR 3.2, 95% CI 1.3-7.7; first pregnancies: OR 3.8, 95% CI 1.0-13.9) and for those who applied pesticides (all orders of pregnancy: OR 2.6, 95% CI 1.0-6.6; first pregnancies: OR 3.7, 95% CI 0.7-20,6)

CONCLUSIONS

The observed results support the hypothesis of an association between maternal work in greenhouses and spontaneous abortion. The main limitations of the study are lack of information on the specific chemicals used and the small number of pregnancies heavily exposed to pesticides.

The influence of the environment and other exogenous agents on spontaneous abortion risk

It is estimated that close to 30% of all pregnancies end in spontaneous abortion. Although about 60% of spontaneous abortions are thought to be due to genetic, infectious, hormonal, and immunological factors, the role of the environment remains poorly understood. Pregnancy involves a delicate balance of hormonal and immunological functions, which may be affected by environmental substances. Many toxic substances that are persistent in the environment and accumulate in the fatty tissues may disrupt this equilibrium. This overview addresses known risk factors for spontaneous abortions and examines the role, if any, that environmental factors (chemical and physical) may play in the etiology of this adverse health outcome.

Oral exposure of male and female mice to formulations of organophosphorous pesticides: congenital malformations

Birth outcome was studied in pre-partum litters of mice exposed to oral doses of organophosphorous pesticides at low and high concentrations before mating. Exposed and unexposed pregnant dams were delivered by Caesarean section 1 day before partum, the fetuses were collected, counted and weighed, and the numbers of resorptions were recorded. Live litter sizes were non-significantly higher in all the exposed groups compared with the control group. The numbers of resorptions were significantly higher in all the exposed groups than in the comparison groups. The incidence of intra-uterine growth retardation was significantly higher in all the exposed groups than in the comparison groups. The incidences of congenital malformations were significantly higher in the exposed groups than in one or more of the comparison groups for the defects of the ears, eyes, jaws, brain, and tongue in all the exposed groups. Low set microtia, cataract or open eyelids, microcephaly or anencephaly, maxillary or mandibular hypoplasia, and protruding tongue were observed in all groups, but the numbers were significantly higher in the exposed groups compared with one or more of the comparison groups. Curled or missing tail and intra-auricular septal or intra-ventricular septal defects were observed in higher numbers in the groups in which both the males and the females were exposed than in the comparison groups. Male:female sex ratios were significantly higher in the groups in which males only and females only were exposed.

Pesticides use by smallholder farmers in vegetable production in Northern Tanzania

Small-scale farmers in Northern Tanzania grow vegetables that include tomatoes, cabbages and onions and use many types of pesticides to control pests and diseases that attack these crops. Based on the use of questionnaires and interviews that were conducted in Arumeru, Monduli, Karatu, and Moshi rural districts, this study investigates farmers' practices on vegetable pest management using pesticides and related cost and health effects. The types of pesticides used by the farmers in the study areas were insecticides (59%), fungicides (29%) and herbicides (10%) with the remaining 2% being rodenticides. About a third of the farmers applied pesticides in mixtures. Up to 90% had a maximum of 3 pesticides in a mixture. In all cases there were no specific instructions either from the labels or extension workers regarding these tank mixtures. Fifty three percent of the farmers reported that the trend of pesticide use was increasing, while 33% was constant and 14% was decreasing. More than 50 percent of the respondents applied pesticides up to 5 times or more per cropping season depending on the crop. Insecticides and fungicides were routinely applied by 77% and 7%, respectively by these farmers. Sixty eight percent of farmers reported having felt sick after routine application of pesticides. Pesticide-related health symptoms that were associated with pesticides use included skin problems and neurological system disturbances (dizziness, headache). Sixty one percent of farmers reported spending no money on health due to pesticides. These results can be used to develop a tool to quantify the cost of pesticide use in pest management by small-scale vegetable farmers in Northern Tanzania and contribute to the reformation of pesticide policy for safe and effective use of pesticides.

Maternal miscarriage history and risk of anencephaly

Women with a history of reproductive loss may be at an increased risk of having an unfavourable outcome in subsequent pregnancies. Using data from a matched case-control study based on the record of the Epidemiological Surveillance System of Neural Tube Defects, we evaluated the association between history of maternal reproductive loss and the risk of anencephaly in three Mexican states. Mothers of 157 cases of anencephaly and 151 controls born during the period March 2000 to February 2001, were interviewed about their reproductive history and other additional factors, including socio-economic characteristics, prenatal care, use of tobacco and alcohol, presence of chronic diseases, acute illnesses and fever during the periconceptional period, and consumption of multivitamins and medicines during this period; mothers who reported no prior pregnancies were excluded from the analysis; 58 matched case-control pairs were used for the analysis. After adjusting for potential confounders, women with a history of miscarriage in previous pregnancies had 4.58 times more risk of having a child with anencephaly, than those who did not have this history; OR = 4.58, [95% CI 1.22, 17.23]. Our results suggest that a history of previous miscarriages is a risk indicator for anencephaly in future gestations. This does not necessarily mean that the miscarriage itself is the cause, but that common mechanisms could be involved in the aetiology of both events. Thus, women who have had histories of reproductive losses, especially miscarriages, should be a priority group for the primary and secondary prevention of neural tube defects.

Occupational Exposure to Pesticides and Pregnancy Outcomes in Gardeners and Farmers: A Study Within the Danish National Birth Cohort

OBJECTIVE

We conducted a follow-up study to examine whether exposure to pesticides during pregnancy had an adverse effect on pregnancy outcomes among Danish gardeners and farmers.

METHODS

Using data from the National Birth Cohort in Denmark, we identified 226 pregnancies of gardeners and 214 pregnancies of farmers during 1997 through 2003. Work activities and exposure to pesticides were reported in an interview (around 16 weeks of gestation). Totally, 62,164 other workers in the cohort served as a reference group. Pregnancy outcomes were obtained by linkage to the national registers. Cox regression was applied to analyze late fetal loss and congenital malformations, and logistic regression was used to analyze preterm birth and small for gestational age.

RESULTS

There were no significant differences in the studied pregnancy outcomes between gardeners or farmers and all other workers, except for an increased risk of very preterm birth for gardeners and a favorable birth weight for farmers. With the exception of biologic approach used in gardening, neither work activities nor exposure to pesticides showed a significant increased risk of adverse birth outcomes among gardeners or farmers.

CONCLUSIONS

Our data suggest little effect of occupational exposures to pesticides on pregnancy outcomes among gardeners or farmers in Denmark. The results may not apply to other countries.

Exposure to pesticides and time to pregnancy among female greenhouse workers

The aim of the study was to evaluate the possible effect of maternal work in greenhouses, as characterised by potentially high exposure to pesticides, on female fertility. Nine hundred and ten women active in 34 greenhouse flower growing enterprises in 1998-2000, with at least one pregnancy, and aged less than 50 years were identified. Seven hundred and seventeen (79%) agreed to be interviewed and reported 1699 pregnancies, of which 713 had complete information on time to pregnancy and occupation. These pregnancies were classified as exposed or non-exposed according to the maternal occupation in greenhouses at the moment of conception and analysed using logistic regression and survival analysis methods. We found a slightly higher proportion of pregnancies with delayed conception (more than 6 months) in the exposed group. However, after adjustment for confounding variables, the estimated hazard ratio for reduced fertility among the exposed was not significantly different to that of the non-exposed pregnancies (HR=0.96, 95%CI: 0.81, 1.13). A significant reduction in fecundability was observed in older women and with a daily consumption of one or more alcoholic beverages or cups of tea.

Pesticides and the induction of aneuploidy in human sperm

Pesticides are some of the most frequently released toxic chemicals into the environment. Exposure to them has been associated with reproductive dysfunction, but the knowledge of the genotoxic risks of these substances is still limited. In vitro and in vivo, many pesticides are shown to induce aneuploidy. Analysis of sperm chromosomes by fluorescence in situ hybridization (FISH) with chromosome-specific probes has obtained increasing popularity in genetic toxicology. Sperm-FISH studies on men exposed to pesticides have yielded conflicting results: in men exposed to multiple pesticides during spraying no increased disomy frequencies in sperm were observed, although one study reported an increased rate of sex chromosome nullisomy. In contrast the two studies conducted in pesticide factories showed increased frequencies of sperm aneuploidy in exposed men compared to controls. The available data indicates that at least some of the commonly used pesticides are capable of inducing aneuploidy in human sperm when the exposure level is high enough.

Time to first pregnancy among women working in agricultural production

OBJECTIVES

This study explores several factors potentially associated with reduced fecundability among women working in cut flowers production.

METHODS

A cross-sectional study of first pregnancies was undertaken in 47 Colombian floriculture companies. Two thousand and eighty-five women were interviewed regarding potential reproductive, lifestyle and work history predictors of time-to-pregnancy (TTP), measured in months. Fecundability odds ratios (fOR) were estimated using a discrete time analogue of Cox's proportional hazard model.

RESULTS

Associated with longer TTP were: irregular relationships with her partner (fOR 0.82, 95% CI 0.73-0.91), illness in the year prior to pregnancy (fOR 0.78, 95% CI 0.62-0.98), smoking tobacco (fOR 0.71, 95% CI 0.59-0.85), and work in flower production, less than 24 months (fOR 0.86 95% CI 0.75-0.98) or 2 years or more (fOR 0.73, 95% CI 0.63-0.84).

CONCLUSIONS

Work in flower production, irregular relationship, illness and tobacco exposure would be associated with impaired fecundability.

Exposure to pesticides and heavy work in greenhouses during pregnancy: does it effect birth weight?

OBJECTIVES

Work in greenhouses is performed in warm microclimate during the most time of the year, involves usually moderately intense or heavy work. The working conditions in greenhouses might involve also indirect exposure to pesticides resulting from contact with pesticide-treated flowers and vegetables. The aim of the study was to investigate whether the work in greenhouse during pregnancy adversely influenced infant birth weight and, if so, which of the two main potential hazards typical for such environment (heavy physical work or exposure to pesticides) played the major role in this process.

METHODS

The list of 14 major greenhouses (each above 5 ha) growing vegetables (cucumbers and tomatoes) was obtained from the Polish Chamber of Horticulture. Between January 2001 and December 2003, 460 women at the age below 45 years, married or who lived with a partner and who had been working for a period of at least 2 years in greenhouses in Poland were asked to participate in the project. We classified pregnancies of women working in, and out of, greenhouses on the basis of energy expenditure during mother's work into three groups: A (200-700 kcal/shift); B (701-1000 kcal/shift); and C (1001-1200 kcal/shift). Information about application of pesticides in 1997-2001 was received from persons responsible for chemical protection in each examined greenhouse. Trade names of pesticides, names and amounts of the active ingredients, type of cultivation and its area were abstracted from pesticide application registers run by each greenhouse operator. Pesticides were classified as reproductive and developmental (RD) toxins according to Pan American Pesticide Database classification.

RESULTS

The mean birth weight of infants whose mothers worked in greenhouse during pregnancy (work expenditure >1000 kcal/shift) was 177 g lower than that of those whose mothers worked out of greenhouse (light work <700 kcal/shift) (p = 0.05). Mothers who during work in greenhouse were potentially exposed to RD pesticides, delivered infants with birth weight lower by about 70 g. than infants' mothers not working at places where pesticides RD were applied, but these findings were not statistically significant.

CONCLUSION

Our results indicate that infants of mothers performing heavy work inside greenhouse during pregnancy had lower mean birth weight than infants of mothers working out of greenhouse. No similar effects of current exposure to pesticides was observed.

Association of in utero organophosphate pesticide exposure and fetal growth and length of gestation in an agricultural population

Although pesticide use is widespread, little is known about potential adverse health effects of in utero exposure. We investigated the effects of organophosphate pesticide exposure during pregnancy on fetal growth and gestational duration in a cohort of low-income, Latina women living in an agricultural community in the Salinas Valley, California. We measured nonspecific metabolites of organophosphate pesticides (dimethyl and diethyl phosphates) and metabolites specific to malathion (malathion dicarboxylic acid), chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro-2-pyridinyl) phosphoro-thioate], and parathion (4-nitrophenol) in maternal urine collected twice during pregnancy. We also measured levels of cholinesterase in whole blood and butyryl cholinesterase in plasma in maternal and umbilical cord blood. We failed to demonstrate an adverse relationship between fetal growth and any measure of in utero organophosphate pesticide exposure. In fact, we found increases in body length and head circumference associated with some exposure measures. However, we did find decreases in gestational duration associated with two measures of in utero pesticide exposure: urinary dimethyl phosphate metabolites [beta(adjusted) = -0.41 weeks per log10 unit increase; 95% confidence interval (CI), -0.75 -- -0.02; p = 0.02], which reflect exposure to dimethyl organophosphate compounds such as malathion, and umbilical cord cholinesterase (beta(adjusted) = 0.34 weeks per unit increase; 95% CI, 0.13-0.55; p = 0.001). Shortened gestational duration was most clearly related to increasing exposure levels in the latter part of pregnancy. These associations with gestational age may be biologically plausible given that organophosphate pesticides depress cholinesterase and acetylcholine stimulates contraction of the uterus. However, despite these observed associations, the rate of preterm delivery in this population (6.4%) was lower than in a U.S. reference population.

Pesticide exposure and women's health

BACKGROUND

Research on pesticide-related health effects has been mostly focused in industrialized countries and in men. This paper discusses critical issues related to women's pesticide exposure and its effects on women's health.

METHODS

The literature on pesticides was reviewed with emphasis on data related to women. Attention was focused on research suggesting different conditions of exposure or different response to pesticides by sex. Studies on cancer and reproductive effects were used as illustrative examples.

RESULTS

Women are increasingly exposed to pesticides in developing countries, where women's poisoning and other pesticide-related injuries seem to be greatly underestimated. Many of the effects of pesticides in human health will be the same for men and women, but not always. Some organochlorine pesticides have been related to breast cancer in post-menopausal women. However, knowledge about other pesticides is much more limited. Epidemiological studies assessing maternal exposure to individual pesticides and abortion, fetal death, or congenital defects are not conclusive, although some suggestive associations have been observed.

CONCLUSIONS

Gender-sensitive research is needed to properly address the study of women's pesticide exposures and related adverse outcomes. A better understanding of potential gender-environment and sex-environment interactions related to pesticide exposure and health effects in women is needed.

Agricultural chemical exposures and birth defects in the Eastern Cape Province, South Africa: a case-control study

BACKGROUND

South Africa is one of the major users of pesticides on the African continent. The Eastern Cape is the second largest province in South Africa. There has been growing concern about the occurrence of certain birth defects which seemed to have increased in the past few years. In this paper we investigate associations between exposure to agricultural chemicals and certain birth defects. Few such studies have been undertaken in the developing world previously.

METHODS

Between September 2000 and March 2001 a case - control study was conducted among rural women in the area of the Eastern cape to investigate the association between women's exposure to pesticides and the occurrence of birth defects. Information on birth defects was obtained from the register of the Paediatrics Department at the Cecilia Makiwane Hospital in Mdantsane, one of the largest referral hospitals in the province. The cases were children who were diagnosed with selected birth defects. The controls were children born in the same areas as the cases. Exposure information on the mothers was obtained by interview concerning from their activities in gardens and fields. Data were analysed using conditional logistic regression.

RESULTS

A total of 89 case mothers and 178 control mothers was interviewed. Babies with birth defects were seven times more likely to be born to women exposed to chemicals used in gardens and fields compared to no reported exposure (Odds Ratio 7.18, 95% CI 3.99, 13.25); and were almost twice as likely to be born to women who were involved in dipping livestock used to prevent ticks (OR 1.92, 95% CI 1.15, 3.14). They were also 6.5 times more likely to be born to women who were using plastic containers for fetching water (OR 6.5, 95% CI 2.2, 27.9). Some of these containers had previously contained pesticides (OR 1.87, 95% CI 1.06, 3.31).

CONCLUSIONS

These findings suggest a link between exposure to pesticides and certain birth defects among the children of rural South African women who work on the land. Education programmes for women alerting them to the dangers to their babies from the use of pesticides and alternative farming methods and elimination of the reuse of pesticide containers are indicated as preventive measures.

The use of pesticides in a Polish rural population and its effect on birth weight

INTRODUCTION

The risk of adverse reproductive outcomes related to pesticide exposure has been investigated in few studies; however, the results have not been consistent. The goal of the present study was to evaluate the influence of maternal residual exposure to pesticides on birth weight among women in an agricultural district in Central Poland.

METHOD

Subjects included 104 women who delivered a single, live infant between 1 January 1994 and 31 December 2000. Based on maternal reports, the type of farming (crops, orchards, non-farming jobs), involvement in field work and the trade names of pesticides used within last pregnancy were established. Birth weight for the most recent pregnancy was abstracted from the medical data of the local maternity unit.

RESULTS

Mothers who reported involvement in field work had a similar pregnancy duration but delivered infants with a significantly higher birth weight than mothers not reporting such activities in the first or second trimester of pregnancy (P=0.04). However, after controlling for pregnancy duration and other factors affecting birth weight, we found that maternal exposure to synthetic pyrethroids in the first or second trimester was associated with a small but statistically significant decrease in birth weight (P=0.02).

CONCLUSIONS

We postulate that the observed effect of pyrethroids exposure was related to a slower pace of foetal development corresponding to the small-for-gestational-age (SGA) birth.

Environmental risk factors and male fertility and reproduction

Several environmental substances and pesticides exert a direct, cytotoxic effect on male germ cells. However, an increasing concern has been raised by compounds that may act through more subtle mechanisms, for example, specific pesticides that are potentially capable of modulating or disrupting the endocrine system. Overall, exposure to pesticides with endocrine-disrupting potential raise a particular concern for male fertility because of the possible occurrence of both effects at low concentrations and additive interactions with other environmental risk factors. Delayed reproductive problems deserve special attention, since experimental data consistently indicate a high vulnerability in the developing male reproductive system. Epidemiologic studies have confirmed an increased risk of conception delay associated with occupational exposure to pesticides. Moreover, an increased risk of spontaneous abortion has been noted among wives of exposed workers.

Review of recent epidemiological studies on paternal occupations and birth defects

The main findings reported by recent epidemiological studies on paternal occupations and birth defects are reviewed, and the main limitations associated with these studies discussed. Epidemiological studies on paternal occupations and birth defects were reviewed for the period 1989 to 1999 inclusive. Systematic searches were made with search engines with related keywords. There were several common paternal occupations that were repeatedly reported to be associated with birth defects. These paternal occupations were janitors, painters, printers, and occupations exposed to solvents; fire fighters or firemen; and occupations related to agriculture. The common weaknesses in most of these studies include inaccurate assessment of exposures, different classification systems, different inclusion criteria of birth defects, and low statistical power. It is concluded that epidemiological studies, reported in the past decade, suggest that several common paternal occupations are associated with birth defects. Future studies could be focused on these specific, rather than general, occupational groups so that causative agents may be confirmed and thus enable appropriate preventive measures to be taken.

Human reproductive system disturbances and pesticide exposure in Brazil

The observation of reproductive disturbances in humans and in the wildlife has been reported in the last decade in different countries. Exposure to different chemicals possibly acting in the endocrine system or endocrine disruptors, including pesticides, has been a hypothesis raised to explain the observed changes. This paper aimed to present results of an epidemiological ecologic study carried out to explore population data on pesticides exposure in selected Brazilian states in the eighties and human reproductive outcomes in the nineties. Pearson correlation coefficients were ascertained between available data pesticides sales in eleven states in Brazil in 1985 and selected further reproductive outcomes or their surrogates. Moderate to high correlations were observed to infertility, testis, breast, prostate and ovarian cancer mortality. Despite the restrains of ecologic studies to establish cause-effect relationships, the observed results are in agreement with evidence supporting a possible association between pesticides exposure and the analyzed reproductive outcomes.

Pesticide usage and health consequences for women in developing countries: out of sight, out of mind?

Pesticide exposures of women in developing countries are aggravated by economic policy changes associated with structural adjustment programs and globalization. Women in these countries, particularly in the agricultural sector, are increasingly exposed. Since they are concentrated in the most marginal positions in the formal and informal workforces, and production is organized in a gender-specific way, opportunities for women to control their exposures are limited. Data from developing countries show that: 1) women's exposures to pesticides are significantly higher than is recognized; 2) poisonings and other pesticide-related injuries are greatly underestimated for women; 3) for a given adverse outcome from exposure, the experience of that outcome is gender-discriminatory; 4) erroneous risk perception increases women's exposures. The hiatus in knowledge of gender-specific exposures and effects is related to gender biases in the nature of epidemiologic inquiry and in the literature, and the gendered nature of health workers' practices and surveillance. Recommendations are made for strong, independent organizations that provide opportunities for women to control their environments, and the factors affecting their health, as well as gender-sensitive research to address the particularities of women's pesticide exposures.

Reproductive male-mediated risk: spontaneous abortion among wives of pesticide applicators

This study was conducted among 32 pesticide applicators occupationally exposed to pesticides to determine whether paternal exposure is associated with an increased risk of spontaneous abortion. The ratio of abortion was compared between applicators and a group of 51 food retailers (control population). The ratio of abortions/pregnancies for applicators was 0.27 and for retailers 0.07. OR for spontaneous abortion adjusted for age of wife and smoking of parents is 3.8 times greater than for the control population in the multiple logistic regression model and 7.6 times with interaction effects model.

Maternal occupational exposure to chemical substances and the risk of infants small-for-gestational-age

BACKGROUND

The association between maternal occupational exposure to specific chemical substances (organic solvents, carbon tetrachloride, herbicides, chlorophenols, polychlorinated biphenyls, aromatic amines, lead and lead compounds, mercury and mercury compounds) and birth of small-for-gestational-age (SGA) infants was evaluated using data from a prospective cohort study of 3,946 pregnant women in West Germany from 1987 to 1988.

METHODS

Occupational, medical, and psychosocial information was gathered through a questionnaire from pregnant women who were recruited between 15 and 28 gestational weeks. Exposure to chemical substances at the current workplace was assessed by a job-exposure matrix constructed by Pannett in 1985 and weighted for the number of working hours per week. Women not working at the time of the interview, women with multiple births, and women with stillbirths were excluded from analysis. Data were analyzed using dichotomous and polytomous logistic regression to control for age, smoking status, alcohol consumption, body mass index, and number of former births.

RESULTS

The results of the dichotomous logistic regression analysis suggest that leather work might be associated with the birth of infants small-for-gestational-age through exposure to chlorophenols (P = 0.02) and aromatic amines (P = 0.05). In the polytomous logistic regression analysis, only the association between exposure to mercury and growth retardation reached statistical significance (P = 0.02); however, the power of the study is limited. Further adjustment for income, shift work, and heavy physical work had no substantial effect on the results.

CONCLUSIONS

These findings suggest that maternal exposure to specific chemicals at work may be a risk factor for the birth of SGA infants.

Drinking water source and spontaneous abortion: A cross-sectional study in a rural Chinese population

The authors examined the association between the risk of spontaneous abortion and the type of drinking water source in a rural Chinese population. Information about pregnancy outcomes and various exposures was collected by means of a detailed interview questionnaire. 2,876 pregnancies occurring in 1989-1993 among 2,201 nonsmoking and non-alcohol-drinking women were analyzed by logistic regression. Generalized estimating equations were used to adjust for correlations between multiple pregnancies in the same woman. The use of pond water as a drinking water source was associated with a higher risk of spontaneous abortion than the use of well or river water (odds ratio, 1.63; 95% confidence interval, 1.11 to 2.39), adjusting for potential confounders. More studies are needed to identify the agents responsible for the observed association. The results of this study emphasize the importance of monitoring potential drinking-water contamination in communities.

Levels of dichloro-dyphenyl-trichloroethane (DDT) metabolites in maternal milk and their determinant factors

To document the levels and the determinants of dichloro-dyphenyl-trichloroethane (DDT) metabolites in maternal milk, we conducted a cohort study of 50 adult females who lived in Mexico City. We measured social and dietary characteristics via interview. Levels of DDT metabolites were determined by gas-liquid chromatography. The mean values (lipid milk basis) were 0.162 ppm p,p'-DDT; 0.138 ppm o,p'-DDT; and 0.594 ppm 2,2(bis)p-chlorophyenyl-1-1-dichloroethylene (DDE). The main determinants of DDT metabolites were maternal age, lifetime lactation, history of living in an agricultural area, and consumption of salted meat and fish. We estimated that 6.0% of the breast-fed babies had daily intakes of DDT above the level of 0.005 mg/kg d recommended by the World Health Organization/Food and Agriculture Organization of the United Nations (WHO/FAO). Health-outcomes research among children is needed, and investigators should design or adjust current surveillance programs.

Aneuploidy in sperm and exposure to fungicides and lifestyle factors. ASCLEPIOS. A European Concerted Action on Occupational Hazards to Male Reproductive Capability

Fungicides include chemicals that are known aneugens. The purpose of the present study was to investigate whether occupational exposure to these and other agricultural pesticides induces aneuploidy in human sperm. The contribution of lifestyle factors (smoking and alcohol consumption) to the frequency of aneuploid sperm was evaluated as well. The effects of age and sperm concentration were analyzed as confounders. Spermatozoa from 30 healthy farmers were studied before and after exposure to fungicides, using fluorescence in situ hybridization (FISH). Ten thousand spermatozoa were scored per semen sample to determine the disomy and diploidy frequencies for chromosomes 1 and 7. Exposure to fungicides was not associated with sperm aneuploidy. Smoking was significantly associated with sperm carrying an extra chromosome 1 and with diploid sperm as well as with the aggregate frequency of aneuploid sperm. Alcohol consumption, sperm concentration, and age showed inconsistent results before and after the season of exposure to fungicides. For low-level exposures, such as occupational exposures, the sensitivity of the sperm-FISH method may not be sufficient. The present study supports earlier ones showing that smoking can increase aneuploidy in human sperm.

Pesticide exposures and fetal death: a review of the epidemiologic literature

Despite considerable concern regarding the effects on reproductive outcome of exposures to pesticides, convincing evidence for the developmental toxicity of occupational and environmental pesticide exposure in humans is lacking. In this comprehensive review of the English language epidemiologic literature, we summarize studies that have examined potential associations between fetal deaths (both spontaneous abortions and stillbirths) and specific pesticides, as well as maternal and paternal employment in occupations with potential for exposure. While many of the epidemiologic studies to date suffer from methodologic problems, the data are suggestive of increased risks of fetal deaths associated with pesticides in general and maternal employment in the agricultural industry. There is a clear need for epidemiologic research that focuses on specific pesticide products or chemical families, with improved exposure assessment. The potential role of solvents in developmental toxicity associated with pesticide use by both males and females should also be considered.

Acetylcholinesterase Inhibition as an Indicator of Organophosphate and Carbamate Poisoning in Kenyan Agricultural Workers

Acetylcholinesterase inhibition was determined for 666 Kenyan agricultural workers; 390 (58.6%) mainly pesticide applicators exposed to organophosphate and carbamate pesticides and 276 (41.4%) unexposed controls from four rural agricultural areas during 1993 and 1994. Baseline levels were depressed in the exposed group (6.1 +/- 0.84; 4.09 +/- 0.84) but not in the unexposed group (5.83 +/- 0.91; 5.60 +/- 0.87). Acetylcholinesterase inhibition was found in all exposed individuals and led, on average, to a decrease of baseline acetylcholinesterase levels of 33% (+/-12%). The control groups had a nonsignificant decrease of only 4% (+/- 8%). The exposed subjects in Naivasha (flower growers) had the largest inhibition (36%), followed by Homabay (cotton growers) (35%) and Wundanyi (vegetable growers) (33%). Those in Migori (tobacco growers) had, by far, the least inhibition of acetylcholinesterase activity (26%), indicating inherent factors that led to less inhibition. Acetylcholinesterase activity levels of 115 exposed individuals (29.6%) and no controls were depressed to values below 60% of baseline levels. The dramatic inhibition observed could lead to chronic clinical and subclinical intoxication. These findings show that acetylcholinesterase inhibition can be used as an indicator of organophosphate and carbamate poisoning in occupationally exposed agricultural workers. There is, therefore, an urgent need for primary prevention programs to monitor and address occupational exposures to these hazardous substances in agriculture in Kenya and other developing countries, as well as to use integrated pest management strategies in crop protection.

Biomarkers of human exposure to pesticides

For centuries, several hundred pesticides have been used to control insects. These pesticides differ greatly in their mode of action, uptake by the body, metabolism, elimination from the body, and toxicity to humans. Potential exposure from the environment can be estimated by environmental monitoring. Actual exposure (uptake) is measured by the biological monitoring of human tissues and body fluids. Biomarkers are used to detect the effects of pesticides before adverse clinical health effects occur. Pesticides and their metabolites are measured in biological samples, serum, fat, urine, blood, or breast milk by the usual analytical techniques. Biochemical responses to environmental chemicals provide a measure of toxic effect. A widely used biochemical biomarker, cholinesterase depression, measures exposure to organophosphorus insecticides. Techniques that measure DNA damage (e.g., detection of DNA adducts) provide a powerful tool in measuring environmental effects. Adducts to hemoglobin have been detected with several pesticides. Determination of chromosomal aberration rates in cultured lymphocytes is an established method of monitoring populations occupationally or environmentally exposed to known or suspected mutagenic-carcinogenic agents. There are several studies on the cytogenetic effects of work with pesticide formulations. The majority of these studies report increases in the frequency of chromosomal aberrations and/or sister chromatid exchanges among the exposed workers. Biomarkers will have a major impact on the study of environmental risk factors. The basic aim of scientists exploring these issues is to determine the nature and consequences of genetic change or variation, with the ultimate purpose of predicting or preventing disease.

Occupational exposures and risk of female infertility

This study examined the association between occupational chemical and radiation exposures and risk of medically diagnosed infertility in 281 women compared with 216 fertile women. After adjustment for age and exposures that occurred before case/referent ascertainment, there was an increased risk of infertility among those women exposed to volatile organic solvents (odds ratio [OR], 1.74; 95% confidence interval [CI], 1.11 to 2.71), chemical dusts (OR, 2.66; CI, 1.17 to 6.05), pesticides (OR, 3.02; CI, 1.10 to 8.29), and video display terminals (OR, 2.21, CI, 1.22, to 4.01). Among the medically diagnosed causes of infertility, the adjusted risk associated with having an ovulatory factor increased among those women exposed to solvents (OR, 1.75; CI, 1.03 to 2.98), dusts (OR, 3.00; CI, 1.19 to 7.52), or pesticides (OR, 3.82; 1.28 to 11.42). Solvents and dusts also were associated with a higher risk of tubal-factor infertility (solvents; OR, 1.95; CI, 1.08 to 3.52; dusts: OR, 2.87; CI, 1.05 to 7.88) and endometriosis (solvents: OR, 2.13; CI, 0.96 to 4.72; dusts: OR, 3.63; CI, 0.99 to 13.28). Video display terminal exposure was more likely to be found among those women diagnosed with endometriosis (OR, 3.69; CI, 1.50 to 9.13) and cervical-factor infertility (OR, 2.65; CI, 0.99 to 7.12). Results suggest that among women with a medically confirmed diagnosis, fertility may be adversely affected by a variety of occupational chemical exposures.