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Bibliography Tag: epidemiological studies

Parron et al, 2011

Parron, T., Requena, M., Hernandez, A. F., & Alarcon, R.; “Association between environmental exposure to pesticides and neurodegenerative diseases;” Toxicology and Applied Pharmacology, 2011, 256(3), 379-385; DOI: 10.1016/j.taap.2011.05.006.


Preliminary studies have shown associations between chronic pesticide exposure in occupational settings and neurological disorders. However, data on the effects of long-term non-occupational exposures are too sparse to allow any conclusions. This study examines the influence of environmental pesticide exposure on a number of neuropsychiatric conditions and discusses their underlying pathologic mechanisms. An ecological study was conducted using averaged prevalence rates of Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, cerebral degeneration, polyneuropathies, affective psychosis and suicide attempts in selected Andalusian health districts categorized into areas of high and low environmental pesticide exposure based on the number of hectares devoted to intensive agriculture and pesticide sales per capita. A total of 17,429 cases were collected from computerized hospital records (minimum dataset) between 1998 and 2005. Prevalence rates and the risk of having Alzheimer’s disease, Parkinson’s disease, multiple sclerosis and suicide were significantly higher in districts with greater pesticide use as compared to those with lower pesticide use. The multivariate analyses showed that the population living in areas with high pesticide use had an increased risk for Alzheimer’s disease and suicide attempts and that males living in these areas had increased risks for polyneuropathies, affective disorders and suicide attempts. In conclusion, this study supports and extends previous findings and provides an indication that environmental exposure to pesticides may affect the human health by increasing the incidence of certain neurological disorders at the level of the general population. FULL TEXT

Curl et al., 2020

Curl, C. L., Spivak, M., Phinney, R., & Montrose, L.; “Synthetic Pesticides and Health in Vulnerable Populations: Agricultural Workers;” Current Environmental Health Reports, 2020, 7(1), 13-29; DOI: 10.1007/s40572-020-00266-5.


PURPOSE OF REVIEW: This review aims to summarize epidemiological literature published between May 15, 2018, and May 14, 2019, that examines the relationship between exposure to synthetic pesticides and health of agricultural workers.

RECENT FINDINGS: Current research suggests that exposure to synthetic pesticides may be associated with adverse health outcomes. Agricultural workers represent a potentially vulnerable population, due to a combination of unique social and cultural risk factors as well as exposure to hazards inherent in agricultural work. Pesticide exposure among agricultural workers has been linked to certain cancers, DNA damage, oxidative stress, neurological disorders, and respiratory, metabolic, and thyroid effects.

SUMMARY: This review describes literature suggesting that agricultural workers exposed to synthetic pesticides are at an increased risk of certain cancers and neurological disorders. Recent research on respiratory effects is sparse, and more research is warranted regarding DNA damage, oxidative stress, metabolic outcomes, and thyroid effects. FULL TEXT

Alarcon et al., 2005

Alarcon, W. A., Calvert, G. M., Blondell, J. M., Mehler, L. N., Sievert, J., Propeck, M., Tibbetts, D. S., Becker, A., Lackovic, M., Soileau, S. B., Das, R., Beckman, J., Male, D. P., Thomsen, C. L., & Stanbury, M.; “Acute illnesses associated with pesticide exposure at schools;” JAMA, 2005, 294(4), 455-465; DOI: 10.1001/jama.294.4.455.


CONTEXT: Pesticides continue to be used on school property, and some schools are at risk of pesticide drift exposure from neighboring farms, which leads to pesticide exposure among students and school employees. However, information on the magnitude of illnesses and risk factors associated with these pesticide exposures is not available.

OBJECTIVE: To estimate the magnitude of and associated risk factors for pesticide related illnesses at schools.

DESIGN, SETTING AND PARTICIPANTS: Analysis of surveillance data from 1998 to 2002 of 2593 persons with acute pesticide-related illnesses associated with exposure at schools. Nationwide information on pesticide-related illnesses is routinely collected by 3 national pesticide surveillance systems: the National Institute for Occupational Safety and Health’s Sentinel Event Notification System for Occupational Risks pesticides program, the California Department of Pesticide Regulation, and the Toxic Exposure Surveillance System.

MAIN OUTCOME MEASURES: Incidence rates and severity of acute pesticide-related illnesses.

RESULTS: Incidence rates for 1998-2002 were 7.4 cases per million children and 27.3 cases per million school employee full-time equivalents. The incidence rates among children increased significantly from 1998 to 2002. Illness of high severity was found in 3 cases (0.1%), moderate severity in 275 cases (11%), and low severity in 2315 cases (89%). Most illnesses were associated with insecticides (n=895, 35%), disinfectants (n=830, 32%), repellents (n=335, 13%), or herbicides (n=279, 11%). Among 406 cases with detailed information on the source of pesticide exposure, 281 (69%) were associated with pesticides used at schools and 125 (31%) were associated with pesticide drift exposure from farmland.

CONCLUSIONS: Pesticide exposure at schools produces acute illnesses among school employees and students. To prevent pesticide-related illnesses at schools, implementation of integrated pest management programs in schools, practices to reduce pesticide drift, and adoption of pesticide spray buffer zones around schools are recommended.


Escher et al., 2020

Escher, B. I., Stapleton, H. M., & Schymanski, E. L.; “Tracking complex mixtures of chemicals in our changing environment;” Science, 2020, 367(6476), 388-392; DOI: 10.1126/science.aay6636.


Chemicals have improved our quality of life, but the resulting environmental pollution has the potential to cause detrimental effects on humans and the environment. People and biota are chronically exposed to thousands of chemicals from various environmental sources through multiple pathways. Environmental chemists and toxicologists have moved beyond detecting and quantifying single chemicals to characterizing complex mixtures of chemicals in indoor and outdoeor environments and biological matrices. We highlight analytical and bioanalytical approaches to isolating, characterizing, and tracking groups of chemicals of concern in complex matrices. Techniques that combine chemical analysis and bioassays have the potential to facilitate the identification of mixtures of chemicals that pose a combined risk.  FULL TEXT

Leite et al., 2019

Leite, S. B., Franco de Diana, D. M., Segovia Abreu, J. A., Avalos, D. S., Denis, M. A., Ovelar, C. C., Samaniego Royg, M. J., Thielmann Arbo, B. A., & Corvalan, R.; “DNA damage induced by exposure to pesticides in children of rural areas in Paraguay;” Indian Journal of Medical Research, 2019, 150(3), 290-296; DOI: 10.4103/ijmr.IJMR_1497_17.



Chronic exposure to pesticides can damage DNA and lead to cancer, diabetes, respiratory diseases and neurodegenerative and neurodevelopment disorders. The objective of this study was to determine the frequency of DNA damage through the comet assay and micronucleus (MN) test in two groups of children, under 10 yr of age living in rural Paraguay and in relation to pesticide exposure.


Two groups of 5 to 10 yr old children were formed; the exposed group (group A, n=43), born and currently living in a community dedicated to family agriculture and surrounded by transgenic soybean crops, and the control group (group B, n=41), born and living in a community dedicated to family agriculture with biological control of pests. For each child, 2000 cells were studied for the MN test and 200 cells for the comet assay.


The comparison between exposed and control children revealed significant differences in biomarkers studied for the measurement of genetic damage (cell death and DNA damage). The median of MN was higher in the exposed group (6 vs. 1) (P <0.001). Binucleated cells (2.9 vs. 0.5, P <0.001); broken eggs (5.5 vs. 1.0, P <0.001); karyorrhexis (6.7 vs. 0.5, P <0.001); kariolysis (14.0 vs. 1.0, P <0.001); pyknosis (7.4 vs. 1.2, P <0.001) and condensed chromatin (25.5 vs. 7.0, P <0.001) were significantly higher in the exposed group. The values of tail length (59.1 vs 37.2 mum); tail moment (TM) (32.8 vs. 14.4 mum); TM olive (15.5 vs. 6); % DNA tail (45.2 vs. 27.6) and % DNA head (54.8 vs. 72.4), were significantly different between the two groups.


In children exposed to pesticides, a greater genotoxic and cytotoxic effect was observed compared to non-exposed children. Our findings suggest that monitoring of genetic toxicity in population exposed to pesticides and agrochemicals should be done.


Larsen et al., 2017

Larsen, A. E., Gaines, S. D., & Deschenes, O.; “Agricultural pesticide use and adverse birth outcomes in the San Joaquin Valley of California;” Nature Communications, 2017, 8(1), 302; DOI: 10.1038/s41467-017-00349-2.


Virtually all agricultural communities worldwide are exposed to agricultural pesticides. Yet, the health consequences of such exposure are poorly understood, and the scientific literature remains ambiguous. Using individual birth and demographic characteristics for over 500 000 birth observations between 1997-2011 in the agriculturally dominated San Joaquin Valley, California, we statistically investigate if residential agricultural pesticide exposure during gestation, by trimester, and by toxicity influences birth weight, gestational length, or birth abnormalities. Overall, our analysis indicates that agricultural pesticide exposure increases adverse birth outcomes by 5-9%, but only among the population exposed to very high quantities of pesticides (e.g., top 5th percentile, i.e., ~4200 kg applied over gestation). Thus, policies and interventions targeting the extreme right tail of the pesticide distribution near human habitation could largely eliminate the adverse birth outcomes associated with agricultural pesticide exposure documented in this study.The health consequences of exposure to pesticides are uncertain and subject to much debate. Here, the effect of exposure during pregnancy is investigated in an agriculturally dominated residential area, showing that an increase in adverse birth outcomes is observed with very high levels of pesticide exposure. FULL TEXT

Chiu et al., 2018

Chiu, Y. H., Williams, P. L., Gillman, M. W., Gaskins, A. J., Minguez-Alarcon, L., Souter, I., Toth, T. L., Ford, J. B., Hauser, R., Chavarro, J. E., & Team, Earth Study; “Association Between Pesticide Residue Intake From Consumption of Fruits and Vegetables and Pregnancy Outcomes Among Women Undergoing Infertility Treatment With Assisted Reproductive Technology;” JAMA Internal Medicine, 2018, 178(1), 17-26; DOI: 10.1001/jamainternmed.2017.5038.



Animal experiments suggest that ingestion of pesticide mixtures at environmentally relevant concentrations decreases the number of live-born offspring. Whether the same is true in humans is unknown. Objective: To examine the association of preconception intake of pesticide residues in fruits and vegetables (FVs) with outcomes of infertility treatment with assisted reproductive technologies (ART).


This analysis included 325 women who completed a diet assessment and subsequently underwent 541 ART cycles in the Environment and Reproductive Health (EARTH) prospective cohort study (2007-2016) at a fertility center at a teaching hospital. We categorized FVs as having high or low pesticide residues using a validated method based on surveillance data from the US Department of Agriculture. Cluster-weighted generalized estimating equations were used to analyze associations of high- and low-pesticide residue FV intake with ART outcomes.


Adjusted probabilities of clinical pregnancy and live birth per treatment cycle.


In the 325 participants (mean [SD] age, 35.1 [4.0] y; body mass index, 24.1 [4.3]), mean (SD) intakes of high- and low-pesticide residue FVs were 1.7 (1.0) and 2.8 (1.6) servings/d, respectively. Greater intake of high-pesticide residue FVs was associated with a lower probability of clinical pregnancy and live birth. Compared with women in the lowest quartile of high-pesticide FV intake (<1.0 servings/d), women in the highest quartile (>/=2.3 servings/d) had 18% (95% CI, 5%-30%) lower probability of clinical pregnancy and 26% (95% CI, 13%-37%) lower probability of live birth. Intake of low-pesticide residue FVs was not significantly related to ART outcomes.


Higher consumption of high-pesticide residue FVs was associated with lower probabilities of pregnancy and live birth following infertility treatment with ART. These data suggest that dietary pesticide exposure within the range of typical human exposure may be associated with adverse reproductive consequences. FULL TEXT

Pahwa et al., 2019

Pahwa, M., Beane Freeman, L. E., Spinelli, J. J., Blair, A., McLaughlin, J. R., Zahm, S. H., Cantor, K. P., Weisenburger, D. D., Punam Pahwa, P. P., Dosman, J. A., Demers, P. A., & Harris, S. A.; “Glyphosate use and associations with non-Hodgkin lymphoma major histological sub-types: findings from the North American Pooled Project;” Scandinavian Journal of Work, Environment, & Health, 2019; DOI: 10.5271/sjweh.3830.



Some epidemiological studies have suggested positive associations between glyphosate use and non-Hodgkin lymphoma (NHL), but evidence is inconsistent and few studies could evaluate histological sub-types. Here, associations between glyphosate use and NHL incidence overall and by histological sub-type were evaluated in a pooled analysis of case-control studies.


The analysis included 1690 NHL cases [647 diffuse large B-cell lymphoma (DLBCL), 468 follicular lymphoma (FL), 171 small lymphocytic lymphoma (SLL), and 404 other sub-types] and 5131 controls. Logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI) for NHL overall and sub-types with self-reported ever/never, duration, frequency, and lifetime-days of glyphosate use.


Subjects who ever used glyphosate had an excess of NHL overall (OR 1.43, 95% CI 1.11-1.83). After adjustment for other pesticides, the OR for NHL overall with “ever use” was 1.13 (95% CI 0.84-1.51), with a statistically significant association for handling glyphosate >2 days/year (OR 1.73, 95% CI 1.02-2.94, P-trend=0.2). In pesticide-adjusted sub-type analyses, the ordinal measure of lifetime-days was statistically significant (P=0.03) for SLL, and associations were elevated, but not statistically significant, for ever years or days/year of use. Handling glyphosate >2 days/year had an excess of DLBCL (OR 2.14, 95% CI 1.07-4.28; P-trend=0.2). However, as with the other sub-types, consistent patterns of association across different metrics were not observed.


There was some limited evidence of an association between glyphosate use and NHL in this pooled analysis. Suggestive associations, especially for SLL, deserve additional attention. FULL TEXT

Sagiv et al., 2019

Sagiv, S. K., Bruno, J. L., Baker, J. M., Palzes, V., Kogut, K., Rauch, S., Gunier, R., Mora, A. M., Reiss, A. L., & Eskenazi, B.; “Prenatal exposure to organophosphate pesticides and functional neuroimaging in adolescents living in proximity to pesticide application;” Proceedings of the National Academy of Sciences of the United States of America, 2019; DOI: 10.1073/pnas.1903940116.


We have reported consistent associations of prenatal organophosphate pesticide (OP) exposure with poorer cognitive function and behavior problems in our Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), a birth cohort of Mexican American youth in California’s agricultural Salinas Valley. However, there is little evidence on how OPs affect neural dynamics underlying associations. We used functional near-infrared spectroscopy (fNIRS) to measure cortical activation during tasks of executive function, attention, social cognition, and language comprehension in 95 adolescent CHAMACOS participants. We estimated associations of residential proximity to OP use during pregnancy with cortical activation in frontal, temporal, and parietal regions using multiple regression models, adjusting for sociodemographic characteristics. OP exposure was associated with altered brain activation during tasks of executive function. For example, with a 10-fold increase in total OP pesticide use within 1 km of maternal residence during pregnancy, there was a bilateral decrease in brain activation in the prefrontal cortex during a cognitive flexibility task (β = -4.74; 95% CI: -8.18, -1.31 and β = -4.40; 95% CI: -7.96, -0.84 for the left and right hemispheres, respectively). We also found that prenatal OP exposure was associated with sex differences in brain activation during a language comprehension task. This first functional neuroimaging study of prenatal OP exposure suggests that pesticides may impact cortical brain activation, which could underlie previously reported OP-related associations with cognitive and behavioral function. Use of fNIRS in environmental epidemiology offers a practical alternative to neuroimaging technologies and enhances our efforts to assess the impact of chemical exposures on neurodevelopment. FULL TEXT

Gallegos et al., 2016

Gallegos, Cristina E., Bartos, Mariana, Bras, Cristina, Gumilar, Fernanda, Antonelli, Marta C., & Minetti, Alejandra; “Exposure to a glyphosate-based herbicide during pregnancy and lactation induces neurobehavioral alterations in rat offspring;” NeuroToxicology, 2016, 53, 20-28; DOI: 10.1016/j.neuro.2015.11.015.


The impact of sub-lethal doses of herbicides on human health and the environment is a matter of controversy. Due to the fact that evidence particularly of the effects of glyphosate on the central nervous system of rat offspring by in utero exposure is scarce, the purpose of the present study was to assess the neurobehavioral effects of chronic exposure to a glyphosate-containing herbicide during pregnancy and lactation. To this end, pregnant Wistar rats were exposed through drinking water to 0.2% or 0.4% of a commercial formulation of glyphosate (corresponding to a concentration of 0.65 or 1.30g/L of glyphosate, respectively) during pregnancy and lactation and neurobehavioral alterations in offspring were analyzed. The postnatal day on which each pup acquired neonatal reflexes (righting, cliff aversion and negative geotaxis) and that on which eyes and auditory canals were fully opened were recorded for the assessment of sensorimotor development. Locomotor activity and anxiety levels were monitored via open field test and plus maze test, respectively, in 45- and 90-day-old offspring. Pups exposed to a glyphosate-based herbicide showed early onset of cliff aversion reflex and early auditory canal opening. A decrease in locomotor activity and in anxiety levels was also observed in the groups exposed to a glyphosate-containing herbicide. Findings from the present study reveal that early exposure to a glyphosate-based herbicide affects the central nervous system in rat offspring probably by altering mechanisms or neurotransmitter systems that regulate locomotor activity and anxiety.

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