Geographical differences of cancer incidence in Costa Rica in relation to environmental and occupational pesticide exposure

Could pesticide exposure be implicated in the high incidence rates of depression, anxiety and suicide in farmers? A systematic review

Pesticide exposure and poisoning may rise the risk of mental health problems and suicidal tendencies. To explore the potential connection between chronic occupational exposure to pesticides and depression, anxiety, and suicide-related outcomes in farmers, a systematic review was performed. Systematic review protocol is available in PROSPERO registration number CRD42022316285. A total of fifty-seven studies met inclusion criteria: twenty-nine on depression or other mental disorders, twelve on suicide (two of them on both depression and suicide), and fourteen on pesticide poisoning or self-poisoning and death. Among the fifty-seven selected studies, eighteen were conducted in Asia, seventeen in North America, fourteen in South America, seven in European Union, one in Africa, and one in Australia/Oceania. Selected studies demonstrated an increased prevalence of depressive disorders in farmworkers exposed to pesticides as well as an increased self-reported prevalence of depression in this population. Moreover, previous pesticide poisoning increased the risk estimates for depression or other mental disorders as compared with chronic pesticide exposure. Severe pesticide poisoning and multiple poisoning showed increased risks of depressive symptoms compared with milder cases. In addition, financial difficulties and poor health were positively correlated with depression. Among studies on suicide, nine of them found that suicide rates increased in areas devoted to agriculture with intensive pesticide consumption. Moreover, studies demonstrate a higher suicide risk among farmers. The present review suggests more attention to the farmer's mental health and more detailed studies on occupational exposure to the mixture of these compounds.

Pesticide use in banana plantations in Costa Rica - A review of environmental and human exposure, effects and potential risks

Biodiversity is declining on a global scale. Especially tropical ecosystems, containing most of the planetary biodiversity, are at risk. Agricultural monocrop systems contribute to this decline as they replace original habitats and depend on extensive use of synthetic pesticides that impact ecosystems. In this review we use large-scale banana production for export purposes in Costa Rica as an example for pesticide impacts, as it is in production for over a century and uses pesticides extensively for more than fifty years. We summarise the research on pesticide exposure, effects and risks for aquatic and terrestrial environment, as well as for human health. We show that exposure to pesticides is high and relatively well-studied for aquatic systems and humans, but hardly any data are available for the terrestrial compartment including adjacent non target ecosystems such as rainforest fragments. Ecological effects are demonstrated on an organismic level for various aquatic species and processes but are not available at the population and community level. For human health studies exposure evaluation is crucial and recognised effects include various types of cancer and neurobiological dysfunctions particularly in children. With the many synthetic pesticides involved in banana production, the focus on insecticides, revealing highest aquatic risks, and partly herbicides should be extended to fungicides, which are applied aerially over larger areas. The risk assessment and regulation of pesticides so far relies on temperate models and test species and is therefore likely underestimating the risk of pesticide use in tropical ecosystems, with crops such as banana. We highlight further research approaches to improve risk assessment and, in parallel, urge to follow other strategies to reduce pesticides use and especially hazardous substances.

Paraquat induced oxidative stress, DNA damage, and cytotoxicity in lymphocytes

Paraquat (PQ) is a herbicide belonging to the group of bipyridylium salts. The objective of this study was to evaluate oxidative stress, DNA damage, and cytotoxicity induced by paraquat in peripheral lymphocyte cells in vivo as well as pathological changes in various tissues. For this purpose, 28 male Wistar rats in 6 different groups were poisoned by paraquat gavage and blood samples were taken from the hearts of rats after during the poisoning period. Oxidative stress, DNA damage, cell membrane integrity, serum lactate dehydrogenase, and cytotoxicity, were investigated by Ferric Reducing Antioxidant Potential (FRAP) test, alkaline comet assay, measuring serum lactate dehydrogenase (LDH), Hoechst staining and flow cytometry with propidium iodide (PI) respectively. The lung, kidney, and liver tissues were also examined pathologically. Paraquat caused dose-dependent DNA damage in peripheral lymphocyte cells and significant oxidative cell membrane damage. The most damage was caused by a single dose of 200 mg/kg b.w of paraquat by gavage. The gradual exposure to a dose of 300 mg/kg b.w of paraquat showed less damage, which could be due to the activation of the antioxidant defense mechanism.

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Paraquat induced oxidative stress.

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Paraquat increases serum lactate dehydrogenase.

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Oxidative stress Inducted by exposure to paraquat Inducted DNA damage.

Mutational landscape of gastric adenocarcinoma in Latin America: A genetic approach for precision medicine

Latin-America (LATAM) is the second region in gastric cancer incidence; gastric adenocarcinoma (GA) represents 95% of all cases. We provide a mutational landscape of GA highlighting a) germline pathogenic variants associated with hereditary GA, b) germline risk variants associated with sporadic GA, and c) somatic variants present in sporadic GA in LATAM, and analyze how this landscape can be applied for precision medicine. We found that Brazil, Chile, Colombia, Mexico, Peru, and Venezuela are the countries with more published studies from LATAM explicitly related to GA. Our analysis displayed that different germline pathogenic variants for the CDH1 gene have been identified for hereditary GA in Brazilian, Chilean, Colombian, and Mexican populations. An increased risk of developing somatic GA is associated with the following germline risk variants: IL-4, IL-8, TNF-α, PTGS2, NFKB1, RAF1, KRAS and MAPK1 in Brazilian; IL-10 in Chilean; IL-10 in Colombian; EGFR and ERRB2 in Mexican, TCF7L2 and Chr8q24 in Venezuelan population. The path from mutational landscape to precision medicine requires four development levels: 1) Data compilation, 2) Data analysis and integration, 3) Development and approval of clinical approaches, and 4) Population benefits. Generating local genomic information is the initial padlock to overcome to generate and apply precision medicine.

Assessing the effect of environmental and socio-economic factors on skin melanoma incidence: an island-wide spatial study in Gran Canaria (Spain), 2007-2018

INTRODUCTION

Skin melanoma incidence has risen in the last decades becoming a major public health problem in many regions of the world. Geographic variation of rates is not well understood.

PURPOSE

To assess the spatial distribution of skin melanoma in Gran Canaria Island (Canary Islands, Spain) and to evaluate the role of environmental, socio-economic, and demographic factors in this distribution.

METHODS

We performed a small-area study with disease mapping at the census-tract level (CT) in Gran Canaria between 2007 and 2018. After testing for spatial autocorrelation, we integrated individual-level health data with census-based demographic and socio-economic indicators, and satellite-based environmental data. Finally, we assessed the role of demographic, socio-economic and environmental factors on skin melanoma incidence using a Bayesian analytical framework, with options for non-spatial and spatial random effects.

RESULTS

1058 patients were diagnosed with invasive skin melanoma in the study period and geolocated to a CT (number of CT in Gran Canaria = 565). We found evidence of global spatial autocorrelation in skin melanoma incidence (Moran's I = 0.09, pseudo p-value = 0.001). A few hotspots were detected, fundamentally in urban northern tracts. A radial pattern of high values was also observed in selected ravines with historical isolation. Multivariable conditional autoregressive models identified urbanicity, percent of females, and a high socio-economic status as risk factors for disease. Solar radiation did not show a significant role.

CONCLUSION

Urbanicity and a high socio-economic status were identified as the main risk factors for skin melanoma. These associations might reflect differential melanoma susceptibilities or be explained by health inequalities in detection. This study also uncovered high-risk areas in particular ravines. Future targeted research in these regions might help better understand the role of genetic and toxic factors in melanoma pathogenesis.

Association between pesticide exposure and colorectal cancer risk and incidence: A systematic review

BACKGROUND

Studies investigating the association between pesticide exposure and colorectal cancer (CRC) risk have been inconclusive.

OBJECTIVES

Investigate the association between pesticide exposure and CRC risk through a systematic literature review.

METHODS

CRC has the fourth-highest rate of cancer-caused death in the US after lung cancer, breast cancer in women, and prostate cancer in men. Here we have conducted a systematic literature search on studies examining the association between any pesticide exposure and CRC risk using PubMed, MEDLINE via EBSCO host, and Embase according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist.

RESULTS

Following the review, 139 articles were included for qualitative evaluation. Study participants were farmers, pesticide applicators, pesticide manufacturers, spouses of pesticide applicators, farm residents, Korean veterans of the Vietnam War, rural communities, and those who consumed food with pesticide residues. The studies' results were split between those with significant positive (39 significant results) and inverse (41 significant results) associations when comparing pesticide exposure and CRC risk.

DISCUSSION

From our literature review, we have identified a similar number of significant positive and inverse associations of pesticide exposure with CRC risk and therefore cannot conclude whether pesticide exposure has a positive or inverse association with CRC risk overall. However, certain pesticides such as terbufos, dicamba, trifluralin, S-ethyl dipropylthiocarbamate (EPTC), imazethapyr, chlorpyrifos, carbaryl, pendimethalin, and acetochlor are of great concern not only for their associated elevated risk of CRC, but also for the current legal usage in the United States (US). Aldicarb and dieldrin are of moderate concern for the positive associations with CRC risk, and also for the illegal usage or the detection on imported food products even though they have been banned in the US. Pesticides can linger in the soil, water, and air for weeks to years and, therefore, can lead to exposure to farmers, manufacturing workers, and those living in rural communities near these farms and factories. Approximately 60 million people in the US live in rural areas and all of the CRC mortality hotspots are within the rural communities. The CRC mortality rate is still increasing in the rural regions despite the overall decreasing of incidence and mortality of CRC elsewhere. Therefore, the results from this study on the relationship between pesticide exposure and CRC risk will help us to understand CRC health disparities.

Environmental and ecological factors of stomach cancer incidence and mortality: a systematic review study on ecological studies

OBJECTIVES

Stomach cancer (SC) is one of the most common and deadly types of cancer. It is the third leading cause of cancer deaths worldwide. The effect of environmental and ecological factors in SC have been assessed in some studies. Thus, we aimed to synthesize the environmental and ecological factors of SC incidence and mortality.

CONTENT

In this systematic review study, the scientific databases, including Web of Science, Scopus and PubMed, were searched from inception to November 2019 for all primary articles written in English by using relevant Medical Subject Heading (Mesh) terms. Two independent authors conducted the screening process to decide on the eligibility and inclusion of the articles in the study. The third author acted as an arbiter to resolve any disagreements.

SUMMARY AND OUTLOOK

A total of 157 potentially relevant articles were identified from the initial search 38 of which met the eligibility criteria; finally, 34 articles were included in the systematic review. The results revealed that soil arsenic exposure, coal and other opencast mining installations, living near incinerators and installations for the recovery or disposal of hazardous waste, installations for the production of cement, lime, plaster, and magnesium oxide, proximity to a metal industry sources, dietary iron, ingested asbestos, farming, arsenic in soil, altitude, organochlorines and environmental exposure to cadmium and lead have positive associations with SC incidence or death. Most of the ecological and environmental factors such as living near the mineral industries, the disposal of hazardous waste, metal industry sources and environmental exposure to cadmium and lead are positively related to SC mortality and incidence. However, solar UV-B, heat index and dietary zinc can be taken into account as protective factors against SC mortality and incidence.

Increased Risk of Penile Cancer among Men Working in Agriculture

Background:

Previous Brazilian studies have indicated that working in agriculture could lead to an increased risk of penile cancer. The present descriptive study aimed at establishing a possible association between penile cancer and agricultural occupation.

Materials and methods:

Data on a total of 103 penile cancer patients were obtained from medical records of two reference centres for cancer treatment in the state of Paraíba, Northeast Brazil. Information about sexual behaviour was obtained in interviews for 48 cases.

Results:

Of 103 patients 38 and 52 were illiterate and had not completed graduation, respectively, and 60 earned less than twice the minimum wage. All together, 72 (70%) worked in agriculture and 39 confirmed involvement in application of agrochemicals. A history of phimosis was noted for 42 (69%) out of 61 patients and 40 (59%) out of 68 ever smoked. Pathological signs of HPV infection were detected in 45 (70%) out of 64 patients. Of the 48 interviewed patients, 27 (56%) confirmed sexual contact with prostitutes and eight (19%) out of 43 had sex with animals.

Conclusions:

Data confirmed the presence of several risk factors for penile cancer, like phimosis, smoking, HPV infection and promiscuous sexual behaviour. The high number of Brazilian agricultural workers with penile cancer was unexpected if compared with other professional groups. Future studies should focus on this group of men and elucidate possible reasons for their increased risk.

Risk of lung cancer in Parkinson's disease

Recently, growing evidence has revealed the significant association between Parkinson's disease (PD) and cancer. However, controversy still exists concerning the association between PD and lung cancer. A comprehensive article search for relevant studies published was performed using the following online databases: PubMed, Web of Science and Embase up to August 31, 2016. The pooled risk ratio (RR) and their 95 % confidence intervals (CI) were calculated using the method of inverse variance with the random-effects model. Fifteen studies comprising 348,780 PD patients were included in this study. The pooled result indicated that patients with PD were significantly associated with a decreased risk of lung cancer (RR: 0.53, 95% CI: 0.41-0.70, P < 0.001). In addition, subgroup analyses performed in Western population also confirmed the significant inverse relationship between PD and risk of lung cancer (RR: 0.48, 95% CI: 0.39-0.60, P < 0.001). In the subgroup analysis, a reduced risk of lung cancer in PD patients from Western population was consistent regardless of study design, gender, or study quality. In conclusion, PD patients were significantly associated with a reduced risk of lung cancer in Western population. The relationship between them in Asian population needs to be confirmed by future studies.

Pesticide exposure and risk of bladder cancer: A meta-analysis

OBJECTIVE

We conducted a meta-analysis to quantitatively evaluate the correlation between pesticide exposure and the risk of bladder cancer by summarizing the results of published case-control and cohort studies.

METHODS

A systematic literature search of articles update to February 2015 was conducted via Pubmed, Web of Science, Cochrane Library, and the Chinese National Knowledge Infrastructure (CNKI) databases, and the references of the retrieved articles. Fixed- or random-effect models were used to summarize the estimates of OR with 95% CIs for the highest versus the lowest exposure of pesticide.

RESULTS

The pooled OR estimates indicated that pesticide exposure was associated with an increased risk of bladder cancer (OR=1.649, 95% CI 1.223-2.223). In subgroup analysis, we detected pesticide exposure demonstrated as a significant risk factor on bladder cancer in America (OR=1.741, 95% CI 1.270-2.388). Similar results were discovered in both case-control group and cohort group (OR=2.075, 95% CI 1.183-3.638, OR=1.146, 95% CI 1.074-1.223, respectively). No evidence of publication bias was found by Begg's or Egger's test (P = 0.210, P = 0.358, respectively).

CONCLUSION

In conclusion, our meta-analysis indicated that pesticide exposure was associated with an increased risk of bladder cancer. Further researches should be conducted to confirm the findings in our study and better clarify the potential biological mechanisms.

Association between pesticide exposure and risk of kidney cancer: a meta-analysis

This meta-analysis aimed to evaluate the correlation between pesticide exposure and kidney cancer. We conducted a systematic search of the Cochrane Library, Embase, Web of Knowledge, and Medline (updated to March 1, 2015) to identify all relevant studies. References of the retrieved articles were also identified. Fixed- or random-effect models were used to summarize the estimates of relative risk (RR) with 95% confidence interval for the association between exposure of pesticide and risk of kidney cancer. The pooled RR estimate indicated that pesticide exposure might have an elevated risk for kidney cancer (RR =1.10, 95% confidence interval 1.01–1.19). In a subgroup analysis of high quality articles, we detected that pesticide exposure is a significant risk factor for kidney cancer in a subgroup analysis of case-control studies, (Newcastle–Ottawa Quality Assessment Scale score >6) (RR =1.31, 95% confidence interval 1.12–1.51). North America studies, odds ratio studies, and studies with effect estimate adjusted for more than two confounder studies. In conclusion, pesticide exposure may be a risk factor for kidney cancer.

Melanoma Epidemiology and Prevention

The epidemiology of melanoma is complex, and individual risk depends on sun exposure, host factors, and genetic factors, and in their interactions as well. Sun exposure can be classified as intermittent, chronic, or cumulative (overall) exposure, and each appears to have a different effect on type of melanoma. Other environmental factors, such as chemical exposures-either through occupation, atmosphere, or food-may increase risk for melanoma, and this area warrants further study. Host factors that are well known to be important are the numbers and types of nevi and the skin phenotype. Genetic factors are classified as high-penetrant genes, moderate-risk genes, or low-risk genetic polymorphisms. Subtypes of tumors, such as BRAF-mutated tumors, have different risk factors as well as different therapies. Prevention of melanoma has been attempted using various strategies in specific subpopulations, but to date optimal interventions to reduce incidence have not emerged.

Incidence of cutaneous malignant melanoma by socioeconomic status in Canada: 1992-2006

BACKGROUND

There are no nationwide studies documenting changes in cutaneous malignant melanoma incidence or association of incidence with socioeconomic status (SES) in Canada. We sought to determine whether melanoma incidence increased from 1992 to 2006 and if there was an association between SES and melanoma incidence. Additionally, we studied whether there was a correlation between province of residence and melanoma incidence.

METHODS

Cases from the Canadian Cancer Registry were reviewed. Demographic and socioeconomic information were extracted from the Canadian Census of Population data. Cases were linked to income quintiles by postal code. A negative binomial regression was performed to identify relationships among these variables.

RESULTS

Overall incidence of melanoma in Canada increased by 67 % from 1992 to 2006 (p < 0.0001). The increase in incidence was greater for melanoma in situ compared with invasive melanoma (136 % versus 52 % [p < 0.0001]). Incidence was positively correlated with higher income quintiles; the incidence rates among patients in the lowest income quintiles were 67 % of that for the highest income quintiles (p < 0.0001).

DISCUSSION

A wide variety of explanations have been postulated for an increased incidence in melanoma among persons of higher SES, including access to and awareness of screening, more access to vacations in sunny climates, and increased leisure time. Variations in incidence of melanoma by urban vs. rural location and province may indicate differences in access to dermatologists across Canada.

CONCLUSIONS

Melanoma incidence is increasing in Canada and is higher among people in high SES groups. This rise is likely due to a combination of factors including a true rise in incidence due to increases in sun exposure, and also an increased detection rate, particularly in those who are more aware of the disease and have access to resources for detection.

Lack of association between cyclooxygenase 2-765G/C gene polymorphism and breast cancer risk in Ahvaz, west-south Iran

Cyclooxygenases are key enzymes in conversion of arachidonic acid into prostaglandin H2. Cyclooxygenase-2 (COX-2) increases prostaglandins in neoplastic tissue. COX-2 has important roles in cell proliferation cancers, angiogenesis, and alzheimer. COX-2 is up-regulated in several types of cancer, and it is hypothesized that COX-2 expression may be genetically influenced. Our main objective was to evaluated the association of polymorphism COX-2 with risk of breast cancer in khouzestan province, and the second objective of the study was to evaluate the association with biochemistry parameters. This study consisting of 150 patients with breast cancer and 120 normal DNA was extracted from the white blood cells. Polymorphism cox2 gene was detected by polymerase chain reaction according to the standard methods. The profile lipids and estrogen were measured in two groups by standard methods. Chi square analysis showed that there was no association between breast cancer risk and COX-2 -765G>C genotype and alleles. Also, no association were observed between -765G>C polymorphism and biochemistry parameters. A multiple logistic regression model with cox2 genotypes and LDL and HDL as covariates revealed that there is no significant association between cox2 genotypes and risk of breast cancer, but higher values of LDL and HDL significantly increase risk of breast cancer.

Mortality among a Cohort of Banana Plantation Workers in Costa Rica

The nematocide 1,2-dibromo-3-chloropropane (DBCP), widely used in Costa Rica during the late 1960s and 1970s, causes sterility in men and is a possible carcinogen. Mortality among a cohort of Costa Rican banana plantation workers was investigated. The cohort included 40,959 individuals who worked on banana plantations between 1972 and 1979. Employment records were linked with the Costa Rican Mortality Registry to determine outcomes through 1999. Standardized mortality ratios (SMRs) were calculated for all causes of death. Poisson regression was also used to calculate mortality risk estimates by duration of employment, but provided no additional insight. All-causes SMRs were 0.77 for men (95% CI 0.75-0.80) and 0.90 for women (95% CI 0.80-1.02) relative to national mortality rates. Mortality from septicemia was significantly higher than expected. Nonsignificant increases in mortality were also observed for testicular cancer, penile cancer, Hodgkin's disease, and Parkinson's disease in men, and for cervical cancer and lung cancer in women.

Pesticides and human chronic diseases: evidences, mechanisms, and perspectives

Along with the wide use of pesticides in the world, the concerns over their health impacts are rapidly growing. There is a huge body of evidence on the relation between exposure to pesticides and elevated rate of chronic diseases such as different types of cancers, diabetes, neurodegenerative disorders like Parkinson, Alzheimer, and amyotrophic lateral sclerosis (ALS), birth defects, and reproductive disorders. There is also circumstantial evidence on the association of exposure to pesticides with some other chronic diseases like respiratory problems, particularly asthma and chronic obstructive pulmonary disease (COPD), cardiovascular disease such as atherosclerosis and coronary artery disease, chronic nephropathies, autoimmune diseases like systemic lupus erythematous and rheumatoid arthritis, chronic fatigue syndrome, and aging. The common feature of chronic disorders is a disturbance in cellular homeostasis, which can be induced via pesticides' primary action like perturbation of ion channels, enzymes, receptors, etc., or can as well be mediated via pathways other than the main mechanism. In this review, we present the highlighted evidence on the association of pesticide's exposure with the incidence of chronic diseases and introduce genetic damages, epigenetic modifications, endocrine disruption, mitochondrial dysfunction, oxidative stress, endoplasmic reticulum stress and unfolded protein response (UPR), impairment of ubiquitin proteasome system, and defective autophagy as the effective mechanisms of action.

Malignancy-associated dyslipidemia

Cholesterol and triglycerides, important lipid constituents of cell, are essential to carry out several vital physiological functions. Lipids might be associated with cancers because they play a key role in the maintenance of cell integrity. The pathway for cholesterol synthesis may also produce various tumorigenic compounds and cholesterol serves as a precursor for the synthesis of many sex hormones linked to increased risk of various cancers. In some malignant diseases, blood cholesterol undergoes early and significant changes. The mechanism for the link between cancer and cholesterol remains controversial. The dates from studies are confusing because both hypolipidemia and hypercholesterolemia might be connected with malignancy. Not only cancers but also antineoplastic therapies have an influence on lipid profile. There are also dates suggesting that antihyperlipemic drugs might nfluenced malignancy.

Lifestyle, occupational, and reproductive factors and risk of colorectal cancer

PURPOSE

Lifestyle factors and environmental exposures might help explain the risk of colorectal carcinoma in countries where the incidence is low, but unique patterns of young onset and a high proportion of rectal cancer exist.

METHODS

We obtained detailed lifestyle information from 421 patients with colorectal cancer and 439 hospital-controls in Egypt. Logistic regression models were computed to evaluate the risk factors of colorectal carcinoma.

RESULTS

A history of pesticide exposure and more frequently eating food directly from farms were significantly associated with a higher risk of colorectal carcinoma (odds ratio = 2.6; 95% CI = 1.1-5.9, and odds ratio = 4.6; 95% CI = 1.5-14.6, respectively). Parous women who reported 7 or more live births or breastfed for 19 months or longer per live birth had a significantly lower risk for colorectal carcinoma (odds ratio = 0.3; 95% CI = 0.2-0.7, and odds ratio = 0.2; 95% CI = 0.1-0.4, respectively). Compared with patients aged 40 years or older, industrial exposures were more common in younger patients (P = .05).

CONCLUSIONS

Agricultural and industrial exposures were associated with increased risk of colorectal carcinoma, whereas prolonged lactation and increased parity were inversely associated with colorectal carcinoma in women. Further research to elucidate the biological role of intense environmental and industrial exposures and reproductive factors including lactation may further clarify the etiology of colorectal cancer.

Cancer incidence among paraquat exposed applicators in the agricultural health study: prospective cohort study

Paraquat (1,1'-dimethyl-4, 4'-bipyridinium dichloride) is a nonselective herbicide that is extremely toxic after acute exposure. It was once widely used in North America and is still used in some countries, including the United States. Although there is little firm evidence that paraquat is a carcinogen, previous studies have suggested a potential relationship with some cancers. This prospective cohort study was performed to evaluate the association between lifetime paraquat exposure and cancer incidence among licensed pesticide applicators with 9.1 years of median follow-up. The lifetime ever-use of paraquat was evaluated in 56,224 subjects at baseline and exposure-response relationship was evaluated in 24,667 subjects (44%) who provided detailed information on total life-time paraquat exposure in a second questionnaire. Among the total subjects, the risk for non-Hodgkin's lymphoma (NHL) in the exposed group was marginally elevated (Relative risk [RR], 1.47; 95% confidence interval [CI], 0.97-2.23) compared to the non-exposed group. However, among the 24,667 applicators who supplied total life-time exposure days, the highest tertile of lifetime exposure-days (LE) and intensity-weighted lifetime exposure-days (IWLE) was not significantly associated with NHL risk (RR, 1.57; 95%CI, 0.57-4.23 for LE; RR, 1.42; 95%CI, 0.40-4.71 for IWLE, respectively) and there was no significant exposure-response trend (p-trend > 0.1). There was some suggestion of a possible link between paraquat exposure and NHL risk in humans, but the inconsistency in exposure level trend suggests that this could be a chance finding.

Adverse health effects of pesticides in agrarian populations of developing countries

Developing countries use only 20% of the world's agrochemicals, yet they suffer 99% of deaths from pesticide poisoning. Pesticide poisoning is a significant problem in developing countries primarily because of unsafe pesticide application and handling practices. Safety is further exacerbated by the illiteracy and poverty that prevails in most farming communities of developing countries. Pesticides classified as being extremely or highly hazardous by FAO and WHO, including those banned by other countries, continue to be used in developing countries. Many farmers in developing countries continue to be exposed to pesticides from either storing them in or near their residences, or from inadequate or unsafe application or handling practices. Farming populations exposed to pesticides suffer from several health problems, primarily neurological abnormalities, respiratory ailments, and reproductive, endocrinological, and dermal problems. In developing countries, the scientific literature (including the Indian Institute of Toxicology Research, India) have taken the initiative to monitor health problems resulting from pesticide exposure in agrarian communities. The welfare fund for agricultural laborers could institute a special program for pesticide applicators in developing countries. The primary need, currently, in such countries is creation and implementation of sound national policies to effectively articulate appropriate guidelines for managing farm pest control activities. Such policies should be aimed at both limiting pesticide exposure and usage, but doing so without damaging the yields of food production. If such steps are taken, it is fully expected that the incidence of adverse health consequences for agrarian populations from pesticide toxicity will decrease, and the health of farmers improve.

Field testing passive air samplers for current use pesticides in a tropical environment

Air was sampled for one year in the central valley of Costa Rica using an active high-volume sampler as well as passive samplers (PAS) based on polyurethane foam (PUF) disks and XAD-resin filled mesh cylinders. Extracts were analyzed for pesticides that are either banned or currently used in Costa Rican agriculture. Sampling rates for PUF-based passive air samplers, determined from the loss of depuration compounds spiked on the disks prior to deployment averaged 5.9 +/- 0.9 m3 x d(-1) and were higher during the windier dry season than during the rainy season. Sampling rates for the XAD-based passive sampler were determined from the slopes of linear relationships that were observed between the amount of pesticide sequestered in the resin and the length of deployment, which varied from 4 months to 1 year. Those sampling rates increased with decreasing molecular size of a pesticide, and their average of 2.1 +/- 1.5 m3 x d(-1) is higher than rates previously reported for temperate and polar sampling sites. Even though the trends of the sampling rate with molecular size and temperature are consistent with the hypothesis that molecular diffusion controls uptake in passive samplers, the trends are much more pronounced than a direct proportionality between sampling rate and molecular diffusivity would suggest. Air concentrations derived by the three sampling methods are within a factor of 2 of each other, suggesting that properly calibrated PAS can be effective tools for monitoring levels of pesticides in the tropical atmosphere. In particular, HiVol samplers, PUF-disk samplers, and XAD-based passive samplers are suitable for obtaining information on air concentration variability on the time scale of days, seasons and years, respectively. This study represents the first calibration study for the uptake of current use pesticides by passive air samplers.

Histopathological effects of dimethoate on testes of rats

The aim of the current study was to investigate subchronic effect of dimethoate on the testes of rats. The animals of exposed groups were fed with laboratory chow combined with 2, 8 and 20 mg/kg dimethoate for 90 days. When compared to control, there was a statistically significant decrease in relative testis weights of rats treated with 20 mg/kg dimethoate. In light microscopic examinations, histopathological observation of the treated rats revealed that dimethoate caused dose-related testicular damage characterized by moderate to severe seminiferous tubule degeneration as sloughing, atrophy, germ cell degeneration and by partial arrest of spermatogenesis.

Carbaryl exposure and incident cancer in the Agricultural Health Study

Carbaryl is a carbamate insecticide with a broad spectrum of uses in agricultural, commercial and household settings. It has previously been linked with non-Hodgkin lymphoma (NHL) but studies of cancer risk in humans are limited. We examined occupational carbaryl use and risk of all cancers in the Agricultural Health Study, a prospective study of a cohort of pesticide applicators in North Carolina and Iowa. This analysis included 21,416 subjects (1,291 cases) enrolled from 1993-1997 and followed for cancer incidence through 2003. Pesticide exposure and other data were collected using self-administered questionnaires. Poisson regression was used to calculate rate ratios (RRs) and 95% confidence intervals (CIs) while controlling for potential confounders. Carbaryl was not associated with cancer risk overall. Relative to subjects who never used carbaryl, melanoma risk was elevated with >175 lifetime exposure-days (RR = 4.11; 95%CI, 1.33-12.75; p-trend = 0.07), >10 years of use (RR = 3.19; 95%CI, 1.28-7.92; p-trend = 0.04), or >or=10 days of use per year (RR = 5.50; 95%CI, 2.19-13.84; p-trend < 0.001). Risk remained after adjusting for sunlight exposure. Although not significant, there appeared to be a trend of decreasing prostate cancer risk with increasing level of exposure. A small increase in NHL risk was observed using some, but not all, exposure measures. No associations were observed with other examined cancer sites. Because the observed results were not hypothesized a priori and because of limited study of their biological plausibility, they should be interpreted with caution.

8-Hydroxydeoxyguanosine levels in human leukocyte and urine according to exposure to organophosphorus pesticides and paraoxonase 1 genotype

OBJECTIVE

In order to investigate a role of paraoxonase 1 (PON1) polymorphism in organophosphorus (OP)-induced 8-hydroxydeoxyguanosine (8-OHdG) levels, urinary metabolites of OP, PON1 genotypes, and 8-OHdG levels in leukocyte and urine were measured in OP indoor insecticide sprayers and controls in summer and winter.

METHODS

The study population contained 18 male sprayers and age-matched 18 male controls. Sprayers were primarily exposed to OP insecticides (mainly fenitrothion, dichlorvos, chlorpyrifos, and diazinon), and partially to pyrethroids (mainly permethrin) and carbamates (mainly propoxur). Urinary metabolites of OP were measured by gas chromatography-mass spectrometry. 8-OHdG levels in leukocyte and urine were measured by ELISA kit. PON1 genotype was identified using allele-specific fluorogenic TaqMan probes.

RESULTS

The mean concentrations of urinary dimethyl phosphate (DMP) and total dialkyl phosphates (DAP) in summer and those of 8-OHdG in summer and winter were significantly higher in OP sprayers than controls. This resulted in a significant positive correlation between 8-OHdG levels and urinary DMP or DAP, suggesting a correlation between OP metabolites and production of oxidative stress. Of PON1 genotypes, incidences of Q/Q, Q/R, and R/R types were 17, 39, and 44% in OP sprayers and controls, respectively. Although PON1 polymorphism did not contribute to the leukocyte and urinary 8-OHdG levels, the urinary OP metabolite concentrations in summer showed a significant decrease as the number Q allele decreased.

CONCLUSION

These results indicate that an increase in OP metabolites is associated with a high level of oxidative stress in OP sprayers, although the contribution of the PON1 polymorphism to the metabolism of OP is still unclear.

The geographic distribution of melanoma incidence in Massachusetts, adjusted for covariates

Background

The aims of this study were to determine whether observed geographic variations in melanoma cancer incidence in both gender groups are simply random or are statistically significant, whether statistically significant excesses are temporary or persistent, and whether they can be explained by risk factors such as socioeconomic status (SES) or the percent of the population residing in an urban rather than a rural area. Between 1990 and 1999, 4774 female and 5688 male melanomas were diagnosed in Massachusetts residents. Cases were aggregated to census tracts and analyzed for deviations from random occurrence with respect to both spatial location and time.

Results

Thirteen geographic areas that deviated significantly from randomness were uncovered in the age-adjusted analyses of males: five with higher incidence rates than expected and eight lower than expected. In the age-adjusted analyses of females, six areas with higher incidence rates and eight areas with lower than expected incidence rates were found. After adjustment for SES and percent urban, several of these areas were no longer significantly different.

Conclusion

These analyses identify geographic areas with invasive melanoma incidence higher or lower than expected, the times of their excess, and whether or not their status is affected when the model is adjusted for risk factors. These surveillance findings can be a sound starting point for the shoe-leather epidemiologist.

Urbanization and breast cancer incidence in North Carolina, 1995-1999

PURPOSE

Breast cancer incidence rates are reported to be higher in urban compared with rural areas in the United States. We investigated the relationship between urbanization and breast cancer in North Carolina (1995-1999), and considered hospital characteristics as an explanation.

METHODS

We calculated age-adjusted in situ and invasive female breast cancer incidence rates stratified by race, urbanization (Urban Influence Codes), and the presence of a hospital with a cancer registry and cancer program approval in a county.

RESULTS

For white women, incidence rate ratios (IRRs) comparing the most urban with the most rural counties were 1.60 for in situ and 1.18 for invasive cancer. For non-white women, IRRs were 1.27 and 0.99, respectively. IRRs for incidence in registry hospital counties versus those without were all > 1.00 and differences were greater for in situ cancer than invasive. For most strata, urban excesses were attenuated when further stratified by registry hospital status.

CONCLUSIONS

For most strata, we observed excess incidence in urban counties, but it appeared to be explained through the urban preponderance of registry hospitals. Counties with these hospitals may have higher incidence because of increased detection. Area hospital characteristics should be considered when evaluating geographic patterns of breast cancer incidence.

AN ORGANOPHOSPHATE INSECTICIDE METHYL PARATHION (O- O- DIMETHYL O-4-NITROPHENYL PHOSPHOROTHIOATE) INDUCES CYTOTOXIC DAMAGE AND TUBULAR ATROPHY IN THE TESTIS DESPITE ELEVATED TESTOSTERONE LEVEL IN THE RAT

Methyl parathion (MP) is an organophosphate pesticide used in agriculture, although quite often illegally used indoors to contain insects. The present study was planned to investigate the effects of MP on rat testis. Adult male Wistar rats (13-14 weeks) were treated with MP as follows. Experiment 1-0, 1.75, 3.5 or 7 mg/kg i.p. for 5 days and sacrificed on Day 14; experiment 2 and 3- 0, 0.5, or 1 mg/kg i.p. for 12 days, and sacrificed on Days 130 and 77, respectively; experiment 4- 0, 0.75, or 1.5 mg/kg i.p. for 25 days, and sacrificed on Day 17; experiment 5- 0 or 3.5 mg/kg po for 25 days, and sacrificed on Day 17, after the last exposure. MP decreased the body weight and the testis weight in experiments 4 and 5 (p<0.05-0.001) due to decreased food intake and tubular atrophy respectively. MP increased the intra-testicular testosterone level and decreased the LH level in experiments 4 and 5. The seminiferous epithelium showed sloughing of germ cells, vacuoles, focal necrosis, and formation of multinucleated giant cells, cellular degeneration (nuclear pyknosis, halo appearance and shrinkage of nuclei) and tubular atrophy, especially in experiment 4. The degree of testicular damage was higher in experiment 4>5>1>3>2 indicating more effect of prolonged i.p. treatment. Homogenization-resistant spermatid count was decreased in experiments 1, 4 and 5, and MP also decreased the tubular diameter, and epithelial height (p<0.05-0.001). Incidences of stage XIV tubules, number of meiotic figures and elongating spermatids were also decreased, whereas the incidence of tubules showing epithelial sloughing increased (p<0.05-0.001). We conclude that MP is a reproductive toxicant in male rats which causes significant testicular damage in the testis.

Residential proximity to agricultural pesticide use and incidence of breast cancer in California, 1988-1997

California is the largest agricultural state in the United States and home to some of the world's highest breast cancer rates. The objective of our study was to evaluate whether California breast cancer rates were elevated in areas with recent high agricultural pesticide use. We identified population-based invasive breast cancer cases from the California Cancer Registry for 1988-1997. We used California's pesticide use reporting data to select pesticides for analysis based on use volume, carcinogenic potential, and exposure potential. Using 1990 and 2000 U.S. Census data, we derived age- and race-specific population counts for the time period of interest. We used a geographic information system to aggregate cases, population counts, and pesticide use data for all block groups in the state. To evaluate whether breast cancer rates were related to recent agricultural pesticide use, we computed rate ratios and 95% confidence intervals using Poisson regression models, adjusting for age, race/ethnicity, and neighborhood socioeconomic status and urbanization. This ecologic (aggregative) analysis included 176,302 invasive breast cancer cases and 70,968,598 person-years of observation. The rate ratios did not significantly differ from 1 for any of the selected pesticide categories or individual agents. The results from this study provide no evidence that California women living in areas of recent, high agricultural pesticide use experience higher rates of breast cancer.

In vitro effect of karathane LC (dinocap) on human lymphocytes

Karathane LC (active ingredient dinocap), a contact fungicide and a non-systemic acaricide was investigated for its ability to induce chromosome aberrations (CAs) and sister chromatid exchanges (SCEs) in cultured human lymphocytes of peripheral blood. In addition to the cytogenetic analysis, the effect of karathane LC on the cell proliferation kinetics (CPK) by the replication index (RI) was studied. The mitotic index (MI) was also determined to detect the cytotoxic effect. Lymphocytes were treated with four different concentrations (5, 10, 15 and 20 microg/ml) of karathane LC for 24 and 48 h. Significant differences between exposed and non-exposed groups found in CAs, SCEs and MI demonstrate the mutagenic, clastogenic and also the cytotoxic effect of karathane LC.

Pesticide prioritization for a case-control study on childhood leukemia in Costa Rica: a simple stepwise approach

Multiple exposures and rapidly changing use patterns are obstacles for adequate recall of pesticide exposures in epidemiologic studies. We present a simple stepwise approach for prioritization of pesticides as part of the exposure assessment strategy in an ongoing case-control study on pesticides and childhood leukemia in Costa Rica. Pesticide imports between 1977 and 2000, approximately the pertinent exposure period, were surrogates for use data. In the first phase, 323 active ingredients were identified, of which 219 were eliminated based on low usage and absence or negative results in a preliminary search in three major toxicity databases. In the second phase, the remaining 104 pesticides underwent scoring for their toxicodynamic potential (TDP) with regard to carcinogenicity, mutagenicity, and teratogenicity, weighted in this order. Bioavailability was assessed when TDP was multiplied by a weight for persistence and bioaccumulation, producing the intrinsic toxic potential (ITP). ITP was multiplied by an index of quantity (QI) of pesticide used in the exposure period, resulting in a weighted toxic potential (WTP). The top 25 positions in each of the four rankings (TDP, ITP, QI, and WTP) yielded together 64 highest-priority pesticides. This prioritization process has to be complemented with a further breakdown into crop-, time-, and biocide-specific shortlists to achieve a recall tool suitable for developing countries. Different parameters for prioritization assure inclusion of all relevant pesticides with regard to toxicity and bioavailability. The method contributes to cancer epidemiology in developing countries with access to basic use data and the Internet. The method is adaptable to other health outcomes.

Occupational exposure to carbofuran and the incidence of cancer in the Agricultural Health Study

Carbofuran is a carbamate insecticide registered for use on a variety of food crops including corn, alfalfa, rice, and tobacco. An estimated 5 million pounds of carbofuran is used annually in the United States, and 45% of urban African-American women have detectable levels of carbofuran in their plasma. Nitrosated carbofuran has demonstrated mutagenic properties. We examined exposure to carbofuran and several tumor sites among 49,877 licensed pesticide applicators from Iowa and North Carolina enrolled in the Agricultural Health Study. We obtained information regarding years of use, frequency of use in an average year, and when use began for 22 pesticides using self-administered questionnaires. Poisson regression was used to calculate rate ratios (RR) and 95% confidence intervals (CIs) adjusting for potential confounders. Lung cancer risk was 3-fold higher for those with > 109 days of lifetime exposure to carbofuran (RR = 3.05; 95% CI, 0.94-9.87) compared with those with < 9 lifetime exposure days, with a significant dose-response trend for both days of use per year and total years of use. However, carbofuran use was not associated with lung cancer risk when nonexposed persons were used as the referent. In addition, carbofuran exposure was not associated with any other cancer site examined. Although carbamate pesticides are suspected human carcinogens, these results should be interpreted cautiously because there was no a priori hypothesis specifically linking carbofuran to lung cancer.

The epidemiology of pesticide exposure and cancer: A review

Cancer is a multifactorial disease with contributions from genetic, environmental, and lifestyle factors. Pesticide exposure is recognized as an important environmental risk factor associated with cancer development. The epidemiology of pesticide exposure and cancer in humans has been studied globally in various settings. Insecticides, herbicides, and fungicides are associated with hemopoetic cancers, and cancers of the prostate, pancreas, liver, and other body systems. The involvement of pesticides in breast cancer has not yet been determined. In developing countries, sufficient epidemiologic research and evidence is lacking to link pesticide exposure with cancer development. Agricultural and industrial workers are high-risk groups for developing cancer following pesticide exposure. Children of farm workers can be exposed to pesticides through their parents. Maternal exposure to pesticides can pose a health risk to the fetus and the newborn. The organophosphates are most the commonly used compounds, but the organochlorines are still permitted for limited use in developing countries. Pesticide exposure, independently or in synergism with modifiable risk factors, is associated with several types of cancer.

Cancer Incidence Among Pesticide Applicators Exposed to Chlorpyrifos in the Agricultural Health Study

BACKGROUND

Chlorpyrifos is one of the most widely used insecticides in the United States. We evaluated the incidence of cancer among pesticide applicators exposed to chlorpyrifos in the Agricultural Health Study, a prospective cohort study of licensed pesticide applicators in Iowa and North Carolina.

METHODS

A total of 54,383 pesticide applicators were included in this analysis. Detailed information on pesticide exposure and lifestyle factors was obtained from self-administered questionnaires completed at the time of enrollment (December 1993-December 1997). Poisson regression analysis was used to evaluate the association between chlorpyrifos exposure and cancer incidence after adjustment for potential confounders. All statistical tests were two-sided.

RESULTS

A total of 2070 incident malignant neoplasms were diagnosed through 2001. The rate ratio for all cancers combined among chlorpyrifos-exposed applicators compared with nonexposed applicators was 0.97 (95% confidence interval = 0.87 to 1.08). For most cancers analyzed, there was no evidence of an exposure-response relationship. However, the incidence of lung cancer was statistically significantly associated with both chlorpyrifos lifetime exposure-days (P(trend) = .002) and chlorpyrifos intensity-weighted exposure-days (P(trend) = .036). After adjustment for other pesticide exposures and demographic factors, individuals in the highest quartile of chlorpyrifos lifetime exposure-days (>56 days) had a relative risk of lung cancer 2.18 (95% confidence interval = 1.31 to 3.64) times that of those with no chlorpyrifos exposure.

CONCLUSION

Our findings suggest an association between chlorpyrifos use and incidence of lung cancer that deserves further evaluation.

Breast cancer incidence and its possible spatial association with pesticide application in two counties of England

BACKGROUND

This study examines the spatial distribution of breast cancer incidence in Lincolnshire and Leicestershire, and its association with the application of selected pesticides.

METHODS

The Black-White (BW) join-count statistic and Moran I coefficient were used to investigate the localized distribution of breast cancer. Linear regression techniques were applied to examine the association between the breast cancer incidence rate and pesticide application.

RESULTS

The results from the BW join-count test and the Moran I coefficient test showed no overall evidence of localized distribution, 'clusters', of breast cancer. The regression analyses showed no sign of spatial association between breast cancer and application of pesticides in the urban areas as expected. The findings, however, did reveal a spatial association between the breast cancer incidence rates and the application of three selected pesticides [Aldicarb, Atrazine and Lindane (thought to potentially mimic oestrogen)] in rural Leicestershire. No such association was seen in Lincolnshire.

CONCLUSIONS

Pesticides vary significantly in their spatial application. Overall, consistent associations between breast cancer incidence rates and the selected pesticides were not found, although the ecological study design has limitations and these are discussed. This approach is able to rule out strong associations; assessment of smaller risk would require a large and expensive study in individuals. The results of this study, although derived in the UK, have significance to the debate concerning the possibility of environmental compounds that mimic oestrogen and their consequences for human health.

Residential proximity to agricultural pesticide use and incidence of breast cancer in the California Teachers Study cohort

We examined the association between residential proximity to agricultural pesticide use and breast cancer incidence among members of the California Teachers Study cohort, a large study of professional school employees with extensive information on breast cancer risk factors, followed for cancer incidence since 1995. We identified 1552 invasive breast cancer cases, diagnosed between 1996 and 1999, among 114,835 cohort members. We used California Pesticide Use Reporting data to select pesticides for analysis based on use volume, carcinogenic potential, and exposure potential; a Geographic Information System was used to estimate pesticide applications within a half-mile radius of subjects' residences. We applied Cox proportional hazard models to estimate hazard rate ratios (HR) for selected pesticides, adjusting for age, race, and socioeconomic status. We saw no association between residential proximity to recent agricultural pesticide use and invasive breast cancer incidence. HR estimates for the highest compared to the lowest exposure categories for groups of agents were as follows: probable or likely carcinogens (1.07, 95% confidence interval (CI): 0.86-1.32), possible or suggestive carcinogens (1.06, 95% CI: 0.87-1.29), mammary carcinogens (1.15, 95% CI: 0.90-1.48), and endocrine disruptors (1.03, 95% CI: 0.86-1.25). HR estimates for other groups and individual pesticides did not differ from unity, nor was there a trend for any groupings of or individual pesticides examined. Stratifying by menopausal status or family history of breast cancer did not substantially affect our results. Our analyses suggest that breast cancer incidence is not elevated in areas of recent, high agricultural pesticide use in California.

Central nervous system tumours in children in Costa Rica, 1981-96

Incidence rates of malignant central nervous system (CNS) tumours in children in Costa Rica are presented in an international perspective. For the 16-year period 1981-96, a total of 256 CNS tumours were registered in children below age 15 years by the National Tumour Registry of Costa Rica. The age-standardised incidence rate was 15.2 per million person-years, with a male-to-female ratio of 1.4. The median age-standardised incidence rates of selected registries in other Latin American countries were 19.3, in other developing countries 12.0 and in industrialised countries 29.6 per million person-years. The comparatively low incidence rates in Costa Rica were evident in all diagnostic subgroups, most notably in the youngest age group and for tumours in the brain stem. In the Central Valley, where the capital and the only specialised paediatric hospital are situated, the crude incidence rate was 18.1 [95% CI 15.1, 21.1] compared with 10.5 [95% CI 8.3, 12.8] per million person-years in the rest of the country (RR = 1.7, 95% CI 1.3, 2.3). There was no evidence of any increase over time. The data in this study cannot exclude under-diagnosis and, to a lesser degree, under-registration as a partial explanation of the low incidence rates of malignant CNS tumours in children in Costa Rica.

Organophosphate-based pesticides and genetic damage implicated in bladder cancer

Organophosphate-based pesticides have been associated with pathology and chromosomal damage in humans. There are also epidemiologic links with cancer. The few screening tests for low-level occupational exposure are of doubtful sensitivity; this investigation evaluated four methods. Blood samples were studied from 10 farmers before and after occupational exposure to organophosphate-based pesticides and five unexposed controls. The standard cholinesterase test was insensitive to the exposure (P=0.815). However, a significant increase in Howell-Jolly bodies within erythrocytes was observed (P=0.001). Cytogenetic studies on routine and aphidicolin-induced blood cultures revealed that following organophosphate exposure the total number of gaps and breaks on human chromosomes was significantly increased (P=0.004 and P=0.0006, respectively). We concluded that Howell-Jolly body and fragile site analysis were sensitive indicators of nuclear damage resulting from low-level occupational exposure to organophosphate. Such nuclear damage could be implicated in carcinogenesis. The development of bladder cancer is one such example.

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.

Status of chromosome breaks and gaps in breast cancer. a follow-up study

Genetic susceptibility and environmental factors are believed to be responsible for chromosomal instabilities and higher incidence of breast cancer. We conducted a follow-up study to find the levels of chromosome breaks and gaps in 20 premenopausal women with breast cancer before surgery, 1 month after surgery, and 3 years after surgery with respect to 20 age- and gender-matched controls. The mean level of chromosome breaks and gaps was found to be significantly higher (P<0.001) in breast cancer patients (before surgery) as compared with the controls. The chromosome breaks and gaps after 1 month of surgery were observed significantly decreased (P<0.005) when compared with that of patients before the surgery. Further significant increase in chromosome breaks and gaps was found after 3 years of surgery as compared with both the patients after 1 month of surgery (P<0.05) and controls (P<0.005). The significant increase in chromosome breaks and gaps in breast cancer patients (before surgery) may be due to the effects of genetic susceptibility to environmental carcinogens and endogenous factors. However, the decrease in this level after 1 month of surgery may be due to the removal of cancerous tissues, which in turn removes the effect of mutagens and clastogenic factors. Further increase in chromosome breaks and gaps after 3 years of surgery may be due to the long-term effects of therapeutic agents and genetic susceptibility to environmental carcinogens in the patients. The study furthermore suggests that the high level of chromosome breaks and gaps after 3 years of surgery may be a risk factor for the development of secondary tumor in patients.

[Descriptive study of bladder tumors in the district of Levante-Alto Almanzora]

We present our series of operater bladder cancers in this District and the annual incidence in the period 1996 at 1998, as web as they are distributed by sex, age and smoking in the population; neoplasic stage and relapse were also studied. 61 patients were treated and un found global half incidence of 19.8 for 10(5) inhabitant-year (h-a), while for sexes it was of 4.22 for 10(5) h-y for women and of 15.58 for 10(5) h-y males. 78.69% was male with a masculinity rate of 3.69. The most frequent age group was starting from the seventh decade with 50.81% of our series. There was 36% of intervened patients that they were smoking, while 29.5% had relationship with other factors of risk like hydrocarbons and pesticidas. The superficial tumors were the most frequent with 86.88% of the cases, on the other hand the undifferentiated neoplastics was not very frequent with 13.21%, increasing these neoplastics with the age. In the follow up there were relapses in 36% of the people, being bigger in the T1 of our series. The occupational factors in this district can explain the high frequency in the female sex, although analytic studies are needed to check it.