Exposure to organochlorine pesticides as a predictor to breast cancer: A case-control study among Ethiopian women.

Breast cancer (BC) is becoming one of the most prevalent non-infectious disease in low and middle income countries. The steady rise of BC incidence may be related to the different risk factors. Among many, rampant presence of environmental pollutants might be one of the risk factors. Therefore, the aim of this study is to investigate exposure to organochlorine pesticides as a risk factor to breast cancer. A case-control study design was employed among breast cancer patients and non-breast cancer individuals (controls). Blood samples were collected from 100 study participants (50 cases and 50 controls) followed by serum separation, extraction and cleanup using standard analytical procdures. The findings revealed that ten organochlorine pesticides were detected in the serum of the study participants. From the detected organochlorine pesticides, heptachlor was observed at higher concentration for breast cancer patients (6.90±4.37 µg/L) and controls (9.15±3.84 µg/L). Mean serum level of p,p'-DDE, p,p'-DDT, heptachlor, gamma-chlordane, endosulfan, and dibutyl-chlorendate were significantly higher in the serum of breast cancer patients than the controls. From the studied pesticides, p,p'-DDT and gamma-chlordane are significant predictors for BC, while, others are equivocal. A unit increment of the concentration of p,p'-DDT (AOR; 2.03, 95% CI: 1.041-3.969) increased the odds of developing breast cancer by two, while for gamma-chlordane (AOR;3.12, 95% CI; 1.186-8.203) by three. Our study results suggesting that, organochlorines are a risk factors for breast cancer in Ethiopia. Decreasing exposure to such organochlorines might have a significant public health relevance in reducing non-communicable chronic illnesses. Besides, continues monitoring of persistent organic pollutants using body biomarkers is important for disease prevention and device mitigation measures.

Evaluation of epidemiologic and animal data associating pesticides with Parkinson's disease.

Exposure to pesticides may be a risk factor for developing Parkinson's disease (PD). To evaluate the evidence regarding this association in the scientific literature, we examined both analytic epidemiologic studies of PD cases in which exposure to pesticides was queried directly and whole-animal studies for PD-like effects after systemic pesticide exposure. Epidemiologic studies were considered according to study quality parameters, and results were found to be mixed and without consistent exposure-response or pesticide-specific patterns. These epidemiologic studies were limited by a lack of detailed and validated pesticide exposure assessment. In animal studies, no pesticide has yet demonstrated the selective set of clinical and pathologic signs that characterize human PD, particularly at levels relevant to human populations. We conclude that the animal and epidemiologic data reviewed do not provide sufficient evidence to support a causal association between pesticide exposure and PD.

The organochlorine pesticide heptachlor disrupts the structure of model and cell membranes.

Heptachlor is an organochlorine pesticide which is particularly toxic for aquatic life. A significant source of this pesticide for infants is breast milk, where its concentration is considerably higher than in dairy milk. Given the lipophilic character of heptachlor, lipid-rich cell membranes are a very plausible target for its interaction with living organisms. In order to evaluate its toxicity towards cell membranes, heptachlor was made to interact with human erythrocytes and molecular models of the red cell membrane. These consisted of multilayers of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE), which are types of phospholipids that are respectively located in the outer and inner monolayers of the erythrocyte membrane, and large unilamellar vesicles (LUV) of DMPC. Observations by scanning electron microscopy showed that 10 mM heptachlor produced various degrees of shape alterations to erythrocytes, which ranged from a few blebs in some cells to a great number of protuberances in others. On the other hand, experiments performed by X-ray diffraction on DMPC and DMPE indicated that the bilayer structure of DMPC was much more affected by heptachlor than that of DMPE. Measurements by fluorescence spectroscopy on DMPC LUV confirmed the X-ray diffraction results in that both the hydrocarbon chain and polar head regions of DMPC were structurally perturbed by heptachlor. The results obtained from the model studies could explain the shape changes induced to red cells by heptachlor. According to the bilayer hypothesis, they were due to the preferential interaction of heptachlor with the phosphatidylcholine-rich external moiety of the erythrocyte membrane. It is therefore concluded that toxic effects of this pesticide can be related to its capacity to perturb the phospholipid bilayer structure, whose integrity is essential for cell membrane functions.

Corporate crime: why we cannot trust industry-derived safety studies.

The control of pesticides, as of all synthetic chemicals, in most industrialized countries relies heavily or even entirely on safety data supplied by the manufacturers. Such a regulatory system can only be effective if the companies conducting and reporting the studies honestly disclose any adverse findings. The record shows, however, that all too often company executives and their scientists knowingly suppress or manipulate information that could affect the licensing and sale of their products. A case in point is the gross manipulation of health and related data on the pesticides heptachlor and chlordane by the U.S. chemical company, Velsicol.

An evaluation of serum pesticide residue levels and liver function in persons exposed to dairy products contaminated with heptachlor.

We studied a group of 45 dairy farm family members who had consumed undiluted raw milk products known to be contaminated with residues of the pesticide heptachlor at concentrations as high as 89.2 ppm (fat basis). We compared results of serum pesticide assays for these exposed persons with results for an unexposed group of 94 persons from the same geographic area and the results from the Second National Health and Nutrition Examination Survey. The exposed group had significantly higher mean levels of primary heptachlor metabolites--ie, heptachlor epoxide (0.84 +/- 1.0 vs 0.50 +/- 0.9 parts per billion) and oxychlordane (0.71 +/- 0.8 vs 0.49 +/- 1.1 parts per billion)--than the unexposed group. In the exposed group, 21.2% had elevated serum concentrations of these same metabolites; this rate was significantly greater than the rates in both the unexposed farm family members (heptachlor epoxide, 3.8%; oxychlordane, 6.3%) and the Second National Health and Nutrition Examination Survey sample (2.5% for both metabolites). However, we found no evidence of related acute and/or subacute hepatic effects in these exposed persons regardless of their serum concentrations of pesticide residues.

Leukemias and blood dyscrasias following exposure to chlordane and heptachlor.

We present 25 new cases of blood dyscrasia, including leukemias, production defects, and thrombocytopenic purpura, generally following home termite treatment with the chlorinated hydrocarbon pesticides chlordane and heptachlor (C/H). These newly reported cases are consistent with 34 previously published case reports associating blood dyscrasias with C/H exposure. Additionally, the newly reported leukemias are consistent with epidemiologic evidence of excess risk of leukemia and other cancers in C/H-exposed populations and with the carcinogenic action of C/H in animals. The importance of case reports in warning of the association of blood dyscrasias to C/H exposure is emphasized. Until the voluntary halt in production in July 1987, millions of homes in the United States were treated with chlordane and heptachlor for termites even though their agricultural uses were phased out in 1978, largely on the grounds of "imminent hazard" because of carcinogenicity. In view of the recognized myelotoxicity, carcinogenicity, and other chronic toxic effects of these pesticides, a national program for monitoring all homes treated is urgently needed to detect persistent contamination.

Mortality of workers employed in the manufacture of chlordane and heptachlor.

A retrospective mortality study has been carried out on workers employed in the manufacture of chlordane and heptachlor between 1946 and 1976. The study group was comprised of 1403 white males who worked for more than three months at either of the two plants in the United States now producing these compounds. Information on deaths among terminated employees was obtained from the Social Security Administration and supplemented by information collected by another investigator by individual follow-up. There were 113 deaths observed in the group, compared to 157 expected, giving a standardized mortality ratio (SMR) of 72. There was no overall excess of deaths from cancer, even among workers followed twenty or more years after entry into the occupation. There was one death from liver cancer. An excess of deaths from lung cancer (12 observed, 9.0 expected) was not statistically significant and was not distributed by duration of exposure or of latency in any pattern suggesting an etiologic role for chlordane-heptachlor exposure. Although diseases of the circulatory system as a whole showed fewer deaths than expected (SMR 83), there was a statistically significant excess of deaths from cerebrovascular disease (17 observed, 9.3 expected). This excess was not related to duration of exposure or latency and occurred exclusively after termination of employment.

Hepatic vein thrombosis in mice ingesting chlorinated hydrocarbons.

Hepatic vein thrombosis, as well as hepatocellular carcinomas, was induced in inbred C3H male and female mice ingesting 10 ppm of dieldrin, aldrin, heptachlor, or heptachlor epoxide in the diet. Thrombosis was present in 5% of mice ingesting dieldrin or aldrin and in 10.5% of mice ingesting heptachlor or heptachlor epoxide. Occlusion of the hepatic vein often resulted in infarcts of the liver. Females ingesting heptachlor or heptachlor epoxide were slightly more susceptible than males. There was no difference between male and female mice ingesting dieldrin or aldrin. Hepatic vein thrombosis did not appear to be related to the development of carcinoma of the liver because it was present in livers without carcinomas as well. Thrombosis was usually seen only in the liver but also rarely was present in the atria of the heart.