Sixty-five farmers reported on pesticide use and the signs and symptoms of acute pesticide poisoning when using two different plant protection strategies: in 2003 using chemical controls and in 2004 using an approach to Integrated Pest Management (IPM) based on an ecological analysis of the field conditions.

Exposure to organophosphates was confirmed as a serious risk factor for occupational poisoning. The adoption of IPM reduced the use of pesticides and halved the incidence of acute pesticide poisoning. Overall, the pesticide use spectrum shifted towards lower WHO Hazard Classes. A reduction of adverse health effects was attained through a reduction in exposure to toxic pesticides and behavioural changes. Given that other strategies to reduce the rate of acute poisoning have proven ineffective, interventions aiming to minimize pesticide poisoning in India and in other developing countries with similar rural conditions should focus on restricting the use of highly toxic compounds and educating farmers on IPM.

Reference: Mancini F, Jiggins JL, O’Malley M., Reducing the incidence of acute pesticide poisoning by educating farmers on integrated pest management in South India, Wageningen University, Int J Occup Environ Health. 2009 Apr-Jun;15(2):143-51

A study involving 678 individuals who apply pesticides, culled from a U.S. Agricultural Health Study of over 50,000 farmers, recently found that exposure to certain pesticides doubles one’s risk of developing an abnormal blood condition called MGUS (monoclonal gammopathy of undetermined significance) compared with individuals in the general population. The disorder, characterized by an abnormal level of a plasma protein, requires lifelong monitoring as it is a pre-cancerous condition that can lead to multiple myeloma, a painful cancer of the plasma cells in the bone marrow. The study will appear in the June 18 issue of Blood, the official journal of the American Society of Hematology.  

“Previously, inconclusive evidence has linked agricultural work to an increased multiple myeloma risk. Our study is the first to show an association between pesticide exposure and an excess prevalence of MGUS,” said lead author Ola Landgren, MD, PhD, of the National Cancer Institute (NCI), which is part of the National Institutes of Health, U.S. Department of Health and Human Services. “This finding is particularly important given that we recently found in a large prospective cancer screening study that virtually all multiple myeloma patients experienced a MGUS state prior to developing myeloma.”  

“As several million Americans use pesticides, it’s important that the risks of developing MGUS from the use of pesticides is known,” added senior study author and NCI investigator Michael Alavanja, DrPH. 

The blood of study participants, who were individuals licensed to apply restricted-use pesticides, was assessed for MGUS prevalence. The median age of participants was 60 years (range 30-94 years), and all lived in either Iowa or North Carolina. Participants also completed questionnaires providing comprehensive occupational exposure information for a wide range of pesticides, including information such as the average number of days of pesticide use per year, years of use, use of protective gear while applying pesticides, and pesticide application methods. Information on smoking and alcohol use, cancer histories of the participants’ first-degree relatives, and other basic demographic and health data were also obtained. Individuals with prior histories of lymphoproliferative malignancies (such as multiple myeloma or lymphoma) were excluded. Cancer incidence and mortality were monitored annually, and, after five years, follow-up interviews were conducted to update the information about participants’ occupational exposures, medical histories, and lifestyle factors. 

For comparison, data were obtained from a large MGUS-screening study conducted by the Mayo Clinic, and the results from the pesticide-exposed group were compared with the assessments of 9,469 men from the general population of Olmsted County, Minnesota. The two groups were similar in terms of age, race, and educational attainment. Because of the low prevalence of women among workers who apply pesticides, women were excluded from the study.  

In the pesticide-exposed group, no MGUS cases were observed among those who were less than 50 years of age, but the prevalence of MGUS in those older than 50 was 6.8 percent, which is 1.9 times higher than the general population study group of men in Minnesota. 

The researchers also evaluated the potential association between MGUS prevalence and 50 specific pesticides for which usage data were known. Of the chemicals studied, a significantly increased risk of MGUS was observed among users of dieldrin (an insecticide), carbon-tetrachloride/carbon disulfide (a fumigant mixture), and chlorothalonil (a fungicide). The MGUS risk for these agents increased 5.6-fold, 3.9-fold, and 2.4-fold, respectively. Several other insecticides, herbicides, and fungicides were associated with MGUS, but not significantly.  

“There is great concern regarding the increase in frequency in mature B-cell malignancies in the Western world and what may be the cause of this. A number of reports in the past have linked exposure to pesticides with increased risk of these types of cancers, but the present study is the first to link agricultural work to a pre-malignant condition,” said John G. Gribben, MD, DSc, Professor of Experimental Cancer Medicine at Barts and the London School of Medicine, who is not affiliated with the study. “It is vital to assess the risk of workplace exposure and disease, and the results lend further support to providing safe workplace practices to limit exposure to potential carcinogens.”

“Our findings are intriguing,” stated Dr. Landgren. If replicated in a larger sample from our study and other large studies, further work should focus on gaining a better understanding of the molecular basis of MGUS and multiple myeloma. Ultimately, this will result in the identification of novel molecular targets involved in the progression from MGUS to multiple myeloma and in the development of targeted therapies.”   

Reference: American Society of Hematology, Individuals Who Apply Pesticides Are Found to Have Double the Risk of Blood Disorder, Press Release, WASHINGTON, June 12, 2009

Paris, France – June 04, 2009 – The cause of Parkinson’s disease (PD), the second most frequent neurodegenerative disease after Alzheimer’s disease, is unknown, but in most cases it is believed to involve a combination of environmental risk factors and genetic susceptibility. Laboratory studies in rats have shown that injecting the insecticide rotenone leads to an animal model of PD and several epidemiological studies have shown an association between pesticides and PD, but most have not identified specific pesticides or studied the amount of exposure relating to the association.  

A new epidemiological study involving the exposure of French farm workers to pesticides found that professional exposure is associated with PD, especially for organochlorine insecticides. The study is published in Annals of Neurology, the official journal of the American Neurological Association.  

Led by Alexis Elbaz M.D., Ph.D., of Inserm, the national French institute for health research in Paris, and University Pierre et Marie Curie (UPMC, Paris 6), the study involved individuals affiliated with the French health insurance organization for agricultural workers who were frequently exposed to pesticides in the course of their work. Occupational health physicians constructed a detailed lifetime exposure history to pesticides by interviewing participants, visiting farms, and collecting a large amount of data on pesticide exposure. These included farm size, type of crops, animal breeding, which pesticides were used, time period of use, frequency and duration of exposure per year, and spraying method. 

The study found that PD patients had been exposed to pesticides through their work more frequently and for a greater number of years/hours than those without PD. Among the three main classes of pesticides (insecticides, herbicides, fungicides), researchers found the largest difference for insecticides: men who had used insecticides had a two-fold increase in the risk of PD. 

“Our findings support the hypothesis that environmental risk factors such as professional pesticide exposure may lead to neurodegeneration,” notes Dr. Elbaz.  

The study highlights the need to educate workers applying pesticides as to how these products should be used and the importance of promoting and encouraging the use of protective devices. In addition to the significance of the study for those with a high level of exposure to pesticides, it also raises the question about the role of lower-level environmental exposure through air, water and food, and additional studies are needed to address this question.  

Reference: Alexis Elbaz, Jacqueline Clavel, Paul J. Rathouz, PhD 6, Frédéric Moisan Jean-Philippe Galanaud, Bernard Delemotte, Annick Alpérovitch, Christophe Tzourio, Professional exposure to pesticides and Parkinson’s disease, Annals of Neurology, Press Release Wiley Blackwell, June 4, 2009

Estrogen-like endocrine disrupting chemicals (EEDC) are exogenous, man-made chemicals that alter the functions of the endocrine system and cause various health defects by interfering with the synthesis, metabolism, binding or cellular responses of natural estrogens.  

EEDCs have been found in various plastic products, flame retardants, pesticides and many other products that are needed for daily use. Some of the greatest effects of EEDCs are on puberty, a period of rapid physiological changes like growth spurt, maturation of the gonads and the brain.  

Estrogen, one of the key hormones required in puberty is crucial for the sexual differentiation. The structural similarity of estrogen disruptors with estrogen allow them to bind and activate estrogen receptors and show a similar response even in the absence of estrogen that can lead to precocious puberty (PP).  

Major EEDCs found abundantly in our environment include; dichlorodiphenyltrichloroethane (DDT), dioxin, polychlorinated biphenyls (PCBs), bisphenol A (BPA), polybrominated biphenyls (PBB), phthalate esters, endosulfan, atrazine and zeranol.  

In girls, DDT has been linked to earlier menarche. Dioxin causes abnormal breast development in pre-pubertal girls. BPA has shown to cause PP in pubertal girls. PBB causes earlier menarche, thelarche and earlier pubic hair stage in pubertal girls. PCB’s showed a significant delay in puberty in pubertal boys. De-feminization, thelarche, or early secondary breast development are shown in pubertal girls when exposed to phthalate esters. Endosulfan affects pubertal boys by slowing down the timing of reproductive maturation.

This article provides a possible structure-function relation of the above mentioned EEDCs which interfere with sexual development during puberty.

Reference: Roy JR, Chakraborty S, Chakraborty TR., Estrogen-like endocrine disrupting chemicals affecting puberty in humans – a review, Department of Biology, Adelphi University, Garden City, New York, NY, U.S.A., Med Sci Monit. 2009 Jun;15(6):RA137-145.

Pyrethrin and Pyrethroide insecticides are commonly applied in homes and businesses and on some agricultural crops. This research used a two-state regional approach to analyze reports of acute pesticide poisonings due to Pyrethrin and Pyrethroide insecticides.  

The Washington State Department of Health and the Oregon Public Health Division collected pesticide poisoning surveillance data from 2001 through 2005. Cases were included if they involved exposure to at least one Pyrethrin or Pyrethroide insecticide. Descriptive statistics were calculated; differences between categories were assessed using Chi-square analysis.  

A total of 407 cases fit our definition. Overall, the rate of poisoning in Oregon was significantly higher than in Washington (incidence rate ratio 1.70, 95% confidence interval 1.40, 2.07), and rates for both states generally increased during the time period. For both states, most exposures resulted in low severity illnesses (92%), and most were classified as possible cases (73%). Only about one-fourth of cases were related to a person’s work. The most common category of clinical signs and symptoms of illness was respiratory (52% of cases), followed by neurological (40% of cases). Exposure route was predominantly inhalation; there was no association between route and case severity. There was a significant association between illness severity and losing time from work or regular activities (p<0.0001).  

Although the majority of Pyrethrin and Pyrethroide poisoning cases were low in severity, adverse reactions have occurred, as transpired in Oregon in 2005. Regional analysis has the potential to improve the surveillance system and provide unique opportunities for targeting preventive interventions. 

Reference:

Walters JK, Boswell LE, Green MK, Heumann MA, Karam LE, Morrissey BF, Waltz JE., Pyrethrin and Pyrethroide illnesses in the Pacific Northwest: a five-year review, Oregon Department of Human Services, Public Health Division, Office of Environmental Public Health, Toxicology, Assessment, & Tracking Services, Oregon Worker Illness and Injury Prevention Program, Portland, OR 97232, USA, Public Health Rep. 2009 Jan-Feb;124(1):149-59.