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 local study completed in Singapore, which was part of an international multi-country study that aims to develop a global assessment of exposure to second-hand smoke in indoor workplaces, gathered data regarding the indoor air quality of public areas. It was hypothesised that air would be less polluted in non-smoking venues compared to places where smoking occurred.  

A TSI SidePak AM510 Personal Aerosol Monitor was used to sample and record the levels of respirable suspended particles (RSP) in the air. A broad range of venues were sampled in Singapore. The primary goal of data analysis was to assess the difference in the average levels of RSP in smoke-free and non smoke-free venues. Data was assessed at 3 levels: (a) the mean RSP across all venues sampled compared with the mean levels of smoke-free and non smoke-free venues, (b) levels in venues where smoking occurred compared with similar venues in Ireland, and (c) comparison between smoke-free and non smoke-free areas according to the type of venue. Statistical significance was assessed using the Mann-Whitney U-test.

The level of indoor air pollution was 96% lower in smoke-free venues compared to non smoke-free venues. Averaged across each type of venue, the lowest levels of indoor air pollution were found in restaurants (17 microg/m3) and the highest in bars (622 microg/m3); both well above the US EPA Air Quality Index hazardous level of >or=251 ug/m3.  

This study demonstrates that workers and patrons are exposed to harmful levels of a known carcinogen and toxin. Policies that prohibit smoking in public areas dramatically reduce exposure and improve worker and patron health. 

Reference: Koong HN, Khoo D, Higbee C, Travers M, Hyland A, Cummings KM, Dresler C., Global air monitoring study: a multi-country comparison of levels of indoor air pollution in different workplaces, Department of Surgical Oncology, National Cancer Centre, Singapore. Ann Acad. Med Singapore. 2009 Mar;38(3):202-6. 

Free Fulltext: Global Air Monitoring Study: A Multi-country Comparison of Levels of Indoor Air Pollution in Different Workplaces

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

Neighborhoods with restaurants, entertainment, cultural facilities and ethnic diversity have lower asthma rates in the city of Chicago than neighbourhoods where residents are less likely to move, and where there are more churches and not-for-profit facilities. 

Published in the spring 2009 issue of  The Journal of Allergy and Clinical Immunology, the two-year study led by Ruchi Gupta, MD, MPH, a researcher at Children’s Memorial Hospital and associate professor of pediatrics at Northwestern University’s Feinberg School of Medicine, showed that neighborhoods with more community vitality, specifically economic potential, community amenities and social capital had lower asthma rates. The study focused on 287 Chicago neighborhoods, where nearly 50,000 children grades K-8 were screened for asthma. Asthma is the leading chronic childhood illness, affecting more than 9 million children nationwide. Chicago has twice the national average asthma mortality rate. 

 â€œPrevious studies showed that neighborhoods right next to each other with similar racial makeup had very different asthma rates; we wanted to see what else was going on in each neighborhood to cause such a disparity,” said Gupta. “So we looked at specific factors in each neighborhood.” 

Ethnically diverse communities with greater potential for economic development that were civically engaged, meaning that there were high percentages of registered voters had low asthma rates while stable communities, defined as communities where residents were less likely to move, with more social interaction had higher asthma rates. Although it is not entirely clear how these factors affect health outcomes, previous research has shown that asthma and other chronic illnesses of childhood are associated with poverty, which may explain why communities with low asthma rates had a greater capacity for economic growth. 

Researchers suspect that the association between neighborhood stability and asthma may indicate that homes in which residents are less likely to move receive less frequent and thorough cleanings, leading to an accumulation of indoor pollutants known to trigger asthma.  Similarly, the association of higher interaction potential and increased asthma may signify overcrowding, which also leads to increased indoor pollutants.

Besides community influence, other factors that affect the rate of childhood asthma include income and education, housing problems with sensitivities to cockroaches, dust mites, mice and rats, exposure to air pollution and individual factors. A collaboration of many factors may ultimately cause asthma.

With these insights, we are better equipped to develop more effective interventions to help reduce asthma in children living in urban environments,” said Gupta. 

Information on the neighborhoods was gathered from the Metro Chicago Information Center. Gupta collaborated on this study with Xingyou Zhang, PhD, Lisa K Sharp, PhD, John J Shannon, MD, and Kevin B Weiss, MD, MPH. In a currently ongoing study, Gupta is further investigating the true importance of these protective factors by talking to and surveying residents in a Chicago neighborhood with a high childhood asthma rate. 

Reference: Childrens Memorial Hospital, Pree Release: Study shows how neighborhood characteristics play a significant role in childhood asthma, June 5, 2009

Exposure during pregnancy to the chemical bisphenol A, or BPA, found in many common plastic household items, is known to cause a fertility defect in the mother’s offspring in animal studies, and now researchers have found how the defect occurs. The results of the new study will be presented Saturday at The Endocrine Society’s 91st Annual Meeting in Washington, D.C.

The study, funded partly by the National Institutes of Health, joins a growing body of animal research showing the toxic health effects of BPA, including reproductive and developmental problems. Last August the U.S. Food and Drug Administration found BPA to be safe as currently used but later said more research on its safety is needed. BPA is used to make hard polycarbonate plastic, such as for baby bottles, refillable water bottles and food containers, as well as to make the linings of metal food cans.

BPA has estrogen-like properties and in pregnant animals has been linked to female infertility.

“The big mystery is how does exposure to this estrogen-like substance during a brief period in pregnancy lead to a change in uterine function,” said study co-author Hugh Taylor, MD, professor and chief of the reproductive endocrinology section at Yale University School of Medicine.

To find the answer to that question, Taylor and his co-workers at Yale injected pregnant mice with a low dose of BPA on pregnancy days 9 to 16. After the mice gave birth, the scientists analyzed the uterus of female offspring and extracted DNA.

They found that BPA exposure during pregnancy had a lasting effect on one of the genes that is responsible for uterine development and subsequent fertility in both mice and humans (HOXA10). Furthermore, these changes in the offspring’s uterine DNA resulted in a permanent increase in estrogen sensitivity. The authors believe that this process causes the overexpression of the HOXA10 gene in adult mice that they found in previous studies.

The permanent DNA changes in the BPA-exposed offspring were not apparent in the offspring of mice that did not receive BPA injection (the controls). This finding demonstrates that the fetus is sensitive to BPA in mice and likely also in humans, Taylor said.

“We don’t know what a safe level of BPA is, so pregnant women should avoid BPA exposure,” Taylor said. “There is nothing to lose by avoiding items made with BPA—and maybe a lot to gain.”

Reference: The Endocrine Society, Bisphenol A exposure in pregnant mice permanently changes DNA of offspring, 10-Jun-2009