(WASHINGTON, June 10, 2009) – The prospective U.S. Agricultural Health Study with over 50,000 farmers recently found that exposure to certain pesticides incurs twice the risk of developing an abnormal blood condition called MGUS (monoclonal gammopathy of undetermined significance) compared to individuals in the general population. The disorder, characterized by an abnormal level of a plasma protein, requires lifelong monitoring as it is considered pre-cancerous for its risk of developing into 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. This finding is particularly important given that we recently found in a large prospective cancer screening study that virtually all multiple myeloma patients are preceded by an MGUS state,” said lead author Ola Landgren, MD, PhD, of the National Cancer Institute. “As several million Americans use pesticides, it’s important that the risks of developing MGUS from the use of pesticides is known,” said senior study author Michael Alavanja, Dr.P.H.
A cohort of 678 individuals licensed to apply restricted-use pesticides were assessed for MGUS prevalence via a blood draw. Their median age 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 mean annual days of use of the individual pesticides, years of use, use of personal protective equipment while applying pesticides, and pesticide application methods. Information on smoking and alcohol use, cancer history of first-degree relatives, and other basic demographic and health data was 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 participants’ occupational exposures, medical histories, and lifestyle factors.
For comparison, data was obtained from a large MGUS-screening study conducted by the Mayo Clinic, and the results from the pesticide-applicator 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. Due to the low prevalence of women among the pesticide applicators, women were excluded from analysis.
In the pesticide-applicator group, no MGUS cases were observed among those who were less than 50 years of age, but the prevalence of MGUS in those greater than 50 was 6.8%. Compared to the Minnesota men of comparable age, the MGUS prevalence was 1.9-fold higher among pesticide applicators.
The researchers also evaluated the potential association between MGUS prevalence and 50 specific pesticides for which usage data was 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 was 5.6-fold, 3.9-fold, and 2.4-fold, respectively. Several other insecticides, herbicides, and fungicides were associated with MGUS, but not significantly. “Our findings are intriguing. If replicated in a larger sample from our study and other large studies, further work should be focused on 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,” said lead author Ola Landgren, MD, PhD.
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The American Society of Hematology (www.hematology.org) is the world’s largest professional society concerned with the causes and treatment of blood disorders. Its mission is to further the understanding, diagnosis, treatment, and prevention of disorders affecting blood, bone marrow, and the immunologic, hemostatic, and vascular systems, by promoting research, clinical care, education, training, and advocacy in hematology. In September, ASH launched Blood: The Vital Connection (www.bloodthevitalconnection.org), a credible online resource addressing bleeding and clotting disorders, anemia, and cancer. It provides hematologist-approved information about these common blood conditions including risk factors, preventive measures, and treatment options.
established in many states
across the country especially along the east coast. It is an easy
traveler in things like motor homes. There is a long list of hosts,
both ornamental and agricultural from maple and birch to pecan, peach,
apple and cucumber. Adults emerge from overwintering about April. All
instars have deep red eyes. Early nymphs are red, then almost black,
and finally brown in color as adults. They are typical stink bugs in
most ways and damage fruit and foliage with their feeding (proboscis)
and saliva. There is a single generation in northern states. To add to
their annoyance, they like to overwinter in protected places such as
structures. This is where you are most likely to first notice them.
