Study Connects Pesticide Use to Follicular Lymphoma
In the past 15 years, a significant amount of scientific and medical research has found connections between non-Hodgkin’s lymphoma (NHL), its specific subtypes, and exposure to various chemicals.
Some studies have looked at the relationship between NHL and specific agricultural and household chemicals. The study, entitled “Non-Hodgkin Lymphoma Risk and Insecticide, Fungicide and Fumigant Use in the Agricultural Health Study (Alavanja),” published in 2014, is one such study.
The 2014 Alavanja study considered whether there was an identifiable relationship between the use of insecticide, fungicide and fumigants and NHL. The study was conducted by several cancer scientists working at the National Cancer Institute (NCI), the National Institute for Occupational Safety and Health (NIOSH), and the National Institute for Environmental Health Sciences (NIEHS).
The Alavanja study found that exposure to certain chemical classes were associated with an excess risk of NHL overall and certain NHL subtypes, including follicular lymphoma.
Follicular lymphoma is the most common slow-growing NHL, and the second most common form of NHL overall. This blood cancer takes its name from the characteristically abnormal lymphoid follicles seen when viewing the cancerous tissue through a microscope.
The Alavanja study specifically links the chemicals lindane and diazinon with a significantly increased risk of follicular lymphoma.
The scientists tracked a group of licensed private pesticide applicators in Iowa and North Carolina over a period of roughly 18 years. Enrollment in the study stretched from 1993 to 1997. The monitoring period for the Iowa group ended on December 31, 2011 and for the North Carolina group on December 10, 2010. During this time frame scientists frequently checked on the applicants, monitoring their health and documenting their exposure to various agricultural and household pesticides.
By the end of the study, 523 of the 54,306 participants developed a subtype of non-Hodgkin’s lymphoma. Of those 523 cases, 67 had been diagnosed with the NHL subtype known as follicular lymphoma.
Among the other participants in the study, 6,195 were diagnosed with other cancers besides NHL and 4,619 died with no record of cancer. The study also recorded 1,248 participants that left the state and could not be followed up with.
Lindane is an insecticide used in the United States until 2009, when its production was banned worldwide. The U.S. ended production of lindane in 1976, but continued to import the chemical until 2009. Lindane was used not only for agricultural pest control, but also for household use including the treatment of scabies and lice.
Household products containing lindane include several household pesticides such as Doff Ant Killer, Doom Flea Killer, DB Green Liquid and more. Lindane is also used as a pesticide on crops ranging from corn and wheat to avocado, potatoes, peanuts, and many others. It was also used on cotton, flowers and trees to control pests.
The Alavanja study defined a “high” level of exposure as any level above the median amount found in the study. Conversely, the “low” amount was any level below the median. The study found that the likelihood of developing NHL increased along with one’s exposure to lindane. Subjects who reported more than 56 days of lifetime exposure to lindane were 250% more likely to develop NHL than those who reported zero days of exposure. Participants who reported a “high” level of exposure were 360% more likely to develop follicular lymphoma, specifically. Even those who reported a “low” level of lifetime exposure were found to be more than 300% more likely to develop follicular lymphoma.
Lindane hasn’t been manufactured in the United States since the 1970’s, but was imported through 2009. It goes by the trade names Lindagam, Lindafor, Isotox, Inexit, Lindamul, Lindalo, Lindagranox, Lindagrain, Silvanol, Novigan, Lindaterra, and Lindapoudre.
U.S. companies known to manufacture, produce or supply lindane include Drexel Chemical Company, American Radiolabeled Chemicals, Spectrum Quality Products, ICN Biomedical Research Products, Accustandard, Pfaltz and Bauer, Inc, ChemService, Inc., Rentokil, Wilbur-Ellis Company, Trace Chemicals LLC, and Dragon Chemical Corporation.
The chemical is classified as an “extremely hazardous substance” according to the U.S. Emergency Planning and Community Right-to-Know Act. The International Agency for Research on Cancer (IARC) also classified lindane as a known human carcinogen in 2015. A decade earlier, the U.S. Department of Health and Human Services determined lindane “may reasonably be anticipated to cause cancer in humans.”
Lindane is a “persistent organic pollutant,” remaining in the environment for a long time and moving long distances through natural processes. Its production and use are the primary cause of environmental lindane contamination. The chemical can accumulate in food chains, though it can be eventually eliminated once the exposure ends. Lindane used in agriculture can leach from the soil into surface and ground water. An estimated 12 to 30 percent of lindane volatilizes into the atmosphere where it can be transported over a wide range via the water cycle.
Algae, fungi and bacteria can break down lindane in soil, sediment and water into less harmful substances over time. However, the process is slow. Environmental scientists continue to debate the ecological impact of lindane’s persistence.
Cancer epidemiologists have concluded with overwhelming certainty that lindane causes NHL in humans.
The IARC report, titled “Carcinogenicty of lindane, DDT and 2,3-dichlorophenoxyacetic acid,” says lindane is fat soluble and readily absorbed into the human body.
“Epidemiological cohort and case-control studies of non-Hodgkin lymphoma in several countries provided sufficient evidence in humans for the carcinogenicity of lindane,” the IARC study said.
Likewise, the Alavanja study said lindane has been linked with genetic aberrations on humans in the womb, and with non-Hodgkin’s lymphoma in previous studies.
“A significant association between lindane use and NHL was observed in a pooled analysis of three population-based case control studies conducted in the Midwestern U.S.,” the Alavanja study said. “Stronger relative risks were observed for greater duration and intensity of use.”
Diazinon is an insecticide registered for a variety of uses on plants and animals in agriculture. Developed in 1952 by the Swiss company Ciba-Geigy, it was used to control household pest insects. The chemical is still used in flea collars for domestic pets in Australia and New Zealand. It was previously used in several household insecticide products until the EPA phased out all residential registrations for diazinon in December 2004. It is still used in U.S. agriculture to this day. Consumers can legally use diazinon products if they were purchased before the ban. Diazinon is used on rice, fruit trees, sugarcane, corn, tobacco, potatoes and on horticultural plants.
Trade names for diazinon include Basudin, Dazzel, Gardentox, Kayazol, Knox Out, Nucidol, and Spectracide.
Products known to include diazinon include Gordon’s Trimec Weed and Feed, Drexel LV6 Weed Killer, Riverdale Fertilizer Plus and many more. Products including diazinon are sold in dust, granules, seed dressings, wettable powder, and emulsifiable solution formulations.
The Alavanja study found that the likelihood of developing follicular lymphoma increased along with one’s exposure to diazinon. Subjects who reported a “low” level of diazinon exposure were 220% more likely to develop follicular lymphoma. Those who reported “high” levels of diazinon exposure were found to be 380% more likely to develop follicular lymphoma.
“While there was no link between diazinon and NHL overall in this analysis, there was a statistically significant exposure-response association between diazinon and the follicular lymphoma subtype,” according to the Alavanja study.
The scientists said diazinon was previously associated with NHL in pooled case-control studies from the U.S., particularly with small lymphocytic lymphoma.
If you believe your recent follicular lymphoma diagnosis might be related to exposure to lindane or diazinon, please contact the trial attorneys of Allen Stewart, P.C. The firm has decades of combined experience in helping those who have developed cancer due to toxic exposure.