22
Apr
Grandmothers’ Exposure to DDT Increases Granddaughters’ Breast Cancer and Cardiometabolic Disorder Risk
(Beyond Pesticides, April 22, 2021) Past maternal exposure to the pesticide dichlorodiphenyltrichloroethane (DDT) during pregnancy can increase the risk of breast cancer and cardiometabolic disorders (e.g., heart disease, obesity, diabetes) up to three successive generations, according to a new study published in Cancer Epidemiology, Biomarkers & Prevention. Although previous studies highlight early life or in utero exposure to DDT increasing breast cancer risk later in life, this study is the first to note generational effects on grandchildren’s health. DDT continues to adversely affect the health of the U.S. population, nearly 50 years after its ban. However, this ban is not global, as many countries still use or manufacture the chemical compound. Furthermore, residues of DDT metabolite, DDE, continue to readily contaminate food and water worldwide. Therefore, studies like these highlight the need to investigate how first-generation pesticide exposure can impact future generational health in order to prevent adverse health outcomes, especially during sensitive developmental periods (i.e., in utero, infancy/childhood). The study researchers note, “Discovery of actionable biomarkers of response to ancestral environmental exposures in young women may provide opportunities for breast cancer prevention.”
To assess the association between multi-generational health risks and chemical exposure, researchers used the Public Health Institute’s Child Health and Development Studies (CHDS). CHDS has been following a cohort of 20,000 pregnant women since the 1960s and examines how diseases can pass from one generation to the next. Researchers gathered archived blood serum samples from pregnant grandmothers (F0) during and after pregnancy to measure o,p’-DDT, p,p’-DDT and p,p’-DDE concentrations. After adjusting for body mass index (BMI) and health effects among daughters (F1), researchers estimated granddaughter (F2) health outcomes, including waist circumference, weight, height, via log-linear models. Health outcomes like obesity and early menstruation are risk factors for breast cancer later in life.
The results find obesity risk increases two to three-fold in granddaughter when grandmothers have high o,p’-DDT levels, especially among grandmothers of average weight. There is also a positive association between grandmother o,p’-DDT levels, and early-onset menstruation among granddaughters, regardless of grandmother’s BMI. (See ”Pesticides and the Obesity Epidemic.”)
DDT, an organochlorine (OC) insecticide, was widely used to control mosquitoes and in agriculture. However, a massive environmental movement spurred by Rachel Carson’s Silent Spring resulted in the chemical ban in 1972. DDT, and its major metabolite DDE, still remain in the environment decades after use ended, with the U.S. Environmental Protection Agency (EPA) finding chemical concentrations that exceed acceptable levels. DDT/DDE are persistent organic pollutants (POPs) resistant to environmental degradation through chemical, biological, and photolytic processes. These POPs persist in soil and water sediments, glacier meltwater runoff, U.S. national parks, and food webs. Additionally, these compounds readily dissolve into body fat and linger for many years, adversely affecting the hormonal system, metabolic function, and brain development. Exposure to DDT, as an endocrine (hormone) disruptor, increases the risk associated with diabetes, early onset menopause, reduced sperm count, endometriosis, birth defects, autism, vitamin D deficiency, non-Hodgkin’s Lymphoma, and obesity. Past studies indicate DDE exposure has multi-generational health effects on obesity and diabetes, with DDE uniquely augmenting multi-generational breast cancer occurrences. Climate change only threatens to exacerbate residual DDT/DDE exposure, as warming may affect chemical movement and concentration in the environment. Therefore, animals and humans may experience a weakened ability to tolerate those chemicals.
Many studies have long demonstrated that childhood and in utero exposure to DDT increases the risk of developing breast cancer later in life. However, studies find many current-use pesticides and chemical contaminants play a role in similar disease prognosis, including mammary tumor formation. Recent research from the Silent Spring Institute links 28 different EPA registered pesticides with the development of mammary gland tumors in animal studies. Many of these said chemicals are endocrine disruptors, thus have implications for breast cancer risk. Even household cleaners, most of which are pesticides, contain endocrine-disrupting chemicals that increase breast cancer risk. Furthermore, long-term exposure to organophosphate (OP) pesticides increases adverse health and cancer risk, specifically among women. Like DDT, exposure to other POPs like per- and polyfluoroalkyl substances (PFAS) during pregnancy can increase cardiometabolic disorders like obesity, diabetes, and cardiovascular diseases among offspring. Since DDT/DDE residues, current-use pesticides, and other chemical pollutants contaminate the environment, exposure to these chemical mixtures can synergize to increase toxicity and disease effects.
Inheritance of health issues spanning generations relating to hereditary influence is a familiar phenomenon. However, this study represents the first study to demonstrate multi-generational health problems from DDT exposure, a non-genetic factor. Therefore, exposure to pesticides poses just as much of a multi-generational health risk as hereditary illnesses. A plethora of research links pesticide exposure to endocrine disruption with epigenetic (non-genetic influence on gene expression) effects. As far back as 15 years ago, a Washington State University study linked pesticide exposure to multi-generational impacts on male fertility in rodents. According to multiple studies, glyphosate exposure has adverse multi-generational effects causing negligible observable effects on pregnant rodents but severe effects on the two subsequent generations. These impacts include reproductive (prostate and ovarian) and kidney diseases, obesity, and birth anomalies. New findings suggest exposure to the pesticide atrazine causes multi-generation resistance to the chemical in wasps by altering gut bacteria composition. Moreover, chemical byproducts made during the pesticide manufacturing process, such as dioxin, have multi-generational consequences on reproductive health.
Researchers note that past studies investigating DDT exposure measured bodily DDE concentration, as the metabolite stays in the body longer than the parent chemical itself. However, this study finds o,p’-DDT, rather than DDE, is the most sensitive biomarker for DDT exposure, indicating exposure during pregnancy many decades ago. The compound metabolizes much quicker than the main ingredient for DDT (p,p’-DDT) that breakdowns to DDE. Furthermore, studies find less endocrine disruption potential associated with breast cancer risk for DDE compared to o,p’-DDT. Lastly, the study’s researchers note that higher rates of obesity among granddaughters are most likely due to grandmother’s DDT exposure rather than exposure to present-day obesogenic chemicals from diet or other means. DDT-associated compounds are commonly detectable in most of the U.S. population, especially among people of color (POC) communities. Therefore, it is essential to understand the impacts these residual compounds, and others like them, have on the future of human, animal, and environmental health.
Study co-author and scientist at Public Health Institute Barbara Cohn, Ph.D., stresses, “In combination with our on-going studies of DDT effects in the grandmother’s and mother’s generations, our work suggests we should take precautionary action on the use of other endocrine-disrupting chemicals, given their potential to affect generations to come in ways we cannot anticipate today…We don’t want to wait [for] the next three generations to find out the chemicals that are in use now cause breast cancer.”
It is essential to understand the effects that endocrine-disrupting pesticides may have on the health of current and future generations. There is a lack of understanding behind the etiology of pesticide-induced diseases, including predictable lag time between chemical exposure, health impacts, and epidemiological data. Therefore, lawmakers and regulators should consider taking a more precautionary approach before introducing these chemicals into the environment. With far too many diseases in the U.S. associated with pesticide exposure, reducing pesticide use is a critically important aspect of safeguarding public health and addressing cost burdens for local communities.
Learn more about the effects of pesticides on human health by visiting Beyond Pesticides’ Pesticide-Induced Diseases Database, supporting a shift away from pesticide dependency. This database is a fantastic resource for additional scientific literature, documenting elevated rates of Endocrine Disruption, Cancer, Body Burdens, and other chronic diseases and illnesses among people exposed to pesticides. Beyond Pesticides believes that we must mitigate the multi-generational impacts pesticides pose on human and animal health. Adopting regenerative-organic practices and using least-toxic pest control can reduce harmful exposure to pesticides. Solutions like buying, growing, and supporting organic can help eliminate the extensive use of pesticides in the environment. Learn more about the multi-generation impacts of pesticides on our health via Beyond Pesticide’s journal Pesticides and You. Additionally, read more and help spread the word about the hazards pesticides pose to children through our Children and Pesticides Don’t Mix fact sheet.
Help Beyond Pesticides educate and build the movement that will bring long-needed protection to humans, animals, and the entire environment by attending the National Pesticide Forum this spring. Cultivating Healthy Communities will bring together expert scientists, farmers, policymakers, and activists to discuss strategies to eliminate harms from toxic chemical use in favor of non-toxic organic solutions. It begins with a pre-conference session on Monday, May 24, and continues every Tuesday beginning May 25, June 1, June 8, and ending June 15, 2021. Registration is open today and available through the webpage on this link. It starts with US.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Cancer Epidemiology, Biomarkers & Prevention, Environmental Health News
