Pesticide DDT linked to increased breast cancer risk generations after exposure

A woman’s exposure to the pesticide DDT during pregnancy can increase her granddaughter’s risk for breast cancer decades later, according to a new study.

Published today in Cancer Epidemiology, Biomarkers & Preventionthe study found a significant association between DDT in grandmothers’ blood during pregnancy, and obesity and early first menstrual periods in their granddaughters—factors known to increase the risk for breast cancer, high blood pressure, diabetes, and heart disease.

“This is the first three-generation study that [shows] it’s plausible that an environmental chemical in a grandparent can impact obesity and timing of menarche in the grandchild,” Barbara Cohn, a study author and director and senior research scientist at the Public Health Institute’s Child Health and Development Studies(CHDS), told EHN.

Transgenerational impacts of DDT

Researchers have established health effects from transgenerational exposure to chemicals in laboratory animals, but never before in humans. Grandchildren’s exposure can occur when their mothers are in utero and their mother’s egg cells are in development.

DDT compounds are known endocrine-disrupting chemicals that can alter and interfere with natural hormones that are essential for development. DDT exposure has been linked to breast cancerbirth defectsreduced fertility, and an increased risk of diabetes. It was banned in the United States in 1972 but is still used in other countries to kill mosquitoes that carry malaria.

Conducted by researchers at CHDS and the University of California at Davis, the study relied on blood samples collected from pregnant women between 1959 and 1967 as part of the CHDS study that has followed 20,000 pregnant women in California’s Bay Area, and their families, for more than 60 years. CHDS investigates how health and disease are passed on between generations. The original cohort of women, the grandmothers, gave blood samples at each trimester during pregnancy and one sample shortly after they gave birth. 04-15-21

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