Insecticide Linked to Increased Breast Cancer Risk — 40 Years After Exposure

“The latest study, published earlier this month in the Journal of the National Cancer Institute, found a 40-year lag between the timing of a woman’s first DDT exposure and her breast cancer diagnosis. Women who would first have been exposed to DDT in infancy had the highest risks of developing breast cancer before age 50, while women whose first exposure would have been between ages 3 and 13 had a three-fold increased risk of developing breast cancer between ages 50 and 54.”

Insecticide Linked to Increased Breast Cancer Risk — 40 Years After Exposure

Melinda Lewis remembers splashing in the irrigation canals that outlined her grandpa’s walnut and almond groves in the late 1960s.

Two decades earlier, her mother had played in those same Escalon, California, farm fields as crop dusters flew overhead, releasing a new “miracle” chemical—a war-time innovation—the insecticide known as DDT. Since a bout with atypical hyperplasia, a pre-cancerous breast condition, in 1997 at age 36, Lewis often has wondered whether exposures to farm chemicals in childhood—her own and her mother’s—may have heightened her health risks.

In recent decades, it’s become increasingly clear that certain adult diseases may have their origins in childhood—or before. Early-life exposures—including those that take place in the womb—may hold the key to understanding who gets diseases such as breast cancer or heart disease, say environmental researchers.

Some of the most reliable evidence for this link comes from exposures that took place during World War II. Years after the Dutch “Hunger Winter” of 1944-1945, babies conceived during the famine were more likely to suffer from obesity, diabetes, and heart disease in adulthood than their peers born shortly afterwards.

Teenage girls in Hiroshima and Nagasaki were far more likely to develop breast cancer years after the atomic bombings than women who had been 35 years or older when the radiation exposures occurred.