New Haven, Conn. — A new study led by researchers at Yale University suggests that early-life exposure to two widespread environmental pollutants— small particle air pollution and outdoor artificial light at night—could increase the risk of pediatric thyroid cancer.

The study—a collaborative effort involving multiple Yale departments and institutions across the U.S.—found a “significant association” between exposure to ambient fine particulate matter air pollution (PM2.5) and outdoor artificial light at night (O-ALAN) and increased risk of papillary thyroid cancer in children and young adults up to 19 years old. The exposures occurred during the perinatal stage of life, typically defined as the time from when pregnancy occurs up to a year after birth.