The authors say this study provides the first evidence supporting the hypothesis that residential pesticide exposure from agricultural use is associated with an increased risk of thyroid cancer. The authors performed a case-controlled study using thyroid cancer cases from the California Cancer Registry (1999-2012) and controls sampled in a population-based manner. Study participants were diagnosed with thyroid cancer, lived in the study area when diagnosed and were age 35 or older. Control subjects were recruited from the same geographic area and were eligible if age 35 or older and had been living in California for at least five years before the research interview. The study sample included 2067 thyroid cancer cases and 1003 control participants. The researchers examined residential exposure to 29 agricultural-use pesticides known to cause DNA damage or endocrine disruption. They utilized a validated geographic information-based system to generate exposure estimates for each study participant.