In 2019, a study of the adverse effects of x-rays on subsequent cancer among children was done using records from several large children’s hospitals from 1990 to 1995. 10,000 children were selected as a representative population of children seen at the hospitals during that time. Participants were classified according to whether or not they received an x-ray during their stay in the hospital and were followed from their hospital stay through 2019 for cancer development. During the follow-up period, 49 incident cancers occurred in 3,263 children who had received an x-ray, and 47 incident cancers occurred in the 6,737 children who had not received an x-ray during their hospitalization. What type of study design is this? Prospective cohort study Case-control study Cross-sectional study Retrospective cohort study

In 2019, a study of the adverse effects of x-rays on subsequent cancer among children was done using records from several large children’s hospitals from 1990 to 1995. 10,000 children were selected as a representative population of children seen at the hospitals during that time. Participants were classified according to whether or not they received an x-ray during their stay in the hospital and were followed from their hospital stay through 2019 for cancer development. During the follow-up period, 49 incident cancers occurred in 3,263 children who had received an x-ray, and 47 incident cancers occurred in the 6,737 children who had not received an x-ray during their hospitalization. What type of study design is this? Prospective cohort study Case-control study Cross-sectional study Retrospective cohort study