Researchers are interested in the possible association between exposure to airplane engine emissions and cancer development. To study this association, they launch an investigation involving 1600 members from the community in the town in which the airport is located and follow them for 12 years. A total of 760 individuals live within a 10-mile radius of the airport and the remaining 840 live outside of a 10-mile radius of the airport. The researchers assess the participants' incidence of disease 4 years into the study and again at the end of the study after 12 years. At the 4-year mark, they found that 80 participants (62 within a 10-mile radius and 18 outside a 10-mile radius) had developed cancer after 4 years of the study, and when they reassessed the participants at the end of the study, they discovered that an additional 160 participants (124 within a 10-mile radius and 36 outside a 10-mile radius) had developed cancer. Assume that all participants were at risk for cancer at the beginning of the study, and that no one was lost to follow-up (i.e., all participants completed the study).

Given the study design described, what type of study is this (0.5 point) and what is the best measure of association to calculate using the data provided? (0.5 point).