Review Question - QID 216231

Researchers are investigating the impact of obesity and tobacco use on complication rates after elective cholecystectomies. The investigators have completed a study where they recorded body mass index (BMI) and presence of tobacco use within 3 months prior to surgery for all patients undergoing elective cholecystectomy at their institution. Four groups of patients are created based on the presence or absence of obesity and tobacco use. The patients are then followed for a minimum of 3 months after surgery. Complications, including surgical site infection, pulmonary embolus, cardiovascular events, and acute kidney injury, are recorded for all patients. Analysis of their data shows that obesity and tobacco use are independently associated with an increased risk of postoperative complications. What type of study design is exhibited by this study?