Q. A 47-year-old woman presents to the primary care clinic with intermittent episodes of right upper quadrant abdominal pain, especially after eating fatty meals. These episodes are often accompanied by nausea but no vomiting. She has a history of obesity and recently lost 15 kg over the past 5 months through a very low-calorie diet. She also has a history of type 2 diabetes mellitus. Physical examination is unremarkable, except for tenderness in the right upper quadrant. An abdominal ultrasound reveals multiple gallstones in the gallbladder, with no evidence of cholecystitis. What are the most common risk factors for developing gallstones?