مشخصات پژوهش

Gallstone disease is a disease with high incidence of 10–15% in developed countries [1]. The incidence of gallstone disease is approximately 10% [2]. Treatments for gallstone diseases are expensive. Studies have shown that in 2004, the conservative cost of treatment for gallstone disease in the US was approximately 4 billion USD, while the cost of surgical treatment reached more than 6.5 billion USD [3, 4]. Therefore, studies on gallstone diseases are very important. Gallstone consists mostly of cholesterol, bile pigment, phospholipids, proteins, bacteria, metal ions, and other components [5]. However, cholesterol and bile pigments account for the largest proportions. Gallstone has been classified conventionally into three types: cholesterol gallstone, pigment gallstone, and mixed gallstone. The classification criteria are based on cholesterol content. The cholesterol and pigment types have cholesterol content of more than 70 and less than 30%, respectively. Other components constitute mixed type gallstones. Pigment and mixed gallstones are also called non-cholesterol gallstones. Several hypotheses have suggested the possible causes of gallstones. Evidence from studies have suggested that abnormal lipid metabolism may be responsible for gallstone formation. Abnormal lipid metabolism induces lipid metabolism disorders, excessive cholesterol secretion and supersaturating, cholesterol crystallization, mucus overproduction, and imbalance between nucleating and anti-nucleation factors. These phenomena lead to gallstone formation [6]. Abnormal lipid metabolism is related to several factors such as age, sex, and eating habits, as well as polymorphism in lipid metabolism loci. Thus, studies on polymorphism of lipid metabolism loci could enhance understanding of the pathogenesis of gallstone disease.