What causes gallbladder stones

What are gallstones, their causes & risk factors

What are gallstones?

Gallstones are collections of crystals in the gallbladder or bile ducts. They either consist predominantly of cholesterol (cholesterol stones) or predominantly of bilirubin pigment material (pigment stones). Cholesterol stones are the most common. They can grow to be several centimeters, but are mostly multiple. Gallstone precursors can occasionally be seen as sludge in the gallbladder; however, sludge can also spontaneously dissolve again or be washed out.

Gallstones usually arise in the gallbladder. Less often (5-10%) they arise in the biliary tract. Gallstones are common: 15-20% of all Germans are affected, mostly without knowing it. In a quarter of them, however, the stones lead to painful discomfort at some point.


One form of gallstone called cholesterol stones occurs when the composition of the bile changes. Usually bile acids and cholesterol are present in a certain ratio. The bile acids ensure that the water-insoluble cholesterol remains in solution. Typical of the stone-forming bile is the high proportion of cholesterol and / or the reduced proportion of bile acids, so that the bile is oversaturated with cholesterol. If there is an excess of cholesterol or a lack of bile acids, the cholesterol crystallizes out. The cholesterol crystals accumulate and gradually form a gallstone. If the gallbladder cannot contract and empty properly, the risk of a gallstone increases.

Pigment stones form when bilirubin (yellow blood pigment) increases in the body (e.g. during hemolysis) and the conversion into its soluble breakdown products or their outflow is disturbed. This can be the case with severe liver diseases such as cirrhosis, but also with infections. Pigment stones usually arise in the bile ducts.

Most gallstones form in the gallbladder. Gallstones in the bile ducts have mostly migrated there. A blockage in the bile ducts encourages bacterial growth and can lead to bacterial infection. This can develop into a scarred obstruction that obstructs the flow of bile even after the stone has come off.

Risk factors

The risk of developing gallstones increases significantly from the age of 40. Women are 2 to 3 times more likely to be affected than men. Most gallstones are caused by environmental factors, such as B. improper diet. However, there is also a genetic make-up for it.

Today it is assumed that 70-80% of the disease is caused by environmental influences, e.g. B. improper diet is caused. Overweight people who have already had gallstones in their families are more likely to develop gallstones after the age of 40: 20% overweight double the risk of gallstones. Women are more at risk than men. Female hormones seem to play a role here, because women who take estrogens for oral contraception or during hormone therapy are more likely to suffer from gallstones. Gallstones also occur more often during pregnancy due to hormonal changes.

In addition to the above-mentioned factors, a disturbed emptying function of the gallbladder is also an important factor, which is mainly controlled by food pulp and fat in the proximal small intestine. The disturbed emptying function also explains the increased risk of gallstones in the case of diabetes. The same applies to the significantly increased risk of stone stones (30%) after gastric bypass operations. In addition, there is a genetic predisposition to the disease. A gene variant has recently become known that significantly increases the risk of gallstones. Every tenth European has this variant in his genetic make-up. In the course of their lives, those affected are 2 to 3 times more likely to have a gallstone than other people. The gene contains the building instructions for a molecular pump that transports cholesterol from the liver cells into the biliary tract. The genetic change apparently causes this pump to run at full speed all the time.

The lack of emptying of the gallbladder at night (lack of food stimulus) is another important factor in gallstone formation.