Why Did I Get Gallstones, and How Common Are They?

Gallstones are very common. While several specific risk factors increase the likelihood of developing them—such as genetics, age, and metabolic changes—many people develop gallstones without any clear, preventable cause. Most people who have gallstones will never experience symptoms or require treatment ^[1]. However, understanding your risk factors can help you and your doctor make informed decisions about your care.

How Common Are Gallstones?

Gallstone prevalence varies substantially depending on age, sex, geography, and how the data is collected:

• Current active stones: Recent studies relying strictly on ultrasound screening place the global rate of active gallstones at around 6% to 7% of adults ^[2].
• Lifetime burden: Broader estimates that include people who have already had their gallbladders removed place the overall lifetime burden closer to 10% to 20% ^[3][4].
• Age and Sex: The risk of developing gallstones increases steadily as you get older ^[2]. They are also generally more common in women than in men, though this gap can narrow in older age groups ^[5][2].
• Geography: Where you live plays a major role. For example, gallstones are particularly common in Western countries and parts of South America, while they tend to be less common in parts of Asia ^[2][6].

Why Do Gallstones Form?

Gallstones form when the liquid bile stored in your gallbladder becomes unbalanced. This imbalance causes solid crystals to form, which can eventually clump together into stones. The underlying cause depends largely on the type of gallstone you have. (Note: Stone type often cannot be known from a routine ultrasound and is usually only confirmed if the stones are removed.)

Cholesterol Stones

These are the most common type, accounting for up to 80% of stones in Western countries ^[7]. They form when your liver secretes more cholesterol than your bile can dissolve, causing the excess cholesterol to crystallize ^[8]. This process is often aided by gallbladder stasis—a condition where the gallbladder does not empty fully or often enough ^[8].

Pigment Stones

Pigment stones are made primarily from bilirubin, a chemical produced when red blood cells naturally break down. They are divided into two categories:

• Black pigment stones are associated with chronic conditions that cause a rapid breakdown of red blood cells (a process called hemolysis), such as sickle cell disease, or severe liver scarring called cirrhosis ^[9][10].
• Brown pigment stones are often softer and typically form in the setting of infected or stagnant bile in the ducts. This is frequently associated with blockages, structural diseases, or bacterial biofilms ^[11][12].

Common Risk Factors

Having one or more risk factors increases the chances of developing gallstones, but it is rarely a single event that causes them. Risk factors include:

• Genetics and Family History: Inherited susceptibility plays a major role. For instance, common variations in certain cholesterol-transporting genes (like the ABCG8 gene) are major contributors to cholesterol stone risk at the population level, though it is hard to quantify the exact risk for one person ^[11][13].
• Estrogen and Pregnancy: Female sex hormones increase cholesterol levels in the bile and slow down gallbladder emptying ^[14]. Because of this, pregnancy, oral contraceptives, and estrogen replacement therapies are all associated with an increased risk of cholesterol stones ^[15]. Do not stop prescribed contraceptives or hormone therapy without discussing it with your doctor.
• Weight and Metabolism: Being overweight and having insulin resistance (when your body’s cells don’t respond well to insulin) or diabetes can alter bile composition and reduce gallbladder motility, increasing the risk of cholesterol stones ^[16].
• Rapid Weight Loss: Losing a large amount of weight very quickly is a major trigger for cholesterol gallstones ^[17]. This is common in patients who crash diet or who have recently undergone bariatric (weight-loss) surgery ^[18]. Gradual, clinician-guided weight loss is generally safer.
• Digestive and Liver Diseases: Conditions affecting the end of the small intestine (the terminal ileum), such as Crohn’s disease or prior intestinal resections, reduce the body’s ability to recycle bile acids, raising your risk of stones ^[19].
• Medications and Nutrition: Intravenous feeding (total parenteral nutrition) and certain medications—including somatostatin analogues and the antibiotic ceftriaxone—can cause bile to thicken into “sludge” or promote stone formation ^[20][21]. Ceftriaxone-related sludge (pseudolithiasis) is often reversible depending on the dose and duration ^[20]. Never stop a prescribed medication without speaking to your prescriber.

When to Seek Immediate Medical Attention

Most people with incidentally discovered gallstones do not need treatment. However, if you experience repeated typical attacks, inflammation, or if a stone becomes trapped in the bile duct, you will require medical care ^[1][22].

Seek emergency medical care if you develop signs of a serious complication, such as:

• Severe or persistent pain in the upper-right or center of your abdomen (especially if it lasts for several hours)
• Fever or chills
• Yellowing of your skin or the whites of your eyes (jaundice)
• Dark urine or pale-colored stools
• Repeated vomiting or an inability to keep fluids down
• Confusion or rapidly worsening illness

Risk Does Not Equal Certainty

When diagnosed with gallstones, it is natural to wonder what you did to cause them. However, it is important to understand that gallstone formation is highly complex. While adopting a healthy lifestyle—such as eating a balanced, high-fiber diet and engaging in regular physical activity—can help lower your risk ^[23][24], genetics and age play major, unavoidable roles ^[11][2].

Having a risk factor does not mean you are to blame for your gallstones, and many people develop them simply due to inherited traits and the natural aging process.