Gallstones - Causes of gallstones
- Introduction
- Symptoms of gallstones
- Causes of gallstones
- Diagnosing gallstones
- Treating gallstones
- Complications of gallstones
- Preventing gallstones
- 'I have my gallstones to thank for my new calling in life'
- See what the doctor sees with Map of Medicine
It is thought that gallstones develop because of an imbalance in the chemical make-up of bile inside the gallbladder. Bile is a liquid produced by the liver to aid digestion.
It is still unclear exactly what leads to this imbalance, but it is known that gallstones can form if:
- there are unusually high levels of cholesterol inside the gallbladder – about four in every five gallstones are made up of cholesterol
- there are unusually high levels of bilirubin (a waste product produced when red blood cells are broken down) inside the gallbladder – about one in every five gallstones is made up of bilirubin
These chemical imbalances cause tiny crystals to develop in the bile, which gradually grow (often over many years) into solid stones that can be as small as a grain of sand or as large as a pebble.
Sometimes only one stone will form, but there are often several at the same time.
Who’s at risk?
Gallstones are more common in the following groups:
- women, particularly those who have had children
- overweight or obese people – people who are overweight with a body mass index (BMI) of 25 or above
- people aged 40 years or older (the older you are, the more likely you are to develop gallstones)
- people with cirrhosis (scarring of the liver)
- people with the digestive disorders Crohn’s disease and irritable bowel syndrome (IBS)
- people with a family history of gallstones (around a third of people with gallstones have a close family member who has also had gallstones)
- people who have recently lost weight, either as a result of dieting or weight-loss surgery such as gastric banding
- people who are taking a medication called ceftriaxone, which is an antibiotic used to treat a range of infections, including pneumonia, meningitis and gonorrhoea
Women who are taking the combined oral contraceptive pill or undergoing high-dose oestrogen therapy (which is sometimes used to treat osteoporosis, breast cancer and the menopause) also have an increased risk of developing gallstones.
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