In the Western world, about 15% of all people have gallstones in their gallbladder but the majority are unaware of this and have no symptoms. Over ten years, 15–26% will sufferhave one or more episodes of [[biliary colic]] (abdominal pain due to the passage of gallstones through the bile duct into the digestive tract), and 2–3% will develop complications of obstruction: [[acute pancreatitis]], [[cholecystitis]] or acute cholangitis.<ref name=Williams/> Prevalence of gallstone disease increases with age and [[body mass index]] (a marker of [[obesity]]). However, the risk is also increased in those who lose weight rapidly (e.g. after [[bariatric surgery|weight loss surgery]]) due to alterations in the composition of the bile that makes it prone to form stones. Gallstones are slightly more common in women than in men, and pregnancy increases the risk further.<ref>{{cite journal |author=Bateson MC |title=Fortnightly review: gallbladder disease |journal=BMJ |volume=318 |issue=7200 |pages=1745–8 |date=June 1999 |pmid=10381713 |pmc=1116086 |doi=10.1136/bmj.318.7200.1745}}</ref>
