Abnormalities in bile constituents

Cholesterol and mixed gallstones may precipitate out of solution owing to a rise in cholesterol or a decrease in bile salts.

Factors associated with a rise in cholesterol include:

• obesity
• age } especially between puberty
• female sex } menopause in women
• drugs such as oral contraceptives, clofibrate

Factors associated with a decrease in bile salts include:

• any interruption to the enterohepatic circulation, e.g.:
  • gastrointestinal disease
  • small bowel or ileal resection or bypass
  • cholestyramine therapy