Obesity is a major risk factor for the formation of gallstones. This is felt to derive from the tendency of obese people to have fewer bile salts in bile, increasing the risk of gallstone formation. Decreased gallbladder emptying is also seen in obese people. Estrogen, whether from birth control pills, pregnancy, or from hormone replacement therapy can also lead to gallstones by increasing cholesterol levels in bile and decreasing gallbladder emptying. Native Americans are at ethnic risk of gallstones.
Females are twice as likely as males to have gallstone disease in mid life.
People over sixty years of age are also more likely to have gallstones than others. People on cholesterol lowering drugs are also at increased risk of gallstones due to increased secretion of cholesterol in bile. Diabetics are also at higher risk of having gallstones than other nondiabetics of the same age and gender. Rapid weight loss and prolonged fasting can also precipitate gallstone formation. A typical attack can cause severe sharp pain in the upper abdomen that radiates to the back between the shoulder blades, increases rapidly, and lasts from 30 minutes to several hours.