By Kathryn Doyle (Reuters Health) – People who have had gallstone disease are more likely than others to develop coronary heart disease, according to a large analysis of past studies. Hardened deposits known as gallstones form in the gallbladder when the bile contains too much cholesterol or other abnormal substances, and while the cause is not fully understood, factors like obesity, high-calorie diets and metabolic syndrome are associated with gallstone risk. The same factors increase the risk for coronary heart disease, which kills 370,000 Americans per year, according to the Centers for Disease Control and Prevention.