*Those who have undergone intestinal bypass or ostomy surgery are also at increased risk for kidney stones.
*Some medications also raise the risk of kidney stones. These medications include some diuretics, calcium-containing antacids, and the protease inhibitor indinavir (Crixivan), a drug used to treat HIV infection.
*Dietary factors and practices may increase the risk of stone formation in susceptible individuals. In particular, inadequate fluid intake predisposes to dehydration, which is a major risk factor for stone formation. Other dietary practices that may increase an individual's risk of forming kidney stones include a high intake of animal protein, a high-salt diet, excessive sugar consumption, excessive [[vitamin D ]] supplementation, and possible excessive intake of oxalate-containing foods such as spinach. Interestingly, low levels of dietary calcium intake may alter the calcium-oxalate balance and result in the increased excretion of oxalate and a propensity to form oxalate stones.* According to a recent study, [[vitamin C]] supplements can cause kidney stones. The study tracked records of more than 22,000 men, over a period of 10 years, and found that those who toke high doses of vitamin C doubled their risk of kidney stones.
* Soda drinks with phosphoric acid may also raise the risk of kidney stones.