NEW YORK (Reuters Health) — Morbidly obese adults who undergo a particular type of stomach bypass surgery called Roux-en-Y gastric bypass (RYGB) appear to be at increased risk of developing kidney stones earlier than previously thought. The increase in stone risk was evident just three months after the surgery.

"Although this study demonstrates that there is a higher risk for developing kidney stones (after RYGB), it is important to weigh the risk against the many benefits that RYGB has for the morbidly obese patient, including decreasing cardiac (illness) and improving diabetes," Dr. Manoj Monga, from the University of Minnesota Medical School in Minneapolis, noted in a written statement. RYGB restricts the amount of food the stomach can hold, and a person can eat, by making it smaller, into a "pouch".

It also reduces the amount of nutrients absorbed because the pouch bypasses parts of the small intestine.

Although RYGB has proven to be a safe and effective treatment for morbid obesity, the formation of kidney stones has recently raised concerns among patients undergoing RYGB.

Kidney stones are small, pebble-like deposits that can result in severe pain and require an operation to remove them.