Obesity Linked To Kidney Stones

About ten percent of American men and five percent of women develop the condition known as kidney stones, which can be excruciatingly painful. New research suggests obesity puts people at much higher risk of getting them.

The Early Show medical correspondent Dr. Emily Senay explains that the stones are collections of crystals and protein that form in the kidney, then painfully make their way down, the urinary tract and usually pass out of the body.

The first symptom is usually extreme pain in the lower back or abdomen. The pain may spread to the groin.

Senay advises that sufferers see their doctor for treatment. Most kidney stones can pass through the system with the help of two to three quarts a day of water to help move the stone along and pass them out. Pain medication can help, Senay says, but there are other treatments if drugs and lots of water don't help.

But a new study in the Journal of the American Medical Association shows that obesity and weight gain can increase the risk of kidney stones, especially for women.

The study, which looked at 250 thousand medical records, found obese men were 30 percent more likely to develop a kidney stone than men at healthy weights, and women were twice as likely to develop the stones than women at healthy weights.

The study also found that becoming overweight over time increased the risk of developing kidney stones, particularly in women.

Men who gained 35 pounds from early adulthood were about 40 percent more likely to develop kidney stones. Women who gained over 35 pounds were about 75 percent more likely to suffer from a kidney stone compared to those with normal weights, the study shows.

"The number of people developing kidney stones has gone up in the last decade or so," Senay pointed out, "which isn't a surprise, when you look at the obesity epidemic and see these two things are linked."

The study didn't find an explanation for the difference in the risk between men and women.

How does being obese hike the odds of developing kidney stones? It's unclear, Senay answered. It may have something to do with obese people having more insulin in their blood, or simply from their consuming more of the compounds the stones are made of.

The study didn't look at the effect weight loss may have on chance of developing kidney stones. More study is needed to see if that's the case.

But the hope is that keeping the weight off will help keep people from developing them, Senay adds.

How do you prevent kidney stones?

A family history or previous kidney stones are risk factors, Senay notes. Generally speaking the most important lifestyle change to prevent stones is to drink plenty of water.