Mom always told you to stop watching so much TV, get up off the couch and exercise more or you become a bum, right? Well, a new study by British researchers has uncovered something else that couch potatoes may need to be concerned about: kidney disease.

Researchers at the University of Leicester and the University Hospitals of Leicester NHS Trust surveyed 5,560 Britons and found a link between hours spent sitting and kidney problems, even after they factored in smoking, age, gender, ethnicity, body-mass index, blood pressure, medications and exercise.

Women who sat for short periods of time had a 30 percent lower chance of kidney disease than those who sat more; men who spent more time on their feet experienced a 20 percent reduction in risk compared to chronic sitters.

According to study co-author Thomas Yates, it's not entirely clear how sitting relates to kidney problems. But, he points out, sitting has already been linked to other diseases such as type II diabetes.

Still, Dr. Jeffrey S. Berns, a professor at the University of Pennsylvania School of Medicine, isn't convinced there's a direct link between the two. "While it’s certainly plausible to think that sitting may contribute to diabetes, obesity, and high blood pressure, it’s much harder to come up with a way that inactivity could be a direct cause of kidney disease," said Berns. "The flip side of this is that people with chronic kidney disease are known to be less active. And my suspicion is that these results are confounded by that."

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