A study released on Monday by the University of California found a strong relationship between obesity and kidney failure.
Dr Chi-yuan Hsu, an assistant professor of medicine and lead author of the study, said: "There are more and more people with kidney failure, but it hasn't been appreciated much that kidney failure can be a consequence of obesity."
Even moderately overweight people had a higher risk of kidney failure than people whose weight was in a normal, healthy range, he said. And for the morbidly obese, the risk was more than 700% greater, Hsu said.
When the kidneys fail, and cannot process waste and excess fluid, the patient requires dialysis or transplantation.
The study, conducted jointly with Kaiser Permanente of Northern California Division of Research and supported by the National Institutes of Health, is published in the 3 January issue of the Annals of Internal Medicine.
The research is based on data from more than 320,000 Northern California Kaiser members whose height and weight were tracked between 1964 and 1985. A total of 1471 cases of end-stage renal disease occurred among study participants during an average follow-up period of about 26 years.
Being obese or overweight was seen as a risk factor even after the researchers adjusted for high blood pressure and diabetes, other known risk factors, Hsu said.