Disease Proof

The researchers compared 65,000 Norwegians and 20,000 Americans in an attempt to gain a better understanding of why the incidence of end-stage renal disease (ESRD), as well as permanent loss of kidney function requiring dialysis or kidney transplantation, is so much higher in the United States than in Norway.

The study authors noted that overall prevalence of chronic kidney disease (CKD) is similar in both countries -- 11 percent in the United States and 10.4 percent in Norway. However, once a person develops CKD, the risk of progression to ESRD was found to be 2.5 times higher among American patients.

American and Norwegian ESRD patients are similar in many ways, including age and level of remaining kidney function when they begin dialysis, the study noted. However, the American patients in this study had much higher rates of obesity and diabetes, which are two major and closely related risk factors for kidney disease.

"Obesity and physical inactivity lead to high blood pressure and type 2 diabetes, which are now the most important causes of ESRD," study leader Dr. Stein Hallan, of St. Olav University Hospital in Trondheim, said in a prepared statement.