Body mass index 'in and of itself' increases risk of developing chronic kidney disease, study shows
A new UCSF-led study of nearly 3,000 individuals links obesity to the development of kidney disease. The work also shows that, when properly measured, declines in kidney function are detectable long before the emergence of other obesity-related diseases such as diabetes and high blood pressure.
Healthy kidneys are vital to the proper functioning of the heart and brain, as well as the skeletal and immune systems, and the research adds additional urgency to the call for doctors to intervene early in life with obese patients, the researchers said.
"We're getting larger and larger at younger and younger ages, so the problems we will see that are directly related to obesity are going to become more common and they're going to start earlier in life," said Vanessa Grubbs, MD, UCSF assistant adjunct professor of medicine and first author of the new study. "Even before the level at which we can diagnose illnesses, decline in kidney function is happening. Is it reversible? We're not sure. Preventable? It stands to reason that it would be."
In the new study, published online in the American Journal of Kidney Diseases on December 2, 2013, Grubbs and senior author Kirsten Bibbins-Domingo, PhD, MD, professor of medicine, led a team that analyzed 10 years' worth of health data from CARDIA (Coronary Artery Risk Development in Young Adults), a national multi-center research project that has tracked the health of thousands of black and white young adults since its beginnings in 1985.
The 2,891 CARDIA participants included in the study were categorized according to four ranges of body mass index (BMI): normal weight, overweight, obese, and extremely obese. At the beginning of the time period studied, the patients averaged 35 years of age and all had normal kidney function in the normal range, though higher-BMI patients were at the lower end of that range. Kidney function diminished over time in all participants, but the decline was significantly greater and more rapid in heavier patients, and appeared to stem exclusively from BMI.