Oct. 29, 2012 -- Being overweight or obese as a teen is tied to higher risk of kidney failure by midlife, a new study shows.
The study points to yet another looming consequence of the childhood obesity epidemic -- growing ranks of adults who will need dialysis or transplants to replace their ailing kidneys.
“We should not underestimate how much harm obesity can cause in our children and young adults. That is definitely something that this paper conveys,” says Halima Janjua, MD, of the Cleveland Clinic Children's Hospital, in Ohio. Janjua was not involved in the research.
The study, which is published in the Archives of Internal Medicine, followed more than 1.2 million Israeli 17-year-olds who were given thorough medical exams before they started mandatory stints in that country’s military service.
Some 25 years later, those who were overweight or obese as teens were roughly three to seven times more likely to be on dialysis for end-stage kidney disease compared to their normal-weight peers.
Among 100,000 people followed for a year, there were 2.32 cases of end-stage kidney disease diagnosed among those who had been at a healthy as teens; 6.08 cases diagnosed in adults who had been overweight; and 13.4 cases diagnosed in adults who had been obese when they entered the military.
Obesity and Kidney Disease
Obesity has long been a recognized risk factor for end-stage kidney disease, a costly and complicated problem.
But doctors have believed that the link was an indirect one; obesity raises the risk of both diabetes and high blood pressure, two conditions known to damage the kidneys.
Surprisingly, though, when researchers only considered cases of end-stage kidney disease in people who didn’t also have diabetes, the associations with body weight remained, suggesting that having too much body fat may be a more direct danger to the kidneys.
High blood pressure may be another explanation. Researchers only measured blood pressure once, at the start of the study, so they weren’t able to account for cases that developed later in life. Experts think that high blood pressure may ultimately explain much of the higher risks.
“It’s quite possible that the obese people were slightly more hypertensive and that does contribute, for sure, to the development and progression of kidney diseases,” says Kirsten L. Johansen, MD, a nephrologist at the San Francisco Veterans Affairs Medical Center.
“This is one more reason why we really need to be concerned about overweight and obesity in kids,” says Johansen, who was not involved in the research.