Epidemiology of obesity and chronic kidney disease.

The obesity epidemic has reached nephrology in the form of increasing numbers of patients with chronic kidney disease (CKD) caused by obesity-related metabolic disorders, IgA nephropathy, stone disease, and a unique glomerulopathy now known as obesity-related glomerulopathy (ORG). Obesity has been identified as an independent risk factor for CKD, and patients with central adiposity or high waist-to-hip ratios appear to have the highest risk. The metabolic syndrome is a risk factor for albuminuria and CKD, and studies now show that the risk of CKD increases with increased numbers of components of the metabolic syndrome. Obesity is not just a bystander or accelerator of other kidney diseases, but has unique histopathologic characteristics that can cause progressive kidney disease. ORG may accompany and worsen IgA nephropathy, urate nephropathy, and possibly even diabetic nephropathy. The origins of obesity-related kidney disease can be traced to insufficient glomerular complement from birth, and low birth weight may be an important precursor to obesity and its many comorbidities. Intervention strategies may need to target prenatal care through the elderly to combat this problematic epidemic.