Abstract
Concurrent with the global obesity epidemic, there is an increasing number of people of all ages developing chronic kidney disease associated with obesity. In adults, the definition of obesity is a BMI greater than 30 kg/m2. Whereas, in children, a BMI greater than the 85th percentile for age is considered overweight and greater than the 95th percentile is classified as obese. Clinical and pathologic characteristics of a distinct nephropathy have emerged independent of that of diabetic or hypertensive glomerulosclerosis. These include a silent presentation in an obese individual with heavy proteinuria, normal serum albumin and the absence of edema. Renal pathologic findings are notable for mesangial matrix expansion, glomerular hypertrophy and reduced density of podocytes with detachment of foot processes from the glomerular basement membrane. These findings are frequently associated with the development of secondary focal segmental glomerulosclerosis. Obesity alone does not appear to be the sole mediator of this nephropathy. It is most likely the ‘second hit’ for individuals who have congenital or acquired reduced nephron mass as well as an inherited genetic vulnerability to the metabolic consequences imposed by cytokines released by adipose tissue. In children, those born of low birthweight, whether small for gestational age and/or preterm, are likely to have reduced nephron mass as well as an increased tendency for early insulin resistance and the development of obesity and the metabolic syndrome. This in turn is perpetuated by the practice of feeding high-calorie fortified formulas to low-birthweight infants. Rapid catch-up growth, early obesity and insulin resistance are major contributors to the emergence of obesity-related glomerulopathy in children and adolescents. Early detection requires recognizing the demographics of high-risk infants and monitoring them for the development of hypertension, elevated glomerular filtration rate, hyperfiltration and proteinuria. After 6 months of age, angiotensin-blocking agents may be used to control blood pressure, glomerular hyperfiltration and proteinuria. If obesity is present, a comprehensive program of weight loss, including diet and exercise, should be the mainstay of treatment. In older children and adolescents, lipid-lowering medications may be indicated. With morbid obesity, bariatric surgery may be an option.
Financial & competing interests disclosure
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. No writing assistance was utilized in the production of this manuscript.