Obesity and Kidney Disease: Hidden Consequences of the Epidemic

Special Article - Kidney Transplantation

Austin Med Sci. 2017; 2(1): 1014.

Obesity and Kidney Disease: Hidden Consequences of the Epidemic

Kovesdy CP1,2, Furth S3 and Zoccali C4

1Department of Medicine, University of Tennessee Health Science Center, USA

2Nephrology Section, Memphis VA Medical Center, USA

3Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, USA

4CNR - IFC Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Italy

*Corresponding author: World Kidney Day, International Society of Nephrology, in collaboration with International Federation of Kidney Foundation, Rue de Fabriques 1B, 1000, Brussels, Belgium

Received: February 02, 2017; Accepted: March 02, 2017; Published: March 13, 2017


Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease and also for Chronic Kidney Disease. A high body mass index is one of the strongest risk factors for new-onset Chronic Kidney Disease. In individuals affected by obesity, a compensatory hyper filtration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing Chronic Kidney Disease in the long-term. The incidence of obesity-related glomerulopathy has increased ten-fold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year the World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle and health policy measures that make preventive behaviors an affordable option.


In 2014, over 600 million adults worldwide, 18 years and older, were obese. Obesity is a potent risk factor for the development of kidney disease. It increases the risk of developing major risk factors for Chronic Kidney Disease (CKD), like diabetes and hypertension, and it has a direct impact on the development of CKD and its progression to End-Stage Renal Disease (ESRD). In individuals affected by obesity, a (likely) compensatory mechanism of hyper filtration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidney structure and raise the risk of developing CKD in the long-term.

The good news is that obesity, as well as the related CKD, are largely preventable. Education and awareness of the risks of obesity and a healthy lifestyle, including proper nutrition and exercise, can dramatically help in preventing obesity and kidney disease. This article reviews the association of obesity with kidney disease on the occasion of the 2017 World Kidney Day.

Epidemiology of obesity in adults and children

Over the last 3 decades, the prevalence of overweight and obese adults (BMI=25 kg/m2) worldwide has increased substantially [1]. In the US, the age-adjusted prevalence of obesity in 2013-2014 was 35% among men and 40.4% among women [2]. The problem of obesity also affects children. In the US in 2011-2014, the prevalence of obesity was 17% and extreme obesity 5.8% among youth 2-19 years of age. The rise in obesity prevalence is also a worldwide concern, [3,4] as it is projected to grow by 40% across the globe in the next decade. Low- and middle-income countries are now showing evidence of transitioning from normal weight to overweight and obesity as parts of Europe and the United States did decades ago [5]. This increasing prevalence of obesity has implications for Cardiovascular Disease (CVD) and also for CKD. A high Body Mass Index (BMI) is one of the strongest risk factors for new-onset CKD [6,7].

Definitions of obesity are most often based on BMI (i.e. weight [kilograms] divided by the square of his or her height [meters]). A BMI between 18.5 and 25 kg/m2 is considered by the World Health Organization (WHO) to be normal weight, a BMI between 25 and 30 kg/m2 as overweight, and a BMI of >30 kg/m2 as obese. Although BMI is easy to calculate, it is a poor estimate of fat mass distribution, as muscular individuals or those with more subcutaneous fat may have a BMI as high as individuals with larger intra-abdominal (visceral) fat. The latter type of high BMI is associated with substantially higher risk of metabolic and cardiovascular disease. Alternative parameters to more accurately capture visceral fat include Waist Circumference (WC) and a Waist Hip Ratio (WHR) of >102 cm and 0.9, respectively, for men and >88 cm and >0.8, respectively, for women. WHR has been shown to be superior to BMI for the correct classification of obesity in CKD [8].

Association of obesity with CKD and other renal complications

Numerous population based studies have shown an association between measures of obesity and both the development and the progression of CKD (Table 1). Higher BMI is associated with the presence [9] and development [10-12] of proteinuria in individuals without kidney disease. Furthermore, in numerous large populationbased studies, higher BMI appears associated with the presence [9- 13] and development of low estimated GFR, [10,11,14] with more rapid loss of estimated GFR over time, [15] and with the incidence of ESRD [16-19]. Elevated BMI levels, class II obesity and above, have been associated with more rapid progression of CKD in patients with pre-existing CKD [20]. A few studies examining the association of abdominal obesity using WHR or WC with CKD, describe an association between higher girth and albuminuria, [21] decreased GFR [9] or incident ESRD [22] independent of BMI level.