Obesity and Kidney Disease: Know how excess weight affects your kidneys
Obesity, uncontrolled diabetes and hypertension are the main risk factors for the development of kidney diseases. In this article, we have explained how excess weight affects our kidneys.
According to the World Health Organization (WHO), obesity is defined as "excess or abnormal fat accumulation that presents a health risk". Body mass index (BMI) and waist circumference are used for measuring overweight or obesity. BMI ≥25.0 kg/m2 is considered overweight and ≥30 kg/m2 is obesity. Obesity, particularly abdominal obesity, measured by waist circumference is on the rise in our country. As per the National Family Health Survey (NFHS), 40% of women and 12% of men are abdominally obese. The incidence is much higher in the elderly and the urban population. Android or apple-shaped abdominal obesity (fat accumulation in the upper body such as the visceral or abdominal region) contributes to metabolic disease and ill health.
When we spoke to Dr Krishna Chaitanya Gunda, Consultant Nephrologist, Asian Institute of Nephrology and Urology Chennai, he said that Kidney disease (CKD), as per Kidney Disease Improving Global Outcomes (KDIGO) is defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 for at least three months or presence of markers of kidney damage (urinary abnormalities, structural abnormalities). The prevalence of kidney disease in our country varies from 3 - 10 % based on the various studies, underlying the importance of developing a national registry. The incidence of kidney disease is also on the rise with >100,000 new patients requiring renal replacement therapy ( dialysis / renal transplantation) annually.
How obesity affects the body
Obesity with increased visceral fat affects all the organs of our body resulting in diabetes, hypertension, coronary vascular disease, stroke, obstructive sleep apnoea and many more. It has implications not only on the physical health but also affects the psychosocial function of individuals decreasing their productivity, increasing Disability-Adjusted Life Year (DALY) and direct health care expenses.
Risk factors
Chronic kidney disease of unknown aetiology (CKDu) is also on the rise. the main risk factors for the development of kidney diseases are hypertension and uncontrolled diabetes.
Body fat itself is considered a dynamic endocrine organ. It produces various hormones like leptin and adiponectin and their actions are altered in obesity resulting in an increased inflammatory state of our body. It affects the vascular system and increases insulin resistance causing hypertension and diabetes which further has a direct effect on the kidney causing kidney damage. Increased central fat is responsible for metabolic syndrome and causes target organ damage of every organ.
Obesity affects the kidneys
Obesity affecting the kidneys directly is called obesity-related glomerulopathy. This is due to the increased workload on the kidney resulting in glomerulomegaly (increased glomerulus size), and increased protein excretion in the urine. Many studies have shown obesity as an independent risk factor for chronic kidney disease. It accelerates the progression of pre-existing CKD, promotes renal stone formation, increases kidney donor risk for end-stage kidney disease and also affects the kidneys in the post-renal transplantation phase. Obesity has been associated with better outcomes only in the dialysis population which is called reverse epidemiology.
Reversal of established obesity-associated kidney disease is only partial, so it is paramount to devise ways to identify and prevent it. Lifestyle modifications like limiting calorie intake and increasing physical activity have been helpful in weight reduction which has been shown to prevent the progression of established kidney disease. Certain newer medications like Glucagon-like peptide-1 (GLP-1) analogues and bariatric surgery in people with morbid obesity have been promising in improving kidney and general outcomes. Irrespective of the availability of newer modalities to improve outcomes in obesity, the age-old wisdom that "prevention is better than cure" scores the best.
ALSO READ: 5 warning signs and symptoms of colorectal cancer, here's how to protect yourself