Editorial Comment

Abstract

The metabolic syndrome, and specifically obesity, is becoming a major concern in patients with urolithiasis. Nowfar et al in a recent study reviewed the Nationwide Inpatient Sample database in the United States to examine the relationships among obesity, gender, and nephrolithiasis. 1 Nowfar S. Palazzi-Churas K. Chang D.C. et al. The relationship of obesity and gender prevalence changes in United States inpatient nephrolithiasis. Urology. 2011; 78: 1029-1033 Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar The cohort included 898,172 patients discharged with urolithiasis. They found an increase in the prevalence of obesity from 3.06-4.99% during their study period (1998-2003), with a decrease of male:female ratio of patients with stones from 1.6:1-1.2:1. The relationship between obesity and female gender was found to be stronger than obesity and male gender. Taylor et al in a prospective study of 3 large cohorts demonstrated an increase in incidence of urolithiasis with increasing obesity. 2 Taylor E.N. Stampfer M.J. Curhan G.C. Obesity, weight gain, and the risk of kidney stones. JAMA. 2005; 293: 455-462 Crossref PubMed Scopus (819) Google Scholar They concluded that obesity and weight gain increases the risk of urolithiasis, especially in women. Both studies explain their findings by insulin resistance that is also associated with obesity, which can alter the composition of the urine and reduce the urinary pH. It was suggested that the higher percentage of body fat in women compared with men might explain these findings, but the exact mechanism remains unknown. Similar findings were recently reported by Scales et al 3 Scales Jr., C.D. Smith A.C. Hanley J.M. et al. Prevalence of kidney stones in the United States. Eur Urol. 2012; 62: 160-165 Abstract Full Text Full Text PDF PubMed Scopus (1458) Google Scholar and was demonstrated in the pediatric population as well. 4 Ayoob R. Wang W. Schwaderer A. Body fat composition and occurrence of kidney stones in hypercalciuric children. Pediatr Nephrol. 2011; 26: 2173-2178 Crossref PubMed Scopus (11) Google Scholar Increased Body Mass Index is Associated With Larger Renal CalculiUrologyVol. 80Issue 5PreviewTo examine the relationship between the body mass index and the size of renal stones in a group of patients with urolithiasis. Full-Text PDF ReplyUrologyVol. 80Issue 5PreviewWe would like to thank the reviewer for his valuable comments. We totally agree that metabolic syndrome, in particular obesity, influences many clinical aspects of renal stone disease, namely epidemiology, gender prevalence, and diagnostic criteria, and it certainly influences the medical and surgical management of renal stones. Full-Text PDF