Increasing Body Mass Index and Kidney Stone Disease

Does obesity lead to an increased risk for the development of kidney stones? Well, yes and no.

An interesting study this month in the Journal of Urology addresses this question. Previous epidemiological works have reported that obesity is a risk factor for kidney stone disease. However, the effect of increasing degrees of obesity on stone formation has yet to be defined. Is the risk linear? The more obese you are, the higher your risk? Is there a cut off?

This study evaluated claims from a 5-year period (2002 to 2006) in a national private insurance database to identify subjects diagnosed with or treated for kidney stones. From a data set of 95,598 patients, subjects were identified by ICD-9 or CPT codes specific to kidney stone disease.

Conclusions

An obese body mass index is associated with an increased risk of kidney stone disease. However, the magnitude of this risk appears to be stable in the morbidly obese population. Once body mass index (BMI) is greater than 30, further increases do not appear to significantly increase the risk of stone disease.