Unraveling the stone-bone-vessel liaison in the relationship between calcium kidney stones, arterial stiffness, and bone density, "Beyond the Abstract," by Giovanni Gambaro, MD, PhD

BERKELEY, CA (UroToday.com) - Kidney stones are quite common in the general population. Patients affected with kidney stones also seem to have an increased prevalence of reduced bone density, possibly due to abnormal loss of calcium with their urine. More recently, it has been suggested that stone formers are also at higher risk of developing coronary events compared with non-stone formers with a similar cardiovascular risk profile.

Since reduced bone density has been suggested as an independent predictor of cardiovascular disease, it might be hypothesized that part of the excess cardiovascular risk observed in stone formers could be mediated by reduced bone density: in this theoretical framework, kidney stone formation, calcium mobilization from bone and abnormal deposition of calcium in vessels (leading to subsequent vascular events) might be interpreted as facets of common abnormalities of calcium metabolism. However, no study has ever been performed to simultaneously evaluate bone density and vascular abnormalities in idiopathic stone formers.

We prospectively studied 42 idiopathic calcium stone formers with recurrent disease with pulse-wave velocity (PWV) and DEXA measurements. Measures obtained from this group of stone formers were compared with those obtained from a group of 42 non-stone formers individually matched by age and sex.

We found that, compared with non-stone formers, all the measures of arterial stiffness considered (PWV measures at carotid-radial and carotid-femoral sites and augmentation index) were significantly higher, suggesting an increased stiffness of the arterial bed in this population. We also found that bone density was significantly reduced in this group. However, we couldn’t detect a relationship between the presence of abnormal arterial stiffness and reduced bone density, with only a negligible amount of the “effect” of having stones on arterial stiffness being mediated by reduced bone density. This surprised us since a relationship between reduced bone density and increased vascular stiffness or calcification has been shown in a number of conditions such as osteoporosis, hypertension, and renal failure. On the other hand, in another cohort of calcium stone formers, such a relationship was indeed recently reported, possibly suggesting that we missed it because of lack of power to detect it.

Written by:
Giovanni Gambaro, MD, PhD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

Division of Nephrology and Dialysis
Columbus-Gemelli University Hospital
Catholic University, School of Medicine
Rome, Italy

The relationship between calcium kidney stones, arterial stiffness and bone density: Unraveling the stone-bone-vessel liaison - Abstract

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