Mineral density and bone remodelling markers in patients with calcium lithiasis

Abstract

What's known on the subject? and What does the study add? Hypercalciuria is related with bone mineral density loss. This study demonstrates the relationship between recurrent calcium nephrolithiasis and bone mineral density loss and their correlation with bone markers.

Objectives: • To show that a relationship exists between the loss of bone mineral density (BMD) and calcium renal lithiasis and that bone remodelling markers correlate with changes in BMD. • It is possible that many cases hypercalciuria are related to the increase of bone turnover and the predominance of bone resorption phenomena.

Patients and methods: • The present study comprised a transversal investigation in three groups: group O, without lithiasis; group A, with a single episode of lithiasis; and group B, with relapsed calcium renal lithiasis. • An analysis was made of body mass index; abdominal X-ray and/or urography and renal ultrasonography; osteocalcin and β-crosslaps bone markers; calcium and citrate concentrations in the urine; and femur and spinal column bone densitometry. • The results were analyzed by analysis of variance and Pearson's correlation coefficient.

Results: • Patients with relapsed calcium renal lithiasis present a greater BMD loss than those in the O or A groups. • Densitometry: T-score femur -0.2 group O, -0.5 group A, -1.2 group B (P= 0.001); T-score column -0.6 group O, -0.6 group A, -1.3 group B (P= 0.05). • A statistically significant negative correlation exists between values of β-crosslaps and T-score femur (R=-0.251; P= 0.009) and T-score column (R=-0.324; P= 0.001); thus, a higher concentration of β-crosslaps was accompanied by a lower value of the T-score and a greater loss of BMD. • A positive relationship is observed between β-crosslaps and osteocalcin (R= 0.611; P < 0.001) and between calciuria and cocient β-crosslaps/osteocalcin (R= 0.303; P= 0.001).

Conclusions: • A statistically significant relationship is shown between the loss of BMD and relapsed calcium renal lithiasis. • Determination of bone remodelling markers (i.e. osteocalcin and β-crosslaps) facilitates the diagnosis of osteopaenia/osteoporosis in these patients.