Reduced bone mass in 7-year-old children with asymptomatic idiopathic hypercalciuria

Abstract

Background: Idiopathic hypercalciuria (IHC), i.e. an elevated urinary calcium excretion without concomitant hypercalcemia, is a common disorder in children and can have a range of urinary clinical presentations and decreased bone mineral density (BMD).

Aim: To assess the effect of IHC on bone mineral content in children without urological symptoms.

Methods: Calcium excretion, BMD (by dual-energy X-ray absorptiometry), and anthropometry were assessed in 175 seven-year-old children who were classified as IHC or controls. Calcium intake and physical activity were measured as confounding factors.

Results: The prevalence of IHC was 17.7%. Both groups (controls and IHC) showed similar baseline characteristics in terms of their anthropometry, gender distribution, and protein and calcium dietary intakes as well as physical activity scores. Urinary calciuria was independent of the calcium dietary intake and anthropometry. BMD correlated with anthropometry and physical activity but not with calcium dietary intake. IHC children had lower whole-body BMD z-scores compared to controls. The role of IHC in reducing the whole-body BMD z-score was still significant even when anthropometry, physical activity, and calcium intake were included as confounders in multivariate analyses.

Conclusions: The prevalence of IHC in this population of 7-year-old children was about 17%. IHC diagnosis was associated with lower BMD z-scores and osteopenia in 22% of them.