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Reduced bone mass in children with idiopathic hypercalciuria and in their asymptomatic mothers
Michael Freundlich1, Evelyn Alonzo, Ezequiel Bellorin-Font
1University of Miami School of Medicine, Miami, Florida, USA. mfmefex@pol.net
Insights
Idiopathic hypercalciuria (IH) in children is linked to reduced bone mineral density (BMD), potentially starting early in life. This study found low BMD in many children with IH and their mothers, suggesting a genetic link and future osteoporosis risk.
Area of Science:
- Pediatric Endocrinology
- Bone Metabolism
- Nephrology
Background:
- Idiopathic hypercalciuria (IH) and nephrolithiasis are associated with reduced bone mineral density (BMD).
- Previous BMD studies in IH patients primarily focused on adults, with a lack of research in North American children.
- Optimal bone health during childhood is crucial for achieving peak bone mass and preventing future skeletal issues.
Purpose of the Study:
- To evaluate bone mineral metabolism in children with IH and their asymptomatic mothers.
- To investigate potential genetic influences on bone health in families with IH.
- To assess BMD and related factors in a pediatric population with idiopathic hypercalciuria.
Main Methods:
- Quantitative bone mineral density (BMD) assessment using dual-energy X-ray absorptiometry (DEXA) in 21 children with IH and their mothers.
- Measurement of urinary bone resorption markers (pyridinoline and deoxypyridinoline).
- Determination of calcium-modulating hormones (parathyroid hormone, 1,25(OH)(2)D(3)) and interleukin-1alpha (IL-1alpha) expression in peripheral blood mononuclear cells (PBMCs).
Main Results:
- Reduced BMD was observed in 38% of children and 33% of mothers.
- Children of mothers with osteopenia had significantly lower lumbar spine BMD Z-scores.
- Hypercalciuria was present in 25% of mothers and correlated with reduced femoral BMD in osteopenic mothers.
Conclusions:
- A significant proportion of children with idiopathic hypercalciuria exhibit reduced bone mineral density.
- Reduced BMD and hypercalciuria can be present in asymptomatic mothers, suggesting early onset and potential genetic factors.
- Diminished BMD in IH may originate in childhood, posing a risk for future osteoporosis.
Background:
Patients with nephrolithiasis and idiopathic hypercalciuria (IH) may exhibit reduced bone mineral density (BMD). Most studies measuring BMD in IH patients employing dual-energy X-ray absorptiometry (DEXA) have been performed in adults, and no study has been conducted in North-American children. Optimal bone mineral accretion during childhood and adolescence is critical to the attainment of a healthy adult skeleton. Bone mineral accretion and eventual adult peak bone mass are largely dependent on genetic factors. Hypercalciuria is also frequently linked to genetic determinants. Therefore, we carried out a cross-sectional evaluation of bone mineral metabolism in children with IH, and in their asymptomatic premenopausal mothers.
Methods:
Quantitative BMD using DEXA was performed in 21 children with IH and in their asymptomatic mothers. Bone resorption was assessed by measuring the urinary concentrations of pyridinoline and deoxypiridinoline. Simultaneous calcium-modulating hormonal determinations, including serum intact immunoreactive parathyroid hormone and 1,25(OH)(2)D(3), were performed. The expression of interleukin-1alpha (IL-1alpha) by peripheral blood mononuclear cells (PBMCs) was determined by polymerase chain reaction.
Results:
Reduced BMD values were observed in eight children (38%) and in seven mothers (33%). The children of osteopenic mothers exhibited significantly reduced BMD Z-score values of lumbar spine (P<0.05) when compared with children of mothers with normal BMD. Bone resorption markers were normal in most children with IH. Hypercalciuria was detected in five out of 20 (25%) asymptomatic mothers and it correlated (r=-0.81) to femoral BMD in mothers with osteopenia. The expression of IL-1alpha mRNA by PBMCs from IH children did not differ from controls.
Conclusions:
Reduced BMD was detected in a large proportion of children with IH. Hypercalciuria and reduced BMD were uncovered in a substantial number of their otherwise healthy asymptomatic mothers. The diminished BMD in adults with IH may start early in life, could be influenced by genetic factors, and may represent a risk factor for osteoporosis later in life.