Mineral metabolism in children with dermatomyositis.
OBJECTIVE
To measure calcium metabolism in 12 children with juvenile dermatomyositis (JDM).


METHODS
We used dual-tracer stable isotope studies to measure calcium metabolism in 12 children with JDM and a group of 43 healthy children (Group HC) of similar ages. Five of the JDM subjects were receiving steroids (Group JDM-ST) and 7 were not (Group JDM-NS).


RESULTS
The rate of calcium absorption in Group JDM-ST was lower than that in Group HC (19 +/- 10% vs 30 +/- 11%, p < 0.05). The lower rate of absorption was associated with a net loss of calcium each day (calculated calcium retention, Vbal, of -35 +/- 14 mg/day compared to +140 +/- 97 mg/day in Group HC, p < 0.01). Group JDM-NS showed slightly lower calcium absorption than Group HC and significantly lower Vbal (+33 +/- 70 mg/day, p < 0.01 vs Group HC) than Group HC. Group JDM-ST subjects also had decreased bone calcium deposition rates.


CONCLUSIONS
Patients with JDM may be at risk for significant loss of bone mineral associated with decreased calcium absorption, especially in the acute phase of their disease when they are receiving steroid therapy.
Perez
M D
MD
Section of Pediatric Rheumatology, Baylor College of Medicine, Houston, TX.
Abrams
S A
SA
Koenning
G
G
Stuff
J E
JE
O'Brien
K O
KO
Ellis
K J
KJ
D000042:Absorption; D000293:Adolescent; D000469:Alkaline Phosphatase / Q000097:blood; D015519:Bone Density; D001842:Bone and Bones / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D003882:Dermatomyositis / Q000188:drug therapy / Q000378:metabolism*; D005260:Female; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood; D008297:Male; D015675:Osteocalcin / Q000097:blood; D011241:Prednisone / Q000627:therapeutic use; D011863:Radioimmunoassay; D012189:Retrospective Studies
D006887:Hydroxycholecalciferols; D015675:Osteocalcin; D000469:Alkaline Phosphatase; D002118:Calcium; D011241:Prednisone