Pathophysiology of calcium metabolism in children with vitamin D-deficiency rickets☆,☆☆,★
Section snippets
METHODS
We studied 51 children (33 boys) with VDR, 2 to 36 months of age (median, 16 months). The patients were not selected and attended several pediatric clinics, mainly from the northern part of Germany, from 1989 to 1994. All children had a history of deficient vitamin D intake.
The diagnosis of VDR was based on radiologic signs of rickets and laboratory findings such as elevated AP activity, low 25(OH)D concentration (<12.5 nmol/L; 5 ng/ml), and low or normal Ca and P levels in serum. None of the
Calcium metabolism in different stages of VDR
Table I summarizes the median values and ranges of several biochemical variables in the untreated patients, who were divided into three groups according to the stage of VDR. As previously defined, serum Ca level was low in stages 1 and 3 but normal in stage 2, whereas serum P level was normal in stage 1 but low in stages 2 and 3.
The median value of serum AP activity was elevated in stage 1, with a significant further increase in stage 2 and a decrement thereafter. The index of bone degradation,
DISCUSSION
The present study confirms that vitamin D depletion (low serum 25(OH)D levels), secondary hyperparathyroidism, and high bone turnover are the hallmarks of VDR in children. The serum levels of Ca, P, and 1,25(OH) 2 D are of minor diagnostic relevance; these values may be normal, and 1,25(OH) 2 D may even be increased in VDR. The latter observation confirms investigations in other vitamin D-deficient children 8, 9 and adults. 10, 11 In the face of secondary hyperparathyroidism, hypocalcemia, and
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Cited by (0)
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From the Department of Pediatrics, Medical University of Luebeck, Luebeck, Germany
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Reprint requests: Klaus Kruse, MD, Klinik fuer Paediatrie der Medizinischen Universitaet zu Luebeck, Kahlhorststrasse 31-35, D-23538 Luebeck, Germany.
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0022-3476/95/$3.00 + 0 9/20/62438