Rmr. Pereira et al., Abnormalities in the biochemical markers of bone turnover in children withjuvenile chronic arthritis, CLIN EXP RH, 17(2), 1999, pp. 251-255
Objective
To study the biochemical markers of bone turnover in children with juvenile
chronic arthritis (JCA) and to compare these parameters with those in heal
thy children in order to evaluate the relationships between age, disease ac
tivity and biochemical variables.
Methods
Sixty-two children with JCA and 157 healthy children were studied. Serum sa
mples were analyzed for their concentrations of minerals, osteocalcin (OC)
and bone-specific alkaline phosphatase (BAP). Urine samples were examined t
o monitor the excretion of hydroxyproline (HYP) and deoxypyridinoline cross
links (DPD).
Results
OC, BAP, HYP/Cr, DPD/Cr values were decreased in healthy girls more than 12
years of age and in healthy boys more than 14 years of age compared to you
nger children from the same population. Lower levels of OC and BAP were obs
erved in younger children with JCA (girls less than or equal to 12 yrs.; bo
ys less than or equal to 14 yrs.) compared to healthy children of the same
age. Older girls with JCA (greater than or equal to 13 yrs.) were found to
have increased HYP/Cr and DPD/Cr values compared to older healthy children.
Conclusion
These results indicate that abnormalities of bone metabolism occur in an ag
e-related fashion in JCA. This was demonstrated by a reduction in the marke
rs of bone formation in younger JCA patients. Moreover; in older girls the
markers of bone resorption were found to be elevated. Taken together; these
findings suggest that bone formation is reduced from early childhood to mi
d-puberty, while resorption levels increase in children with JCA after this
time.