URINARY FREE DEOXYPYRIDINOLINE LEVELS DURING CHILDHOOD

Free urinary deoxypyridinoline (DPD) levels, corrected for the urinary concentration of creatinine (nmol/mmol), were determined in 144 healt hy children (76 males and 68 females, mean age+/-SE: 9.1+/-0.2 yr, age range: 5.1-14.0 yr) in order to detect the possible age-related chang es of this reliable index of bone resorption activity and the relation ships between free DPD, gender and pubertal development. Multiple regr ession analysis revealed that most of the variation in DPD levels was explained by chronological age (coefficient: 2.89, p<0.02), whereas se x and pubertal stage did not add significance to the variance. Urinary DPD levels were similar in males (24.7+/-1.8 nmol/mmol urinary creati nine) and females (24.2+/-2.0 nmol/mmol urinary creatinine) and signif icantly higher (p<0.02) in pubertal (Tanner stage tl-V: 28.6+/-2.8 nmo l/mmol urinary creatinine) than in prepubertal children (22.4+/-1.4 nm ol/mmol urinary creatinine), both in males and in females. The pattern of DPD levels was clearly different between females and males, the ma ximum increase being evident at Tanner stage II-III (mid-puberty) in f emales and at Tanner stage IV-V (mid-late puberty) in males. The incre ase of DPD paralleled the elevation of urinary GH (pmol/mmol urinary c reatinine), a non-invasive and acceptable index of physiological GH se cretion, observed during the pubertal growth spurt. The progressive in crease of urinary GH in older children was not followed by a further s timulation of bone resorption. Although the relationships between urin ary GH and DPD need-to be better investigated, it seems plausible to h ypothesize that the determination of urinary free DPD, as a marker of GH action on bone, might have some potential in the follow-up of growt h promoting treatments, such as GH. (C) 1998, Editrice Kurtis.