Factors affecting height velocity in normal prepubertal children.

PURPOSE

To analyze the effects of clinical and laboratory factors, including insulinlike growth factor (IGF) levels, on the height velocity of normal prepubertal children.

METHODS

Ninety-five healthy prepubertal children (33 boys, 62 girls) were enrolled. The mean chronological age was 6.3±1.4 years, with a height standard deviation score (SDS) of -0.88±0.70. IGF-1, IGF binding protein-3 (IGFBP-3), SDS for anthropometric measurements, and changes in SDS for anthropometric measurements were analyzed for 1 year, and their associations with 1-year height velocity were investigated.

RESULTS

The group of children with a 1-year height velocity of ≥6 cm were chronologically younger than the group with a 1-year height velocity of <6 cm (5.9±1.3 years vs. 6.7±1.3 years, P=0.004), with a lesser increase of SDS for body mass index (BMI) over 1 year (-0.18±0.68 vs. 0.13±0.53, P=0.014). There were no differences between the 2 groups in IGF-1 SDS and IGFBP-3 SDS. Multiple linear regression showed that baseline chronological age (r=0.243, P=0.026) and height SDS (r=0.236, P=0.030) were positively associated with IGF-1 SDS. Binomial logistic regression showed that an older chronologic age at referral (odds ratio [OR], 0.68; 95% confidence interval [CI], 0.47-0.99) and an increase of BMI SDS over 1 year (OR, 0.41; 95% CI, 0.18-0.89) were associated with a decreased growth possibility of an above-average height velocity (≥6 cm/yr).

CONCLUSION

Height velocity of normal prepubertal children is affected by an increase of BMI SDS and chronological age. Prepubertal IGF-1 SDS reflects height SDS at the time of measurement but is not associated with subsequent height velocity.