Changes in Predicted Adult Height over Time in Girls with Early Puberty and Related Factors

Abstract

Background: One of the most important concerns parents have about their daughters’ precocious puberty is the reduction in final height. This study evaluates the changes in predicted adult height (PAH) over time in girls with early puberty. Materials and Methods: Girls with aged 7 to 9.5 years old with the beginning of puberty after seven years were evaluated. Two non-dominant hand x-ray were taken at 6 to 24 months. The predicted adult height (PAH) was estimated using bone age and the Bayley-Pinneau method. Changes in PAH were determined. The relationship between age, height and weight at birth, target height and puberty stages, and bone age and BMI with PAH changes were investigated. Results: Seventy girls with a mean age of 8.23 years (SD: 0.65) and an average time interval of 0.99 years (SD: 0.47) were studied. At the first evaluation, the average bone age was 8.6 years (p value=0.225 SD: 1.25), and the average predicted adult height was 158.95 cm (SD: 5.66). At the second evaluation, the average bone age was 10.06 years (P-value=0.15 SD: 1.36), and the average predicted adult height was 158 cm (SD: 6.75). The mean difference in predicted adult height is -0.94 ± 4.8 cm. The mean final height predicted in the first and second visits showed a significant relationship with PAH changes and in the group that increased PAH by more than 3 cm, the average growth rate was 69.7 cm per year. In other words, the group growth velocity was higher, the higher their PAH. Two factors associated with expected adult height changes were found: height growth velocity and bone age velocity. Conclusion: Girls with early puberty are not altogether at risk of reduced adult height. However, if there is concern about reducing final height, the expected adult height will still need to be re-estimated at the appropriate interval.