ESPE Abstracts

Background: Rapid BMI increase in early childhood was found to be a contributing factor for impaired final height in boys with Cystic Fibrosis (CF). This may be explained by early adrenarche triggering an accelerated bone maturation resulting in a compromised growth spurt during puberty, comparable to children with SGA. In healthy Dutch boys, adrenarche starts from the age of 9 years with DHEAS ≥ 1 µmol/L. In Dutch girls, the onset of adrenarche is from age 8 onwards.

Aim: We aimed to analyse the timing of adrenarche in boys with CF and associate early rapid BMI increase to timing of adrenarche. Also, we aimed to analyse differences in DHEAS-levels between boys and girls with CF.

Methods: Boys and girls with CF, aged 8-9 years, visiting the CF expertise center UMCU were included. Since 2018, anthropomorphic, pubertal and endocrine data were collected. Early adrenal activation in boys was defined as a DHEAS ≥ 1 µmol/l before the age of 9 years.

Results: Thirteen boys (mean age 8.55 ± 0.27 yrs) and 13 girls (mean age 8.52 ± 0.31 yrs) were enrolled until June 2022. The median (range) DHEAS level was 1.3 µmol/l (0.40 – 6.30) and 0.96 µmol/l (0.25 – 1.80) in boys and girls respectively (P=0.199). Eight boys (61.5%) had an early rise in DHEAS-levels ≥ 1 µmol/l (i.e. before the age of 9 years). Five out of 11 boys (45.5%) and 4 out of 8 girls (50%) had a mean accelerated bone-age of 1.55 ± 0.97 and 0.75 ± 0.96 yrs respectively. The mean difference between chronological age and bone-age was more pronounced in boys and girls with DHEAS-levels ≥1 µmol/l (Δ0.65 ± 1.47 (n=8) and Δ0.75 ± 0.72 yrs (n=4)) in comparison to boys and girls with DHEAS-level <1 µmol/l (Δ-0.91 ± 0.29 (n=3) and Δ-0.25 ± 0.21 respectively) (P=0.11 and P=0.036). A moderate, significant correlation was found between the ΔBMI-SDS and DHEAS-levels between 1-6 years (r=0.653, P=0.029) in boys. This relationship was absent in girls.

Conclusion: In this small cohort, 61.5 % of boys with CF between 8-9 years had an early rise of DHEAS, which could be correlated to ΔBMI-SDS between 1-6 years. In comparison to girls, boys had higher DHEAS levels. Early adrenal activation may be one of the factors contributing to early and suboptimal growth during puberty and impaired final height in boys with CF.