P-207: Menarche in young-onset type 1 diabetes: data from the australasian diabetes data network (ADDN) registry
S James, K C Donaghue, J Couper, P Colman, L Perry, J Lowe, O James, R Wan, A Stell, R Sinnott, M E Craig, the ADDN study groupAbstract
Introduction
Australasian data on age at menarche in youth with type 1 diabetes (T1D) are limited.
Objectives
Data on age at menarche in youth with type 1 diabetes (T1D) remain limited. We examined factors associated with age at menarche and longitudinal trajectories of insulin dose, glycaemia, and body mass index (BMI) before and after menarche in an Australasian cohort.
Methods
Longitudinal sociodemographic and clinical data for females with T1D and a documented menarche date were extracted from the Australasian Diabetes Data Network (ADDN) registry. Generalised estimating equations were used to examine factors associated with age at menarche (< vs. ≥ cohort median age), including Index of Relative Socioeconomic Disadvantage score, T1D duration, total daily insulin dose/kg (TDD/kg), HbA1c, insulin pump use, and BMI standard deviation score (SDS). Trajectories of TDD/kg, HbA1c, and BMI SDS across nine clinically defined pre- and post-menarche time intervals were analysed using linear mixed models with time modelled as a categorical fixed effect, accounting for repeated measures and within-subject correlation.
Results
Overall, 601 females from nine centres were included. Median (IQR) age at menarche was 12.6 (12.0, 13.3) years. Later menarche was associated with longer T1D duration (B = 0.10; 95% CI 0.01-0.19; p = 0.04), lower TDD/kg (-1.20; -2.00 to -0.42; p = 0.003), higher HbA1c (0.21; 0.02-0.39; p = 0.03), and lower BMI SDS (-0.48; -0.79 to -0.17; p = 0.002). TDD/kg increased in the pre-menarcheal period, peaking around menarche then declining; BMI SDS increased progressively from pre- to post-menarche; and HbA1c rose over time from pre- to post-menarche (all p < 0.001), demonstrating distinct trajectories.
Conclusions
Menarche represents a key metabolic transition in adolescents with T1D, with increasing insulin requirements preceding menarche and ongoing increases in HbA1c and BMI SDS into the post-menarcheal period. These findings highlight the importance of considering pubertal progression in diabetes care and may inform anticipatory management during adolescence.