Longitudinal Variability of Lipoprotein(a) in Children with Type 1 Diabetes: Implications for Cardiovascular Risk Stratification

Abstract Context Lipoprotein(a) [Lp(a)] is a genetically determined and independent cardiovascular risk factor, traditionally considered stable across the lifespan, supporting a single lifetime measurement strategy. However, its longitudinal behavior during childhood and adolescence remains poorly characterized, particularly in individuals with type 1 diabetes who are at increased lifetime risk of cardiovascular disease. Objective We aimed to characterize intra- and inter-individual trajectories of Lp(a) in youth with type 1 diabetes and to assess the implications of variability for cardiovascular risk classification. Methods We conducted a retrospective single-center cohort study of children and adolescents with type 1 diabetes followed at Geneva University Hospitals between 2012 and 2023. Annual fasting Lp(a) concentrations were analyzed longitudinally. Variability was assessed in participants with more than two measurements. Clinically relevant thresholds were used to evaluate risk reclassification. Statistical analyses included paired Wilcoxon tests, Pearson and Kendall correlations, and Holm-adjusted p-values. Results A total of 287 participants contributed 1,408 Lp(a) measurements over a median follow-up of 6.2 years (IQR 2.9-9.6). At baseline, 26% had elevated Lp(a) (above or equal 300 mg/L). Among participants with serial measurements, 32% exhibited intraindividual fluctuations exceeding 50% of their maximum value. Reclassification across the 300 mg/L threshold occurred in 11.9% of participants. Lp(a) concentrations peaked between ages 10 and 13 years and declined thereafter. Modest seasonal variation was observed, with higher levels in autumn and winter (P < 0.05). Conclusions In youth with type 1 diabetes, Lp(a) demonstrates clinically relevant intraindividual variability over time. These findings suggest that reliance on a single lifetime measurement may lead to misclassification of cardiovascular risk and support repeated assessment, particularly during adolescence, to improve risk stratification.