IGF-1 as a biomarker for symptom severity in adolescents with traumatic brain injury.

Objective: This study assessed the relationship between insulin-like growth factor 1 (IGF-1) level and symptom severity in adolescents with traumatic brain injury (TBI), focusing on correlation with post-injury symptom severity, depression, and anxiety.

Design: This retrospective observational study included adolescents aged 13-17 years (n = 52) with mild TBI (mTBI, n = 30) or moderate/severe TBI (msTBI, n = 22), based on best Glasgow Coma Scale score recorded in the first 24 h post-injury. Participants were 3-12 months post-TBI with available IGF-1 values and complete Rivermead Post Concussion Symptoms Questionnaire (RPQ-13), Generalized Anxiety Disorder-7 (GAD-7), and Patient Health Questionnaire-9 (PHQ-9) responses. Outcome measures were correlated with IGF-1 z-scores with Kendall's Tau analysis.

Results: RPQ-13 and GAD-7 scores were significantly higher in msTBI (p = 0.0472 and p = 0.0085, respectively). IGF-1 z-scores negatively correlated with RPQ-13 scores in mTBI (tau = -0.65, p < 0.0001) and msTBI (tau = -0.85, p < 0.0001), and with GAD-7 scores in mTBI (tau = -0.30, p = 0.0302) and msTBI (tau = -0.39, p = 0.0144). Only msTBI demonstrated a significant negative correlation between IGF-1 z-score and PHQ-9 scores (tau = -0.82, p < 0.0001).

Conclusions: Adolescents with msTBI experienced greater post-injury symptom severity and anxiety than those with mTBI. Low IGF-1 levels correlated with greater post-injury symptom severity, anxiety, and depression (msTBI only), supporting IGF-1 as a potential biomarker in adolescent TBI.