IGF-1 as a Biomarker for Symptom Severity in Adult Traumatic Brain Injury: Evidence from an Observational Study

Area of Science:

• Neuroscience
• Endocrinology
• Traumatology

Background:

• Traumatic brain injury (TBI) can lead to growth hormone deficiency, often undertreated, impacting physical, metabolic, and neuropsychiatric functions.
• Insulin-like growth factor-1 (IGF-1) plays a crucial role in brain regions regulating learning, memory, mood, cerebral blood flow, neurogenesis, and neuroplasticity.

Purpose of the Study:

• To investigate the association between IGF-1 levels and the severity of post-TBI symptoms, anxiety, and depression.
• To determine if IGF-1 levels can predict symptom severity in individuals with TBI.

Main Methods:

• A retrospective observational study included 3-12 months post-TBI participants with available IGF-1 values and completed questionnaires (RPQ-13, GAD-7, PHQ-9).
• Participants were stratified by TBI severity (mild vs. moderate-to-severe) based on Glasgow Coma Scale (GCS) scores.
• IGF-1 Z-scores were standardized for age and gender, and analyzed for correlations with symptom severity scores using Generalized Linear Models.

Main Results:

• Significant negative correlations were observed between IGF-1 Z-scores and symptom severity (RPQ-13), anxiety (GAD-7), and depression (PHQ-9) across all TBI severity groups.
• Lower IGF-1 Z-scores were associated with higher reported symptoms of TBI, depression, and anxiety.
• The IGF-1 Z-score was a significant predictor, with a one-point increase associated with a 39.23% decrease in TBI symptoms, 29.85% decrease in anxiety, and 16.30% reduction in depression.

Conclusions:

• Decreased IGF-1 levels are significantly associated with increased symptom severity, depression, and anxiety following TBI.
• IGF-1 may serve as a potential biomarker for assessing TBI symptom severity and guiding treatment strategies.
• Further research is warranted to explore the therapeutic potential of targeting IGF-1 in TBI recovery.