Relationship between anterior pituitary volume and IGF-1 serum levels in soldiers with mild traumatic brain injury history
Castellano AK, Powell JR, Cools MJ, Walton SR, Barnett RR, Delellis SM, Goldberg RL, Kane SF, Means GE, Zamora CA, Depenbrock PJ, Mihalik JP.
Purpose: A high mild traumatic brain injury (mTBI) incidence rate exists in military and sport. Hypopituitarism is an mTBI sequela; however, few studies have examined this phenomenon in those with an mTBI history. This cross-sectional study of Special Operations Forces combat soldiers aimed 1) to relate anterior pituitary gland volumes (actual and normalized) to insulin-like growth factor 1 (IGF-1) concentrations, 2) to examine the effect of mTBI history on anterior pituitary gland volumes (actual and normalized) and IGF-1 concentrations, and 3) to measure the odds of demonstrating lower anterior pituitary gland volumes (actual and normalized) or IGF-1 concentrations if self-reporting mTBI history. Methods: Anterior pituitary gland volumes were manually segmented from T1-weighted 3D brain MRI sequences; IGF-1 serum concentrations were quantified using commercial enzyme-linked immunosorbent assays. Correlations and linear regression were used to determine the association between IGF-1 serum concentration and anterior pituitary gland volume (n = 74). Independent samples t-tests were used to compare outcomes between mTBI groups and logistic regression models were fit to test the odds of demonstrating IGF-1 concentration or anterior pituitary volume less than sample median based on mTBI group (n = 54). Results: A significant linear relationship between the subjects’ anterior pituitary gland volumes and IGF-1 concentrations (r72 = 0.35, P = 0.002) was observed. Soldiers with mTBI history had lower IGF-1 concentrations (P < 0.001) and lower anterior pituitary gland volumes (P = 0.037) and were at greater odds for IGF-1 serum concentrations less than the sample median (odds ratio = 5.73; 95% confidence interval = 1.77-18.55). Conclusions: Anterior pituitary gland volume was associated with IGF-1 serum concentrations. Mild TBI history may be adversely associated with anterior pituitary gland volumes and IGF-1 concentrations. Longitudinal IGF-1 and anterior pituitary gland monitoring may be indicated in those who report one or more mTBI.
Castellano AK, Powell JR, Cools MJ, Walton SR, Barnett RR, Delellis SM, Goldberg RL, Kane SF, Means GE, Zamora CA, Depenbrock PJ, Mihalik JP. Relationship between Anterior Pituitary Volume and IGF-1 Serum Levels in Soldiers with Mild Traumatic Brain Injury History. Med Sci Sports Exerc. 2022 Aug 1;54(8):1364-1370. doi: 10.1249/MSS.0000000000002892. Epub 2022 Feb 8. PMID: 35838301; PMCID: PMC9287595.