Prevalence and Etiology of Hypogonadism Among Men with Chronic Spinal Cord Injury

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 554-583-Male Reproductive Endocrinology & Case Reports
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-555
Shannon Danielle Sullivan*1, Maria Menucci2, Marc R Blackman3 and Suzanne Groah4
1MedStar Washington Hospital Center, Washington, DC, 2Medstar Washington Hospital Center/Georgetown University Hospital, Washington, DC, 3Washington DC VAMC, Bethesda, MD, 4Medstar National Rehabilitation Hospital, Washington, DC
Background: 300,000 individuals with spinal cord injury (SCI) currently reside in the U.S., with 12,000 new injuries occurring each year, most commonly in young men.  Clinical observation suggests that hypogonadism is a common complication of SCI in men, that it is frequently overlooked and that it may contribute to increased morbidity and mortality in this population, despite the ready availability of endocrine screening and testosterone replacement therapy.

Objectives: To evaluate the prevalence and etiology (primary vs secondary) of hypogonadism in a cohort of non-elderly men with SCI.

Methods: 36 men aged 18-50 with chronic (≥1 year) SCI and no prior history of hypogonadism were evaluated as part of an ongoing, larger study.  Blood was collected in the early morning after an overnight fast,  stored at -80 C and subsequently assayed  for total testosterone (TT) by RIA; estradiol (E2) by immunoassay; and LH, FSH, and SHBG by immunoradiometric assay.  Free T (fT) was calculated using TT and SHBG.  Fisher’s exact test with P<0.05 was used to compare prevalence of hypogonadism between these SCI patients and healthy, non-SCI men aged 20-49 yr in NHANES III (controls).

Results: Hypogonadism was present in 7 (19%) of the men with SCI based on TT<300 ng/dL and 12 (33%) men based on fT<9 ng/dL. 7 (19%) men with SCI had both low TT and low fT; 12 (33%) had either low TT or low fT.  The overall prevalence of hypogonadism in this group of SCI men is significantly higher than the 2.3-8.7% prevalence of TT<300 ng/dL reported in healthy, non-SCI men aged 20-49 in NHANES III (p<0.0001).

In our study, higher SHBG correlated with higher TT (r=0.6, all subjects, p<0.0001; r=0.8, hypogonadal subjects, p=0.002).  SHBG did not correlate with fT (r=0.2 all subjects; r=0.2, hypogonadal subjects). Among the 12 SCI men with low TT or low fT, 10 (83%) had LH and/or FSH <5 IU/L, suggesting secondary hypogonadism; 2 (17%) had LH and/or FSH >10 IU/L, suggesting primary hypogonadism. Among hypogonadal SCI men, higher E2 levels were related to lower TT (r= -0.52, P=0.08) and lower fT (r= -0.54, P=0.07), both trending toward significance. E2 had no relation to SHBG among hypogonadal SCI men. 

Conclusions: Our findings of a several-fold increased prevalence of hypogonadism in nonelderly men with SCI compared to non-SCI controls, in frequent association with central hypogonadism and elevated estrogens, should prompt routine screening of reproductive axis function is in this population.

Nothing to Disclose: SDS, MM, MRB, SG

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