Relationship Between Gonadal Function and Cardiometabolic Risk in Young Men with Chronic Spinal Cord Injury

BACKGROUND: We previously reported that young men with chronic spinal cord injury (SCI) have a higher prevalence of testosterone deficiency when compared to an age-matched healthy control population. Young men with SCI are also at increased risk for developing cardiometabolic dysfunction after injury. It is unclear whether or not testosterone deficiency is associated with heightened cardiometabolic risk in men with SCI. OBJECTIVE: To investigate associations among levels of testosterone in young men with chronic SCI and surrogate markers of cardiometabolic risk. DESIGN: Secondary cross-sectional analysis. SETTING: Rehabilitation research centers in Washington, DC, and Miami, Florida, USA. PARTICIPANTS: Men (n=58) aged 18–45 with chronic (≥1 year), motor complete SCI without comorbidities or use of testosterone therapy. METHODS: Plasma concentrations of testosterone, lipids, inflammatory markers (CRP and IL-6), HbA1C%, glucose, and insulin were measured in a fasting state using standard assays. A two-hour oral glucose tolerance test (OGTT) and Framingham Risk Score (FRS) were assessed for each subject. Body composition was assessed by DXA scan. MAIN OUTCOME MEASUREMENTS: Surrogate markers of cardiometabolic risk among men based on the level of total testosterone (TT)(≤300, 301–500, or >500 ng/dL) and free testosterone (fT) (≤9 or >9 ng/dL). Comparisons were made between men with normal and low TT or fT. RESULTS: FRS was significantly higher in men with low fT (P.08), were higher in men with low TT or low fT. Men with low TT or low fT had lower high density lipoprotein cholesterol (HDL) levels (P.1) or low density lipoprotein cholesterol (LDL) (P>.07). Men with low TT had higher levels of inflammatory markers CRP (P.8). CONCLUSIONS: In young men with chronic SCI, who undergo an accelerated aging process post-injury, hypogonadism is associated with an unfavorable cardiometabolic risk profile. Further research is needed to determine if a causal relationship exists between hypogonadism and heightened cardiometabolic risk in men with SCI, and whether routine screening for testosterone deficiency is warranted in this population.