Abstract
BACKGROUND: Ruptured abdominal aortic aneurysm (AAA) is associated with high mortality risk. Few studies found a relationship between testosterone levels and AAA development, but were limited by small event numbers and single-center design.</p>
OBJECTIVE: To assess the associations of serum testosterone and sex hormone-binding globulin (SHBG) levels with symptomatic AAA risk in male participants from the UK Biobank.</p>
METHODS: Study exposures included baseline serum total testosterone (TT), free testosterone (cFT and FTZ), bioavailable testosterone, and SHBG. Multivariable Cox proportional hazards regression models were used for outcome analyses. The joint association of male hormones and AAA polygenic risk score (PRS) was further investigated with AAA risk.</p>
RESULTS: This study followed 190,627 males over 15 years, with 1903 symptomatic AAA cases identified. Compared with those in higher quartiles, individuals in the lowest quartile of TT, FTZ, cFT and BioT had a 19% (95% confidence interval [CI], 1.07-1.33), 16% (95% CI, 1.05-1.28), 8% (95% CI, 0.98-1.19), and 13% (95% CI, 1.03-1.25) higher risk of AAA, respectively. For SHBG, individuals in the highest quartile had a 20% (95% CI, 1.07-1.34) greater risk of AAA compared with those in lower quartiles. Stratified analysis by AAA, PRS found that individuals with higher PRS and either lower testosterone levels or higher SHBG levels, had a greater risk of developing AAA.</p>
CONCLUSIONS: This large population-based cohort study found that higher PRS and either lower testosterone or highest SHBG were associated with a greater risk of symptomatic AAA among male individuals. Owing to the observational nature of this study, further research is warranted to establish whether or not a causal relationship exists between lower testosterone and the development or growth of an AAA, and whether testosterone treatment might decrease the risk of AAA.</p>