Branched-chain amino acids levels associated with risk of erectile dysfunction: A Mendelian randomization analysis

Erectile dysfunction (ED) is a prevalent male sexual dysfunction that remarkably impacts patients' quality of life and is also recognized as a precursor to cardiovascular disease (CVD) events. Branched-chain amino acids (BCAAs) are derived from dietary intake and mainly involved in energy metabolism. Previous studies have underscored the association between BCAAs and CVD, but the causal link between BCAAs and ED remains uncertain.

The bidirectional Mendelian randomization (MR) study used the genetic data from genome-wide association studies (GWAS) to identify single nucleotide polymorphisms (SNPs) associated with total BCAAs, leucine, isoleucine, and valine. The genetic data for ED were acquired from the FinnGen study (n = 95,178). The primary method used to assess causal associations was the inverse variance-weighted (IVW) method, supplemented by MR-Egger, weighted median, and simple median analyses. Cochrane's Q test was utilized to evaluate heterogeneity within the results, while the MR-Egger intercept test was utilized to evaluate the Level pleiotropy. A sensitivity analysis was performed employing leave-one-out analysis.

The MR analysis results indicate a positive correlation between levels of total BCAA (OR = 1.984, 95 % CI = 1.018-3.868, P = 0.044), leucine (OR = 2.277, 95 % CI = 1.121-4.626, P = 0.023), isoleucine (OR = 2.584, 95 % CI = 1.167-5.722, P = 0.019), valine (OR = 1.894, 95 % CI = 1.119-3.206, P = 0.017), and the risk of ED. Sensitivity tests confirmed the accuracy and robustness of the study findings. Moreover, the reverse MR analysis found no association between ED and the BCAAs.

The results of this analysis indicate a positive association between the circulating BCAA concentrations and the risk of ED, but their underlying mechanisms require further investigation.