Racial/Ethnic differences in male reproductive health: a systematic review and meta-analysis of semen parameters and hormonal profiles in the United States.

We conducted systematic review and meta-analysis of differences in semen parameters and reproductive hormones between White, Black, Asian, Hispanic, and non-Hispanic men in the United States. We systematically searched PubMed, Scopus, and Web of Science. Of 2624 studies identified, 25 studies were included for meta-analysis. The pooled analysis revealed that White men compared to Black men had higher sperm concentration of +26.43 million/ml (95%CI = 7.81, 45.05; I = 98.98%), higher total sperm count of +128.35 million (95%CI = 82.10, 174.60; I = 98.46%), lower age-adjusted free testosterone of -15.12 pmol/L (95%CI = -29.89, -0.35; I = 99.55%), lower age-adjusted estradiol of -15.23 pmol/L (95%CI = -27.61, -2.85; I = 99.96%), and lower age-adjusted SHBG of -1.52 nmol/L (95%CI = -2.60, -0.44; I = 95.65%). Compared to Asian men, White men had higher age-adjusted estradiol of +0.97 pmol/L (95%CI = 0.81, 1.14; I = 0%) and Black men had higher SHBG of +2.93 nmol/L (95%CI = 2.63, 3.23; I = 0%). Hispanic compared to non-Hispanic men had higher sperm concentration of +5.12 million/ml (95%CI = 4.17, 6.06; I = 60.67%) and higher total motility of +5.28% (95%CI = 0.49, 10.07; I = 93.11%), lower age-adjusted total testosterone of -0.77 nmol/L (95%CI = -1.22, -0.33; I = 98.51%), lower age-adjusted estradiol of -12.54 pmol/L (95%CI = -23.26, -1.81; I = 99.82%), and lower age-adjusted SHBG of -2.08 nmol/L (95%CI = -4.13, -0.02; I = 99.57%). In conclusion, this meta-analysis found ethnic variations in male reproductive parameters in the United States.