Objective: To investigate the correlation of seminal plasma homocysteine (Hcy) and its metabolic factors folate (FA) and cobalamin (VB12) with semen quality in obese men.
Methods: We randomly selected 83 male patients with idiopathic infertility for this study and, according to the body mass index (BMI), divided them into a normal BMI (n = 28), an overweight (n = 28) and an obesity group (n = 27). We determined the levels of Hcy, FA and VB12 in the seminal plasma by ELISA and analyzed their correlation with the semen parameters of the patients in different groups.
Results: Compared with the normal BMI group, the obese males showed significant decreases in the semen volume (［3.23 ± 0.86］ vs ［2.58 ± 0.77］ ml, P < 0.05), total sperm count (［191.35 ± 103.00］ vs ［121.55 ± 88.08］ ×106, P < 0.05), percentage of progressively motile sperm (［52.88 ± 15.58］ % vs ［38.97 ± 16.52］ %, P < 0.05), seminal plasma Hcy (［7.41 ± 1.29］ vs ［6.62 ± 0.85］ μmol/L, P < 0.05), and VB12 (［282.41 ± 30.38］ vs ［230.07 ± 37.75］ pmol/L, P < 0.05). There were no statistically significant differences in the semen parameters between the overweight group and the normal BMI or the obese group (P > 0.05), or in sperm concentration or the FA level among the three groups of patients (P > 0.05). The levels of seminal plasma Hcy and VB12 were correlated positively with the semen volume (r = 0.281 and 0.242, P < 0.05) and total sperm count (r = 0.229 and 0.258, P < 0.05) but negatively with BMI (r = －0.293 and －0.238, P < 0.05). No correlation, however, was found either between sperm concentration and the percentage of progressively motile sperm (P > 0.05) or between the FA level and BMI or semen parameters (P > 0.05).
Conclusions: The levels of seminal plasma Hcy and VB12 are correlated with BMI, semen volume and total sperm count, which suggests that the concentrations of seminal plasma Hcy and VB12 may be associated with the fertility of obese men.
Keywords: cobalamin; folate; homocysteine; semen parameter; obesity.