Association of Copper-to Zinc Ratio with Sperm Concentration among Males Investigated for Infertility

Abstract

The importance of copper and zinc in the fertility potential of males are well understood. The close relationship and the antagonistic interactions between copper and zinc requires further investigation especially because of conflicting reports in literature on the association of the trace elements with sperm quantity and quality. This study evaluates seminal plasma copper and zinc concentrations, copper-to-zinc ratio and their associations with sperm concentration in infertile males. This is a cross-sectional study of 400 males investigated for infertility and 100 male control subjects. Seminal plasma copper and zinc were determined using atomic absorption spectrophotometry technique (Buck Scientific Model VGP-210, Germany). The subjects were grouped based on sperm count; normozoospermia (>15 x 10⁶cells/mL), oligozoospermia (<15x10⁶cells/mL) and azoospermia (no sperm cell). The levels of copper, zinc and Cu/Zn ratio were compared using unpaired Students-t-test and analysis of variance while Pearson correlation coefficient was used to assess the correlation between measured variables and sperm count. Seminal plasma zinc was significantly lower (p<0.001) while copper and Cu/Zn ratio were significantly higher (p<0.001) in infertile than fertile males. The Cu/Zn ratio was significantly higher (p<0.001) among infertile males than controls. Seminal plasma levels of copper and Cu/Zn ratio increased with decreasing concentrations of sperm cells while zinc levels increase with increasing concentration of sperm cells. In conclusion: Copper-to-zinc ratio correlated with sperm concentration in infertile males. The interaction between copper and zinc may be routinely considered in the clinical evaluation of the infertile men.