Factors contributing to gender differences in serum retinol and α-tocopherol in infertile couples

Oxidative stress is detrimental to fertility potential. Retinol and α-tocopherol are natural antioxidants that inhibit lipid peroxidation and protect against cell damage induced by oxidative stress. This study evaluated whether gender-related differences in antioxidant status exist among couples with infertility and, if so, to evaluate relevant factors that may contribute to such differences. Retinol and α-tocopherol in the sera of 40 couples and in the semen of 40 men were measured using high performance liquid chromatography. Serum retinol and α-tocopherol in women were significantly higher than in men (both P < 0.001). There was an inverse relationship between body mass index and serum retinol and α-tocopherol in both men and women. Heavy smokers (≥20 cigarettes/day), compared with non-smokers, had lower serum concentrations of retinol and α-tocopherol. Serum concentrations of retinol and α-tocopherol in men with normal sperm parameters were significantly higher than in those with oligozoospermia and asthenozoospermia (both P < 0.001). Lower serum retinol and α-tocopherol in men compared with their female partners could be related to their older age, higher body mass index and smoking habits. Low concentrations of these natural antioxidants were associated with abnormal semen parameters in men and anovulation in women.