After stratifying patients, the frequencies of null genotype of gene GSTM1 in oligospermia (68.3% versus 57.7%, p = 0.027, OR = 1.580, 95% CI = 1.051-2.375) and GSTT1 in azoospermia (66.9% versus 46.8%, p < 0.001, OR = 2.299, 95% CI = 1.484-3.562) as well as oligospermia (57.9% versus 46.8%, p = 0.025, OR = 1.567, 95% CI = 1.057-2.322) were still significantly higher compared with controls.
Our case-control study showed the GSTM1 null genotype was significantly associated with idiopathic oligozoospermia, while the null genotype of GSTT1 was significantly associated with normozoospermia and azoospermia.
Thus, the findings of our study suggest that there are no significant associations between GSTM1 and GSTP1 polymorphisms and sperm parameters at conventional or at molecular levels including OS status, sperm chromatin integrity or maturity in Iranian infertile men with OAT and normozoospermia.
In conclusion, these results support that the GSTM1 null genotype mainly contributes to idiopathic male infertility susceptibility, particularly to OAT.