The association between dietary inflammatory index and C-reactive protein in plasma and semen with semen quality: A cross-sectional study

Infertility affects couples worldwide, with male factors being responsible for half of all cases. This study aimed to investigate the relationship between dietary inflammatory index (DII) and levels of C-reactive protein (CRP) in plasma and semen with the quality of semen in infertile males. In this cross-sectional study, 88 infertile men referring to Besat hospital, Tehran, Iran from December 2021-November 2022 were enrolled. A detailed questionnaire requesting information, and a 168-item semiquantitative food frequency questionnaire, were completed by participants. A food frequency questionnaire was used to calculate the DII. Additionally, semen and blood samples were collected from each participant for semen analysis and CRP-level assessment. Statistical analyses were performed to explore the association between DII and CRP levels with sperm quality. The correlation between DII and serum/semen CRP, besides assessing nutrients in each DII quartile group, was also explored. A significant difference was observed between different DII quartiles considering sperm motility (p = 0.006) and morphology (p = 0.014). Post hoc study revealed a significant difference between the 1 and 2 quartiles and the 1 and 4 quartiles of DII regarding sperm motility (p = 0.011, and 0.017 respectively) and a significant difference between the 1 and 2 quartiles of DII considering sperm morphology (p = 0.009). A statistically significant inverse correlation was also observed between DII and sperm motility (p 0.017). Carbohydrates and β-carotenes were significantly different between the 4 DII quartiles (p = 0.043 and p = 0.026, respectively). Finally, no significant correlation was observed between DII and CRP levels in blood and semen (p 0.05). The findings suggested a notable correlation between DII and semen quality; however, no significant association were observed between DII and CRP levels in blood and semen.