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

Abstract

Background: Infertility affects couples worldwide, with male factors being responsible for half of all cases. Objective: 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. Materials and Methods: 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. Results: 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 1st and 2nd quartiles and the 1st and 4th quartiles of DII regarding sperm motility (p = 0.011, and 0.017 respectively) and a significant difference between the 1st and 2nd 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). Conclusion: 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. Key words: Infertility, C-reactive protein, CRP, Inflammation, Sperm.