Association between dietary inflammatory index and self‐reported female infertility from the National Health and Nutrition Examination Survey 2013–2020

BACKGROUND: To explore the association between the diet inflammatory index (DII) and infertility. METHODS: Multivariable logistic regression was performed to investigate the relationship between infertility and DII, and restricted cubic spline (RCS) was utilised to test for nonlinear relationships in this cross-sectional study. Data of this study were collected from the 2013 to 2020 National Health and Nutrition Examination Survey (NHANES) database. Considering women's child-bearing age, we enrolled a total of 2066 women aged 20-45 years in this study. RESULTS: After all covariates were adjusted, a positive association was found between DII score and odds of infertility by multivariable logistic regression (odds ratio [OR] = 1.19, 95% confidence interval [CI] 1.03, 1.38; p = 0.027). Compared with participants with DII scores in the lowest quartile, those with DII scores in the highest quartile had significantly higher odds of infertility (OR = 2.42, 95% CI 1.09, 5.34; p = 0.034). The RCSs model suggested a linear relationship between DII and infertility (p for nonlinear = 0.1827). CONCLUSIONS: A positive association between a pro-inflammatory diet and self-reported infertility was detected. Our study extends the application of the DII scoring system to infertility prevention.