Abstract
BACKGROUND: This study investigates the relationship between the Dietary Inflammation Index (DII) and the risk of infertility among women of childbearing age in the United States. METHODS: This cross-sectional study analyzed data from 3184 women aged 20 to 45 years, utilizing information from the National Health and Nutrition Examination Survey (NHANES, 2013-2020). Dietary intake was assessed using 24-hour recall interviews to calculate the DII score, which is based on 28 dietary components. The DII score is used to assess the inflammatory potential of diet, with higher scores indicating a greater likelihood of inducing inflammation. Multivariate logistic regression and restricted cubic splines (RCS) were employed to evaluate the association between DII and infertility risk, adjusting for potential confounders such as age, BMI, and lifestyle factors. LASSO regression was used to identify key predictors, and a nomogram for predicting infertility risk was developed. RESULTS: Among the participants, 12.41% were classified as infertile. Women with infertility had significantly higher DII scores compared to those without infertility (2.27 [1.09, 3.14] vs 1.99 [0.92, 2.97]; p =0.016). The analysis revealed a positive association between higher DII scores and increased infertility risk, even after adjusting for confounding variables. RCS analysis indicated no significant nonlinear relationship between DII and infertility (p for non-linearity = 0.118). Furthermore, DII was identified as a more effective predictor of infertility risk than the Healthy Eating Index (HEI). The nomogram prediction model, developed from the predictive factors identified via LASSO regression, exhibited robust predictive performance, achieving an AUC of 85.1% (95% CI: 74.7%-95.5%). CONCLUSION: A pro-inflammatory diet, indicated by a high Dietary Inflammatory Index (DII) score, is associated with an elevated risk of infertility in American women, thereby supporting dietary interventions to reduce inflammation for improved fertility outcomes and highlighting the relevance of dietary counseling in fertility care.