The relationship between Dietary Inflammatory Index and Polycystic Ovary Syndrome in Iranian Women: A Case-Control Study

Background Polycystic ovary syndrome (PCOS) is a common endocrine-metabolic disorder among women of reproductive age, marked by reproductive, metabolic, and psychological issues. Chronic low-grade inflammation is involved in PCOS pathogenesis. This study examines the association between Dietary Inflammatory Index (DII) and PCOS odds in Iranian women. Methods This case-control study included 100 newly-diagnosed PCOS patients and 100 healthy age-matched controls in Kashan, Iran. Dietary intake was assessed using a validated 117-item Food Frequency Questionnaire (FFQ). DII was calculated using 29 food components. Biochemical measures, including fasting blood glucose, lipid profiles, and C-reactive protein (CRP) levels, were assessed. Results After adjustment for all confounding variables, compared to people in the lowest tertile of DII, those in the highest tertile had significantly 2.44-fold greater odds for PCOS (95% CI: 1.09, 5.47; P-trend = 0.03). Although women in the third tertile of DII had higher levels of triglyceride (TG), systolic blood pressure (SBP), diastolic blood pressure (DBP), and c-reactive protein (CRP) as well as lower high-density lipoprotein cholesterol (HDL-C) compared to those in the first tertile of DII, this association was not statistically significant (P > 0.05). Conclusion A pro-inflammatory diet, as reflected by a higher DII, is associated with an increased odds of PCOS in Iranian women. Longitudinal studies are suggested to further explore this finding.