The dietary inflammatory index is directly associated with polycystic ovary syndrome: A case‐control study

Abstract Introduction The association between diet and polycystic ovary syndrome (PCOS) might be mediated by the inflammatory properties of the diet. The study aimed to investigate the relationships between the dietary inflammatory index (DII) with odds of PCOS among the adult population. Methods In the hospital‐based case‐control study, 203 patients with PCOS and 291 non‐PCOS controls were enroled. DII was calculated via a validated 147‐item quantitative food frequency questionnaire (FFQ). Thirty‐six macro‐ and micronutrients were extracted from FFQ and used to calculate DII. Employing a case‐control design, odds ratios (ORs) and 95% confidence intervals (CIs) were obtained, with a dose‐response effect confirmed by the test for trend ( p for trend). Results The mean ± SD age and body mass index (BMI) of the study participants were 29.67 ± 5.92 years and 24.51 ± 4.71 kg/m 2 , respectively. Compared with controls subjects, PCOS patients had significantly higher weight, BMI, and waist circumferences, but had lower physical activity. PCOS subjects had higher intakes of carbohydrate, cholesterol, and refined grains, but lower intakes of polyunsaturated fatty acids, fibre, vitamin B 12 , vitamin D, and dairy as compared to controls. Compared with participants in the lowest quartile of DII, those in the highest quartile had a significantly higher OR for PCOS after further adjustment for potential confounders (OR = 1.75, 95% CI: 0.95–3.22). Conclusion Our data suggest that high DII was associated with an increased odds of PCOS diagnosis. Prospective dietary intervention studies and observational prospective cohorts are required to confirm these findings.