Association between dietary inflammatory index and odds of diminished ovarian reserve: a case–control study

This study aimed to evaluate the association between the Dietary Inflammatory Index (DII) and the odds of diminished ovarian reserve (DOR), as assessed by serum anti-Müllerian hormone (AMH) levels and antral follicle count (AFC), given the role of diet-induced inflammation in modulating reproductive function. This study included 370 Iranian women, comprising 120 individuals diagnosed with DOR and 250 age- and body mass index (BMI)-matched control subjects. DII was calculated using food frequency questionnaire-derived dietary data. Logistic regression models were employed to estimate multivariable odds ratios (ORs) for DOR across tertiles of the DII. Women in the highest DII tertile (i.e., those consuming more pro-inflammatory diets) were 31% more likely to have DOR (OR: 1.31; 95% CI: 1.06–2.23) compared to those in the lowest tertile. This association remained statistically significant after adjusting for physical activity and energy intake (OR: 1.29; 95% CI: 1.10–2.30), and persisted following additional adjustment for fat mass, BMI, occupation and education (OR: 1.19; 95% CI: 1.04–2.15). Besides, women with DOR in the lowest tertile of DII had significantly higher antral follicle count (2.69 ± 1.26 vs. 2.27 ± 1.17, P = 0.03) compared to those in the lowest tertile. This study highlights a significant association between elevated DII scores and an increased likelihood of DOR. However, these findings require confirmation through prospective cohort and interventional studies with longitudinal assessment of dietary intake and ovarian reserve to validate their reliability.