Abstract
BACKGROUND AND OBJECTIVES: Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women, often associated with metabolic abnormalities and ovulatory dysfunction. This study aimed to assess the effect of body mass index (BMI) and its interactions on nutritional intervention outcomes in PCOS patients. METHODS AND STUDY DESIGN: A total of 360 PCOS patients were retrospectively analyzed. Ovulation rates and metabolic indices before and after treatment were compared across BMI groups. A multivariate regression analysis was used to assess the influence of BMI, age, symptom duration, family history, and ovarian enlargement on intervention outcomes. Interaction effects between BMI and other variables were also examined. RESULTS: After treatment, ovulation rates, homeostasis model assessment of insulin resistance (HOMA-IR), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and fasting plasma glucose (FPG) improved significantly in all groups, with the obese group showing the greatest BMI reduction (-5.8%) and most favorable response. A multivariate analysis indicated that poorer outcomes were associated with older age (odds ratio (OR) = 0.993), longer symptom duration (OR = 0.982), a family history of PCOS (OR = 0.745), ovarian enlargement (OR = 0.887), and a higher number of ovarian cysts (OR = 0.882). Conversely, higher BMI (OR = 1.089) and HDL (OR = 1.010) were associated with better outcomes. Interaction analysis revealed that age attenuated the positive effect of BMI (OR = 0.992), and ovarian enlargement further diminished BMI's beneficial impact (OR = 0.759). CONCLUSION: Obese patients derived the greatest benefit from nutritional intervention. Higher BMI was associated with better outcomes, particularly among younger patients and those with less ovarian enlargement. These findings support the use of personalized nutrition strategies to enhance treatment efficacy in PCOS management.