The uterus is an end organ: a preliminary study of the association between abnormal uterine bleeding and hyperinsulinemia.

Objective: This preliminary study aimed to conduct initial, exploratory analyses of the association between hyperinsulinemia and biomarkers of metabolic syndrome in reproductive-aged women with abnormal uterine bleeding (AUB), with the goal of motivating future hypothesis-driven research.

Methods: A cross-sectional study was conducted from June 2019 to August 2023 at a single institution's outpatient gynecology clinics. A total of 205 premenopausal women aged 18-54 were enrolled, including 116 with AUB and 89 with normal menstrual cycles. Participants underwent fasting insulin assessment with additional markers of metabolic syndrome, including body mass index (BMI), high-density lipoprotein, and waist-to-hip ratio. Logistic regression was used to examine the association between hyperinsulinemia and AUB, adjusting for confounders such as age, race, and low-density lipoprotein. Model selection prioritized low Akaike Information Criterion and model parsimony.

Results: Hyperinsulinemia was a significant predictor of AUB (OR=3.009, 95% CI: 1.372-6.832; P =0.0085). Including BMI in the model diminished the significance of hyperinsulinemia, suggesting overlapping or mediating pathways. The final model which included age, race, low-density lipoprotein, and waist-to-hip ratio achieved 73% concordance and improved model fit.

Conclusion: This study highlights an association between hyperinsulinemia and AUB, with BMI playing a unique role in this relationship. These exploratory findings underscore the need for larger, longitudinal studies to clarify causal mechanisms and evaluate the potential of addressing hyperinsulinemia and BMI as part of AUB prevention and treatment strategies. Limitations, including small sample size and cross-sectional design, should be considered when interpreting these results.