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Reproductive Endocrinology

SUN-169 - Glycemic Patterns from Continuous Glucose Monitoring Devices in Relation to PCOS and Early-Life Cycle Irregularity in A Digital Cohort in the United States

Sunday, June 14, 2026
9:00 AM - 4:00 PM CT
Location: ENDOExpo; Poster Floor


Background: Polycystic ovary syndrome (PCOS) and early-life (EL) menstrual irregularities are associated with prediabetes (preDM) or type 2 diabetes (T2D) risk, but real-world glycemic patterns in affected individuals are not well characterized. Leveraging continuous glucose monitoring (CGM) data from a large cohort, we examined daily glycemic outcomes in relation to PCOS/EL-irregular cycles and assessed whether diet or medications modified these associations.

Methods: We analyzed 222,258 days of glucose data from 650 participants in the Apple Women’s Health Study, who provided consent, enrolled from 11/2019 to 07/2025, responded to relevant surveys, and shared glucose data from CGM devices (99% Dexcom G6; 1% FreeStyle Libre) in the Apple Health app. We evaluated average daily values of both glucose levels and time-in-range (TIR) (range: 70-180 mg/dL). Exposures were classified as: 1) PCOS (self-reported physician diagnosis, n=151); 2) “EL irregular” (no PCOS, reported irregular cycles for 5+ years post-menarche); and 3) “EL regular” (no PCOS, reached regularity ≤4 years post-menarche). We fit cluster-weighted generalized estimating equations (GEE), adjusting for sociodemographic factors, pre-existing preDM (16%), T2D (35%), or type 1 diabetes (28%), BMI, and physical activity at enrollment. Secondary analyses examined effect modification by daily dietary pattern from logged dietary macronutrient data (54 participants; 2,496 days of dietary record) or diabetes medications among those who shared health records (163 participants; 60,873 days).

Results: Compared to the EL regular group, having PCOS or EL irregular cycles was associated with elevated mean glucose [PCOS: β (95% CI) = 7.2 (5.9, 8.4) mg/dL; EL irregular: β (95% CI) = 5.9 (4.8, 7.0) mg/dL] and lower TIR percentages [PCOS: β (95% CI) = -3.5 (-4.1, -2.8) % ; EL Irregular: β (95% CI) = -3.1 (-3.7, -2.5) %]. Among those with PCOS, elevated glucose and lower TIR were mainly observed in those with a hyperandrogenism phenotype (self-reported hirsutism or moderate/severe acne). Low-carbohydrate diets and fiber-rich diets lessened these glycemic differences. For example, differences in glucose levels associated with PCOS/EL irregular was β (95% CI) = 30.0 (21.0, 39.0) mg/dL on person-days with diet rich in refined carbohydrate (i.e., carbs-to-fiber ratio >10:1), compared to β (95% CI) = 4.9 (-1.5, 11.2) mg/dL on person-days with diet rich in fiber (i.e., carbs-to-fiber ratio ≤10:1). Use of glucagon-like peptide-1 (GLP-1) receptor agonists and metformin during glucose monitoring was associated with lower glucose and higher TIR.

Conclusions: PCOS and EL irregularity are associated with elevated glucose and lower TIR. Dietary interventions, especially increasing fiber intake, and specific medications (GLP-1, metformin) may help offset these risks, underscoring opportunities for personalized metabolic management.

*Unless otherwise noted, all abstracts presented at ENDO must not be released to the press or the public until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.*