MON-222 The Impact of Insulin Daily Dose on BMI Z-Score Changes and Rising Obesity Risks in Youth With Type 1 Diabetes

Abstract Disclosure: J.D. Hillenbrand: None. H. Mohammed: None. M. Modupe: None. C. Odhiambo: None. V.C. Benavides: None. Background: The rising prevalence of overweight and obesity among youth with type 1 diabetes (T1D) presents a significant clinical challenge, with registry estimates ranging from 15.3% to 36.0%. Excess adiposity significantly increases cardiovascular disease risk in this population, yet longitudinal data on weight trajectories and their determinants in pediatric T1D remain limited.Methods: We conducted a single-center, retrospective analysis of 194 youth (58.8% male) with T1D. Inclusion criteria comprised antibody-positive T1D and a minimum of three follow-up visits. Patients were excluded with other diabetes types, comorbidities affecting weight (celiac disease, hypothyroidism), or were taking weight-inducing medications. We analyzed BMI Z-scores from two years pre-diagnosis through ten years post-diagnosis, along with demographic factors, glycemic control, and treatment type. Statistical analysis included ANOVA with Bonferroni post-hoc comparisons and linear modeling to evaluate associations between BMI Z-scores and clinical parameters.Results: The cohort was predominantly White (84.5%) and privately insured (59%). Mean BMI Z-scores demonstrated significant variation across time points (F=7.432, p<0.01), revealing a distinct pattern of weight change. Pre-diagnosis BMI Z-scores (0.71±1.29) dropped significantly at diagnosis (-0.04±1.72), followed by a rebound at 6 months (0.76±1.88, p<0.001). This upward trajectory continued, with BMI Z-scores reaching 0.85±1.07 at 2 years, 0.84±1.16 at 3 years, and peaking at 0.95±1.46 at 4 years post-diagnosis, surpassing pre-diagnosis levels. Post-hoc analysis confirmed significant differences between diagnosis and all post-diagnosis time points (p<0.001), with no significant differences between post-diagnosis periods, suggesting sustained elevation. Treatment modalities evolved during this period, with multiple daily injections declining substantially, while automated insulin delivery (AID) systems became predominant by Year 3. Linear modeling revealed total daily insulin dose as a significant predictor of increasing BMI Z-score (β=1.071, p=0.022), independent of glycemic control (HbA1c: β=-0.0016, p=0.972).Conclusions: Youth with T1D show a concerning pattern of post-diagnosis weight gain, with BMI Z-scores rebounding and exceeding pre-diagnosis levels and remaining elevated through follow-up. The link between insulin daily dose and BMI Z-score, regardless of delivery method or glycemic control, underscores insulin's role in obesity risk. These findings highlight the critical need for early, targeted weight management strategies in pediatric T1D care. Future research should focus on developing treatment approaches that optimize both glycemic control and weight outcomes, particularly as diabetes technology continues to evolve. Presentation: Monday, July 14, 2025