Global prevalence and clinical correlates of obesity in children and adolescents with type 1 diabetes: a systematic review and meta-analysis

Abstract Background The intersection of Type 1 Diabetes (T1D) and obesity in children represents a growing clinical concern. Objective This systematic review and meta-analysis synthesizes evidence of obesity prevalence among children with T1D through assessment of global hospital based studies. Methods Following PRISMA guidelines and a pre-registered PROSPERO protocol (CRD420251109718), a comprehensive literature search was conducted across PubMed, Google Scholar, and ScienceDirect to identify eligible studies. The synthesis was primarily based on hospital-based cohorts; registry-derived studies were treated as distinct cohorts, with only one dataset retained per registry to minimize population overlap. Studies reporting data on both prevalence and clinical impact of overweight or obesity in individuals aged 0–18 years with T1D were included. Results This review synthesized data from 13 studies published between 2014 and 2025, including 62,132 children and adolescents with T1D drawn predominantly from hospital-based cohorts across multiple countries (including the United States, Australia, European nations, Saudi Arabia, and Turkey), with additional data from multinational registries treated as separate cohorts, with most studies employing cross-sectional designs. Mean age of participants ranged from early childhood (4.6 years) to late adolescence (15.4 years), with a mean disease duration of 5.2 years. Among studies reporting sex distribution, the proportion of male participants ranged from 44.6% to 54.9%, with most studies demonstrating a near-equal sex distribution. Glycemic control was suboptimal across cohorts, with mean HbA1c values around 8.2% and reaching as high as 11.2% in some groups. Insulin requirements varied between 0.65 and 0.92 units/kg, with higher doses generally observed in older children and those with longer disease duration. Insulin delivery was heterogeneous, with Continuous Subcutaneous Insulin Infusion (CSII) used in approximately half of patients (average 50%), while CGM usage was reported between 57 and 85%. Epidemiologically, the pooled prevalence of overweight and obesity was estimated as 25.8% (95% CI 20.15–31.40%) and 9.85% (95% CI 8.97–12.20%), respectively, both with substantial heterogeneity ( I 2 > 95%). Small number of studies showed a higher prevalence among girls compared to boys for both obesity (11.68% vs. 7.89%) and overweight (22.94% vs. 21.99%), with disparities more pronounced during adolescence. Conclusion This review reveals a significant burden of excess weight in children with T1D, with one in four overweight and over one in ten obese. These findings underscore the urgent need for targeted, age- and development appropriate interventions, particularly during puberty period, to prevent onset of metabolic syndrome and long-term cardiovascular disease. Integrating weight surveillance and tailored lifestyle support into routine diabetes care is essential to mitigate future cardiometabolic risk.