Sex differences in body composition in youth with type 1 diabetes and its predictive value in cardiovascular disease risk assessment

Background: Women with type 1 diabetes (T1D) are more susceptible than men to cardiovascular disease (CVD). Signs of increased risk may already appear among adolescent girls. Objectives: We explored the contribution of body composition to the development of CVD risk factors among youth with T1D. Methods: One hundred and eighty nine subjects with T1D (mean age 15.3 ± 5.1 years, 55% boys) followed between January 2018–January 2022 were included in this observational study. Sociodemographic and clinical data were extracted from medical files. Body composition was measured by bioelectrical impedance analysis, and muscle-to-fat ratio (MFR) z-scores were calculated. Logistic regression model assessed the association between body composition (MFR z-scores) and evidence of CVD risk factors. Results: Females were characterised by higher median BMI z-scores (0.47 vs. 0.04, p = 0.012), higher fat and truncal fat percentage levels (p ≤ 0.001) and lower median MFR z-scores (−0.64 vs. −0.25, p ≤ 0.001), higher median triglyceride (TG) levels (71 vs. 61 mg/dl, p = 0.05), longer disease duration to initiation of insulin pump therapy (p = 0.041), and more time spent in marked hypoglycemia (1 vs. 0.2%, p = 0.007) than males. Males' MFR z-scores were associated with several diabetes-related parameters (age at diagnosis, CGM metrics, HbA1c and insulin dose), while the females'' MFR z-scores were linked to the atherogenic dyslipidemia index (TG:HDL ratio). The odds for CVD risk factors were doubled for every 1 SD decrease in MFR z-score (OR = 0.50, CI [0.30–0.84], p = 0.009) and also increased with age (OR = 1.07, CI [1.004–1.148], p = 0.038). Conclusions: Body composition measurement has a predictive value in CVD risk assessment in youth with T1D, with unique characteristics and influences in each sex.