Association Between Physical Activity, Sedentary Behavior and Physical Fitness and Glycated Hemoglobin in Youth with Type 1 Diabetes: A Systematic Review and Meta-analysis

Background Scientific literature suggests poor glycemic control in youth with type 1 diabetes (T1D) and physical inactivity, sedentary behavior and low physical fitness levels, although results are not entirely consistent. Objective To meta-analyze the association between glycated hemoglobin and physical activity, sedentary behavior, and physical fitness in children and adolescents with T1D. Methods Our meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines (PRISMA). Three databases were searched for studies. All studies meeting the following criteria were included: (1) Population: children and adolescents with a mean age between 3 and 18 years diagnosed with T1D; (2) Exposition: physical activity and/or sedentary behavior and/or cardiorespiratory fitness and/or muscular fitness; (3) Outcome: glycated hemoglobin; (4) Study design: cross-sectional, longitudinal, and case-control studies. Pooled effects were calculated using a random effects inverse-variance model with the Hartung-Knapp-Sidik-Jonkman adjustment. Results Thirty-seven studies were included, accounting for a total of 34,863 youths with T1D (51.9% girls). Twenty-nine studies evaluated physical activity, eight sedentary behavior, 14 cardiorespiratory fitness, and two muscular fitness. A negative association between physical activity (r = - 0.09, 95% CI - 0.14 to - 0.04; I-2 = 63.5%), cardiorespiratory fitness (r = - 0.31, 95% CI - 0.44 to - 0.19; I-2 = 57.0%) and glycated hemoglobin was found. Also, the association with sedentary behavior was positive (r = 0.20, 95% CI 0.04 to 0.35; I-2 = 92.6%). All the associations were independent of the glycated hemoglobin levels and diabetes duration. Conclusions Low levels of physical activity and cardiorespiratory fitness and extensive sedentary behavior may explain part of the variance in glycated hemoglobin and part of the risk for poor glycemic control in youth with T1D. Prospero Registration number: CRD42021254362.