Cardiorespiratory Fitness and Physical Activity among Children and Adolescents with Diabetes: A Systemic Review and Meta-analysis

Background It is unclear if cardiorespiratory fitness (CRF) and physical activity (PA) are lower among youth with type 1 (T1D) and type 2 diabetes (T2D) compared to youth without diabetes. The objective of this study was to describe the magnitude, precision and constancy of the differences in CRF and PA between youth with and without diabetes. Methods We searched MEDLINE, Embase, CINAHL, and SPORTDiscus from 2000 to May 2022 for cross sectional studies that included measures of CRF and PA in children and adolescents with and without T1D or T2D. The main outcomes were objectively measured CRF obtained from a graded maximal exercise test and subjective or objective measures of PA. Three reviewers independently screened studies for eligibility, extracted data, and assessed studies for bias. Random effects meta-analysis model was used to estimate differences in main outcomes. The pooled effect estimate was measured as standardized mean differences (SMD) with its 95% confidence intervals (95%CI). This study was registered with PROSPERO (CRD42022329303) and followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline. Results Of 7857 unique citations retrieved, we included 9 studies (n = 755 participants) with measures of CRF and 9 studies (n = 1233 participants) with measures of PA for youth with T2D, as well as 23 studies (n = 2082 participants) and 36 studies (n = 12,196 participants) for youth with T1D. Random effects models revealed that directly measured CRF was lower in youth with T2D [SMD = - 1.06; 95% CI: -1.57 to -0.56, I 2 =84%, n=9 studies; n=781 youth] and in youth with T1D compared to controls [SMD = -0.39; 95% CI: -0.70 to -0.09, I 2 =89%, n=22 studies; n=2082 youth]. Random effects models revealed that daily PA was marginally lower in youth with T1D [SMD= -0.29, 95% CI −0.46 to -0.11, I 2 =89%, n=32 studies; n = 12196 youth] but not different among youth with T2D compared to controls [SMD= -0.56, 95% CI −1.28 to +0.16, I 2 =91%, n=9 studies; n=1233 youth]. When analyses were restricted to studies with objective measures, PA was significantly lower in youth with T2D [SMD -0.71, 95% CI −1.36 to -0.05; I 2 =23%, n=3 studies; n=332 youth] and T1D [SMD -0.67, 95% CI –1.17 to -0.17; I 2 =93%; n=12 studies; n=1357 youth] compared to controls. Conclusions Children and adolescents living with T1D and T2D display lower CRF and objectively measured PA compared to controls without diabetes. Deficits in CRF, but not PA are larger and more consistent in youth with T2D, compared to youth with T1D. These data may contribute to the increased risk for cardiovascular disease-related morbidity observed in adolescents with diabetes, particularly those with T2D. Funding This study was funded by the Canadian Institutes of Health Research