Relationship of Cardiac Structure and Function to Cardiorespiratory Fitness and Lean Body Mass in Adolescents and Young Adults with Type 2 Diabetes

Abstract

Objective: To investigate the relationships of cardiac structure and function with body composition and cardiorespiratory fitness (CRF) among adolescents with type 2 diabetes in the Treatment Options for Type 2 Diabetes in Adolescents and Youth study.

Study design: Cross-sectional evaluation of 233 participants (median age 18.3 [min-max 12.4-24.2] years, 63% females, median hemoglobin A1c 6.8%) who had echocardiography measurements of left ventricular (LV) mass, ejection fraction, left atrial dimensions, LV diastolic function (early transmitral flow velocity to early mitral annular velocity ratio from tissue Doppler imaging), and right ventricular function (tricuspid annular plane systolic excursion [TAPSE]) and body composition (dual-energy x-ray absorptiometry) and CRF (cycle ergometry determination of physical work capacity at heart rate of 170 beats per minute).

Results: LV mass correlated positively with CRF (r = 0.5, P < .0001), lean body mass (LBM) (r = 0.7, P < .0001), and fat mass (FM) (r = 0.2, P = .00047); LV ejection fraction did not. Early transmitral flow velocity to early mitral annular velocity was positively related to FM (r = 0.14, P = .03) and % body fat (r = 0.18, P = .007), and left atrial internal diameter correlated with FM (r = 0.4, P < .0001), LBM (r = 0.3, P < .001), and CRF (r = 0.2, P = .0033). TAPSE weakly correlated with CRF (r = 0.2, P = .0014) and LBM (r = 0.13, P < .05) but not with FM. In multivariable regression analyses, LBM (β = 2.13, P < .0001) and CRF (β = 0.023, P = .008) were related to LV mass independent of race, sex, age, hemoglobin A1c, hypertension, smoking, and diabetes medications. CRF (β = 0.0002, P = .0187) and hemoglobin A1c (β = -0.022, P = .0142) were associated with TAPSE.

Conclusions: In youth with type 2 diabetes, LV size is related to physical fitness. LV ejection fraction is within normal limits. LV diastolic function is inversely related to FM. Greater fitness may counteract adverse effects of poor glycemic control on right ventricular function.

Trial registration: ClinicalTrials.gov:NCT00081328.

Keywords: body composition; echocardiography; fitness; left ventricular function; right ventricular function; type 2 diabetes.