Physical fitness, dietary intake, and metabolic control in adolescents with type 1 diabetes

Purpose: We examined whether physical fitness and dietary intake predicted better glycemic control and lipid profile in adolescents with type 1 diabetes mellitus (T1DM). Methods: The sample consisted of 109 adolescents with T1DM [age, 15.3 ± 1.9 yr; diabetes duration, 6.2 ± 3.7 yr; body mass index (BMI), 23.3 ± 4.0 kg/m²; and hemoglobin A1c (HbA1c), 8.7 ± 1.6%]. Stepwise regression analyses were performed with the following independent variables: age, sex, duration of diabetes, BMI, Tanner stage, physical fitness, and average carbohydrate and total and saturated fat intake, and the following dependent variables: total cholesterol, low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), triglycerides, and HbA1c. Physical fitness was measured by peak oxygen consumption (VO_2peak) during progressive cycle ergometry, and 3-day food intake was analyzed using N utritionist Pro™ software. Results: Sex and VO_2peak explained 19% of the variance for HbA1c. Age, VO_2peak, and saturated fat intake predicted 23% of the variance for total cholesterol, although only diabetes duration and saturated fat intake predicted LDL-c (11%). Duration of diabetes explained 5% of the variance in triglyceride levels, and there were no significant independent predictors for HDL-c. Conclusions: Greater fitness levels predicted both better glycemic control and total cholesterol in adolescents with T1DM, whereas lower saturated fat affected total cholesterol but not glycemic control. These findings support the importance of physical fitness and diets of lower saturated fat for overall metabolic health in adolescents with T1DM.