Heart rate variability in adolescents with type 1 diabetes. A cross-sectional study.
AIMS We aimed to compare heart rate variability (HRV) between adolescents with type 1 diabetes and healthy age- and sex-matched control participants. We were also interested in how HRV may change during puberty. RESEARCH DESIGN AND METHODS Eighty-five adolescents with type 1 diabetes (mean diabetes duration 7.0 ± 3.6 years) and 103 healthy age- and sex-matched youths consented to this cross-sectional study. We derived HRV data for time domain and power spectra analyses from Holter recordings (mean duration 17.8 h) and analyzed associated risk factors for HRV deterioration during total recording time and nighttime separately. RESULTS Total low frequency (LF) and very low frequency (VLF) domains (ms2) were significantly lower in children with type 1 diabetes than in healthy controls (LF, P = 0.049 and VLF, P = 0.005, respectively), whereas no differences were found in the measurements taken at night. The most significant predictors for untoward changes in power spectra were skinfold sum and lipids. Mean heart rate (beats/min), or any of the time domain variables did not differ significantly between study groups. Compared with those in the lowest HbA1c tertile, adolescents with type 1 diabetes in the highest HbA1c tertile had significantly lower LF and VLF power spectra results. CONCLUSIONS Adolescents with type 1 diabetes have depressed HRV from low to very low frequencies. Deterioration of autonomic nervous system function in adolescents with type 1 diabetes, measured with HRV power spectra is mainly associated with metabolic factors, although it is not possible to establish causal links between these variables.