Impaired short-term blood pressure regulation and autonomic dysbalance in children with type 1 diabetes mellitus.

AIMS: Because reduction in baroreceptor sensitivity (BRS) has been associated with hypertension in the normal population and with increased cardiovascular morbidity and mortality in patients with diabetes mellitus, we measured BRS in a patient cohort of children with type 1 diabetes mellitus. METHODS: Two hundred and eight children (150 patients with type 1 diabetes mellitus, mean age 13.9 +/- 2.8 years, 70 boys, mean HbA(1c) 7.8 +/- 1.4%; and 58 healthy controls, mean age 14.1 +/- 3.1 years, 32 boys) were studied. BRS and heart rate variability (HRV) were analysed from a short-time ECG and BP recording using the sequence method (BRS) and the frequency domain method (HRV). RESULTS: There were 111 of 150 patients (74%) and 5 of 58 controls (8.6%) that showed impaired BRS. Mean BRS differed significantly between patients and controls (18.4 +/- 7.2 vs 25.8 +/- 8.2 ms/mm, p < 0.001). BRS correlated inversely with systolic BP (r = -0.23, p = 0.009) and was related to diabetes duration (r = -0.194, p = 0.027). Analysis of HRV showed greater sympathetic and less parasympathetic influence in patients than in controls (low frequency/high frequency ratio 1.3 +/- 0.8 vs 0.9 +/- 0.6, p < 0.05); the low frequency/high frequency ratio was inversely correlated with BRS (r = -0.28, p = 0.001). CONCLUSIONS/INTERPRETATION: Diabetic children show reduced BRS. In our patient group, the single risk factor for this finding was found to be the disease duration. The degree of BRS impairment was related to the degree of autonomic dysbalance.

Young adults born small for gestational age: is reduced baroreceptor sensitivity a risk factor for hypertension?

UNLABELLED: BACKGROUND. Adults born small for gestational age (SGA) are at increased risk for the metabolic syndrome and cardiovascular disease. HYPOTHESIS: Impaired short-term blood pressure regulation may contribute to the development of hypertension in patients born SGA. METHODS: In all, 43 patients born SGA (18 female, age 19.4 +/- 0.3 years) were evaluated by beat-to-beat blood pressure and heart rate registration during rest and mental and orthostatic stress. The study group was divided into Group 1 with normal resting blood pressure (n=32) and Group 2 with slightly elevated blood pressure (n=11). Baroreceptor sensitivity (BRS) was calculated. Fasting insulin as well as lipid levels were correlated with hemodynamic parameters. RESULTS: Eleven of the 43 study patients (25%) had a slightly elevated resting systolic blood pressure (SBP) rising during mental and orthostatic stress. Body mass index (BMI) and fasting insulin levels correlated strongly with SBP in Group 2. Baroreceptor sensitivity was lower in Group 2 at rest (p < 0.05). CONCLUSIONS: Three components of metabolic syndrome (elevated BP, high BMI, elevated insulin levels) correlate strongly in young adolescents born SGA; BRS is reduced in prehypertensive patients. Close follow-up is warranted during adult life as they are predisposed for developing a metabolic syndrome with elevated cardiovascular risk.