Summary

We studied the relationship between blood pressure (BP), body mass index (BMI, kg/m 2) and baroreflex sensitivity (BRS, ms/mmHg) in adolescents. We examined 34 subjects aged 16.2±2.4 years who had repeatedly high causal BP (H) and 52 controls (C) aged 16.4±2.2 years. Forty-four C and 22 H were of normal weight (BMI between 19-23.9), and 8 C and 12 H were overweight (BMI between 24-30). Systolic BP was recorded beat-to-beat for 5 min (Finapres, controlled breathing 0.33 Hz). BRS was determined by the cross-spectral method. The predicting power of BMI and BRS for hypertension was evaluated by sensitivity, specificity, and receiver operating curve (ROC- plot of sensitivity versus specificity). H compared with C had lower BRS (p<0.01) and higher BMI (p<0.05). Multiple logistic regression analysis (p<0.001) revealed that a decreased BRS (p<0.05) and an increased BMI (p<0.01) were independently associated with an increased risk of hypertension. No correlation between BMI and BRS was found either in H or in C. Following optimal critical values by ROC, the sensitivity, specificity and area under ROC were determined for: BMI- 22.2 kg/m 2, 61.8%, 69.2%, 66.0%; BRS- 7.1 ms/mmHg, 67.7%, 69.2%, 70.0%; BMI and BRS- 0.439 n.u., 73.5%, 82.7%, and 77.3%. Decreased BRS and overweight were found to be independent risk factors for hypertension. Key words: Baroreflex sensitivity, blood pressure, overweight, hypertension, adolescent