Relationship between water compartments, body composition assessed by bioelectrical impedance analysis and blood pressure in school children.

BACKGROUND

Electrical bioimpedance analysis (BIA) is becoming more widely used in clinical practice as a method of body composition analysis. In healthy children blood pressure (BP) changes with age, body mass and height. Until now the relation between water compartments and BP in healthy children has not been evaluated. The aim of this study was to evaluate the relationship between body composition as well as water compartments (measured by electrical bioimpedance) and BP.

METHODS

The study was performed in 72 children (32 girls and 40 boys) aged: 6-7 and 12-13 years. BIA measurements were taken using Nutriguard Data Input device with Bianostic electrodes and following parameters were calculated: total body water (TBW), lean body mass (LBM), fat mass (FM), intra- and extracellular water (ICW, ECW) and phase angle alpha. BP was measured twice using the oscillometric method.

RESULTS

Elevated BP > 95th percentile for gender, age and height were observed in 9 children. A significant correlation between systolic (S)BP and TBW (R = 0.4023, p < 0.001), LBM (R = 0.3600, p = 0.002), FM (R = 0.4725, p < 0.001), ECW (R = 0.4598, p < 0.001) and body mass index (BMI) (R = 0.4089, p < 0.001) was found. Furthermore, diastolic (D)BP significantly correlated with TBW (R = 0.3056, p = 0.011), LBM (R = 0.2783, p = 0.021), FM (R = 0.3956, p < 0.001), ECW (R = 0.3869, p = 0.001) and BMI (R = 0.3550, p = 0.002). In the studied group malnutrition (weight < 3rd percentile) was found in 8 children and 2 had obesity (BMI > 95th percentile). Growth disorders were found in 6 children (5 of them being undernourished).

CONCLUSIONS

In the studied children SBP and DBP correlated with water compartments, lean body and fat masses derived from BIA. The problem of unrecognized hypertension and malnutrition in children and adolescents is still underestimated in the Polish population.