The relationship between body composition and blood pressure in children

Introduction: Hypertension (HTN) is relatively a common problem and is associated with target organ damage. Overweight, obesity, male sex, high sodium intake are risk factors for primary HTN. Body mass index (BMI) is currently the most practical and popular method of diagnosing obesity. But it was shown that abdominal obesity and waist circumference is associated with HTN independent of BMI, and BMI does not consider body fat distribution. Body fat ratio (BFR) is more significant in terms of the development of obesity related diseases than only the high BMI. Also, there is a correlation between the fluid and ionic homeostasis and blood pressure. Bioelectrical impedance analysis (BIA) is the most commonly used method for determining BFR and distrubition of body fluid. The objective of our study is to investigate the relationship between blood pressure and body composition in children. Patients and Methods: Children having ambulatory blood pressure monitor were grouped as hypertensive (+) (Group 1) and normotensive (Group 2). Bioelectric impedance analysis (Bodystat Qudscan 4000, Bodystat Limited, British Isles) were performed to all patients and BMI, body fat ratio (BFR), body fat mass index, lean mass index, total body water (TBW), intracellular fluid (ICF), extracellular fluid (ECF), basal metabolic rate, estimated daily caloric need and impedance values were recorded. The groups were compared in terms of anthropometric and demographic caracteristics, laboratory parameters and body composition. In addition, the correlation of these variables with mean blood pressure (BP) (systole, diastole and total) and BP loads (day and night) was evaluated. Results: There were 46 children in Group 1 and 31 children in Group 2. Age and gender were similar in both groups. Body weight, BMI, BMI SDS, waist circumference, hip circumference, waist/hip ratio were higher in Group 1 compared to Group 2 (respectively p=0,012, p=0,000, p=0,000, p=0,000, p=0,005, p=0,007). Blood urea nitrogen and uric acid were higher in Group 1 compared to Group 2 (respectively p=0,028, p=0,003). BFR, body fat mass, body fat mass index, lean mass index, TBW, basal metabolism rate and estimated daily caloric need were higher in Group 1 compared to Group 2 (respectively p=0,030, p=0,000, p=0,040, p=0,011, p=0,013, p=0,020, p=0,045). ECF was smaller in Group 1 than Group 2 (p=0,000). İn addition, a positive correlation was determined between systolic day and night mean BP values and bodf fat mass, lean body mass, lean mass index, dry weight, TBW, ECF, ICF, basal metabolic rate (p<0,05). Conclusion: As body weight, BMI, waist circumference, hip circumference, body fat ratio (BFR), body fat mass index, fat free mass index, TBW, ECF, ICF increase; mean systolic BP also increase. Keywords: Systolic and diastolic blood pressure, body composition