ANTHROPOMETRIC INDICATORS AND HYPERTENSION IN ITALIAN YOUNG ADULTS FROM THE WORD KIDNEY DAYS 2010 - 2011

Gold standard for assessing fat distribution are computed tomography or magnetic resonance; high costs of these methods limit their feasibly in clinical practice. The “traditional” methods are still widely used. BMI is the most common but its reliability is debated being unable to give information on abdominal fat mass. Conicity index (Ci), that includes weight, height and waist circumference (WC) has been proposed as useful index of abdominal adiposity as well as WC alone and weight/height ratio (WHt-ratio). Aim of this study was to investigate whether BMI, Ci, WC, WHt-ratio alone or in combination may be related to presence of HTN in a large cohort of healthy young people. Methods: Study population is represented by students of Italian high school participating to “school project” promoted by Italian National Kidney Foundation on occasion of World Kidney Days. The project consisted in screening for HTN and urinary abnormalities among healthy students attending penultimate or ultimate year of high Italian school. Trained personnel (nephrologists and nurses) assessed systolic and diastolic BP (SBP; DBP). Weight, height and WC were measured. BMI, Ci and WHt-ratio were calculated. HTN was defined as SBP ≥ 140 mmHg and/or DBP ≥ 90 mmHg, pre-hypertension as SBP of 120 mmHg but lower than 140 mmHg or DBP of 80 mmHg but lower than 90 mmHg. Stage-1 HTN as SBP of 140 mmHg but lower than 160 mmHg or DBP of 90 mmHg but lower than 100 mmHg, and Stage-2 HTN as SBP ≥ 160 mmHg or DBP≥ 100 mmHg. According to BMI, normal weight was from 18.5 to 24.9 kg/m2, overweight from 25 to 29.9 kg/m2, class-I obesity from 30,0 to 34.9 kg/m2, class-II from 35 to 39.9 kg/m2, class-III ≥ 40 kg/m2. Normal WC was <88 cm in female and <102cm in male. Linear regression analysis was applied to assess whether BMI, Ci, WC, WHt-ratio were independent predictor of HTN. Results: Data pertaining to 4479 students (median age:18 years; IQR:18-19) were analyzed. Incident HTN was found in n. 71 (1.6%) participants (n.31 female; n.39 male). In hypertensive participants (HP) median SBP and DBP were 144 mmHg (IQR:140-150) and 90 mmHg (IQR:90-94), respectively. Stage-1 HTN and Stage-2 HTN was present in 94.3% and 5.7% of HP, respectively. Overweight, class-I,II,III obesity percentage was 21.1, 10.1, 7.1, 1,4 in HP, respectively. Compared to participants without HTN, HP had median: BMI=23.7(IQR:21.9-27.8) Vs 21.8 (IQR:20.0-24.1), p=0.001; Ci=1.22 (IQR:1.16-1.31)Vs 1.21(IQR:1.14-1.29), p=0.527; WC= 88.0 (IQR:80.0-98.5) Vs 81.0 (IQR:74-89), p=0.001; WHt-ratio:0.50 (IQR:0.46-0.59) Vs 0.47 (IQR:0.44-0.52), p=0.001). Multivariate linear regression analysis showed that WHt-ratio was predictor of HTN (p=0.02) while WC was predictor of SBP (p=0.001). Conclusions: These results suggest that in healthy young people WHt-ratio is significantly associated to the presence of hypertension while WC is associated to levels of SBP. BMI and Ci appear weak predictor of HTN.