IJCS | Volume 33, Nº4, July and August 2020

344 Table 4 - Bivariate linear regression analysis Variables IDF < 40 yrs 40-50 yrs > 50 yrs R 2 p-value R 2 p-value R 2 p-value SBP 0.227 0.002 0.096 0.016 0.009 0.553 SBP ≥ 130 mmHg 0.638 0.002 0.002 0.826 0.000 0.921 DBP 0.227 0.003 0.147 0.002 0.270 0.001 DBP ≥ 85 mmHg 0.057 0.393 0.145 0.061 0.361 0.003 HDL 0.076 0.093 0.098 0.015 0.054 0.150 HDL-cholesterol < 50 mg/dL 0.031 0.554 0.17 0.014 0.059 0.274 NCEP-ATPIII < 40 yrs 40-50 yrs > 50 yrs R 2 p-value R 2 p-value R 2 p-value SBP 0.184 0.023 0.080 0.044 0.084 0.107 SBP ≥ 130 mmHg 0.630 0.011 0.000 0.980 0.063 0.286 DBP 0.212 0.014 0.124 0.011 0.305 0.001 DBP ≥ 85mmHg 0.263 0.025 0.079 0.163 0.359 0.005 HDL 0.028 0.391 0.085 0.038 0.048 0.228 HDL-cholesterol < 50 mg/dL 0.077 0.471 0.180 0.031 0.023 0.525 When dependent variableswere categorized according to the cut-off value of each criterion, the percentage of variability of the risk factor in the altered category, explained by increasedWC, was always greater than the variability of the non-categorized variable (as observed in Table 4). Thus, increased WC ( ≥ 80 cm by the IDF or > 88 cm by the NCE-ATPIII) correlated only with three health risk factors – SBP, DBP, and HDL-cholesterol. IncreasedWC explained 63.8% and 63% of the variability of increased SBP (in women aged < 40 years), 36.1% and 35.9% of that of increased DBP (in women > 50 years), and 17% and 18% of that of altered HDL-c (in women aged 40-50 years), respectively for IDF andNCEP-ATPIII. Discussion The women participating in the present study were grouped according to categories of WC based on cut- off values determined by the IDF and NCEP-ATPIII criteria. The purpose of this distribution was to assess the association of WC categories with the following health risk factors: age and levels of SBP, DBP, HDL-cholesterol, fasting glucose, and triglycerides. The prevalence of increasedWC categorized according to the IDF criteria (≥ 80 cm) was superior to that of increasedWC categorized according to the NCEP-ATPIII criteria (> 88 cm): 84% versus 68%, respectively. This was already expected, considering the lower cut-off recommended by the IDF compared with the NCEP- ATPIII. Considering that the WC is a crucial criteria for the diagnosis of MS, the higher prevalence of increased WC found in this population of women is concerning. We also observed that median SBP, DBP, and WC values increased significantly with age. These results are aligned with data from the literature that show a continuous increase in SBP between the ages of 30 and 84 years and over. Although DBP values have a varying pattern with aging, they also increased until the fifth decade. 15 In contrast, increases in WC with increasing age are more difficult to evaluate, since this evaluation require longitudinal studies and repeated measures Silva et al Waist circumference and increased blood pressure Int J Cardiovasc Sci. 2020; 33(4):340-347 Original Article