Pontos de corte de variáveis antropométricas e aptidão física aeróbica para predição do agrupamento de fatores de risco de doenças cardiovasculares em crianças

Abstract

Cut-off points of body mass index (BMI), waist circumference (WC),waist-to-height ratio (WHtR) and aerobic physical fitness (APF) have been studied to predict the risk of cardiovascular diseases in all age groups. Objective: to identify the capacity of the body mass index, waist circumference, waist-to-height ratio (WHtR) and aerobic physical fitness (APF) for the prediction of cardiovascular risk factors clusteringin children. Methods: cross-sectional study with 290 students, ages 6 to 10, both male and female, from the town of Itaúna, who were randomly selected. The study was approved by the Universidade Federal de Minas Gerais and Universidade de Itaúna Ethics Committee. Written informed consent was obtained. Three blood pressure measurements were considered. Blood was collected after a 12-hour fasting period. Height and WC were evaluated according to international standards. To evaluate the AFP was used the 20m shuttle run test. A clustering was considered when three or more risk factors were noted, according to the following cut-off points: below 45 mg/dl for HDL cholesterol, above 100 mg/dl for LDL cholesterol, triglycerides and blood glucose above the percentage of 80 for insulin and arterial hypertension (systolic and diastolic). A ROC curve was designed, with confidence intervals of 95%, to identify the cut-off points of BMI, WC, WHtR and APF. It was used the correlation of Spearman and the logistic regression analysis to identify the association and odd ratios, respectively. The statistical package SPSS 17.0 was employed. Results: BMI, WC and WHtR resulted in significant areas under the ROC curve. APF didnt result in a significant area under theROC curve. The 52,9th and 53,7th percentile for BMI, 65,0 and 67,6 for WC and 63,5 and 75,7 for WHtR were identified, respectively, as the best cut-off points. These percentiles correspond to BMI from 15,19 to 17,79 km/m2, WC from 54,17 to 66,57 cm and values of WHtR from 0,43 to 0,51. The BMI, the WHtR and the APF correlated significantly with diastolic blood pressure, triglycerides and insulin in both sexes and with systolic blood pressure in the boys. The number of TV hours correlatedsignificantly only with insulin in the boys. Conclusion: body mass index, waist circumference and waist-to-height ratio were good predictors of risk factors clustering of cardiovascular diseases for both sexes. The waist-to-height ratio can be a better predictor for it doesnt need different cut-off points for each age in children. Despite its not a good predictor for risk factors clustering of CVD, the aerobic physical fitness demonstrated significant odd ratio and correlations with most of the variables separately, what justifies its use in the monitoring of health in this age group.