Medidas de localização da gordura corporal e fatores de risco para doenças cardiovasculares em adolescentes do sexo feminino, Viçosa-MG

• Autor(a) principal: Pereira, Patrícia Feliciano
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2694
• topic: Doenças cardiovasculares; Gordura corporal; Obesidade; Adolescentes; Cardiovascular diseases; Body fat; Obesity; Teenagers; CNPQ::CIENCIAS DA SAUDE::NUTRICAO

The prevalence increase in teenager s obesity is accompanied by the accumulation of fat in the abdominal region, which is associated to the presence of cardiovascular risk presented in this stage of life. Thus the simple established measures to the untimely identification of individuals at risk is of great interest to the public health. Our purpose was to verify the association between measures of corporal fat localization with factors of cardiovascular risks, in female teenagers. One hundred and thirteen (113) teenagers with ages varying from 14-19 years old, from public schools, in Viçosa-MG, were submitted to tests. This controlled transversal study consists of 3 groups: G1 (Study) 38 eutrophic teenagers by the index of corporal mass (ICM), but with an elevated fat body percentage (%FB) (≥ 28%); G2 (Control) 40 eutrophic teenagers by the appropriate IMC e %FB (between 20 e 25%) e G3 (Control) 35 teenagers with risk of overweight and with elevated %FB. The sample was chosen trough selection in schools by weight standardization, %FB and height, being the two first ones obtained by bipolar electrical bioimpedance. The teenagers that fitted into one of the 3 groups by their ICM and %FB and filled the criteria for inclusion (no menarche for at least one year, no participation in any kind of weight control program, no inhalation of nicotine, no use of supplements or medicaments that could interfere in the glucide and lipid metabolism, no chronic disease, no use of pacemaker or prosthesis and no occurrence of pregnancy) were called to participate in this study. The %GC was posteriorly confirmed by tetrapolar electrical bioimpedance and only those which obtained the same classification in both methods were submitted to the anthropometric evaluation, standardization of arterial pressure and blood collect. In addition, they answered one questionnaire about aspects of diet, lifestyle and family history of diseases. It was checked the waist circumference (WC), umbilical (TC), hips (HC) and thigh by using an inelastic tape measure; Sagittal abdominal circumference (SAD) e Coronal Diameter (CD) using a metal pachymeter; tricipital, bicipital, subscapular and suprailiac skinfold with a Lange Skinfold Caliper. From these measures we could calculate the waist- hip ratio (WHR), Waist-Height ratio (WTR), waist-thigh ratio (WTH), conicity index (CI), central skinfolds ratio (CSR= subscapular + suprailiac), peripheral skinfolds ratio (PSR= tricipital + bicipital), central/peripheral skinfold ratio (CSR/PSR). The total cholesterol and its fractions, triglicerids, glucose, insuline, homeostasis model assessment (HOMA), homocyateine e leptine were analyzed. The presence of abdominal obesity was considered when WC e/ou WTR ≥ percentile 90of the sample. The "hypertrigliceridemic waist was diagnosed by the concomitant presence of elevated waist (≥ percentile 90) and triglycerides level above desirable (≥ 100 mg/dl), whereas metabolic syndrome was assessed through three different definitions. It was verified the diagnostic validity of four reference tables for the waist circumference of teenagers in order to detect lipid alterations, hyperinsulinemia, elevated HOMA, hyperleptinemia and corporal adiposity. This researched was approved by Comitê de Ética em Pesquisa com Seres Humanos da Universidade Federal de Viçosa . The values of glycemia, insulin and leptin and PAD in G1 were significantly higher G1 when compared to G2; glycemia and PAD did not differ in G1 and G3 but homocysteine was superior in G1. The total corporal fat and its localization are correlated to the factors of cardiovascular risks, inasmuch as they were stronger due to the increase of total adiposity. The results showed that the increase of central fat, represented by WC, TC, WTR, SAD, CD e CSR, as well as the increase of peripheral fat indicated by HC and thigh circumference, were proportional to the increase of BMI and %FB. On the other hand, a WHR, WTH, CI e CSR/PSR were not considered to be good adiposity measures. Height presented correlation to WC, TC, HC, thigh, WTR, SAD and CD, being HC and WTR the most influenced. Furthermore, it was observed that the teenagers who presented abdominal obesity had higher triglyceride values (except for HC), insulin, HOMA, leptin, systolic and diastolic arterial pressure, while HDL tended to be significantly lower (p=0,052) in group with waist ≥ percentile 90. The hypertrigliceridemic waist was presented in 2,6% of the teenagers, whereas the frequency of metabolic syndrome varied from 2,6 to 16% depending on the criterion used. Therefore, these results show the relevance of the localization of corporal fat in adolescence, seeing that WC and WTR were the best predictors of disease risk in the population studied, especially WC. Regarding the cut points for WC proposed in literature, it could be observed that the values of sensibility, in general, were lower for the four references assessed. The positive predictive values were more relevant to the total cholesterol and to corporal fat percentage. Considering that there is no cut point for this measure based on the Brazilian population, it is suggested the reference with greatest sensibility for populational assessement and the one with greatest specificity for clinic, so that it could help professionals to identify the untimely disease risks.