Avaliação de diferentes referências de índice de massa corporal para adolescentes em função dos riscos cardiovasculares e da síndrome metabólica em Viçosa, MG

• Ano de defesa: 2010
• Autor(a) principal: Quintão, Denise Félix
• Orientador(a): Priore, Sílvia Eloiza
• Banca de defesa: Lamounier, Joel Alves , Marins, João Carlos Bouzas
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Ciência da Nutrição
• Departamento: Valor nutricional de alimentos e de dietas; Nutrição nas enfermidades agudas e crônicas não transmis
• País: BR
• Palavras-chave em Português: Adolescente; Índice de massa corporal; Riscos cardiovasculares; Síndrome metabólica
• Palavras-chave em Inglês: Adolescents; Body mass index; Cardiovascular risk; Metabolic syndrome
• Área do conhecimento CNPq: CNPQ::CIENCIAS DA SAUDE::NUTRICAO
• Link de acesso: http://locus.ufv.br/handle/123456789/2723

They have the need and the challenge of studying the various references to existing BMI for teenagers, according to the metabolic changes related to this phase of life, as well as those caused by overweight. The aim was to evaluate different references of BMI for teenagers, according to the risk of cardiovascular and metabolic syndrome (MS). We conducted a cross-sectional study with 172 young men and women from 16 to 19 years old, selected from public and private schools of Viçosa, MG, with the inclusion criteria, the occurrence of menarche for longer than one year for girls and presence of auxiliary hair in boys. Measurements were made of weight, height, waist circumference (WC), calculated BMI and waist/height ratio (WHR), percentage of body fat (% BF), blood pressure (clinical parameters) and assessed the following biochemical parameters: insulin fasting, fasting glucose, triglycerides (TG), total cholesterol (TC), HDL, LDL. Through the values of insulin and fasting glucose, we calculated insulin resistance (HOMA-IR). Nutritional status was classified by BMI using seven references: Must et al. (1991), Himes and Dietz (1994), Anjos et al. (1998), IOTF (Cole et al., 2000), CDC (Kuczmarski et al., 2000), Conde and Monteiro (2006) and WHO (DE ONIS et al., 2007). The percentage of body fat was estimated using the apparatus of horizontal tetrapolar bioelectrical impedance. This study was approved by the Ethics in Human Research, Federal University of Viçosa. As a result it was found higher values for WC and SBP in boys (p <0,05) and body fat, TC, LDL, and HDL in females (p <0,05). In females, the prevalence of undesirable values of TC, LDL, HDL, TG and insulin were 60,0%, 34,0%, 16,0%, 10,0%, 6,0%, and the boys 29,2%, 13,9%, 52,8%, 18,1% and 1,4% respectively. Hyperglycemia occurred in only 1,0% of girls. Blood pressure (BP) was elevated in 6,0% of females and 18,1% in males. Differences between the sexes (p <0,05) were found in the prevalence of changes for TC, LDL, HDL and BP. We identified 4,0% of females and 1,4% of males with WC above the normal range; 81,0% of girls and 81,9% of boys had at least one cardiovascular risk factor, with no differences between the sexes (p> 0,05). SM was diagnosed in 1,0% of girls and 1,4% of boys. In females, all measures of fat distribution (BMI, %BF, WC and WHR) are positively associated with TG, HOMA-IR, SBP and DBP (p <0,05), the latter two best explained by BMI, and the first two ones by the WHR. WC and WHR remained positive association (p <0,05) with biochemical and clinical changes, all independent on %BF, but not BMI. In males, there was a positive association between measures and HOMA-IR, SBP and LDL (p <0,05), with greater explanatory power of the WHR. The effect of WC remained positive (p <0,05) for SBP and is independent on %BF. The WHR, remained positively and significantly associated with LDL, independent on %BF, the TG independently on BMI and HOMA-IR independent on the location of total fat. The use of seven references BMI for nutritional status provided variation in the percentage of change for the overweight, 6,0-12,0% in female and 8,3-20,8% in males, with the highest prevalence were diagnosed by two Brazilian references. The prevalences of high body fat were 42,0% in girls and 8,3% in boys. For females, all references BMI showed low sensitivity (<28,6%) and high specificity (100%) in detecting them with a high body fat percentage, with better performance for the Anjos et al. (1998) and for male, good sensitivity (>66,7%) and high specificity (>86.4%), and the IOTF (Cole et al., 2000) and WHO (2007), who obtained the best results. References BMI presented with slight to substantial agreement with the percentage of body fat, with better performance in boys. BMI was possible to predict between the components of MS, high levels of WC and TG in female and PA in male, with their areas under the curve of 0,98, 0,74 and 0,70. The best cutoff points for this sample showed high sensitivity (83,3% - 100%) and regular high specificities (56,2% - 97,9%) and ranged from 20,3 kg/m² to 25,2 kg/m² lower than those proposed in references studied, except for CC women. The CDC reference (Kuczmarski et al., 2000) obtained the same sensitivity but higher specificity than the other for females. In the male, the reference Anjos et al. (1998) demonstrated the highest sensitivity (33,3%) in detecting hypertension and high specificity (81,7%). The results showed that significant number of adolescents showed disorders in the parameters. The WHR was the most predictive of adverse effects on the cardiovascular system, it is interesting that his diagnosis is done in conjunction with the BMI. References BMI showed low sensitivity to diagnose excess body fat in women, as well as to detect metabolic disorders in both genders, that means they didn t show a good ability to identify cardiovascular risk factors and components of metabolic syndrome.