Carla Cristina Enes

Validação do Questionário de Freqüência Alimentar para Adolescentes (QFAA) por grupos de alimentos em uma população de escolares

OBJETIVO: Verificar a validade do Questionario de Frequencia Alimentar para Adolescentes para avaliar o consumo de grupos de alimentos entre escolares de Piracicaba, Sao Paulo. METODOS: Participaram do estudo 94 adolescentes, com idade entre 11 e 15 anos, matriculados em uma escola da rede publica. O consumo alimentar foi avaliado pelo Questionario de Frequencia Alimentar para Adolescentes (QFAA) e a media de dois Recordatorios de 24 horas (R24h) foi utilizada como metodo de referencia. Os itens alimentares foram classificados em 18 grupos. Foram realizadas analises descritivas, teste t-Student pareado e de Wilcoxon, coeficientes de correlacao de Pearson e de Spearman. Foram tambem utilizadas analise de quartis e estatistica Kappa ponderado. Os coeficientes de correlacao foram corrigidos pela variância intrapessoal dos R24h, estimada a partir de ANOVA com um fator de classificacao. RESULTADOS: Nao foram verificadas diferencas significativas entre os instrumentos para o arroz, massas, carnes, refrigerantes e sucos artificiais. Os coeficientes de correlacao corrigidos pela variabilidade intrapessoal variaram de -0,26 a 0,78. A concordância de classificacao dos individuos no mesmo quartil de consumo para ambos os metodos variou de 22% (massas) a 50% (feijao). Para quartis opostos, os grupos que tiveram mais de 10% dos individuos classificados incorretamente foram massas (19%), carnes (13%) e gorduras (11%). Os valores de Kappa ponderado variaram de - 0,15 (massas) a 0,56 (feijao). O QFAA superestimou o consumo de quase a totalidade dos grupos alimentares e subestimou os grupos dos oleos, feijao, carnes e refrigerantes. CONCLUSAO: O instrumento apresentou boa validade para feijao, verduras e legumes, leite e derivados, biscoitos recheados e para o arroz.

Validation of a food frequency questionnaire to assess the consumption of carotenoids, fruits and vegetables among adolescents: the method of triads

The aim of this study was to validate the intake of carotenoids, fruits and vegetables estimated by the Food Frequency Questionnaire for Adolescents (FFQA) using the method of triads. Blood samples were collected from 80 elementary school adolescents to assess serum levels of β-carotene. Partial correlation coefficients (r) were calculated between an estimated intake of carotenoids, fruits and vegetables and the serum levels of β-carotene. Validity coefficients were calculated using the method of triads. With the exception of carotenoids, partial r from the food frequency questionnaire (FFQ) were greater than those of the 24-hour recall (24hR). The fruit/vegetable group showed the highest partial r for the FFQ (r = 0.235) and the 24hR (r = 0.137). The highest validity coefficient was obtained for the vegetable group, as assessed by the FFQ (r = 0.873). On average, the validity coefficient values for the FFQ were greater than those obtained for the 24hR or the β-carotene serum levels. The FFQA is an accurate tool for estimating the intake of carotenoids, fruits and vegetables in this population group.

Influência do consumo alimentar e do padrão de atividade física sobre o estado nutricional de adolescentes de Piedade, São Paulo

OBJECTIVE: To identify dietary and physical activity factors associated to the nutritional status of adolescent students. METHODS: Cross-sectional study of 105 adolescents of both genders, aged 10 to 14 years, studying at public schools in Piedade, Sao Paulo, Brazil. Data regarding food intake (24 hour recall), physical activity patterns (physical and sedentary activities) and nutritional status measured by body mass index were collected. The adolescents were characterized as insufficiently active if physical activities were practiced for less than 300 minutes per week. They were considered sedentary if they spent two hours or more per day in passive activities. Multiple linear regression was performed to identify factors associated to the nutritional status. RESULTS: The prevalence of overweight was higher among boys (17.9 versus 13.6%, p<0.05) and 18.0% of the adolescents were considered insufficiently active. There was no association between dietary and nutritional status variables. A significant difference was observed only for the time spent playing videogames (p=0.005), that was higher among eutrophic adolescents. Seven in ten adolescents spent more than two hours a day on sedentary activities (watching television, using the computer and playing videogames). In multiple regression analysis, only age was positively associated with the BMI (p=0.001). CONCLUSIONS: Further prospective investigations are necessary to establish clearer relationships among factors related to lifestyle and body mass index among adolescents.

Disponibilidade de energia e nutrientes nos domicílios: o contraste entre as regiões Norte e Sul do Brasil

Com o objetivo de analisar a disponibilidade domiciliar de energia, a participacao relativa dos macronutrientes no Valor Energetico Total (VET) e a contribuicao dos diferentes grupos de alimentos na energia disponivel nos domicilios das regioes Norte e Sul do pais, segundo o rendimento mensal familiar, foi proposto o presente estudo. Utilizou-se para a elaboracao das analises os microdados da Pesquisa de Orcamentos Familiares - 2002/2003 realizada pelo Instituto Brasileiro de Geografia e Estatistica (IBGE). Para as analises nutricionais, utilizou-se o software Virtual Nutri. O teste de regressao linear multipla foi aplicado para analisar o efeito dos rendimentos sobre a disponibilidade de energia e nutrientes. Verificou-se uma relacao inversa entre a participacao dos carboidratos no VET e a renda. A contribuicao dos lipidios para o VET apresentou tendencia de crescimento, de acordo com o aumento da renda. Quanto a participacao dos distintos grupos de alimentos no VET, destaca-se a reduzida contribuicao energetica das frutas, verduras e legumes para praticamente a totalidade dos grupamentos familiares. Foram identificadas indesejaveis contribuicoes (consideradas excessivas) dos doces, acucares e refrigerantes para o VET disponivel para as familias de ambas as regioes estudadas.

Validity and reliability of self-reported weight and height measures for the diagnoses of adolescent's nutritional status

PURPOSE: To assess the validity and reliability of self-reported height, weight, and Body Mass Index (BMI) to diagnose the nutritional status of adolescents. METHODS: The study included 360 public school students of both genders, with ages ranging from 10 to 15 years. Adolescents self-reported their weight and height, and these values were later obtained directly by interviewers. The validity of BMI based on self-reported measures was calculated using sensitivity and specificity indexes, and positive predictive value (PPV). Agreement between self-reported and measured BMI was evaluated using Kappas weight coefficient, the Lin correlation coefficient, and Bland-Altman and Lins plots. RESULTS: Both girls and boys underestimated their weight (-1.0 girls and boys) and height (girls - 1.2 and boys - 0.8) (p < 0.001). BMI presented moderate agreement between measured and self-reported values. Sensitivity of estimated BMI based on reported measures to classify obese subjects was higher for boys (87.5%) than it was for girls (60.9%), whereas specificity was higher for girls (92.7%) than it was for boys (80.6%). PPV was high only for classification of normal-weight adolescents. CONCLUSIONS: Self-reported measures of weight and height in adolescents do not present valid measures; therefore, they should not be used to replace measured values. Additionally, we observed that 10% of obese boys and 40% of obese girls could have remained unidentified if we had used only self-reported measures, emphasizing the effects of the low reliability of self-reporting.

BMI Changes Associated With Dietary Trends Among Brazilian Adolescents

Dietary patterns are a subject of growing interest considering the complex nature of dietary intake and its relationship with health outcomes. The aim of this study was to investigate the relationship between changes in adolescents’ BMI and their dietary trend pattern. This study is a follow-up of the children in the study titled “Dietary Intake and Physical Activity as Determinants of Changes in Body Mass Index in a Cohort of Adolescents Enrolled in Public Schools in Piracicaba, Sao Paulo,” and was conducted in public schools in Piracicaba, Sao Paulo, Brazil, with 372 adolescents participating in wave I (2004) and 268 participating in wave II (2005). Dietary intake was assessed using a semiquantitative food frequency questionnaire (SQFFQ), and height and weight measurements were also collected. The authors identified dietary patterns using principal component analysis. To describe dietary trends, they decided to match patterns across waves. Dietary patterns were gathered from 12 food groups. Relative risk was calculated by dividing the incidence of overweight among boys and girls across quintiles of dietary pattern scores. Matching C1 wave I and C1 wave II shows a multigroup trend pattern based on consumption of high levels of fruit, cereals, fatty foods, meat/eggs, milk, and vegetable groups. The relative risk for overweight was significantly lower for boys between the quintiles of this pattern (P < .05). The main results indicate that sustaining a healthy eating pattern for adolescents living without any nutritional intervention is of primary importance in maintaining or reducing BMI at this age.

Estimativa de valores corrigidos e o efeito da correção pelo erro de medida em dados dietéticos obtidos por Questionário de Frequência Alimentar para Adolescentes (QFAA)

The scope of this study was to estimate calibrated values for dietary data obtained by the Food Frequency Questionnaire for Adolescents (FFQA) and illustrate the effect of this approach on food consumption data. The adolescents were assessed on two occasions, with an average interval of twelve months. In 2004, 393 adolescents participated, and 289 were then reassessed in 2005. Dietary data obtained by the FFQA were calibrated using the regression coefficients estimated from the average of two 24-hour recalls (24HR) of the subsample. The calibrated values were similar to the the 24HR reference measurement in the subsample. In 2004 and 2005 a significant difference was observed between the average consumption levels of the FFQA before and after calibration for all nutrients. With the use of calibrated data the proportion of schoolchildren who had fiber intake below the recommended level increased. Therefore, it is seen that calibrated data can be used to obtain adjusted associations due to reclassification of subjects within the predetermined categories.