Abstract Introduction: A valid food frequency questionnaire (FFQ) is a priority for epidemiological studies. We aimed to perform a relative validity of an FFQ for Portuguese adolescents. Methods: A semi-quantitative Portuguese FFQ (SQ-PortFood-FQ) was developed and the relative validity performed using the multiple-pass 24-h recall. Eighty adolescents (aged 10-17 years) completed both questionnaires to measure energy intake, macroand specific micronutrient intake. We used the following methods for the relative validity: (1) Spearman’s correlation coefficient (r); (2) cross-classification into the same third (agreement) and into the opposite third (disagreement); (3) weighted κ-coefficient (κW); (4) and the Bland-Altman method. Results: We obtained acceptable correlation coefficients between questionnaires for energy (r = 0.59; p < 0.001), protein (r = 0.60; p < 0.001), fat (r = 0.55; p < 0.001), carbohydrates (r = 0.51; p < 0.001) and sodium (r = 0.51; p < 0.001). Tertile agreement for energy, protein, fat, carbohydrates and vitamin C intakes classified correctly more than 50% and grossly misclassified less than 10% of participants. Energy and protein produced moderate agreement between methods with a κW >0.40. The SQ-PortFoodFQ overestimated all analysed data when compared to the 24-h recall, although those estimations were <10% for energy, macronutrients and cholesterol. The 95% limits of agreement showed that all the variables (energy, protein, fat, carbohydrates, fibre, calcium, sodium, iron, saturated fatty acids, monounsaturated fatty acids and cholesterol) were within the desirable limits of agreement of 50-200%, with the exception of vitamin C (76-296%) and polyunsaturated fatty acids (PUFA) (75-232%). Discussion/Conclusion: The SQ-PortFood-FQ showed acceptable relative validity at the individual level for energy, protein, fat, carbohydrates, fibre, calcium, sodium, iron, saturated fatty acids, monounsaturated fatty acids and cholesterol. Non-significant relationships were found for vitamin C and PUFA. Our results are in line with previous studies carried out amongst adolescents. As far as we know this is the first FFQ validated for Portuguese adolescents.

SUMMARY: The adult height percentage (AHP) is an indicator of maturity state, which reflects variation in growth rate. Several methods estimates adult height; however, its similarities or differences have not been documented in a concrete way in literature. The aims of the present work were to compare three common methods of AHP estimation, to identify children and adolescents secular changes and to develop AHP reference values in Portuguese population. Skeletal age, weight and height were measure in 799 children and 736 girls from 7.0 to 16.5 years; in addition, parents height was self-reported by them to estimate the AHP by TW3, RWT and KR methods. ANOVA was used to estimate differences between TW3, KR and RWT methods, as well as Bland-Altman graphs. Also, Kruskal-Wallis test was applied. No differences were found between TW3 and KR methods in all age groups, in both sexes, when subjects were classified by chronological age (P> 0.05). Likewise, no secular changes were observed in AHP (P> 0.05). Not only TW3 and KR protocols can be interchangeable each other because they did not present differences in the AHP estimation at different ages and in both sexes. However, secular changes were not observed in AHP estimation by these methods.

RESUMEN: El porcentaje de estatura adulta (PEA) es un indicador del estado de maduración, que refleja la variación en la tasa y progreso de crecimiento. Existen diversos métodos para estimar la estatura adulta, sin haberse documentado en la literatura de manera concreta sus similitudes o diferencias. Los objetivos del presente trabajo fueron comparar tres métodos de estimación del PEA, identificar cambios seculares en niños y adolescentes y establecer valores de referencia del PEA para población portuguesa. Se midieron en 799 niños y 736 niñas, de 7,0 a 16,49 años, la edad ósea, el peso y la estatura, para estimar el porcentaje de estatura adulta por las metodologías TW3, KR y RWT. Los valores del método TW3 del presente estudio, fueron comparados con los reportados en décadas atrás para identificar cambios seculares. Se utilizó un ANOVA de medidas repetidas para estimar las diferencias entre los métodos en el presente estudio, así como gráficas de Bland y Altman. Se utilizó la prueba de Kruskal-Wallis para analizar las diferencias entre los valores encontrados en la presente investigación y los presentados en décadas atrás en otros estudios. No se encontraron diferencias entre los métodos TW3 y KR en los diferentes grupos de edad cuando se clasificaron los sujetos por edad cronológica, en ambos sexos (P>0,05). Así mismo, no se observaron cambios seculares en el PEA (P>0.05). Los métodos TW3 y KR pueden ser intercambiables entre sí, debido a que no presentan diferencias en la estimación a diferentes edades y en ambos sexos. Además, no existió cambio secular en la estimación de PEA por estas metodologías, lo que las hace útiles en la actualidad.

Este estudo propõe avaliar o processo de maturação biológica de jovens sambistas, em suas relações com a estratificação socioeconômica, com o crescimento e com a composição corporal, enfatizando o desenvolvimento durante a adolescência, que abrange a passagem da infância à idade adulta, assim como as suas diversas etapas intermediárias medidas através de um conjunto de parâmetros sexuais habitualmente assinalados. Com esse objetivo, foram avaliados a maturação sexual e seus mais importantes sinais físicos e sociais. Foram avaliadas 118 moças entre os 9 e 16 anos participantes da escola de samba Beija-Flor de Nilópolis. Para a determinação de algumas características de desenvolvimento maturacional, foram utilizadas as seguintes medidas: pilosidade axilar, idade da menarca pelos métodos retrospectivo e status quo, pilosidade púbica e desenvolvimento da mama através de auto-avaliação, segundo os critérios de Tanner7. Partindo dos resultados aqui apresentados, parece que: a idade média da menarca é semelhante à encontrada em outras amostras, embora mais baixa; o nível social e o rendimento familiar parecem não interferir no número de sambistas que já passaram pela menarca e na idade média de ocorrência do fenômeno; nos grupos de rendimento socioeconômico mais baixo, são as moças que já vivenciaram a menarca as que apresentam maiores níveis de gordura. Ao contrário, quando o rendimento é superior, são as meninas que ainda não vivenciaram a menarca aquelas que apresentam níveis de gordura mais elevados.

The aim of this study is the assessment of young samba dancers biological maturation process and its relationship with socioeconomic stratum, growth and body composition, emphasizing both the development during adolescence comprising infancy and adulthood and the several intermediate stages through a collection of the ordinary used parameters. With this purpose, sexual maturation was assessed as well as its most important physical and social signs. The authors assessed 118 girls aged between 9 and 16 years attending the samba school of Nilópolis. The variables used to determine some characteristics of the maturational development were: axillary hair, menarcheal age through retrospective method and status quo, pubic hair and genital development using Tanner protocol. According to the results presented, it seems that: the mean age of menarche is similar to other samples, although lower; socioeconomic level and familiar income seem not to interfere neither in the number of the girls after menarche and the mean age of the occurrence of this phenomenon. The groups of lower familiar income are composed of girls after menarche, and showing higher levels of fat. On the contrary, when familiar income is higher the authors have found girls before menarche with higher levels of fat.

Este estudio propone evaluar el proceso de maduración biológica de jovenes sambistas, en sus relaciones con la estractificación socioeconómica, con el crecimiento y con la composición corporal, enfatizando el desarrollo durante la adolescencia, que aparece como pasaje de la infancia a la edad adulta, así como sus diversas etapas intermedias medidas a través de un conjunto de parámetros sexuales habitualmente señalados. Con este objetivo, fueron evaluados la maduración sexual y sus mas importantes signos físicos y sociales. Fueron evaluadas 118 chicas, entre los 9 y los 16 años participantes de la escuela de samba Beija-Flor de Nilópolis. Para la determinación de algunas características de desarrollo maduracional fueron utilizadas las siguientes medidas: pilosidad axilar, edad da menarca por los métodos retrospectivo y status quo, pilosidad púbica y desarrollo de mama a través de la auto-evaluación, segun los criterios de Tanner7. Partiendo de los resultados aquí presentados parece que: la edad media de menarca es semejante encontrada en otras muestras, ahora mas baja; el nivel social y el rendimiento familiar parecen no interferir en el número de sambistas que ya pasaran por la menarca y la edad media de ocurrencia del fenómeno; los grupos de rendimiento socioeconómico mas bajo son las chicas que ya vivenciaran la menarca las que presentan mayores niveles de gordura. Al contrario, cuando el rendimiento es superior, son las pequeñas que todavía no vivenciaron la menarca, aquellas que presentan niveles de gordura más elevados.