Técnicas de medición de la actividad física en investigaciones argentinas: necesidad de incorporar técnicas objetivas / Measurement techniques used in physical activity argentinean research: necessity of incorporating objetive techniques

Introducción: actualmente ninguna técnica por sí sola puede medir todas las dimensiones de la actividad física simultáneamente. Por este motivo se sugiere utilizar múltiples monitores objetivos a la vez o una combinación de monitores objetivos y técnicas subjetivas.Objetivos: revisar las técnicas de medición de actividad física utilizadas en las investigaciones argentinas y presentar los resultados de un estudio piloto en el que se utilizó la técnica objetiva de frecuencia cardíaca con calibración individual para la estimación del gasto energético total diario y de las actividades físicas cotidianas. Materiales y métodos: para revisar las técnicas utilizadas se realizó una búsqueda general en PubMed, LILACS, SciELO y Google Académico utilizando los términos "actividad física", "sedentarismo" y "Argentina"; además se consultaron expertos locales. Luego se aplicó la técnica de frecuencia cardíaca con calibración individual en laboratorio y se efectuó un monitoreo de cuatro días de la semana a una muestra piloto de seis sujetos de ambos sexos profesores de Educación Física. Resultados: se identificaron 70 publicaciones donde se midió la actividad física habitual en Argentina. En el 94% se utilizaron cuestionarios. Un sólo estudio empleó cuestionario validado en la población local. El 92% fue de corte transversal. Ningún estudio utilizó la técnica de frecuencia cardíaca. Los sujetos de nuestra muestra tuvieron un gasto energético total promedio±desvío estándar de 2.670±1.062 kcal y un gasto energético por actividades físicas de 1.351±957 kcal siendo estos valores comparables a los de estudios previos. Cuatro sujetos alcanzaron las recomendaciones diarias de actividad física para la salud. Conclusiones: resulta relevante y necesario comenzar a validar técnicas subjetivas en la población argentina y/o utilizar técnicas objetivas para medir la actividad física en futuras investigaciones locales. La técnica de frecuencia cardíaca con calibración individual, aunque con limitaciones, puede resultar eficaz para cumplir con ambas finalidades.

Introduction: currently no single technique can measure all dimensions of physical activity simultaneously. For this rea-son it is suggested to use multiple objective monitors or a combination of objective monitors with subjective techniques simultaneously. Objectives: review the measurement techniques used in physical activity Argentinean research and present the results of a pilot study in which the heart rate objective technique with individual calibration was used for estimating the total daily energy expenditure and daily physical activities.Materials and methods: to review the techniques used, it was conducted a general search in PubMed, LILACS, SciELO and Google Scholar using the terms "physical activity", "se-dentarism" and "Argentina", in addition local experts were consulted. After that, heart rate technique with individual calibration was applied in the laboratory and monitoring four days a week was performed to a pilot sample of six physical education teachers subjects of both sexes.Results: it was identified 70 publications where regular phy-sical activity was measured in Argentina. In 94% of them were used questionnaires. Only one study used a question-naire validated with local population. 92% used a cross-sectional design. No study used the technique of heart rate. The subjects of our sample had a mean±standard deviation total energy expenditure of 2.670±1.062 kcal and a physical activity energy expenditure of 1.351±957 kcal being these values comparable to those of previous studies. Four subjects reached daily physical activity recommendations for health.Conclusions: it is relevant and necessary to begin to vali-date subjective techniques in Argentinean population and/or to use objective techniques for measuring physical activity in future local research. The technique of heart rate with indi-vidual calibration, albeit with limitations, can be an effective way to meet both purposes.

Deficiencia de vitamina A y estado nutricional antropométrico en niños marginales urbanos y rurales en el Estado Zulia, Venezuela / Vitamin A deficiency and the anthropometric nutritional status of urban and rural marginalized children in the state of Zulia, Venezuela

The present transversal study was carried out to estimate the prevalence of both vitamin A deficiency (VAD) and protein-energy malnutrition among children (24 to 85 months) from three urban slums (n = 173) in Maracaibo city, Zulia State, Venezuela and a rural slum area (n = 34), vieinal to Maracaibo, by measuring serum retinol and z score of anthropometric indices Height//Age (H//AZ); Weight//Age (W//AZ) and Weight//Height (W//HZ), compared to NCHS-WHO reference values. The Graffar's methodology adapted to Venezuela by MÚndez Castellano (1986) confirmed the underprivileged socio-economic condition of the children population. For serum retinol analysis, peripheral venous blood was drawn and serum was treated according to the Bieri et al. (1979) technique and HPLC procedure. Values were recorded in microgram/dL. Statistical analysis was done by using Epi Info 2000, release 1.0 and SAS release 6.0 (1996) computer programs. The prevalence of VAD (serum retinol < 20 micrograms/dL) in the total children population (n = 207) was 22.2, being higher in urban children than in rural children (22.5 vs 20.5). No clinical signs of VAD were detected in the children. The nutritional status analysed by Z score of anthropometric indices revealed that 27.4 of children suffered from undernutrition (Z score = -2 to > -3 SD), being 15.4 stunted, 9.6 wasted and 2.6 with acute protein-energy malnutrition. Neither severe malnutrition nor overweight were detected. According with the H//AZ index, 54.6 of children had adequate nutrition. However 23 of them suffered from VAD. In children at risk of developing undernutrition (Z score = -1 to > -2 SD), 20.9 had VAD and of the stunted children, 21.9 presented VAD. With W//AZ, 60.3, 29.9 and 9.1 of children were with adequate nutrition, at risk, or wasted respectively; of each group, 25.6, 17.7 and 15, respectively had serum retinol values below 20 micrograms/dL. The Z score of W//HZ indicator revealed that 87.4, 10.4 and 2.4 of children were in good nutrition, at risk, or with acute protein-energy malnutrition, respectively. In the three groups 22.1, 23.8 and 20, respectively were affected by VAD. These results indicate that VAD coexists indistinctly in healthy, adequately nourished children, as in those malnourished ones. Our VAD prevalence results and others from Venezuela, are higher than the criteria laid down by WHO and PAHO which warrant wide community intervention. This public health problem becomes mor