Impact of methodological approaches in the agreement between subjective and objective methods for assessing screen time and sedentary behavior in pediatric population: a systematic review

Introduction: sedentary behavior is an important target for health promotion. In this systematic review, we aimed to provide evidence to support decisions about measurement approach choices for subjectively assessing sedentary behavior in pediatric population, adopting objective methods as the reference. Methods: in this systematic review with meta-analysis, published studies were retrieved from electronic databases: Medline (PubMed), Web of Science, Embase, SPORTDiscus, BioMed Central and SCOPUS. We considered studies evaluating sedentary behavior agreement through questionnaire and/or diary in comparison with an objective measure. A total of six inclusion criteria v, rere used. We synthesized the data using correlation coefficients (r) as an indicator of agreement estimates. The review protocol is registered in the PROSPERO database (CRD42014015138). Results: a total of 14 studies met the inclusion criteria with ages ranging from 3 to 17.5 years and provided 17 agreement analyses. Thirteen of these agreement analyses (76.5%) reported correlation coefficients. We found two major groups of sedentary activities: screen time (47.1%) and sedentary behaviors (52.9%). The pooled agreement between questionnaires and accelerometers for assessing self-reported screen time was negative (r =-0.15; Cl 95%:-0.17 to-0.13). Conversely, when the sedentary behavior was assessed by questionnaires and accelerometers, the pooled agreement, vas positive for parent-reporting (r = 0.09; Cl 95%; 0.04 to 0.13) and self-reporting (r = 0.43; CI 95%: 0.40 to 0.47) in children and adolescents, respectively. Conclusion: questionnaires have positive agreement with accelerometers for assessing sedentary behavior, whereas the agreement is negative for assessing screen time. Self-reported questionnaires are recommended methods to measure sedentary behavior in adolescents

Prevalence of cardiovascular risk factors, the association with socioeconomic variables in adolescents from Low-Income region

Objectives: To estimate the prevalence of obesity, overweight, abdominal obesity and high blood pressure in a sample of adolescents from a low-income city in Brazil and to estimate the relationship with the socioeconomic status of the family, the education level of the family provider and the type of school. Methods: This cross-sectional study randomly sampled 1,014 adolescents (54.8% girls), between 14-19 years of age, attending high school from Imperatriz (MA). The outcomes of this study were: obesity and overweight, abdominal obesity and high blood pressure (systolic and/ or diastolic). The independent variables were: socioeconomic status (SES) of the family, education level of the family provider (ELFP) and type of school. The confounding variables were: gender, age and physical activity level. Prevalence was estimated, and the association between the endpoints and the independent variables was analyzed using a prevalence ratio (PR), with a 95% confidence interval, estimated by Poisson regression. Results: The overall prevalence of obesity was 3.8%, overweight, 13.1%, abdominal obesity, 22.7% and high blood pressure, 21.3%. The adjusted analysis indicated that girls with high SES showed an increased likelihood to be overweight (PR=1.71 [95% IC: 1.13-2.87]), while private school boys had an increased likelihood of obesity (PR=1.79 [95% CI: 1.04-3.08]) and abdominal obesity (PR =1.64 [95% CI: 1.06-2.54]). Conclusion: The prevalence of CVDR is high in adolescents from this low-income region. Boys from private schools are more likely to have obesity and abdominal obesity, and girls with high SES are more likely to be overweight

Reliability and validity of body weight and body image perception in children and adolescents from the South American Youth/Child Cardiovascular and Environmental (SAYCARE) Study

Objective: To assess the reliability and validity of body weight (BW) and body image (BI) perception reported by parents (in children) and by adolescents in a South American population. Design: Cross-sectional study. BW perception was evaluated by the question, "Do you think you/your child are/is: severely wasted, wasted, normal weight, overweight, obese?" BI perception was evaluated using the Gardner scale. To evaluate reliability, BW and BI perceptions were reported twice, two weeks apart. To evaluate validity, the BW and BI perceptions were compared with WHO BMI Z-scores. Kappa and Kendall's tau-c coefficients were obtained. Setting: Public and private schools and high schools from six countries of South America (Argentina, Peru, Colombia, Uruguay, Chile, Brazil). Participants: Children aged 3-10 years (n 635) and adolescents aged 11-17 years (n 400). Results: Reliability of BW perception was fair in children's parents (k=0·337) and substantial in adolescents (k=0·709). Validity of BW perception was slight in children's parents (k=0·176) and fair in adolescents (k=0·268). When evaluating BI, most children were perceived by parents as having lower weight. Reliability of BI perception was slight in children's parents (k=0·124) and moderate in adolescents (k=0·599). Validity of BI perception was poor in children's parents (k=-0·018) and slight in adolescents (k=0·023). Conclusions: Reliability of BW and BI perceptions was higher in adolescents than in children's parents. Validity of BW perception was good among the parents of the children and adolescents with underweight and normal weight

Perfil enzimático de α-amilase, lipase e tripsina do pâncreas e crescimento do fígado, intestino e pâncreas de frangos de corte na fase de 1 a 21 dias de idade Enzymatic profile of α-amylase, lipase and trypsin in the pancreas and the growth of the liver, intestine and pancreas in broiler chicks from one to 21 days of age

Com o objetivo de avaliar o desenvolvimento de órgãos do aparelho digestório e o perfil enzimático de &#945;-amilase, lipase e tripsina, realizou-se um experimento com duração de 21 dias utilizando-se pintos de 1 dia, machos, Avian Farm, criados em baterias aquecidas e alimentados à vontade com água e dieta purificada contendo os L-aminoácidos essenciais, ácido L-glutâmico (fonte de nitrogênio não-específico), minerais e vitaminas. O delineamento experimental foi inteiramente casualizado com quatro repetições de dez aves. No primeiro dia de vida e aos 7, 14 e 21 dias de idade, quatro animais foram sacrificados por deslocamento cervical e o fígado, pâncreas e intestino delgado foram removidos e pesados para determinação das atividades de &#945;-amilase, lipase e tripsina. Os pesos absolutos aumentaram com a idade. O peso relativo do pâncreas e dos intestinos reduziu aos 21 dias. As atividades específicas (UI/mg de proteína) das enzimas &#945;-amilase e lipase foram maiores no 1º dia, diminuíram no 7º dia, alcançando pico máximo no 14º dia e tornando a reduzir no 21º dia de idade. A atividade específica (UI/mg de proteína) de tripsina não se alterou com a idade. As atividades relativas da a-amilase, lipase e tripsina (UI/100 g de peso corporal) aumentaram do 1º ao 14º dia de idade e reduziram no 21º de idade. As atividades máximas das enzimas digestivas &#945;-amilase e lipase ocorrem no 14º dia de idade. O perfil enzimático da tripsina, de modo geral, não se altera com a idade, o que pode ser explicado pelo fato de os animais serem criados com dietas purificadas, que não estimulam a produção de enzimas proteolíticas.<br>With the objective of assessing the development of organs of the digestive tract and the enzymatic profile &#945;-amylase, lipase and trypsin, an experiment lasting 21 days was carried out using one-day-old male Avian Farm broiler chicks, reared in heated batteries and fed ad libitum with water and purified diets containing all L-essential amino acids, glutamic acid (nonspecific nitrogen source), minerals and vitamins. A randomized complete design was used with four replications of ten birds. At one, seven, 14 e 21 days of age, four chicks were sacrificed and the liver, pancreas and intestine were removed and weighed to determine the pancreas a-amylase, lipase e trypsin activities. The absolute weights increased with age. The pancreas and intestine relative weight reduced at 21 days of age. Specific activities (UI/mg protein) of &#945;-amylase and lipase were higher on the 1st day, decreased on the 7th day, reaching the maximum peak on the 14th day decreasing again on the 21st day. Trypsin specific activity (UI/mg protein) did not vary with age. The activities per 100 g of body weight of &#945;-amylase, lipase and trypsin (UI/100g body weight) increased from the first to the 14th day of age and showed a reduction on the 21st day. The maximum activities of the digestive enzymes &#945;-amylase and lipase occurred on the 14th day of age. The enzymatic profile of trypsin in general did not alter with age, that can be explained by the fact that the animals were raised on purified diets, that did not stimulate proteolytic enzymes

Características do processo de ingestão de forragem por novilhas holandesas em pastagens de capim-mombaça Forage intake characteristics on mombaçagrass pastures grazed by Holstein heifers

Para avaliação da influência da estrutura do dossel de pastagens tropicais sobre o processo de ingestão de forragem por bovinos, cinco alturas de dossel (60, 80, 100, 120 e 140 cm) de uma pastagem de capim-mombaça (Panicum maximum, Jacq.) foram estabelecidas, em um delineamento inteiramente casualizado, com duas repetições. Quatro novilhas da raça Holandês Preto e Branco com coletores de fezes e urina foram utilizadas em testes de pastejo de 45 minutos. O número de bocados e o tempo de alimentação foram registrados com o uso de contadores e cronômetros. A massa de forragem total consumida foi obtida pela técnica de dupla pesagem. Com o aumento na altura do dossel, observou-se aumento linear na massa de bocado. O aumento do comprimento das lâminas foliares expandidas e em expansão resultou em consumo quase que individual de folhas, refletindo em aumento linear no tempo por bocado e em redução linear na taxa de bocados. Uma vez que o aumento no tempo por bocado foi proporcionalmente maior que o aumento da massa de bocado, a massa de forragem total consumida e a taxa de ingestão estabilizaram-se nas maiores alturas da pastagem. As limitações físicas impostas pela estrutura do dossel levaram a menor eficiência de captura de forragem pelos animais nas maiores alturas do dossel. O consumo de forragem foi maximizado à altura de 109,3 cm.<br>In order to evaluate the influence of tropical grass sward structure on the intake of grazing cattle, five sward heights (60, 80, 100, 120, and 140 cm) of Panicum maximum Jacq. were established, in a completely randomized design with two replications. Four black-and-white coat Holstein heifers, carrying feces and urine bags, were used in grazing tests of 45 minutes each. Number of bites and feeding time were registered by counters and chronometers. Total herbage mass consumed was obtained by double sampling technique. Increasing sward height increased bite mass, followed by an increase in chewing number. The increase in the length of both expanded leaves and expanding leaves, resulted in individual bite per leaf, leading to an increase in biting time, and consequent linear decrease in bite rate. Since increases in time per bite was proportionally greater than that for bite mass, total herbage mass consumed and intake rate stabilized at the highest sward heights. Under these conditions, the physical limitation imposed by sward structure led to a lower efficiency of foraging by the animals, even at high forage allowance situation. Intake rate was maximized at pasture height of 109.3 cm

Alfa-amilase em frangos de corte: efeitos do balanço eletrolítico e do nível protéico da dieta Alpha-amylase in broiler chickens: effects of electrolytic balance and dietary protein level

Um experimento foi conduzido com pintos de corte macho para o estudo dos efeitos dos níveis de 20 e 23% de PB combinados com 0, 50, 100, 150, 200, 250 mEq/kg de balanço dietético eletrolítico (BDE) sobre a atividade da alfa-amilase pancreática de frangos de corte de 1 a 21 dias de idade. O delineamento utilizado foi o inteiramente casualizado. Dietas e água foram fornecidas ad libitum. Aos 1, 7, 14 e 21 dias, três aves de cada tratamento foram sacrificadas por deslocamento cervical para remoção do pâncreas, o qual foi removido, homogeneizado, congelado em nitrogênio líquido e liofilizado. Uma alíquota de cada amostra foi solubilizada em água deionizada e centrifugada a 7500 x g por 3 minutos a 4ºC, para determinação da atividade da alfa-amilase no sobrenadante. Aves alimentadas com 20% de PB apresentaram atividades específicas (U/mg de proteína) superiores à daquelas que receberam 23%, exceto para os níveis de BDE de 100 a 200 mEq/kg, aos 14 dias. Observou-se tendência de aumento da atividade específica dos 7 aos 14 dias e redução dos 14 aos 21 dias. Para maior atividade específica de alfa-amilase, recomendam-se dietas com 20% de PB e 200 mEq/kg de BDE na fase pré-inicial e dietas com 20% de PB e 135 a 250 mEq/kg de BDE para frangos de corte dos 8 aos 21 dias de idade.<br>An experiment was conducted with male broiler chicks to study the effects of 20 and 23% of crude protein (CP) combined with 0, 50, 100, 150, 200, 250 mEq/kg of dietary electrolytic balance (DEB) on the pancreatic alpha-amylase activity from 1 to 21 days. A completely randomized factorial design was used. Feed and water were supplied ad libitum. At days 1, 7, 14 and 21, three birds from each treatment were sacrificed by cervical dislocation, pancreas were removed, homogeneized and frozen in liquid nitrogen which were then freeze-dried. An aliquot of each sample was solubilized with deionized water and centrifuged at 7500 x g for three minutes at 4ºC. Activities of the pancreatic alpha-amylase in the supernatants were determined. Chicks fed 20% of CP showed specific activities (U/mg protein) higher than those fed 23%, except for DEB levels from 100 to 200 mEq/kg at 14 days. A tendency to increase specific activity was observed from 7 to 14 days and to reduce from 14 to 21 days. The highest specific activity of pancreatic alpha-amylase was observed in diets with 20% CP and 200 mEq/kg of DEB from 1 to 7 days, diets with 20% of CP and 135 to 250 mEq/kg of DEB from 8 to 21 days of age