Higher adiponectin concentrations are associated with reduced metabolic syndrome risk independently of weight status in Brazilian adolescents

Objective: To evaluate the association between adiponectin concentrations and metabolic syndrome (MetS) risk and to investigate if this association is independent of weight status in adolescents. Methods: Adiponectin concentrations and MetS risk were assessed in 4546 Brazilian adolescents (12–17 years old) enrolled in The Study of Cardiovascular Risks in Adolescents (“ERICA”), a cross-sectional multicenter study in Brazil. For analyses, adiponectin was categorized in sex and age-specific quartiles and MetS risk was expressed as a continuous score, calculated as the average of the standardized values (z-score) of the five MetS components. Multiple linear regression models were used to investigate the association between the quartiles of adiponectin and MetS risk. Results: Adiponectin was inversely associated with waist circumference and log-transformed triglycerides, and positively associated with HDL-c. We also observed an inverse association between adiponectin concentrations and MetS risk. After adjustment for sociodemographic variables, physical activity, skipping breakfast and body mass index (BMI), higher quartiles of adiponectin remained inversely associated with waist circumference and MetS risk. A direct association between adiponectin and HDL-c was also observed. In further analysis, the sample was stratified by weight status and an inverse association between quartiles of adiponectin and MetS risk was observed in both normal weight and overweight/obese adolescents. Conclusion: Higher adiponectin concentrations were independently and inverse associated with MetS risk in Brazilian adolescents, even after adjusting for BMI. These results were similar in normal weight and overweight/obese adolescents, suggesting that adiponectin may play a role in early development of MetS

Visão geral das meta-análises sobre prevenção e tratamento da obesidade infantil

Objectives: This study aimed to assess the quality of systematic reviews on prevention and non-pharmacological treatment of overweight and obesity in children and adolescents. Data source: A search was done in electronic databases (Medline via PubMed, Web of Science, Scopus, LILACS, the Cochrane Library, and Clinical Trials), including only systematic reviews with meta-analysis. Reviews were selected by two researchers, and a third one solved the divergences. PRISMA statement and checklist were followed. Summary of data: A total of 4574 records were retrieved, including 24 after selection. Six reviews were on obesity prevention, 17 on obesity treatment, and one on mixed interventions for prevention and treatment of obesity. The interventions were very heterogeneous and showed little or no effects on weight or body mass index. Mixed interventions that included dieting, exercise, actions to reduce sedentary behavior, and programs involving the school or families showed some short-term positive effects. Reviews that analyzed cardiovascular risk factors demonstrated significant improvements in the short-term. Conclusion: The systematic reviews of interventions to prevent or reduce obesity in children and adolescents generally showed little or no effects on weight or body mass index, although cardiovascular profile can be improved. Mixed interventions demonstrated better effects, but the long-term impact of obesity treatments of children and adolescents remains unclear.Objetivos: Este estudo teve como objetivo avaliar a qualidade das revisões sistemáticas sobre prevenção e tratamento não farmacológico do sobrepeso e da obesidade em crianças e adolescentes. Fontes de dados: Foi realizada uma busca em bases de dados eletrônicas (Medline via Pubmed, Web of Science, Scopus, LILACS, The Cochrane Library e Ensaios Clínicos), incluindo apenas revisões sistemáticas com meta-análise. As revisões foram selecionadas por dois pesquisadores e um terceiro resolveu as divergências. A lista de recomendações do PRISMA foi seguida. Síntese dos dados: Foram identificados 4.574 publicações, e 24 foram incluídas após a seleção. Seis publicações eram sobre prevenção da obesidade, 17 sobre tratamento da obesidade e 1 sobre intervenções mistas para prevenção e tratamento da obesidade. As intervenções eram muito heterogêneas e mostraram pouco ou nenhum efeito sobre o peso ou índice de massa corporal. Intervenções mistas que incluíam dieta, exercícios, ações para reduzir o comportamento sedentário e programas que envolviam a escola ou as famílias mostraram alguns efeitos positivos de curto prazo. Revisões que analisaram fatores de risco cardiovascular demonstraram melhoras significativas em curto prazo. Conclusão: As revisões sistemáticas de intervenções para prevenir ou reduzir a obesidade em crianças e adolescentes geralmente mostraram pouco ou nenhum efeito sobre o peso ou índice de massa corporal, embora o perfil cardiovascular possa ter melhorado. Intervenções mistas demonstraram melhores efeitos, mas o impacto em longo prazo dos tratamentos da obesidade de crianças e adolescentes ainda não está claro

Prevalência de tempo excessivo de tela e tempo de TV em adolescentes brasileiros : revisão sistemática e meta-análise

Purpose: To evaluate the prevalence of excessive screen-based behaviors among Brazilian adolescents through a systematic review with meta-analysis. Data source: Systematic review and meta-analysis were recorded in the International Prospective Register of Ongoing Systematic Reviews (PROSPERO-CRD 2017 CRD42017074432). This review included observational studies (cohort or cross-sectional) that evaluated the prevalence of excessive screen time (i.e. combinations involving different screen-based behaviors) or TV viewing (≥2 h/day or >2 h/day in front of screen) through indirect or direct methods in adolescents aged between 10 and 19 years. The research strategy included the following databases: MEDLINE, LILACS, SciELO and ADOLEC. The search strategy included terms for “screen time”, “Brazil”, and “prevalence”. Random effect models were used to estimate the prevalence of excessive screen time in different categories. Data summary: Twenty-eight out of 775 studies identified in the search met the inclusion criteria. The prevalence of excessive screen time and TV viewing was 70.9% (95% CI: 65.5–76.1) and 58.8% (95% CI: 49.4–68.0), respectively. There was no difference between sexes in both analyses. The majority of studies included showed a low risk of bias. Conclusions: The prevalence of excessive screen time and TV viewing was high among Brazilian adolescents. Intervention are needed to reduce the excessive screen time among adolescents.Objetivo: Avaliar a prevalência de tempo excessivo de tela e de TV em adolescentes brasileiros através de revisão sistemática com meta-análise. Fontes de dados: A revisão sistemática e a meta-análise foram registradas no o inglês (não tem tradução para português): International Prospective Register of Ongoing Systematic Reviews (PROSPERO-CRD 2017 CRD42017074432). Esta análise incluiu estudos observacionais (coorte ou transversais) que avaliaram a prevalência de tempo excessivo de tela (ou seja, combinações que envolvem diferentes comportamentos baseados em tempo de tela) ou tempo em frente à TV (≥ 2 horas/dia ou > 2 horas/dia em frente à tela) por avaliação direta ou indireta em adolescentes com idades entre 10 a 19 anos. A estratégia de pesquisa incluiu as seguintes bases de dados: MEDLINE, LILACS, SciELO e ADOLEC. A estratégia de busca incluiu termos como “tempo de tela”, “Brasil” e “prevalência”. Os modelos de efeito aleatório foram utilizados para estimar a prevalência de tempo excessivo de tela em diferentes categorias. Resumo de dados: 28 dos 775 estudos identificados na busca atenderam aos critérios de inclusão. A prevalência de tempo excessivo de tela e tempo de TV foi 70,9% (IC de 95%: 65,5 a 76,1) e 58,8% (IC de 95%: 49,4 a 68,0), respectivamente. Não houve nenhuma diferença entre os sexos nas duas análises. A maior parte dos estudos incluídos mostrou baixo risco de viés. Conclusões: A prevalência de tempo excessivo de tela e tempo de TV foi alta entre os adolescentes brasileiros. São necessárias intervenções para reduzir o tempo excessivo de tela entre os adolescentes

Diminishing benefits of urban living for children and adolescents’ growth and development

Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6 . Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m–2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified

Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories : a pooled analysis of 2181 population-based studies with 65 million participants

Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m². In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in subSaharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks