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Abstract(s)
Introdução: Uma alimentação inadequada, níveis insuficientes de atividade física (AF) e o excesso de peso podem desencadear alterações nefastas no metabolismo ósseo, representando um risco acrescido de osteopénia já na adolescência. Este estudo teve como objetivo analisar a associação entre o aporte alimentar de cálcio, níveis de AF e conteúdo mineral ósseo (CMO) em adolescentes com excesso de peso, de forma a identificar fatores de risco de osteopénia nesta população. Métodos: Foram incluídos 123 adolescentes (52,0% raparigas), com excesso de peso (Mdn= 2,90 z-score IMC), recrutados para um estudo não-randomizado controlado. O CMO foi avaliado através de DXA (Absorciometria de Raios-X de dupla energia), a AF através de acelerómetros, e o aporte alimentar de cálcio estimado através de diário alimentar. As associações entre CMO, níveis de AF e aporte alimentar de cálcio foram analisadas através de correlações parciais (controlando para sexo e estatura) e modelos de regressão linear com CMO (g) e %CMO como variáveis dependentes. Resultados: Observou-se um aporte alimentar de cálcio nos participantes inferior às recomendações (394,5 ± 212,4 vs. 1000 mg/dia). Identificou-se ainda uma correlação negativa entre %CMO e z-score do IMC (r=-,592,p<.001), percentagem de massa gorda total (%MGT) (r=-,633,p<,001) e de massa gorda do tronco (%MGTronco) (r=-,600,p<,001); e uma correlação positiva com a massa muscular (%MM) (r=,733,p<,001), massa isenta de gordura e osso (%MIGO) (r=,694,p<,001) e aporte alimentar relativo de gordura monoinsaturada (%AGMI) (r=,285, p=,023) em valores percentuais. O z-score do IMC mostrou ser o melhor preditor do CMO e %CMO (F=5,31, p=,024; F=49,44, p<,001). O R2 dos modelos aumentou com a inclusão da %MIGO (F= 41,93, p<,001), aporte alimentar de cálcio (F= 33,70, p<,001),e %AGMI (F= 27,48, p<.001). Não se observou qualquer associação entre o CMO ou %CMO e a AF. Conclusão: Apesar de se observar um declínio da %CMO com o agravamento do excesso de peso, uma alimentação mais adequada, com maior aporte alimentar de cálcio e maior conteúdo relativo de AGMI, poderá melhorar o CMO em adolescentes com excesso de peso. Mais estudos terão de ser realizados para melhor perceber o papel da AF nesta relação. Palavras-chave: Adolescentes, Excesso de peso, Obesidade, Conteúdo mineral ósseo, Aporte alimentar de cálcio, Aporte alimentar de gordura, Atividade física.
Introduction: Unhealthy diet, low levels of physical activity (PA), and excess weight (comprising overweight and obesity) may be associated with changes in bone metabolism, increasing the risk of osteopenia already in adolescence. The main aim of this study was to analyze the relationship between calcium intake, PA levels and bone mineral content (BMC) in adolescents with excessive weight, in order to identify risk factors of osteopenia in this population. Method: Data from 123 adolescents (52,0% women) with excess weight (Mdn= 2,90 z-score BMI), previously recruited for a non-randomized controlled trial, were analyzed. BMC was assessed by DXA (Dual-energy X-ray absorptiometry), PA by accelerometers, and calcium intake by food records. The relationship between BMC, PA and calcium intake was analyzed using partial correlations (controlling for sex and height) and linear regressions, using both absolute BMC values and percentage (%BMC) as dependent variables. Results: Participants reported decreased calcium intake compared to the recommendations (394,5 ± 212,4 vs. 1000 mg/day). A negative correlation between %BMC and BMI z-score (r=-,592, p<.001), total fat mass (%TFM) (r=-,633, p<,001), and relative trunk fat mass (%FMTrunk) (r=-,600, p<,001); and a positive correlation between muscle mass (%MM) (r=,733, p<,001), fat free mass (%FFM) (r=,694, p<,001), and relative monounsaturated fatty acids intake (%MUFA) (r=,285, p<,023) was found. BMI z-score showed to be the best predictor of BMC and %BMC (F=5,31, p<,024; F=49,44, p<,001). Models’ R2 increased with the inclusion of %FFM (F= 41,93, p<,001), calcium intake (F= 33,70, p<,001), and %MUFA (F= 27,48, p<.001). No relationship between BMC or %BMC and PA were observed. Conclusion: Although increased excess weight may lead to %BMC impairment, improvements in diet quality, with increased calcium intake and greater relative content of MUFA may improve BMC in adolescents with excess weight. Further studies are needed to better understand the role of PA in this relationship.
Introduction: Unhealthy diet, low levels of physical activity (PA), and excess weight (comprising overweight and obesity) may be associated with changes in bone metabolism, increasing the risk of osteopenia already in adolescence. The main aim of this study was to analyze the relationship between calcium intake, PA levels and bone mineral content (BMC) in adolescents with excessive weight, in order to identify risk factors of osteopenia in this population. Method: Data from 123 adolescents (52,0% women) with excess weight (Mdn= 2,90 z-score BMI), previously recruited for a non-randomized controlled trial, were analyzed. BMC was assessed by DXA (Dual-energy X-ray absorptiometry), PA by accelerometers, and calcium intake by food records. The relationship between BMC, PA and calcium intake was analyzed using partial correlations (controlling for sex and height) and linear regressions, using both absolute BMC values and percentage (%BMC) as dependent variables. Results: Participants reported decreased calcium intake compared to the recommendations (394,5 ± 212,4 vs. 1000 mg/day). A negative correlation between %BMC and BMI z-score (r=-,592, p<.001), total fat mass (%TFM) (r=-,633, p<,001), and relative trunk fat mass (%FMTrunk) (r=-,600, p<,001); and a positive correlation between muscle mass (%MM) (r=,733, p<,001), fat free mass (%FFM) (r=,694, p<,001), and relative monounsaturated fatty acids intake (%MUFA) (r=,285, p<,023) was found. BMI z-score showed to be the best predictor of BMC and %BMC (F=5,31, p<,024; F=49,44, p<,001). Models’ R2 increased with the inclusion of %FFM (F= 41,93, p<,001), calcium intake (F= 33,70, p<,001), and %MUFA (F= 27,48, p<.001). No relationship between BMC or %BMC and PA were observed. Conclusion: Although increased excess weight may lead to %BMC impairment, improvements in diet quality, with increased calcium intake and greater relative content of MUFA may improve BMC in adolescents with excess weight. Further studies are needed to better understand the role of PA in this relationship.
Description
Tese de mestrado, Doenças Metabólicas e Comportamento Alimentar, Universidade de Lisboa, Faculdade de Medicina, 2022
Keywords
Adolescentes Excesso de peso Obesidade Densidade óssea Aporte alimentar de cálcio Aporte alimentar de gordura Atividade física Teses de mestrado - 2022