Efeito concorrente entre massa livre de gordura e tecido adiposo sobre os ganhos de densidade mineral óssea de membros inferiores de adolescentes esportistas: abcd-growth study
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Data
2019-03-28
Autores
Marco, Rafael Luiz de [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A saúde óssea tem recebido crescente atenção da comunidade acadêmica e sociedade por conta do grande peso social e econômico que a osteoporose representa. Por outro lado, o desenvolvimento da osteoporose na velhice é fortemente determinado por eventos que ocorrem na juventude, neste caso os baixos ganhos de massa óssea. Nesse sentido, a ação do tecido muscular no fortalecimento da estrutura óssea tem sido investigada em jovens, mas muitas lacunas ainda existem. Objetivo: Discriminar o impacto de modificações na massa livre de gordura (MLG) e gordura corporal (GC) sobre o ganho ósseo de adolescentes de ambos os sexos, bem como, identificar o efeito de ambos tecidos sobre os ganhos ósseos em condições envolvendo diferentes níveis de impacto mecânico, em ambiente de hipogravidade (natação), em ambiente sem prática esportiva (grupo controle) e ambiente com prática esportiva com impacto (futebol, basquetebol e artes marciais). Métodos: Estudo longitudinal com doze meses de seguimento (dois momentos de coleta de dados) que foi conduzido na cidade de Presidente Prudente - SP. A amostra foi composta por 262 jovens classificados como: Controle, Natação e Esportes de impacto (modalidades combinadas: caratê, judô, kung-fu, futebol, basquetebol e voleibol). A densidade mineral óssea (DMO), MLG e GC foram estimados por meio da absortiometria de Raio-X de Dupla energia nos i) membros inferiores, ii) perna esquerda e iii) perna direita. Foram tratados como variáveis de confusão: idade cronológica, maturação biológica e consumo de vitamina D. Resultados: Em primeiro momento de acordo com as análises apresentadas, podese observar que a MLG constitui o determinante mais relevante no que se diz respeito ao ganho de DMO explicando em 56% (R2 ajustado= 0,569) a variância encontrada na DMO de membros inferiores mesmo ao considerar os efeitos do sexo, idade e maturação somática, por outro lado, a GC parece não afetar de forma expressiva a DMO. Em análises longitudinais (após doze meses de seguimento e ajustadas por fatores de confusão), pode-se observar que para todo o grupo amostral e para os praticantes de esporte de impacto a MLG foi a variável mais determinante para o acúmulo de DMO de membros inferiores com média para ambas as pernas aproximadamente acima de 55% de explicação. Já quando a amostra foi dividida por sexo, pode-se observar que para os meninos a MLG foi a maior preditora para o acúmulo de DMO em membros inferiores, porem para o sexo feminino a GC foi a variável que mais teve explicação para o acúmulo DMO em membros inferiores (ambas as pernas). Conclusões: Os achados do presente estudo concluem que a MLG constitui o determinante mais relevante no que se diz respeito ao ganho de DMO de membros inferiores em adolescentes do sexo masculino mesmo ao considerar os efeitos do sexo, idade e maturação somática. Por outro lado, longitudinalmente, a GC de membros inferiores parece afetar de forma significante o acúmulo de DMO de membros inferiores de adolescentes do sexo feminino ao longo de 12 meses.
Bone health has received increasing attention from the academic community and society because of the great social and economic weight that osteoporosis represents. On the other hand, the development of osteoporosis in old age is strongly determined by events that occur in youth, in this case the low gains of bone mass. In this sense, the action of the muscular tissue in the strengthening of the bone structure has been investigated in young people, but many gaps still exist. Objective: To discriminate the impact of changes in lean soft tissue (LST) and body fat (BF) on the bone gain of adolescents of both sexes, as well as to identify the effect of both tissues on the bone gains in conditions involving different levels of impact mechanic, in environment of hypogra-phy (swimming), environment without sports (control group) and environment with sports practice with impact (soccer, basketball and martial arts). Methods: A longitudinal study with twelve months of follow-up (two moments of data collection) that was conducted in the city of Presidente Prudente - SP. The sample consisted of 262 young people classified as: Control, Swimming and Impact Sports (combined forms: karate, judo, kung-fu, soccer, basketball and volleyball). Bone mineral density (BMD), LST and BF were estimated by means of the dual energy X-ray absorptiometry in the i) lower limbs, ii) the left leg and iii) the right leg. Confounding variables were: chronological age, biological maturation, and vitamin D intake. Results: First, according to the analyzes presented, it can be observed that LST is the most relevant determinant of BMD gain explaining the variance found in BMD of lower limbs in 56% (adjusted R2 = 0.569) when considering the effects of gender, age and somatic maturation, on the other hand, BF does not seem to significantly affect BMD. In longitudinal analyzes (after twelve months of follow-up and adjusted for confounding factors), it can be observed that for the whole sample group and for those who practice sport of impact, LST was the most determinant variable for the accumulation of BMD in the lower limbs with mean for both legs approximately above 55% explanation. When the sample was divided by sex, it can be observed that for boys, LST was the greatest predictor for BMD accumulation in lower limbs, but for females BF was the variable that had the most explanation for BMD accumulation in lower limbs (both legs). Conclusions: The findings of the present study conclude that LST is the most relevant determinant regarding BMD gain in lower limbs in adolescent males even when considering the effects of sex, age and somatic maturation. On the other hand, longitudinally, lower limb BF seems to significantly affect BMD accumulation of lower limbs of female adolescents over 12 months.
Bone health has received increasing attention from the academic community and society because of the great social and economic weight that osteoporosis represents. On the other hand, the development of osteoporosis in old age is strongly determined by events that occur in youth, in this case the low gains of bone mass. In this sense, the action of the muscular tissue in the strengthening of the bone structure has been investigated in young people, but many gaps still exist. Objective: To discriminate the impact of changes in lean soft tissue (LST) and body fat (BF) on the bone gain of adolescents of both sexes, as well as to identify the effect of both tissues on the bone gains in conditions involving different levels of impact mechanic, in environment of hypogra-phy (swimming), environment without sports (control group) and environment with sports practice with impact (soccer, basketball and martial arts). Methods: A longitudinal study with twelve months of follow-up (two moments of data collection) that was conducted in the city of Presidente Prudente - SP. The sample consisted of 262 young people classified as: Control, Swimming and Impact Sports (combined forms: karate, judo, kung-fu, soccer, basketball and volleyball). Bone mineral density (BMD), LST and BF were estimated by means of the dual energy X-ray absorptiometry in the i) lower limbs, ii) the left leg and iii) the right leg. Confounding variables were: chronological age, biological maturation, and vitamin D intake. Results: First, according to the analyzes presented, it can be observed that LST is the most relevant determinant of BMD gain explaining the variance found in BMD of lower limbs in 56% (adjusted R2 = 0.569) when considering the effects of gender, age and somatic maturation, on the other hand, BF does not seem to significantly affect BMD. In longitudinal analyzes (after twelve months of follow-up and adjusted for confounding factors), it can be observed that for the whole sample group and for those who practice sport of impact, LST was the most determinant variable for the accumulation of BMD in the lower limbs with mean for both legs approximately above 55% explanation. When the sample was divided by sex, it can be observed that for boys, LST was the greatest predictor for BMD accumulation in lower limbs, but for females BF was the variable that had the most explanation for BMD accumulation in lower limbs (both legs). Conclusions: The findings of the present study conclude that LST is the most relevant determinant regarding BMD gain in lower limbs in adolescent males even when considering the effects of sex, age and somatic maturation. On the other hand, longitudinally, lower limb BF seems to significantly affect BMD accumulation of lower limbs of female adolescents over 12 months.
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Palavras-chave
Saúde óssea, Esportes de impacto, Tecido mole magro, Bone health, Impact sports, Lean soft tissue