Repercussões do estado nutricional do zinco em crianças e adolescentes com síndrome de Down
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Data
2022-02-01
Autores
Delambert, Cristina Helena Lima
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A Síndrome de Down (SD) é uma afecção cromossômica. Estudos têm buscado os mecanismos envolvidos na fisiopatologia de doenças associadas a SD, bem como os fatores contribuintes para o comprometimento do crescimento e desenvolvimento. Disfunções tireoideanas, bem como deficiência de micronutrientes, já foram evidenciados. O zinco é um dos micronutrientes envolvido nos processos de diferenciação celular, crescimento estatural, desenvolvimento neurológico e defesa imunológica, sendo que a sua deficiência pode levar à prejuízos em crianças com a SD. No Brasil não se conhece a real magnitude dessa deficiência na população em geral e mais especificamente entre os com a SD. O objetivo deste estudo foi avaliar o estado nutricional do zinco em crianças e adolescentes com SD e suas repercussões sobre o crescimento e a função tireoideana, e verificar a resposta à suplementação deste micronutriente, propondo um protocolo de assistência à esta população. Método: Estudo clínico caso-controle e ensaio clínico, realizado em 2020 e 2021, em um serviço ambulatorial de Hospital Universitário, com uma amostra de conveniência. Grupo Caso: crianças e adolescentes com SD, com pareamento por sexo e idade com o grupo controle, sem a síndrome (1:1). Etapas do estudo: 1- Avaliação e classificação antropométrica, análises laboratoriais de TSH e T4 livre, dosagens de zinco eritrocitário e sérico, e de IGF-1, além de ingesta de zinco da dieta; 2- administração de sulfato de zinco heptahidratado durante 6 meses e reavaliação dos parâmetros iniciais. Estudo aprovado pelo Comitê de Ética em pesquisa. Resultados: Foi realizado o pareamento de 42 pacientes, e iniciada a suplementação destas crianças. Foram significantes as diferenças entre os grupos em relação ao peso de nascimento (p=0,04), e quanto ao zinco eritrocitário (p<0,001), deficitário no grupo controle, apesar de a dieta de ambos os grupos não apresentar insuficiência no consumo deste micronutriente. A dosagem de IGF-1 foi normal em ambos os grupos. A disfunção tireoideana foi estatisticamente significante no grupo com a SD (p<0,001) e a relação estatura/idade foi majoritariamente adequada em ambos os grupos. A análise comparativa pré e pós suplementação foi concluída para 16 pacientes, sendo que apenas um apresentou zinco sérico abaixo do valor de referência após a suplementação, e seis (37,5%) pacientes tiveram um incremento maior ou igual a 0,5 no z-score de estatura do momento da inclusão no estudo. Houve melhora no perfil tireoideano em 6,2% dos pacientes, com redução do TSH e implemento no T4 livre. Não foram significantes as variações de TSH, T4 livre, estatura, IGF-1, zinco sérico e eritrocitário. Considerações: Assim, em contraposição ao descrito na literatura, as crianças e adolescentes com a síndrome de Down apresentaram melhor adequação do estado nutricional do zinco, em relação ao grupo controle. A repercussão da suplementação de zinco observada, abre expectativas sobre alteração na estatura/idade dos que tem a SD. Os resultados ressaltam a relevância do seguimento regular em serviço de assistência à saúde com abordagem integral e multiprofissional, desde os primeiros meses de vida.
Down Syndrome (DS) is a chromosomal disorder. Studies have sought the mechanisms involved in the pathophysiology of diseases associated with DS, as well as the factors that contribute to changes growth and development. Thyroid dysfunctions as well as micronutrient deficiencies have already been evidenced. Zinc is one of the micronutrients involved in the processes of cell differentiation, height growth, neurological development and immune defense, and its deficiency can lead to damage in children with DS. There are no studies in Brazil and the real magnitude of this deficiency is not known in the general population and more specifically among those with DS. The objective of this study was to evaluate the nutritional status of zinc in children and adolescents with DS and its effects on growth and thyroid function, and to verify the response to supplementation of this micronutrient, proposing an assistance protocol for this population. Method: A case-control clinical study and a clinical trial, accomplished in 2020 and 2021, in an outpatient service of a University Hospital, with a convenience sample. Case Group: children and adolescents with DS, paired by sex and age with the control group, without the syndrome (1:1). Study steps: 1- Anthropometric assessment and classification, laboratory analysis of TSH and free T4, erythrocyte and serum zinc dosages, and IGF-1, in addition to assessment of dietary zinc intake; 2- administration of zinc sulfate heptahydrate for 6 months and reassessment of initial parameters. Study approved by the Research Ethics Committee. Results: Step 1 concluded, with pairing of 42 individuals, and the supplementation of these children started. Differences between groups were significant in relation to birth weight (p=0.04), and regarding the level of erythrocyte zinc (p<0.001), lower in the control group, despite the fact that the diet of both groups did not show insufficiency in the consumption of this micronutrient. The dosage of somatomedin C did not show insufficient results in any of the groups. Thyroid dysfunction was statistically significant in the DS group (p<0.001) and the height/age ratio was mostly adequate in both groups. The pre- and post-supplementation comparative analysis was completed for 16 patients, with only one having serum zinc below the reference value after supplementation, and six (37.5%) patients had an increase greater than or equal to 0.5 in stature z -score at the time of inclusion in the study. There was an improvement in the thyroid profile in 6.2% of the patients, with a reduction in TSH and implementation in free T4. The variations in TSH, free T4, height, IGF-1, serum zinc and erythrocytes were not significant. Considerations: In opposition to what is described in the literature, children and adolescents with Down syndrome presented better adequacy of the nutritional status of zinc than the control group. The repercussion of zinc supplementation observed opens expectations about changes in height/age of those with DS. The results highlight the relevance of regular follow-up in a health care service, with integral care and multidisciplinary team, from the first months of life.
Down Syndrome (DS) is a chromosomal disorder. Studies have sought the mechanisms involved in the pathophysiology of diseases associated with DS, as well as the factors that contribute to changes growth and development. Thyroid dysfunctions as well as micronutrient deficiencies have already been evidenced. Zinc is one of the micronutrients involved in the processes of cell differentiation, height growth, neurological development and immune defense, and its deficiency can lead to damage in children with DS. There are no studies in Brazil and the real magnitude of this deficiency is not known in the general population and more specifically among those with DS. The objective of this study was to evaluate the nutritional status of zinc in children and adolescents with DS and its effects on growth and thyroid function, and to verify the response to supplementation of this micronutrient, proposing an assistance protocol for this population. Method: A case-control clinical study and a clinical trial, accomplished in 2020 and 2021, in an outpatient service of a University Hospital, with a convenience sample. Case Group: children and adolescents with DS, paired by sex and age with the control group, without the syndrome (1:1). Study steps: 1- Anthropometric assessment and classification, laboratory analysis of TSH and free T4, erythrocyte and serum zinc dosages, and IGF-1, in addition to assessment of dietary zinc intake; 2- administration of zinc sulfate heptahydrate for 6 months and reassessment of initial parameters. Study approved by the Research Ethics Committee. Results: Step 1 concluded, with pairing of 42 individuals, and the supplementation of these children started. Differences between groups were significant in relation to birth weight (p=0.04), and regarding the level of erythrocyte zinc (p<0.001), lower in the control group, despite the fact that the diet of both groups did not show insufficiency in the consumption of this micronutrient. The dosage of somatomedin C did not show insufficient results in any of the groups. Thyroid dysfunction was statistically significant in the DS group (p<0.001) and the height/age ratio was mostly adequate in both groups. The pre- and post-supplementation comparative analysis was completed for 16 patients, with only one having serum zinc below the reference value after supplementation, and six (37.5%) patients had an increase greater than or equal to 0.5 in stature z -score at the time of inclusion in the study. There was an improvement in the thyroid profile in 6.2% of the patients, with a reduction in TSH and implementation in free T4. The variations in TSH, free T4, height, IGF-1, serum zinc and erythrocytes were not significant. Considerations: In opposition to what is described in the literature, children and adolescents with Down syndrome presented better adequacy of the nutritional status of zinc than the control group. The repercussion of zinc supplementation observed opens expectations about changes in height/age of those with DS. The results highlight the relevance of regular follow-up in a health care service, with integral care and multidisciplinary team, from the first months of life.
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Palavras-chave
Síndrome de Down, Doenças por deficiência de zinco, Hormônios tireoidianos, Crescimento, Promoção da saúde, Down Syndrome, Zinc deficiency diseases, Thyroid deficiency, Growth, Health promotion