Teses e Dissertações

• Teses
• Dissertações

A obesidade tem aumentado em todo o mundo nas últimas décadas, inclusive entre as crianças. Segundo Barker, exposições no período intrauterino podem determinar o desenvolvimento de mecanismos adaptativos, que visam garantir a sobrevivência em curto prazo, mas que podem programar o desenvolvimento de doenças em idade adulta. Entretanto, alguns pesquisadores, baseados em achados mais recentes, propõem que fatores ocorridos após o nascimento é que determinam a presença de co-morbidade na vida adulta.
A velocidade do ganho de peso, particularmente o rápido ganho de peso ou crescimento acelerado, está associada a maior risco de sobrepeso ou obesidade, tanto na infância quanto na vida adulta. Alguns estudos mostram que o crescimento acelerado ocorrido depois dos dois anos de idade pode ter maior influência na composição corporal na vida adulta em termos de massa gorda quando comparado àquele ocorrido antes dos dois anos de idade.
Este estudo será realizado com dados da Coorte de Nascimentos de 2004 de Pelotas. Todos os nascidos vivos desse ano foram acompanhados ao nascer, aos 3, 12, 24 e 48 meses e serão novamente examinados aos 6-7 anos de idade. A partir de medidas como o índice de massa corporal (IMC) e do registro do peso nos acompanhamentos anteriores, será determinado o ganho de peso entre zero e três meses, três e 12 meses, 12 e 24 meses e 24 e 48 meses de idade.
Este projeto de pesquisa tem por objetivo identificar o período do crescimento acelerado e de relacioná-lo ao sobrepeso ou obesidade aos 6-7 anos. Além disso, será realizada análise estratificada para avaliar o risco de sobrepeso no grupo de crianças nascidas pequenas para a idade gestacional (PIG) e adequado para a idade gestacional (AIG) e identificar fatores determinantes do crescimento acelerado.

Artigo 1 - Determining factors for accelerated growth in childhood: A systematic review

Abstract

Several studies have shown that accelerated growth in the postnatal period is critical for the development of chronic diseases. The term catch-up has been used for the accelerated growth of children who have suffered some sort of restriction of nutrition or oxygen supply. However, accelerated growth has been observed among children who have an appropriate birth weight for their gestational age (AGA) and with no apparent morbidity. Therefore, this systematic review was carried out on the associated factors of accelerated growth, or catch-up, using the Medline/Pubmed database. Only cohort studies written in Portuguese, English or Spanish, with children between zero and 12 years old who presented accelerated growth or catch-up as the outcome were included. Out of the 2,155 articles found, 9 were selected. There is no uniformity in the operational definition of accelerated growth, or in the concept of catch-up. According to this review, accelerated growth is associated with primiparity, maternal smoking during pregnancy, lower birth weight, and early weaning. The main limitations in the available literature are the high number of follow-up losses and the lack of control for confounding factors. The determinants of accelerated growth still need to be studied further, especially among AGA children.


Artigo 2 – Rápido ganho de peso e rápido ganho em estatura entre 0 e 4 anos: um estudo de coorte prospectiva

Abstract

Background: Evidence suggests that rapid weight gain (RWG) and rapid growth in height (RGH) during childhood are associated with adult chronic degenerative diseases.
Objective: This study aimed to assess the prevalence of RWG and RGH in children 0 to 3, 3 to 12, 12 to 24 and 24 to 48 months of age.
Methods: Data were obtained from the 2004 Pelotas Birth Cohort. RWG was defined as weight gain greater than 0.67 standard deviations (SD) of the weight-for-age z-scores (WAZ), and RGH was defined as growth in height greater than 0.67 SD of the height-for-age z-scores. Both RWG and RGH were also defined as conditional weight and height gain, respectively.
Results: Children were born with greater birth weight and lower length compared with the WHO growth reference charts for children. Higher rates of RWG and RGH were seen in children up to 12 months and 24 months, respectively. Both RWG and RGE greater than 0.67 SD and conditional gain were more common among children of higher socioeconomic condition, female children younger than 24 months of age and male children older than 24 months of age, and those born to mothers with higher education.
Conclusions: Most of the children presented RWG and RGH at the first 24 months of life, whereas 15% had RWG after this age. The fact of the period when RWG took place over the development of adult chronic diseases needs to be investigated.
Keywords Weight gain, growth


Artigo 3 – Rápido ganho de peso e rápido ganho em estatura nos primeiros anos de vida e composição corporal aos 6 anos de idade: um estudo de coorte prospectiva

Abstract

To assess the relationship between rapid weight gain (RWG) and rapid growth in height (RGH) in children 0 to 48 months of age and adiposity at 6 years of age. Methods: A total of 3,428 children from the 2004 Pelotas Birth Cohort were studied. The fat mass index (FMI) and fat-free mass index (FFMI) were determined by dual-energy X-ray absorptiometry (DXA) and air displacement plethysmography (Bod Pod). Both RWG and RGH were defined as conditional gain. Multivariate analyses were conducted using linear regression.
Results: Both FMI and FFMI were associated with RWG. Among male children, the highest FMI was associated with RWG at 24–48 months of age (1.12, 95% CI 1.03–1.20) and FFMI was associated with RWG in all age groups. Among female children, there was found an association between RWG and FMI in those aged 3 months but without any specific age of greatest risk. An association of RWG and increased FFMI was seen only at 12 months. RGH was associated with FMI in males at all ages and in females at 3–12 months only (1.15, 95% CI 0.27–2.02). No association between RGH and FFMI was found in both sexes. When RWG and RGE were categorized into early (0–2 years of age), late (2–4 years), and early and late (0–4 years), mean weights and FMI were greater among children showing early and late RWG. Conclusions: RWG or RGH during the first 2 years or between 2 to 4 years of life are associated with increased FMI. But this association was stronger in both male and female children when RWG and RGH started between 0–2 years and persisted through 4 years of age.
Keywords: body fat, weight gain