RESUMO
BACKGROUND: An increase in the prevalence of overweight and asthma has been observed. Both conditions affect negatively lung function in adults and children. The aim of this study was to analyze the effect of overweight and asthma on lung function in children. METHODS: We designed a case-control study of healthy and asthmatic subjects nested within an epidemiological asthma prevalence study in children between 8 and 16 years of age. The effect of asthma and overweight on lung function was assessed by impulse oscillometry and spirometry obtained at baseline and 10-15 min after salbutamol. RESULTS: 188 children were recruited, 114 (61%) were asthmatics and 72 (38%) were overweight or obese. Children with asthma and overweight had a higher FVC (+1.16 z scores, p < 0.001) and higher FEV1 (+0.79 z scores, p = 0.004) and lower FEV1/FVC (-0.54 z scores, p = 0.008) when compared to healthy controls. Compared to normal weight asthmatics, the overweight had higher FVC (+0.78 z scores, p = 0.005) and lower FEV1/FVC (-0.50 z scores, p = 0.007). In the multivariate analysis, overweight was associated with an increase of 0.71 and 0.44 z scores in FVC and FEV1, respectively, and a reduction in FEV1/FVC by 0.40 z scores (p < 0.01 for all). Overweight had no effect on maximal flows and airway resistance at baseline, and this was not modified by inhalation of a bronchodilator. Asthma was also associated with higher post-BD FVC (0.45 z scores, p = 0.012) and FEV1 (0.35 z scores, p = 0.034) but not with FEV1/FVC and FEF25-75%. Two-way analysis of variance did not detect any interaction between asthma and overweight on lung function variables before or after bronchodilator. CONCLUSION: Our results suggest that asthma and overweight are independently associated with airway dysanaptic growth in children which can be further scrutinized using impulse oscillometry. Overweight contributed more to the reduction in FEV1/FVC than asthma in children without increasing airway resistance. Spirometry specificity and sensitivity for obstructive diseases may be reduced in populations with high prevalence of overweight. Adding impedance oscillometry to spirometry improves our understanding of the ventilatory abnormalities in overweight children.
RESUMO
Aims: Published evidence suggests that Vitamin D supplementation may have a protective effect on infectious disease of the lower respiratory tract. The objective of this review was to critically appraise the effects of vitamin D intake in the prevention of acute viral bronchiolitis in children. Methods: We searched the databases Medline, EMBASE, Web of Science, LILACS, and Cochrane Central Register of Controlled Trials, until December 2014, using the keywords: "Vitamin D" or cholecalciferol or ergocalciferol and "bronchiolitis, viral" or "viral bronchiolitis" or "bronchiolitides, viral" or "viral bronchiolitides". Studies evaluating the effect of vitamin D intake in the prevention of acute viral bronchiolitis in young children were included. Studies with less than two weeks of intervention and review articles were excluded. Results: The search identified 241 articles, among which 20 articles were selected for full reading and two articles were included in the systematic review, comprising 296 children. No study measured serum levels of vitamin D. One of the included studies was a clinical trial, where the number of episodes of acute viral bronchiolitis was significantly lower in children supplemented with vitamin D (Group I: mean 0.6±0.7 Group II: mean 1.4±0.9; P=0.001). The other, a case-control study, did not find a significant relationship between the occurrence of acute viral bronchiolitis cases and the intake of vitamin D (odds ratio 1.7, 95% confidence interval 0.7-4.0). Conclusions: Current scientific evidence is insufficient to prove clinical benefits of vitamin D in preventing acute viral bronchiolitis.
Objetivos: Evidências publicadas sugerem que a suplementação da vitamina D pode ter efeito protetor nas infecções do trato respiratório inferior. O objetivo desta revisão foi avaliar os efeitos da ingestão de vitamina D na prevenção da bronquiolite viral aguda em crianças. Métodos: Foram feitas buscas nas bases de dados Medline, EMBASE, Web of Science, LILACS e Cochrane Central Register of Controlled Trials, até dezembro de 2014, usando os descritores "Vitamin D" ou cholecalciferol ou ergocalciferol e "bronchiolitis, viral" ou "viral bronchiolitis" ou "bronchiolitides, viral" ou "viral bronchiolitides". Foram incluídos estudos que avaliaram o efeito da ingesta da vitamina D na prevenção da bronquiolite viral aguda em crianças. Estudos com intervenção menor que duas semanas e artigos de revisão foram excluídos. Resultados: A busca identificou 241 artigos, entre os quais 20 artigos foram selecionados para leitura na íntegra e dois artigos foram incluídos na revisão sistemática, incluindo 296 crianças. Nenhum estudo mediu os níveis séricos de vitamina D. Um dos estudos incluídos foi um ensaio clinico, no qual o número de episódios de bronquiolite foi significativamente menor nas crianças suplementadas com vitamina D (Grupo I: média 0,6±0,7 Grupo II: média 1,4 ±0,9; P=0,001). No outro, um estudo de casos e controles, não se encontrou relação significativa entre casos de bronquiolite viral aguda e ingesta de vitamina D (odds ratio 1,7 intervalo de confiança 95% 0,7-4,0). Conclusões: As evidências científicas atuais são insuficientes para comprovar os benefícios clínicos da vitamina D na prevenção da bronquiolite viral aguda.
