Observations on the physiological interactions between obesity and asthma.

Division of Pulmonary, Critical Care, and Sleep Medicine, MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH 44109, USA.
Journal of Applied Physiology (Impact Factor: 3.43). 10/2008; 105(5):1533-41. DOI: 10.1152/japplphysiol.01260.2007
Source: PubMed

ABSTRACT To explore whether asthma and obesity share overlapping pathogenic features, we examined the impact of each alone, and in combination, on multiple aspects of lung function. We reasoned that if they influenced the lungs through similar mechanisms, the individual physiological manifestations in the comorbid state should interact in a complex fashion. If not, then the abnormalities should simply add. We measured specific conductance, spirometry, lung volumes, and airway responsiveness to adrenergic and cholinergic agonists in 52 normal, 53 asthmatic, 52 obese, and 53 asthmatic and obese patients using standard techniques. Six-minute walks were performed in subsets from each group. Asthma significantly lowered specific conductance and the spirometric variables while increasing airway reactivity and residual volume. Obesity also reduced the spirometric variables as well as total lung capacity and functional residual capacity. Residual volume, specific conductance, and airway responsivity were unaltered. With comorbidity, the disease-specific derangements added algebraically. Features that existed in isolation appeared unchanged in the combination, whereas shared ones either added or subtracted depending on the individual directional changes. Synergistic interactions were not observed. Body mass index weakly correlated with spirometry and lung volumes in asthma, but not with specific conductance or bronchial reactivity. Exercise performance did not aid in differentiation. Our findings indicate asthma and obesity appear to influence the respiratory system through different processes.

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    ABSTRACT: OBJETIVO: Avaliar e comparar a frequência e intensidade do broncoespasmo induzido pelo exercício (BIE) em adolescentes asmáticos obesos e não-obesos. MÉTODOS: Estudo transversal e descritivo realizado com 39 adolescentes de ambos os sexos, com idade entre dez e 16 anos, divididos em dois grupos conforme o histórico clínico de asma e/ou rinite alérgica e o índice de massa corporal: asmáticos obesos (n=18); asmáticos não-obesos (n=21). Utilizou-se o teste de broncoprovocação com exercício para a avaliação do BIE, considerando-se positiva uma diminuição do volume expiratório forçado no primeiro segundo (VEF1) >15% do valor pré-exercício. Para avaliar a intensidade e a recuperação do BIE, foram calculadas a queda percentual máxima do VEF1 (QM%VEF1) e a área acima da curva (AAC0-30). A análise estatística utilizou o teste exato de Fischer para comparar a frequência de BIE e o teste de Mann-Whitney para a intensidade e recuperação. Rejeitou-se a hipótese de nulidade se p<0,05. RESULTADOS: Não houve diferença significativa na frequência de BIE entre os grupos de asmáticos obesos (50%) e não-obesos (38%). Entretanto, a queda máxima do VEF1 e a AAC0-30 foram maiores nos asmáticos obesos em comparação aos não-obesos (respectivamente 37,7% e 455 versus 24,5% e 214, p<0,03). CONCLUSÕES: A obesidade não contribuiu para o aumento da frequência do BIE em asmáticos e não-asmáticos, entretanto, a obesidade contribuiu para o aumento da intensidade e do tempo de recuperação da crise de BIE em asmáticos.
    Revista Paulista de Pediatria 03/2010; 28(1):36-40.
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    ABSTRACT: Obesity has complex and incompletely understood effects upon the respiratory system in childhood, which differs in some aspects to those seen in adults. There is increasing evidence that excess adiposity will impact negatively upon static and dynamic respiratory function as measured through lung volumes, lung compartment mechanics, measures of airway function and exercise capability to varying degrees. Further information is needed to better understand the effects in children, and the importance of onset and duration of obesity on subsequent outcomes. Consensus about how best to express adiposity is also an essential part of this process and fat distribution is another important factor. From a clinical standpoint this creates challenges in distinguishing a deconditioned obese young person from a non-atopic asthmatic because of symptom overlap and lung function testing results, including response seen during airway challenges. There is evidence to support the role of weight loss in achieving normalisation of lung function parameters, but as always with obesity there are enormous challenges in realising this goal for many subjects.
    Paediatric respiratory reviews 09/2014; · 2.22 Impact Factor
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    Respirology 09/2014; · 3.50 Impact Factor