Does Age Impact the Obese Asthma Phenotype?
Division of Pulmonology, Allergy and Immunology, Center for Pharmacogenomics and Translational Research, Nemours Children's Clinic, 807 Children's Way, Jacksonville, FL 32207, USA. Chest
(Impact Factor: 7.48).
07/2011; 140(6):1524-33. DOI: 10.1378/chest.11-0675
The relationship between obesity and asthma remains inadequately defined. Studies about how obesity affects asthma control and lung function show conflicting results. Additional focus on the effect of age as a modifier may make clearer the interaction between obesity and asthma phenotype. We sought to use a diverse and well-phenotyped cohort of asthmatic patients to determine how age impacts the relationship between obesity and spirometry, peak flow variability, airflow perception, and asthma control.
The characteristics of 490 patients with mild persistent asthma taken from 2,794 study visits from a prospective trial studying strategies of step-down therapy were included in this post hoc analysis. A longitudinal mixed-effect model was used to determine if age affects the relationship between obesity and asthma characteristics, including spirometry, asthma control, airway pH, and perception of airflow changes.
The effect of obesity on asthma outcomes changes with age and gender. Obese 6- to 11-year-old children had the largest reduction in lung function but reported relatively fewer asthma symptoms than did similar nonobese asthmatics. Obese 12- to 17-year-olds showed a trend toward greater airflow obstruction and asthma symptoms compared with nonobese asthmatics. Adults in general displayed few obesity-related alterations in asthma phenotype. Female gender among 12- to 17- and 18- to 44-year-olds was associated with greater obesity-related asthma impairment.
Age is a significant effect modifier on the relationship between obesity and asthma phenotype. With increasing age, the influence of obesity on the asthma phenotype is generally reduced. The asthma phenotype may be most impacted by obesity among children and women.
ClinicalTrials.gov; No.: NCT00156819; URL: www.clinicaltrials.gov.
Available from: PubMed Central
- "Otherwise, both obese age-of-onset groups had similar lung function impairment, atopy, adipokines and markers of systemic inflammation . Although not addressing age-of-asthma onset, Lang et al., concluded that obesity had a greater detrimental effect on the lung function of children and adolescents as opposed to adults . "
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ABSTRACT: Asthma is a heterogenous disorder that can be classified into several different phenotypes. Recent cluster analyses have identified an "obese-asthma" phenotype which is characterized by late onset, female predominance and lack of atopy. In addition, obesity among early-onset asthmatics clearly exists and heightens the clinical presentation. Observational studies have demonstrated that asthma among the obese has a clinical presentation that is more severe, harder to control, and is not as responsive to standard controller therapies. While weight loss studies have demonstrated improvement in asthma outcomes, further studies need to be performed. The current knowledge of the existence of two obesity-asthma phenotypes (early- versus late-onset asthma) should encourage investigators to study these entities separately since just as they have distinct presentations, their course, response to therapies, and weight loss strategies may be different as well.
Available from: Maria Pedrosa
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ABSTRACT: Asthma and obesity have a considerable impact on public health and their prevalence has increased in recent years. Numerous studies have linked both disorders. Most prospective studies show that obesity is a risk factor for asthma and have found a positive correlation between baseline body mass index (BMI) and the subsequent development of asthma, although these results are not conclusive when studying the association between airway hyperresponsiveness with BMI. Furthermore, several studies suggest that whereas weight gain increases the risk of asthma, weight loss improves the course of the illness. Different factors could explain this association. Obesity is capable of reducing pulmonary compliance, lung volumes and the diameter of peripheral respiratory airways as well as affecting the volume of blood in the lungs and the ventilation-perfusion relationship. Furthermore, the increase in the normal functioning of adipose tissue in obese subjects leads to a systemic proinflammatory state, which produces a rise in the serum concentrations of several cytokines, the soluble fractions of their receptors and chemokines. Many of these mediators are synthesized and secreted by cells from adipose tissue and receive the generic name of adipokines, including IL-6, IL-10, eotaxin, TNF-α, TGF- 1, PCR, leptin y adiponectin. Finally, specific regions of the human genome which are related to both asthma and obesity have been identified. Most studies point out that obesity is capable of increasing the prevalence and incidence of asthma, although this effect appears to be modest. The treatment of obese asthmatics must include a weight control program.
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ABSTRACT: OBJECTIVE: The relationship between weight status and asthma characteristics in children remains inadequately defined. Very little has been published on the risk of exacerbation, physician perception of severity, and the level controller treatment prescribed to underweight and obese children with asthma in a real-world setting. METHODS: We assessed the diagnostic severity, pulmonary function, exacerbation prevalence, and controller treatment level in 10,559 new asthma patients seen at one of four pediatric asthma subspecialty clinics among three BMI groups. Participants were analyzed by body mass index (BMI)-percentile based on Centers for Disease Control & Prevention classification. Multivariable logistic regression models were used to assess the associations between BMI-percentile cohort group and asthma outcomes. RESULTS. Underweight asthmatics were rare (2.5%) relative to obese asthmatics but appeared to have the greatest impairment in forced vital capacity and had the greatest controller treatment burden. Obese asthmatic children made up 26.2% of our cohort and were more likely to have severe disease (odds ratio (OR) 1.40, 95% confidence interval (CI) 1.06-1.85) and airflow obstruction (OR 1.36, 95% CI 1.16-1.59) compared to normal weight asthmatics. Obese asthmatics were not at greater risk for exacerbation (OR 1.41, 95% CI 0.64-3.11) or high treatment burden (OR 1.03, 95% CI 0.83-1.28). CONCLUSIONS. Obesity is more common than underweight status among children with asthma. Both underweight and obese children with asthma have worse lung function and asthma-related outcomes compared to similar normal weight children, though the phenotypic characteristics of underweight and obese asthmatics differed considerably.
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