Association of asthma with obesity among adolescents exposed to environmental tobacco smoke

Asthma interactions between obesity and other risk factors

OBJECTIVE

To review and critically discuss published evidence on interactions between obesity and selected risk factors on asthma in children and adults, and to discuss potential future directions in this field.

DATA SOURCES

National Library of Medicine (via PubMed) STUDY SELECTION: A literature search was conducted for human studies on obesity and selected interactions (with sex, race and ethnicity, socioeconomic status, indoor and outdoor pollutants, depression, anxiety, and diet) on asthma. Studies that were published in English and contained a full text were considered for inclusion in this review.

RESULTS

Current evidence supports interactions between obesity and outdoor and indoor air pollutants (including second-hand smoke [SHS]) on enhancing asthma risk, although there are sparse data on the specific pollutants underlying such interactions. Limited evidence also suggests that obesity may modify the effects of depression or anxiety on asthma, whereas little is known about potential interactions between obesity and sex-hormone levels or dietary patterns.

CONCLUSION

Well-designed observational prospective studies (eg, for pollutants and sex hormones) and randomized clinical trials (eg, for the treatment of depression) should help establish the impact of modifying coexisting exposures to reduce the harmful effects of obesity on asthma. Such studies should be designed to have a sample size that is large enough to allow adequate testing of interactions between obesity and risk factors that are identified a priori and thus, well characterized, using objective measures and biomarkers (eg, urinary or serum cotinine for SHS, epigenetic marks of specific environmental exposures).

An Overview of the Obese-Asthma Phenotype in Children

Asthma is the most common chronic disease in childhood. Overweight and obesity are included among the comorbidities considered in patients with difficult-to-treat asthma, suggesting a specific phenotype of the disease. Therefore, the constant increase in obesity prevalence in children and adolescents raises concerns about the parallel increase of obesity-associated asthma. The possible correlation between obesity and asthma has been investigated over the last decade by different authors, who suggest a complex multifactorial relationship. Although the particular non-eosinophilic endotype of obesity-related asthma supports the concept that high body weight precedes asthma development, there is ongoing debate about the direct causality of these two entities. A number of mechanisms may be involved in asthma in combination with obesity disease in children, including reduced physical activity, abnormal ventilation, chronic systemic inflammation, hormonal influences, genetics and additional comorbidities, such as gastroesophageal reflux and dysfunctional breathing. The identification of the obesity-related asthma phenotype is crucial to initiate specific therapeutic management. Besides the cornerstones of asthma treatment, lifestyle should be optimized, with interventions aiming to promote physical exercise, healthy diet, and comorbidities. Future studies should clarify the exact association between asthma and obesity and the mechanisms underlying the pathogenesis of these two related conditions with the aim to define personalized therapeutic strategies for asthma management in this population.

Comorbid Obesity and Depressive Symptoms in Childhood Asthma: A Harmful Synergy

BACKGROUND

Overweight/obesity (OV/OB) and depression have each been separately associated with worsened childhood asthma severity and control. Pathways by which these factors may jointly affect childhood asthma have not been elucidated.

OBJECTIVE

To examine the interrelationship of OV/OB and depressive symptoms with childhood asthma and explore associated psychobiologic pathways. The present study investigated whether comorbid OV/OB and depressive symptoms are associated with impaired baseline lung function and increased airway resistance during emotional stress, and to assess whether such effects may be mediated by autonomic nervous system (ANS) dysregulation, specifically through predominance of vagal over sympathetic reactivity (vagal bias).

METHODS

A total of 250 children with asthma, aged 7 to 17, were assessed for OV/OB using body mass index, depressive symptoms using the Children's Depression Inventory (CDI), and asthma severity using National Asthma Education and Prevention Program Expert Panel Report 3 criteria. Baseline pulmonary function (forced expiratory volume in 1 second [FEV₁]) was assessed. The film "E.T. the Extra-Terrestrial" was used in a laboratory paradigm to evoke emotional stress/arousal. Airway resistance (R_int) was measured before and after the film to determine changes in airway function. ANS reactivity was assessed by measuring parasympathetic/vagal and sympathetic reactivity throughout the film.

RESULTS

In OV/OB children with asthma, depressive symptoms predicted lower baseline FEV₁ (β = -0.67, standard error [SE] = 0.24, P = .008), CDI predicted vagal bias under emotion stress/arousal (β = 0.27, SE = 0.09, P = .009), and vagal bias predicted increased R_int (β = 3.55, SE = 1.54, P = .023).

CONCLUSION

This study is the first to link OV/OB and depressive symptoms in their relationship to childhood asthma. In OV/OB children with asthma, depression may potentiate airway compromise, mediated by vagal bias. Use of antidepressant and anticholinergic therapies should be studied in this subgroup of patients.

United States prevalence of pediatric asthma by environmental tobacco smoke exposure, 2016-2017

OBJECTIVES

We sought to update the prevalence estimates of parent-reported asthma diagnosis by Environmental Tobacco Smoke (ETS) exposure in the United States (US) pediatric population.

METHODS

This cross-sectional study included 71,811 families with children who participated in the 2016-2017 National Survey of Children's Health (NSCH). Weighted asthma prevalence estimates were calculated for ETS-exposed and non-exposed children. Chi-square analysis compared asthma prevalence between the two exposure groups and logistic regression analysis generated adjusted odds ratios (aORs) of asthma diagnosis by ETS exposure by sex, race/ethnicity, and household education and income level.

RESULTS

Asthma prevalence estimates were significantly higher in ETS-exposed vs. non-exposed children (10.7% vs. 7.8%, p < 0.001). Children with a smoker in the house are 30% more likely to have an asthma diagnosis vs. children with no smokers in the house (aOR 1.29, 95% Confidence Interval [CI] 1.09-1.52). Significant predictors for ETS exposure included < high school education and lower family income. Conversely, non-Hispanic black and Hispanic children were less likely to have ETS exposure vs. non-Hispanic white children.

CONCLUSIONS

ETS exposure is a significant risk factor for asthma in the US pediatric population. Smoking cessation initiatives targeting non-Hispanic white parents from lower socioeconomic may improve children's chronic pulmonary health risk.