What Is New In Small Airways Research
By Ves Dimov, M.D.
Allergist/Immunologist, Assistant Professor of Medicine and Pediatrics
University of Chicago
Web Content Editor, WAO Small Airways Working Group
Posted: 13 July 2012
Breastfeeding protects against asthma up to 6 years of age
This prospective birth cohort from New Zealand included 1,105 infants. Information about wheezing and current asthma was collected at 2, 3, 4, 5, and 6 years.
Each month of exclusive breastfeeding was associated with reductions in current asthma from 2 to 6 years. Current asthma at 2, 3, and 4 years was also reduced by each month of any breastfeeding.
In atopic children, exclusive breastfeeding for ≥3 months reduced current asthma at ages 4, 5, and 6 by 62%, 55%, and 59%, respectively.
The authors concluded that breastfeeding, particularly exclusive breastfeeding, protects against current asthma up to 6 years. The degree of protection beyond 3 years was more pronounced in atopic children.
Silvers KM, Frampton CM, Wickens K, Pattemore PK, Ingham T et al., and the New Zealand Asthma and Allergy Cohort Study Group. Breastfeeding protects against current asthma up to 6 years of age. The Journal of Pediatrics 2012; 160(6):991-996.e1.
Image source: Wikipedia, GNU Free Documentation License
Asthma death is a rare but devastating event. What are the risk factors?
This small retrospective review of medical records included 22 patients who died of asthma outside the hospital during a 4-year period (2004 to 2008). The study was based in Milwaukee, Wisconsin, USA.
The mean age of the patients was 32 years, and 64% were African American. 77% died during the night or shortly on awakening. 55% died during the summer in June, July, or August. A history of illicit drug, alcohol, or tobacco use was discovered in 59%. Toxicologic test results for drugs of abuse were positive in 18%.
20 out of 22 patients were using or overusing a short-acting β-agonist. None were taking long-acting β-agonists alone. Two patients were taking no medications. Lung pathologic testing revealed eosinophils in 18 (out of 22) patients. There was no neutrophil infiltration.
The risk characteristics for asthma deaths in this small study included:
- being African Americans
- symptoms at night and during the summer months
- substance abuse
- not taking anti-inflammatory asthma medications
Mohiuddin M, Zacharisen MC, Poulos C, Levy MB. Asthma deaths outside the hospital in an urban community from 2004 to 2008. Annals of Allergy, Asthma & Immunology 2012; 108(6):412-417.
Inflammation and bronchial hyperresponsiveness persist in most patients with well-controlled asthma
Little research has been devoted to the characteristics of bronchial inflammation in patients with stable, well-controlled asthma. The aim of this study was to assess the airway inflammation and bronchial hyperresponsiveness in well controlled asthma in 84 adult patients (mean age 43 years).
59 patients had persistent bronchial inflammation: 28 cases were considered eosinophilic, 28 neutrophilic. A positive correlation was found between eosinophil percentage and the methacholine response. The study authors concluded that inflammation and bronchial hyperresponsiveness persist in most patients with well-controlled asthma.
It is interesting to notice that less than 50% of the patients had eosinophilic inflammation. This finding may limit the usefulness of FeNO monitoring devices for asthma evaluation and follow-up because they detect FeNO which is produced by eosinophilic inflammation. Patients with neutrophilic inflammation may not have elevated FeNO levels and could be misclassified as having controlled asthma (or no asthma at all) if significant emphasis is placed on FeNO assessment.
Muñoz X, Sanchez-Vidaurre S, Roca O, Torres F, Morell F, Cruz MJ. Bronchial inflammation and hyperresponsiveness in well-controlled asthma. Clinical & Experimental Allergy 2012; Accepted Article, 30 March. doi: 10.1111/j.1365-2222.2012.04004.x
Posted: 13 July 2012