Epidemiology of bronchial hyperresponsiveness

Area of Science:

• Respiratory Medicine
• Pulmonology
• Clinical Allergy and Immunology

Background:

• Asthma prevalence and severity are increasing in developed nations.
• Objective measurement of airway abnormality in asthma is critical.
• Bronchial hyperresponsiveness (BHR) is the sole practical objective method for assessing airway abnormality in asthma.

Purpose of the Study:

• To examine BHR measurement for asthma detection and improve test sensitivity and specificity.
• To investigate the association between BHR severity and long-term asthma morbidity.
• To explore risk factors for BHR development for potential preventive strategies.

Main Methods:

• Analysis of BHR measurements, focusing on specific thresholds (PD20FEV1 < 0.8 mumol histamine).
• Comparison of BHR severity levels in populations.
• Investigation into dose-response curve parameters (shape, similarity) for enhanced specificity.
• Review of existing literature on BHR prevalence in North America.

Main Results:

• Community BHR measurements are not currently reliable asthma markers and require careful interpretation, especially in adults.
• Moderate to severe BHR levels are strongly linked to clinically significant morbidity.
• Comparative analysis of BHR severity may offer more insights than broader ranges.
• Limited studies exist on BHR prevalence in large North American pediatric and adult populations.

Conclusions:

• BHR measurement is vital for asthma assessment, but its interpretation needs refinement.
• Severe BHR is a strong indicator of morbidity, warranting further investigation into its long-term impact.
• Identifying BHR risk factors is essential for developing future preventive measures.
• Large-scale North American studies are needed to understand regional asthma and BHR prevalence differences.