Increased nonspecific bronchial reactivity in cigarette smokers with normal lung function

Area of Science:

• Pulmonology
• Environmental Health
• Occupational Health

Background:

• Smoking is a major risk factor for respiratory diseases.
• Nonsmokers can also develop respiratory symptoms and airway hyperresponsiveness.

Purpose of the Study:

• To compare respiratory symptoms, allergy markers, and bronchial reactivity between smoking and nonsmoking male teachers.
• To investigate the role of nonspecific bronchial reactivity in smokers with normal lung function.

Main Methods:

• Cross-sectional study comparing 17 lifetime nonsmoking male teachers and 17 smoking male teachers.
• Assessment of respiratory symptoms (cough, sputum, wheezing, dyspnea).
• Measurement of allergy markers (skin prick tests, serum IgE) and lung function (volumes, flow rates, specific airway conductance [SGaw]).
• Determination of bronchial reactivity using histamine provocation concentration (PC35) to reduce SGaw by 35%.

Main Results:

• Smokers reported significantly higher prevalence of cough, sputum production, and wheezing compared to nonsmokers.
• No significant differences were found in allergy history, skin test reactivity, or serum IgE levels.
• Lung function tests and specific airway conductance (SGaw) did not differ significantly between groups.
• Smokers demonstrated significantly lower histamine PC35 (1.84 mg/ml) than nonsmokers (4.83 mg/ml), indicating increased nonspecific bronchial reactivity.

Conclusions:

• Smoking is associated with increased respiratory symptoms and heightened nonspecific bronchial reactivity in male teachers, even with normal lung function.
• Increased bronchial reactivity may be an early indicator and contributing factor to the development of obstructive airway diseases in smokers.
• Further research is warranted to understand the long-term implications of these findings.