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Factors that affect normal lung function in white Australian adults
E G Belousova1, M M Haby, W Xuan
1Department of Medicine, University of Sydney, Australia.
Chest
|December 24, 1997
Summary
Airway hyperresponsiveness (AHR), respiratory symptoms, and smoking significantly impair lung function. These factors are key predictors of reduced spirometric values in adults.
Area of Science:
- Pulmonary Medicine
- Epidemiology
- Respiratory Physiology
Background:
- Establishing normative values for lung function is crucial for identifying abnormalities in epidemiological studies.
- Factors such as airway hyperresponsiveness (AHR), respiratory symptoms, asthma history, and smoking status can influence spirometric measurements.
Purpose of the Study:
- To define "normal" lung function values in Australian white adults.
- To investigate the impact of AHR, respiratory symptoms, asthma, and smoking on spirometric measures.
Main Methods:
- A cohort of 1,527 adults (aged 18-73) was surveyed for respiratory symptoms and smoking history.
- Airway hyperresponsiveness was assessed using a histamine inhalation test.
- Regression models were developed using data from 729 "normal" subjects (asymptomatic, non-smokers, without AHR).
Main Results:
- Regression models were established for Forced Vital Capacity (FVC), Forced Expiratory Volume in 1 second (FEV1), Peak Expiratory Flow Rate (PEFR), and Forced Expiratory Flow between 25% and 75% of FVC (FEF25-75%).
- AHR was associated with an average reduction of 0.1 L in FVC and 0.2 L in FEV1.
- Current asthma led to significant reductions in FVC (0.3 L) and FEV1 (0.5-0.6 L), while smoking decreased FEV1 by 0.002 L per cigarette daily.
Conclusions:
- Recent respiratory symptoms, AHR, and current smoking are significant predictors of diminished lung function.
- These findings highlight the importance of considering these factors when interpreting spirometric data in population studies.