The Darlington and Northallerton long term asthma study: pulmonary function

Area of Science:

• Pulmonology
• Epidemiology
• Longitudinal Studies

Background:

• Observational cohort study initiated in 1983 to investigate long-term asthma outcomes.
• Limited understanding of reversible disease and airway remodeling's impact on asthma progression.
• Focused on tracking changes in overall and fixed lung function over time.

Purpose of the Study:

• To report 15-year trends in pulmonary function decline in asthma patients.
• To analyze the relationship between age and lung function changes.
• To explore factors influencing the rate of pulmonary function deterioration.

Main Methods:

• Recruited asthmatics from secondary care in 1983, 1988, and 1993.
• Recorded pulmonary function and estimated potential best function.
• Calculated decline rates over 5-year periods and used linear regression for continuous participants.

Main Results:

• 1724 measurements in 912 subjects; 200 subjects had complete data.
• Significant decline rates: FEV1 (male 41.0, female 28.9 ml/year), FVC (male 63.1, female 45.8 ml/year).
• Age showed a dominant cubic relationship with lung function decline, with fluctuations in middle age.

Conclusions:

• Pulmonary function declines non-linearly and faster than in normal populations.
• First report of a cubic relationship between age and pulmonary function in asthma.
• Findings necessitate re-evaluation of existing research on asthma function changes over time.