Continuous longitudinal regression equations for pulmonary function measures

Area of Science:

• Pulmonary Physiology
• Longitudinal Aging Studies
• Biostatistics

Background:

• Understanding lung function changes over the lifespan is crucial for identifying normal aging patterns and potential disease markers.
• Previous studies often relied on cross-sectional data, limiting insights into individual lung function trajectories.
• Longitudinal data allows for a more accurate description of developmental and decline phases in respiratory health.

Purpose of the Study:

• To describe the age-related development and decline of maximal expiratory flow-volume (MEFV) measures using longitudinal data.
• To compare these trajectories between sexes and with existing cross-sectional findings.
• To identify specific age intervals for distinct phases of lung function change.

Main Methods:

• Analysis of data from 930 healthy, nonsmoking adults in the Tucson Longitudinal Population Study (1972-1988).
• Utilized statistical methods for continuous piecewise linear regression with repeated, unequally spaced measures.
• Estimated age intervals for linear segments of MEFV indices, comparing results between sexes.

Main Results:

• All MEFV measures exhibit accelerated development during the adolescent growth spurt.
• A plateau phase of approximately 10 years for FEV1 and FVC in males is followed by a consistent decline.
• Flow measures lacked a distinct plateau but showed later-life increases in decline rates, differing from volume measures.

Conclusions:

• Lung function (MEFV measures) follows distinct developmental, plateau, and decline phases influenced by age and sex.
• Longitudinal analysis reveals nuanced patterns in lung function changes, particularly the absence of a plateau in flow measures.
• Findings provide a detailed, age-specific reference for healthy lung function development and decline over the adult lifespan.