Relative and absolute lung function change in a general population aged 60-102 years

Area of Science:

• Gerontology
• Pulmonology
• Epidemiology

Background:

• Longitudinal data on lung function decline in older adults are limited.
• Understanding factors influencing lung function changes is crucial for geriatric health.
• The utility of absolute versus relative change metrics in elderly lung function studies is unclear.

Purpose of the Study:

• To analyze longitudinal changes in absolute and relative forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) in a geriatric population.
• To identify demographic and clinical risk factors associated with lung function decline.
• To compare the clinical relevance of absolute versus relative change in lung function.

Main Methods:

• A population-based sample of 3736 individuals aged 60-102 years underwent spirometry over 13.5 years.
• Repeated measurements models were used, adjusting for age, sex, smoking, comorbidities, and lifestyle factors.
• Analysis included absolute and relative annual changes in FEV1 and FVC, FEV1 quotient (Q), and z-scores (GLI-2012, NHANES III).

Main Results:

• Adjusted annual decline was -51.7 mL for FEV1 and -56.2 mL for FVC (absolute).
• Adjusted annual decline was -2.97% for FEV1 and -2.46% for FVC (relative).
• Female sex, older age, smoking, elevated C-reactive protein, and low education were risk factors for greater relative decline.

Conclusions:

• Relative lung function decline correlates better with functional status markers than absolute decline.
• Relative change is potentially superior for risk factor analysis in elderly populations.
• Current lung function reference standards (GLI-2012) identify a higher proportion of elderly individuals as having abnormal lung function compared to NHANES III.