Comparing FEV1 in adults in two community-based studies

Area of Science:

• Pulmonary Medicine
• Epidemiology
• Longitudinal Studies

Background:

• Age-related decline in lung function, specifically forced expiratory volume in one second (FEV1), is a key indicator of respiratory health.
• Understanding variations in FEV1 decline across different populations and study designs is crucial for accurate health assessments.

Purpose of the Study:

• To estimate age-related changes in FEV1 among nonsmoking adults.
• To identify and quantify differences in FEV1 decline rates between two large-scale longitudinal respiratory studies.

Main Methods:

• Analysis of data from two longitudinal respiratory studies: one in the Netherlands (21 years) and one in the US (6 years).
• Comparison of FEV1 decline rates, adjusting for age and other factors, between the Netherlands and Six Cities cohorts.
• Statistical modeling to assess the influence of age, survey period, and height on FEV1 decline.

Main Results:

• Significant differences in FEV1 decline rates were found between the Netherlands and Six Cities cohorts, with the latter showing a 32-33% greater decline.
• Age-specific rates of FEV1 decline differed significantly between male participants in the two cohorts.
• Inclusion of survey period effects had a minimal impact on FEV1 decline acceleration, particularly in the Six Cities men.

Conclusions:

• Substantial variation exists in FEV1 decline between different study populations, even with similar analysis methods.
• Initial age distributions and participant follow-up rates are critical factors influencing observed differences in longitudinal FEV1 decline.
• Using standard prediction equations for age adjustment may lead to biased comparisons if population-specific FEV1 decline rates and age distributions differ.