Impact of alpha-1 antitrypsin level on longitudinal lung function change: The Nagahama Study

Abstract

Background: Systemic inflammation can be associated with an accelerated decrease in pulmonary function in the general population. Alpha-1 antitrypsin (AAT) is a major protease inhibitor and its deficiency is one of the most common risk factors for developing early onset emphysema and chronic obstructive pulmonary disease. Recently, AAT has been recognized as a systemic inflammation marker. However, the association between AAT levels and longitudinal forced expiratory volume in one second (FEV1) changes has been unknown in the general population. Aims and Objectives: To examine the association between baseline AAT levels and longitudinal FEV1 changes in a general population-based large-scale cohort study. Methods: This study included 9,053 Japanese participants (male 2,962; female 6,091), in whom 7,525 (male 2,397; female 5,128) were included in the longitudinal analysis. The change in FEV1 was calculated by dividing the difference between the baseline and follow-up by follow-up periods (years). The change in FEV1 was categorized into two groups: rapid decline (change in FEV1 Results: Follow-up period was 1815 ± 135 days. FEV1 decreased by 34.2 ± 0.6 ml/year during the follow-up period. There were 862 (11.5%) participants with the rapid decline in FEV1. The elevation of baseline AAT levels was independently associated with the rapid decline in FEV1 (odds ratio = 1.09; 95% confidence interval = 1.04–1.14; p = 0.0004), although baseline AAT levels were not associated with baseline FEV1. Conclusions: The present findings imply that baseline AAT levels might become a new predicting factor for longitudinal FEV1 decline.