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This Article Full Text (PDF) All Versions of this Article: chest.07-2405v1 133/5/1095    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to My Personal Article Archive Download to citation manager Google Scholar Articles by Silva, G. E. Articles by Sherrill, D. L. PubMed PubMed Citation Articles by Silva, G. E. Articles by Sherrill, D. L.

Longitudinal Decline of Diffusing Capacity of the Lung for Carbon Monoxide (DL,CO) in Community Subjects with the PiMZ ₁-Antitrypsin Phenotype

¹College of Nursing and Healthcare Innovation, Phoenix, Arizona ²Arizona Respiratory Center ³Mel and Enid Zuckerman College of Public Health ⁴College of Medicine, University of Arizona, Tucson, Arizona

graciela.silva{at}asu.edu

Abstract

Background: It is well known that homozygous deficiency of ₁-antitrypsin, PiZZ, is associated with an increased risk of emphysema. However, studies evaluating associations between the heterozygous form PiMZ, with emphysema and impaired lung function have provided conflicting results.

Study objective: The goal of this study was to determine if the phenotype PiMZ is associated with an accelerated decline in diffusing capacity of the lung for carbon monoxide (Dl,co).

Design and methods: The Tucson Epidemiological Study of Airway Obstructive Disease is a prospective population-based cohort study initiated in 1972. Participants completed standardized questionnaires in up to 12 periodic surveys and Dl,co assessments in up to 4 surveys. Random effects models were used to determine the effects of ₁-antitrypsin phenotypes on percent predicted (% predicted) Dl,co levels among 1,075 subjects 18 years old.

Results: Percent predicted DL,CO declined more rapidly in subjects who smoked compared to nonsmoking subjects. Additionally, in smokers, the PiMZ phenotype was associated with borderline % predicted DL,CO deficits at age 40 (8.6%, p = 0.075) and significant % predicted DL,CO deficits at ages 60 (15.2%, p = 0.001) and 80 (21.9%, p = 0.003), as compared with the PiMM phenotype.

Conclusions: Dl,co may be a more sensitive indicator of the long-term effects of intermediate levels of ₁-antitrypsin on lung function especially in subjects who smoke.