Change in pulmonary diffusion capacity in a general population sample over 9 years.
BACKGROUND
Data on the change in diffusion capacity of the lung for carbon monoxide (DLCO) over time are limited. We aimed to examine change in DLCO (ΔDLCO) over a 9-year period and its predictors.


METHODS
A Norwegian community sample comprising 1,152 subjects aged 18-73 years was examined in 1987 and 1988. Of the 1,109 subjects still alive, 830 (75%) were re-examined in 1996/97. DLCO was measured with the single breath-holding technique. Covariables recorded at baseline included sex, age, height, weight, smoking status, pack years, occupational exposure, educational level, and spirometry. Generalized estimating equations analyses were performed to examine relations between ΔDLCO and the covariables.


RESULTS
At baseline, mean [standard deviation (SD)] DLCO was 10.8 (2.4) and 7.8 (1.6) mmol·min(-1)·kPa(-1) in men and women, respectively. Mean (SD) ΔDLCO was -0.24 (1.31) mmol·min(-1)·kPa(-1). ΔDLCO was negatively related to baseline age, DLCO, current smoking, and pack years, and positively related to forced expiratory volume in 1 second (FEV1) and weight. Sex, occupational exposure, and educational level were not related to ΔDLCO.


CONCLUSIONS
In a community sample, more rapid decline in DLCO during 9 years of observation time was related to higher age, baseline current smoking, more pack years, larger weight, and lower FEV1.
Department of Thoracic Medicine, Haukeland University Hospital, Bergen, Norway.|Department of Clinical Science, University of Bergen, Bergen, Norway; michael@mstorebo.no.
Michael L
ML
Storebø
Department of Thoracic Medicine, Haukeland University Hospital, Bergen, Norway.|Department of Clinical Science, University of Bergen, Bergen, Norway.
Tomas M L
TM
Eagan
Centre for Clinical Research, Haukeland University Hospital, Bergen, Norway.|Life Style Epidemiology Research Group, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
Geir E
GE
Eide
Department of Clinical Science, University of Bergen, Bergen, Norway.
Amund
A
Gulsvik
Department of Clinical Science, University of Bergen, Bergen, Norway.
Einar
E
Thorsen
Department of Clinical Science, University of Bergen, Bergen, Norway.
Per S
PS
Bakke
diffusion capacity for carbon monoxide; longitudinal change; occupational exposure; smoking; socioeconomic status