Airflow limitation, lung volumes and systemic inflammation in a general population

Although several levels of evidence have suggested an association between systemic inflammation and spirometric lung volumes, data addressing the potential interrelationship between airflow limitation and inflammatory markers are sparse and remain controversial. Potential associations between high-sensitivity C-reactive protein (hsCRP), fibrinogen and lung function were investigated in 1,466 individuals aged 25-85 yrs, representing a general population. Within this cross-sectional population, data on body plethysmography, spirometry, helium dilution and diffusing capacity of the lung for carbon monoxide (D(L,CO)) were analysed. After adjustment for potential confounding factors, such as smoking, obesity and cardiorespiratory fitness, there was an inverse association of hsCRP with forced expiratory and static lung volumes. In neither apparently healthy nor the entire population was inflammation associated with airflow limitation in central airways. In smokers only, higher hsCRP and fibrinogen were associated with an impaired D(L,CO). This study shows that higher levels of hsCRP are associated with decreased lung volumes in a general population over a wide age range. A consistent interrelationship of central airflow limitation and inflammation was not verifiable. Smoking is related to an impaired D(L,CO) in association with an increase in systemic inflammation.