Background: The purpose of this cross-sectional study was to investigate whether the presence of serum complement antibodies was associated with reduced one-second forced expiratory volume (FEV1) in adults.
Methods: From a stratified random sample of 18-73 year old adults, we performed measurements of serum complement fixing virus antibodies against influenza type A and B, parainfluenza type 1, 2, and 3, respiratory syncytial virus and adenovirus on 82% (n = 1239).
Results: In the crude data, subjects having five of the seven virus antibodies had significantly lower lung function, given as sex-, age- and height-standardized residuals of FEV1 (SFEV1), compared with those without. After adjusting in addition for smoking habits, lifetime smoking consumption and season, the lung function levels were significantly lower in subjects with influenza type B and respiratory syncytial virus antibodies compared to those without (P < 0.01). Increasing influenza and respiratory syncytial virus antibody titres and increasing numbers of virus antibodies, respectively, were related to progressively lower lung function. Subjects with respiratory symptoms but without obstructive lung disease had lower antibody levels than subjects with obstructive lung disease, but higher levels than asymptomatic subjects. In a final multiple linear regression analysis adjusting in addition for respiratory symptom and disease status as well as for the other respiratory virus antibodies, the presence of respiratory syncytial virus antibodies was a significant predictor for reduced SFEV1 (regression coefficient: -0.226; SE = 0.112; P = 0.04). The magnitude of the effect on lung function remained after excluding subjects reporting symptoms of respiratory infection within 3 weeks prior to the examination (regression coefficient: -0.252; SE = -0.218; P = 0.25).
Conclusions: This cross-sectional community study indicates that respiratory syncytial virus infection or re-infection is an independent predictor for reduced lung function in adults of a wide age range.