Chronic respiratory symptoms, von Willebrand factor and longitudinal decline in FEV1

Abstract

Although some risk factors for accelerated decline in forced expiratory volume in 1 s (FEV1) such as cigarette smoking, are well defined, it is not possible to identify those individuals with the most rapid rates of decline. Von Willebrand factor (vWF) is a product of both the pulmonary and systemic endothelium, and serum levels are raised during episodes of acute bronchitis. We hypothesized that raised serum levels of vWF may indicate sub-clinical pulmonary injury and so may predict subsequent accelerated decline in FEV1. The aims of this study were 1. to define the prevalence of chronic respiratory symptoms and obstructive airway disease in an inner-city British population and 2. to determine whether elevated levels of von Willebrand factor (vWF) identify those individuals at risk for more rapid decline in FEV1 over time. In 1987, all 2013 individuals aged 45 to 74 years at an inner-city general practice were mailed a respiratory symptom questionnaire. One in six of the responders were asked to attend for spirometry and for assessment of serum vWF. In 1996, those individuals who had spirometry and vWF assessed in 1987 were traced, and repeat spirometry was performed. In 1987, 1527 of 2013 (75.8%) individuals completed the questionnaire. Forty-two point two percent of responders reported shortness of breath on hills, 34.7% reported wheeze and 31.6% reported mucus hypersecretion. Smokers were more likely to report these symptoms. Two hundred and ten of the 251 (84%) individuals approached had spirometry and vWF assessed. Eleven percent of these had both an FEV1 < 75% predicted and a forced expiratory ratio (FEV1 forced vital capacity (FVC)) < 70%. Sub-normal spirometry was associated with wheeze, mucus hypersecretion, cigarette smoking and increasing age. By 1996, 32 (15%) of the original group of 210 individuals had died, and 117 of the remaining 178 (66%) had spirometry repeated. FEV1 < 75% predicted was a strong predictor of interim mortality, independent of age, sex and smoking history. The average decline in FEV1 was 46.7 ml yr-1. There was no significant correlation between serum vWF levels and subsequent decline in FEV1. Chronic respiratory symptoms and spirometric evidence of airflow limitation are common in inner-city residents of the U.K., and are associated with smoking history. Much of this disease is unrecognised by health professionals. An FEV1 < 75% predicted is a strong independent predictor of subsequent mortality. The measurement of serum vWF levels is unhelpful in identifying those individuals at increased risk of accelerated decline in FEV1.