The Association between Systemic Inflammatory Cellular Levels and Lung Function: A Population-Based Study

BACKGROUND Lower lung function is associated with an elevated systemic white cell count in men. However, these observations have not been demonstrated in a representative population that includes females and may be susceptible to confounding by recent airway infections or recent cigarette smoking. We tested the hypothesis that lung function is inversely associated with systemic white cell count in a population-based study. METHODS The study population consisted adults aged 17-90+ years who participated in the Third National Health and Nutrition Examination Survey who did not report a recent cough, cold or acute illness in a non-smoking and smoking population. RESULTS In non-smoking adults with the highest quintile of the total white cell count had a FEV(1) 125.3 ml lower than those in the lowest quintile (95% confidence interval CI: -163.1 to -87.5). Adults with the highest quintile of the total white cell count had a FVC 151.1 ml lower than those in the lowest quintile (95% confidence interval CI: -195.0 to -107.2). Similar associations were observed for granulocytes, mononuclear cells and lymphocytes. In current smokers, similar smaller associations observed for total white cell count, granulocytes and mononuclear cells. CONCLUSIONS Systemic cellular inflammation levels are inversely associated with lung function in a population of both non-smokers and smokers without acute illnesses. This may contribute to the increased mortality observed in individuals with a higher baseline white cell count.