title: Serum white blood cell count and pulmonary function test are negatively associated.
abstract: BACKGROUND
  A variety of inflammatory disorders influence the serum white blood cell (WBC) count. Elevated systemic inflammatory insult may contribute to impaired lung function, such as obstructive or restrictive lung disease. The aim of our study is to investigate the correlation between WBC count and pulmonary function.
  
  
  METHODS
  Eligible participants aged ≥18 years (n=16 312) were enrolled from the United States National Health and Nutrition Examination Survey III, 1988-1994. Pertinent information including pulmonary function test, demographics, WBC count, glucose, C-reactive protein and a personal health questionnaire were obtained for subjects without known pulmonary diseases. White blood cell counts were classified into quartiles over the normal range. Multiple hierarchical regression models and trends testing were used to assess the correlation between WBC counts and pulmonary function tests.
  
  
  RESULTS
  In the unadjusted mode of quartile-based analysis, the beta coefficients interpreted as the differences in FEV1% predicted upon comparing subjects in the upper three quartiles of WBC count to those in the lowest quartile were -0.007, -0.022 and -0.041 (P<0.001). After adjusting for multiple pertinent covariates, inverse association between quartiles of WBC count and FEV1% predicted remained essentially unchanged. The negative trends between FEV1% predicted and WBC count quartiles in the stratified comparison with extended-model approach were statistically significant (P for trends<0.001) in quartile-based multiple linear regression.
  
  
  CONCLUSIONS
  Elevated WBC count is independently associated with declined pulmonary function. It may be a simple, accessible and inexpensive indicator of changes in pulmonary function.
authors.affiliation: Division of Family Medicine, Division of Geriatric Medicine, Department of Family and Community Medicine, Tri-Service General Hospital; and School of Medicine, National Defense Medical Center , Taipei, Taiwan.
authors.forename: H-F
authors.initials: HF
authors.lastname: Yang
authors.forename: T-W
authors.initials: TW
authors.lastname: Kao
authors.forename: C-C
authors.initials: CC
authors.lastname: Wang
authors.forename: T-C
authors.initials: TC
authors.lastname: Peng
authors.forename: Y-W
authors.initials: YW
authors.lastname: Chang
authors.forename: W-L
authors.initials: WL
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005541:Forced Expiratory Volume / Q000276:immunology*; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys
keywords: Inflammation; Pulmonary function test; White blood cell count