title: [Predictive equations of lung function for adults in north China urban areas].
abstract: OBJECTIVE
  To establish predictive equations of lung function for adults in urban areas in north China.
  
  
  METHODS
  A survey was conducted in 600 male and 600 female healthy adults in the urban areas in north China. Five flow-volume test parameters were measured including forced vital capacity (FVC) and forced expiratory volume in one second (FEV1). Stepwise multiple regression was carried out to establish the predicative equations for the parameters for male and female adults separately. The predicted values from these equations and those from other commonly used equations (such as ECCS equation and Knudson equation) were compared with the actual measurements in pulmonary function tests.
  
  
  RESULTS
  Four flow-volume test parameters, namely FVC, FEV1, 25% forced expiratory flow (FEF25%), and FEF75%, showed obvious differences between the male and female adults, while FEV1/FVC was not correlated with gender. Multiple regression analysis showed that FVC, FEV1, FEF25% and FEF75% were positively correlated with height and negatively with age, and FEV1/FVC was negatively correlated with both height and age. The parameters were not affected by body weight. The predicted values from our equations were closer to the actual measurements than those calculated from other equations.
  
  
  CONCLUSIONS
  The equations we established are more appropriate than the generally used equations for predicting lung functions in adults in north China urban areas.
authors.affiliation: Nanlou Department of Respiratory Diseases, 3Health Science Center, General Hospital of PLA, Beijing 100853, China. E-mail: tangjiahui2004@126.com.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Kang
authors.forename: Changting
authors.initials: C
authors.lastname: Liu
authors.forename: Ting
authors.initials: T
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Hongxia
authors.initials: H
authors.lastname: Li
authors.forename: Qinghui
authors.initials: Q
authors.lastname: Liu
authors.forename: Yansong
authors.initials: Y
authors.lastname: Zheng
mesh_terms: D000328:Adult; D000367:Age Factors; D001827:Body Height; D001835:Body Weight; D002681:China; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012016:Reference Values; D012044:Regression Analysis; D012129:Respiratory Function Tests / Q000379:methods*; D012737:Sex Factors; D013147:Spirometry / Q000706:statistics & numerical data; D014505:Urban Population; D014797:Vital Capacity