title: [Testing and analyzing the lung functions in the normal population in Hebei province].
abstract: OBJECTIVE
  To investigate the lung function of the normal subjects living in Hebei province and its correlative factors such as living circumstance, age, height, and body weight.
  
  
  METHODS
  The lung volumes and breath capacities of 1,587 normal subjects were tested by portable spirometers (Scope Rotry) from August to October in 2002. The influences of living circumstance, age, gender, height, and body weight on lung functions were observed and analyzed.
  
  
  RESULTS
  No significant difference was found between urban and rural areas in all indexes (P > 0.05); however, significant difference existed between male and female subjects (P = 0.000). The change trends of lung function in male and female subjects were similar. Growth spurt appeared at the age of 12-16 years in male subjects and 12-14 years in female subjects. Vital capacity (VC), forced vital capacity (FVC), and forced expiratory volume in one second (FEV1) reached their peaks at the age of 26-34 years and then decreased with age. Peak expiratory flow (PEF), 25% forced expiratory flow (FEF50%), and 75% forced expiratory flow (FEF75%) appeared at the age of 18 and then went down with age. Both height and weight had a correlation with all the indexes of lung functions, although the influence of height is stronger than weight.
  
  
  CONCLUSIONS
  All the indexes of lung function have correlations with age, height, and weight. Lung function changes with aging, therefore different expected values shall be available for the adolescence, young adults, and middle-aged and old people. This study provides reference values of lung function for normal population.
authors.affiliation: Department of Pathology, Institute of Basic Medical Sciences, CAMS and PUMC, Beijing 100005, China.
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Ming
authors.initials: M
authors.lastname: Zhao
authors.forename: Shao-mei
authors.initials: SM
authors.lastname: Han
authors.forename: Zhong-ming
authors.initials: ZM
authors.lastname: Li
authors.forename: Guang-jin
authors.initials: GJ
authors.lastname: Zhu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D005540:Forced Expiratory Flow Rates; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010366:Peak Expiratory Flow Rate; D012016:Reference Values; D012129:Respiratory Function Tests; D012423:Rural Health; D012494:Sampling Studies; D014504:Urban Health; D014797:Vital Capacity