title: [Study of peak expiratory flow in normal young, middle-aged and old persons in Chengdu area].
abstract: OBJECTIVE
  To build the normal ranges and regression equations of peak expiratory flow (PEF) in normal young, middle-aged and old persons.
  
  
  METHODS
  PEF, FVC, V75, V50, V25 were measured in 393 normal young, middle-aged and old persons with the youngest aged 20 years and the eldest 84 years. Regression equations of PEF were built for younger group (20 yr-49 yr) and elder group (50 yr-84 yr) respectively.
  
  
  RESULTS
  PEF, FVC, V75, V50, V25 were decreased with increase of age. The regression equations showed that both in younger and elder groups, PEF was negatively correlated with age in male (P < 0.0001-0.002, r = 0.32-0.39) and positively correlated with FVC in female (P < 0.0001-0.0005, r = 0.32-0.59). PEF was highly correlated to V75 with r = 0.87-0.94 in male and r = 0.93-0.96 in female. The coefficient of variation (CV) of PEF was in normal range (16%-24%) for all age groups except male and female above 70 years old with CV of 30% and 27% respectively. This confirmed the data was reliable.
  
  
  CONCLUSIONS
  The normal ranges and regression equations of PEF constructed as a result of this study for normal humans of 20-84 years old can be put to use in clinical work and public health.
authors.affiliation: Department of Physiology, School of Basic Medical Sciences, WCUMS, Chengdu 610041, China.
authors.forename: G
authors.initials: G
authors.lastname: Huang
authors.forename: G
authors.initials: G
authors.lastname: Liu
authors.forename: J
authors.initials: J
authors.lastname: Huang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008168:Lung / Q000502:physiology*; D008297:Male; D008449:Maximal Expiratory Flow-Volume Curves; D008875:Middle Aged; D010366:Peak Expiratory Flow Rate; D012016:Reference Values; D014797:Vital Capacity