title: [Predictive equations and analysis of influence factors of lung ventilation based on a large occupational population in North China].
abstract: OBJECTIVE
  To establish suitable predictive equations of lung function for occupational population in North China.
  
  
  METHODS
  A total of 5 002 on the job or retired healthy adults from five enterprises in North China with category of mild or moderate work intensity underwent spirometry using a Chest HI-198 spirometer and the procedures recommended by the American Thoracic Society, were a sample.
  
  
  RESULTS
  The data of 3 913 subjects were used. A normal distribution of our data was shown using the normality test and distribution curve. Univariate analysis showed that both age and height were significantly correlated with FVC, FEV(1), FEV(1)/FVC (%) and MMF. Further multiple linear stepwise regression analysis indicated that the levels of FVC, FEV(1), FEV(1)/FVC (%) and MMF were highly influenced by age, height, and weight rather than chest circumference. Thus, only age, height, and weight were introduced into our regression equations. Data from the studied subjects and other source were utilised to examine the validity of the equations and a high accordance rate (> 90%) was obtained. No significant difference (P > 0.05) was found in the predictive values between the simplified equations and equations in which more variables were included.
  
  
  CONCLUSIONS
  The studied predictive equations for male non-smokers, female non-smokers, and male smokers were established based on data from a large occupational population. These equations should be more applicable for evaluating lung ventilatory function of occupational populations in North China.
authors.affiliation: School of Public Health, Harbin Medical University, Harbin 150086, China. wuyonghui777@163.com
authors.forename: Yong-hui
authors.initials: YH
authors.lastname: Wu
authors.forename: Zhong-yi
authors.initials: ZY
authors.lastname: Zhang
authors.forename: Bao-qi
authors.initials: BQ
authors.lastname: Gang
authors.forename: E J
authors.initials: EJ
authors.lastname: Love
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002681:China; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D009790:Occupations; D011237:Predictive Value of Tests; D012123:Pulmonary Ventilation; D012016:Reference Values; D012044:Regression Analysis; D015203:Reproducibility of Results; D012129:Respiratory Function Tests / Q000592:standards*; D014797:Vital Capacity; D055815:Young Adult