title: Reference values for spirometry, including vital capacity, in Japanese adults calculated with the LMS method and compared with previous values.
abstract: BACKGROUND
  Reference values for lung function tests should be periodically updated because of birth cohort effects and improved technology. This study updates the spirometric reference values, including vital capacity (VC), for Japanese adults and compares the new reference values with previous Japanese reference values.
  
  
  METHODS
  Spirometric data from healthy non-smokers (20,341 individuals aged 17-95 years, 67% females) were collected from 12 centers across Japan, and reference equations were derived using the LMS method. This method incorporates modeling skewness (lambda: L), mean (mu: M), and coefficient of variation (sigma: S), which are functions of sex, age, and height. In addition, the age-specific lower limits of normal (LLN) were calculated.
  
  
  RESULTS
  Spirometric reference values for the 17-95-year age range and the age-dependent LLN for Japanese adults were derived. The new reference values for FEV(1) in males are smaller, while those for VC and FVC in middle age and elderly males and those for FEV(1), VC, and FVC in females are larger than the previous values. The LLN of the FEV(1)/FVC for females is larger than previous values. The FVC is significantly smaller than the VC in the elderly.
  
  
  CONCLUSIONS
  The new reference values faithfully reflect spirometric indices and provide an age-specific LLN for the 17-95-year age range, enabling improved diagnostic accuracy. Compared with previous prediction equations, they more accurately reflect the transition in pulmonary function during young adulthood. In elderly subjects, the FVC reference values are not interchangeable with the VC values.
authors.affiliation: Respiratory Medicine, School of Medicine, Kitasato University, 1-15-1, Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan. Electronic address: masakubo@kitasato-u.ac.jp.
authors.forename: Masaru
authors.initials: M
authors.lastname: Kubota
authors.affiliation: Graduate School of Medical Sciences, Kitasato University, 1-15-1, Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan. Electronic address: hiro@kitasato-u.ac.jp.
authors.forename: Hirosuke
authors.initials: H
authors.lastname: Kobayashi
authors.affiliation: Department of Pulmonary Diseases and Department of Paediatrics-Pulmonary Diseases, Erasmus Medical Centre, Erasmus University, ׳s-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands. Electronic address: pquanjer@gmail.com.
authors.forename: Philip H
authors.initials: PH
authors.lastname: Quanjer
authors.affiliation: Department of Biomedical Laboratory Sciences, Faculty of Life Sciences, Kumamoto University, 4-24-1, Kuhonji, Chuo-ku, Kumamoto-shi, Kumamoto 862-0976, Japan. Electronic address: omorih@gpo.kumamoto-u.ac.jp.
authors.forename: Hisamitsu
authors.initials: H
authors.lastname: Omori
authors.affiliation: Department of Respirology, Graduate School of Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba-shi, Chiba 260-8670, Japan. Electronic address: tatsumi@faculty.chiba-u.jp.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Tatsumi
authors.affiliation: Department of Respiratory Medicine, Saitama Medical University, 38, Morohongo, Moroyama, Iruma-gun, Saitama 350-0495, Japan. Electronic address: mkanazaw@saitama-med.ac.jp.
authors.forename: Minoru
authors.initials: M
authors.lastname: Kanazawa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012044:Regression Analysis; D012189:Retrospective Studies; D013147:Spirometry / Q000379:methods* / Q000592:standards*; D014797:Vital Capacity; D055815:Young Adult
keywords: Lower limit of normal; Reference equation; Reference value; Spirometry; Vital capacity