FEV6 and FEV1/FEV6 in Japanese participants of the community-based annual health check: the Takahata study.
BACKGROUND
Forced expiratory volume in 6 seconds (FEV(6)) is becoming a substitute of forced vital capacity (FVC). However, the Japanese predictive equation for FEV(6) has not been established, and the validity for the use of FEV(1)/FEV(6) for diagnosing airflow limitation in Japanese has not been confirmed.


METHODS
Subjects aged 40 or older, who had participated in a community-based health check in Takahata, Japan, from 2004 through 2005, were enrolled. The smoking histories of these subjects were investigated using a self-reporting questionnaire. FVC, FEV(1), and FEV(6) were measured using spirometric machines. Predictive equations of FEV(6) were obtained from never-smoking subjects without history of pulmonary diseases by multiple linear regression assay.


RESULTS
FEV(6) and FEV(1)/FEV(6) were significantly correlated with FVC (r=0.998, p<0.001) and FEV(1)/FVC (r=0.989, p<0.001), respectively. The cutoff values of percent predicted (%) FEV(6) and FEV(1)/FEV(6) for discrimination of having the restrictive lung disorder determined by %FVC <0.8 and having the airflow limitation determined by FEV(1)/FVC <0.7 were 0.80 and 0.72, respectively (%FEV(6): sensitivity=0.995, specificity=0.983, positive predictive value <PPV>=0.832, negative predictive value <NPV>=1.000; FEV(1)/FEV(6): sensitivity=0.942; specificity=0.971; PPV=0.787; NPV=0.993). When the 5th percentile the lower limit of normal values was used as criterion for discrimination of having airflow limitation, sensitivity, specificity, PPV, and NPV of FEV(1)/FEV(6) were 0.932, 0.985, 0.808, and 0.995, respectively.


CONCLUSIONS
The results of the present study suggest that %FEV(6) and FEV(1)/FEV(6) are excellent substitutes for %FVC and FEV(1)/FVC, respectively. We confirmed the validity of the use of FEV(6) and FEV(1)/FEV(6) for identifying pulmonary diseases in Japanese individuals.
Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
Hiroyuki
H
Kishi
Yoko
Y
Shibata
Daisuke
D
Osaka
Shuichi
S
Abe
Sumito
S
Inoue
Yoshikane
Y
Tokairin
Akira
A
Igarashi
Keiko
K
Yamauchi
Tomomi
T
Kimura
Michiko
M
Sato
Yasuko
Y
Aida
Tetsu
T
Watanabe
Tsuneo
T
Konta
Sumio
S
Kawata
Takeo
T
Kato
Isao
I
Kubota
D000328:Adult; D044466:Asian People; D003153:Community Health Services / Q000379:methods / Q000592:standards*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology*; D006304:Health Status; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012120:Respiration Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D011795:Surveys and Questionnaires / Q000592:standards; D013997:Time Factors