Internal Medicine
Online ISSN : 1349-7235
Print ISSN : 0918-2918
ISSN-L : 0918-2918
ORIGINAL ARTICLES
Impact of Cigarette Smoking on Maximal Expiratory Flows in a General Population: the Takahata Study
Takako NemotoYoko ShibataDaisuke OsakaShuichi AbeSumito InoueYoshikane TokairinAkira IgarashiKeiko YamauchiTomomi KimuraHiroyuki KishiMichiko NishiwakiYasuko AidaKeiko NunomiyaMasamichi SatoTetsu WatanabeTsuneo KontaSumio KawataTakeo KatoTakamasa KayamaIsao Kubota
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JOURNAL OPEN ACCESS

2011 Volume 50 Issue 21 Pages 2547-2555

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Abstract

Background Maximal expiratory flows (MEFs) depend on the elastic recoil pressure in the alveoli, airway resistance and bronchial collapsibility. MEFs at lower levels of vital capacity [MEFs at x% FVC (MEFx)] would indicate the patency of peripheral airways. In Japan, a ratio of MEF50 to MEF25 (MEF50/MEF25) greater than 4.0 is used as an index of injury to the small airways in subjects without airflow limitation. However, to date there have been no epidemiological investigations relating to this index. The aim of this study was to evaluate the impact of cigarette smoking on MEFs in a general population, and to assess the validity of using this index to evaluate injury to the small airways.
Methods Subjects aged 40 years or older (n=2,917), who had participated in a community-based annual health-check in Takahata, Japan, were enrolled in the study. MEF75, MEF50 and MEF25 were measured in these subjects.
Results In smokers, as compared with never-smokers, the percentage predicted MEFs (%MEFs) decreased according to the aging of the population, except in the case of %MEF25 in females. In males, but not in females, %MEFs decreased significantly with an increase in cigarette consumption. In both genders, MEF50/MEF25 was slightly, but significantly, elevated with aging of the population. In addition, 36.5% of subjects who participated in this health-check had MEF50/MEF25 values greater than 4.0. No difference in MEF50/MEF25 was observed between smokers and never-smokers.
Conclusion Cigarette smoking enhanced the age-related decline in MEFs. Since many healthy subjects aged 40 years or older have MEF50/MEF25 values greater than 4.0, the use of this criterion may over-estimate the presence of small airway disease.

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© 2011 by The Japanese Society of Internal Medicine
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