Spirometric Reference Values for Advanced Age from a South German Population

Background: The diagnostic use of lung function using spirometry
dependson the validity of reference equations. A multitude of
spirometricprediction values have been published, but in most of
these studiesolder age groups are underrepresented. Objectives: The
aim of thepresent study was to establish new spirometric reference
values foradvanced age and to compare these to recent prediction
equations frompopulation-based studies. Methods: In the present
study spirometry wasperformed in a population-based sample from the
KORA-F4 and KORA-Agecohorts (2006-2009, Augsburg, Germany)
comprising 592 never-smokingsubjects aged 42-89 years and with no
history of respiratory disease.Using quantile regression analysis,
equations for the median and lowerlimit of normal were derived for
indices characterizing the expiratoryflow-volume curve: forced
expiratory volume in 1 s (FEV1), forced vitalcapacity (FVC),
FEV1/FVC, peak expiratory flow (PEF), and forcedexpiratory flow
rates at 25, 50 and 75% of exhaled FVC (FEF25, FEF50and FEF75).
Results: FEV1 and FVC were slightly higher, and PEF waslower
compared to recently published equations. Importantly,
forcedexpiratory flow rates at middle and low lung volume, as
putativeindicators of small airway disease, were in good agreement
with recentdata, especially for older age. Conclusion: Our study
providesup-to-date reference equations for all major indices of
flow-volumecurves in middle and advanced age in a South German
population. Thesmall deviations from published equations indicate
that there might besome regional differences of lung function
within the Caucasianpopulation of advanced age in Europe.