Lung Function in Growth and Aging
Swiss data PDF Print E-mail

Küster SP, Küster D, Schindler C, Rochat MK, Braun J, Held L, Brändli O. Reference equations for lung function screening of healthy never smoking adults aged 18-80 years. Eur Respir J 2008; 31: 860-868.

In the present cross-sectional study, lung function test results collected by the ‘‘LuftiBus’’ team in the greater Zurich metropolitan area (Zurich, Switzerland) between December 2000 and August 2005 were analysed. The LuftiBus project is maintained by the Lung Association of Zurich. It consists of a bus equipped with two flow-sensing spirometers that tours mainly the greater Zurich area and offers spirometry measurements to the general public. Spirometry data are recorded electronically along with data from a standardised interviewer-administered questionnaire collecting basic information on the health and lifestyle of subjects. Lung function tests are charged at 10 CHF to adults to cover the costs on a nonprofit basis.

Reference population

From a total of 20,460 subjects, 8,684 were included in the sample used to derive normal values for spirometric parameters (table 1). Subjects were excluded if they met at least one of the exclusion criteria (table 2). Never-smokers were defined as subjects with a cumulative smoking history of <1 pack-yr (a pack-yr is defined as years of smoking 6 the number of cigarettes smoked per day divided by 20). Due to the ongoing migration in Europe and mixture of ethnical backgrounds, and due to the very small proportion of non-Caucasian people in Switzerland, no exclusion was made based on race or nationality [20]. Thus, ethnicity was not assessed systematically for the whole study population. Ethnicity was recorded in a subset of 3,061 consecutive subjects of the reference sample (1,356 males and 1,705 females) measured in the years 2004 and 2005 and, thereof, non-Caucasian subjects accounted for 19 (1.1%) females and 17 (1.3%) males.

Spirometry

During the time of data collection, the LuftiBus was equipped with two computerised pneumotachographs (SensorMedics Vmax Legacy 20c spirometer run by Vision 7-2b software; VIASYS, Yorba Linda, CA, USA). The volume signal of the equipment was calibrated at least once daily with a 3-L syringe. Tests were performed in a sitting position according to American Thoracic Society (ATS) guidelines without nose-clips after an oral instruction by the technician [2, 14]. Participants were assisted by eight specially trained lung function technicians who performed immediate on-screen evaluation of major acceptability criteria (including start, duration and end of test) in addition to the automated review performed by the computer software. As recommended by the ATS in 1994 [14], data that did not meet reproducibility criteria were not excluded, but subjects were asked to perform up to a maximum of eight manoeuvres in an attempt to obtain reproducible results. From a minimum of two acceptable tests, the largest forced vital capacity (FVC) and FEV1 were selected, regardless of the manoeuvre. All other parameters were taken from the trial with the largest sum of FVC and FEV1. Selfreported values for height were used.

References

2 American Thoracic Society. Lung function testing: selection of reference values and interpretative strategies. Am Rev Respir Dis 1991; 144: 1202–1218.
14 Standardization of Spirometry, 1994 Update. American Thoracic Society. Am J Respir Crit Care Med 1995; 152: 1107–1136.
20 Kiviranta K, Haahtela T. Caucasian race and lung function: time to revisit the racial groups used in reference values. Eur Respir J 2006; 28: 1280.
Last Updated on Friday, 13 March 2009 18:27