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Below is an overview of the years in which the various data were collected. Also listed is whether the measurements conformed with recommended ATS or ERS standards. | Data set | Acronym | Dates | Standards | | Dutch adolescents | alopau | 1978-1985 | - | | Dutch schoolchildren | wag | 1984-1986 | - | | German schoolchildren | germ | 1994-1999 | - | | Health Survey for England | hse | 1995-1996 | - | | Swiss in Zürich | lufti | 2000-2005 | ATS 1994 | | Norwegian adults | hunt | 1995-1997 | ATS 1987 | | Australians in Adelaide | gore | 1990 | ATS 1987 | | Americans | nhanes | 1988-1994 | ATS 1994 | The differences between the ATS 1987 and ATS 1994 recommendations are as follows: - In 1994 the upper limit for the extrapolated volume (for determining the starting point for timing the FEV1) was raised from 5% or 100 mL, to 5% or 150 mL, whichever is the greatest.
- In 1994 the upper limit for the repeatability of FEV1 and FVC was raised from 5% or 100 mL, to 5% or 200 mL, whichever is the greatest.
Based on published information the criteria applied in selecting the FEV1 and FVC from forced expiratory manoeuvres was as follows:
| Data set | Selection of FEV1 and FVC | | Dutch adolescents | at least 3 acceptable curves, largest FEV1 and largest FVC | | Dutch schoolchildren | at least 5 acceptable curves, largest FEV1 and largest FVC | | German/Austrian schoolchildren | a maximum of 3 efforts, where at least 2 flow-volumes curves were reproducible (FVC difference up to 5%) | | Health Survey for England | 5 manoeuvres, largest FEV1 and FVC from technically acceptable measurements | | Swiss in Zürich | minimum of 2 acceptable tests; reproducibility criteria were not applied but if not met led to up to 8 tests | | Norwegian adults | up to 5 manoeuvres, 3 acceptable and reproducible; the curve with the highest sum of FEV1 + FVC was retained | | Australians in Adelaide | 3 trials within 3% of each other; largest FEV1 and largest FVC | | Americans | 3 acceptable and reproducible efforts, largest FEV1 and largest FVC | There is limited literature on the effects of using 2-5 acceptable curves for deriving FEV1 and FVC. In schoolchildren Houthuijs et al. observed that the FEV1 was 23 mL larger for FVC, and 16 mL larger for FEV1 (1.2% and 0.9% difference with respect to population average, respectively) when using 5 instead of 3 curves. In Schrader's study of adolescents the differences came to 32 mL (FVC) and 21 mL (FEV1), i.e. 1% and 0.6%, respectively. Hankinson et al. observed a difference of 62.5 mL (FVC) and 52 mL (FEV1) that was the same across heights and ages; the differences in these adults appear to be larger than in schoolchildren and adolescents. These differences relate to inexperienced subjects. As shown by Schrader et al. experienced adolescents are capable of producing the largest values for FEV1 and FVC in three technically acceptable FVC manoeuvres. The data from the Dutch adolescents derive from a longitudinal study, where a cross-section was created so that age was as evenly distributed as possible. Compared to the other data sets we are dealing with experienced subjects, so on this account we might expect the FVC and FEV1 to be about 1% higher than in naive subjects. Similarly the data in Dutch schoolchildren are likely to be on average 1% larger because they are based on 5, not on 3, acceptable manoeuvres. Finally a summary of the selection criteria. In all data sets subjects with a past or present history of lung disease and of smoking have been excluded. | Data set | Population criteria | | Dutch adolescents | secondary school and vocational school | | Dutch schoolchildren | 10 primary schools | | German/Austrian schoolchildren | primary schools in Germany and Austria | | Health Survey for England | random sample of population | | Swiss in Zürich | spirometry measurements offered to the public in the greater Zürich metropolitan area | | Norwegian adults | random sample from population of Nord-Trøndelag | | Australians in Adelaide | subsample from a random sample of adult population (18-78 yr) of metropolitan Adelaide who volunteered to undertake a comprehensive fitness assessment | | Americans | random sample of population | References
1. Hankinson JL, Odencrantz JR, Fedan KB. Spirometric reference values from a sample of the general US population. Am J Respir Crit Care Med 1999; 159: 179-187.
2. Houthuijs D, Remijn D, Brunekreef R, Koning R de. Estimation of maximum expiratory flow-volume variables in children. Pediatr Pulmonol 1989.6, 127-132.
3. Schrader PC, Quanjer PH. van Zomeren BC, de Groodt EG, Wever AMJ, Wise ME. Selection of variables from maximum expiratory flow-volume curves. Bull Europ Physiopath Resp 1983; 19: 43-49
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