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Sources of variability between subjects

The variability in FVC between subjects has been estimated (ref. 1) to be attributable to the following factors:

sex 30%
age 8%
standing height 20%
ethnic group 10%
body weight 2%
technical factors 3%
unexplained about 30%

Factors that contribute to variability between subjects:

Ref. 1 - Variability in spirometric indices

  1. Becklake MR. Concepts of normality applied to the measurement of lung function. Am J Med 1986; 80: 1158-1164.
  2. Becklake MR, Permutt S. Evaluation of tests of lung function for ‘screening’ for early detection of chronic obstructive lung disease. In: PT Macklem & S Permutt (eds), The lung in the transition between health and disease. New York, Dekker, 1979, 345-387.
  3. Cotes JE. Lung Function. Assessment and application in medicine. Ed. 5, Blackwell Scientific Publications, Oxford, 1993.
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