Lung function and ethnic group
There are differences in ventilatory function between ethnic groups. so that in general it is best to apply prediction equations that best fit the ethnic group. However, such equations are not always available, or not implemented in software. That is when correction factors come into play. The ECCS/ERS (see reference below) recommendations on corrections for ethnic groups are adhered to in the SpirXpert software package. Hence the predicted values for Caucasians are adjusted as follows:
| Ethnic group | Adjustment of predicted value |
| Negroid, S. India | - 13% |
| N. India, Pakistan, Polynesia | - 10% |
- The lung function of offspring of a marriage of mixed ethnic groups is intermediate between that of the ethnic groups of the parents.
- Information about differences in lung function between Japanese, Chinese and Europeans are unequivocal. According to some sources lung function of Mongoloid persons is intermediate between that of Caucasians and Negroid people, but it is also often assumed that Mongoloid people who grew up with a western lifestyle have the same lung function as Caucasians.
One large study of Chinese subjects suggests that average values of FEV1 and FVC in Chinese males are 5.3% smaller, and in females 3.3% smaller than those predicted by ECCS/ERS. Differences were minimal in North China, and largest in southern China.
Differences in lung function are attributed to various factors, including (more information in Cotes' book (reference below):
- Diet: the lower protein consumption of children in the southern Indian subcontinent compared to their northern counterparts would contribute to the smaller lung for the same height and age.
- Differences in body build: as Negroid people have longer legs for the same trunk height, predicted volumes for the contents of the thoracic cage from standing height would be too high compared to Caucasians. This accounts for some 10% of the difference in lung volumes between black and white people.
Please note that the Pulmonaria Group have assembled a very comprehensive list of prediction equations for FEV1, FVC and FEV1/FVC from the world literature, with extensive documentation and software to compute predicted values and their lower limits of normal, as well as facilities to compare the different prediction equations and additional facilities. The documentation and software can be freely downloaded.
ECCS and ERS
In the revised version (1993) of the 1983 report (Quanjer PhH (ed.)
Standardized lung function testing. Bull Eur Physiopathol
Respir 1983; 19 suppl. 5: 45-51) of the European Community
for Coal and Steel (ECCS) predicted values of lung indices
were unchanged. They are almost universally applied in Europe.
The 1993 report was officially adopted by the European Respiratory
Society (ERS). The following chapter deals with spirometry,
predicted values and bronchodilator responsiveness:
Quanjer PhH, Tammeling GJ, Cotes JE, Pedersen OF, Peslin R,
Yernault JC. Lung volumes and forced ventilatory flows. Eur
Respir J 1993; 6 suppl. 16: 5-40.
Differences
in lung function
Cotes JE. Lung Function. Assessment and application in medicine.
Ed. 5, Blackwell Scientific Publications, Oxford, 1993.
Predicted values for healthy Chinese lifelong nonsmokers
Zheng Jinping, Zhong Nanshan. Normative values of pulmonary function testing in Chinese adults. Chin Med J 2002; 115: 50-54.