[New spirometric reference values for children and adolescents in Germany considering height and non-linear age...

Comparing children's lung function with reference values is important for diagnosing respiratory diseases. The values by Zapletal et al., commonly used nowadays, are not appropriate for the current stage of children's development. We have now developed new reference values and a lower limit of normal (LLN) for children in Germany, divided into small-range age and height categories.

We examined 4- to 18-year-old children in 3 German communities under field conditions. 1943 children were healthy and had a visually acceptable lung function which also fulfilled international quality criteria. We used the regression model LMS, which was introduced by Stanojevic and Quanjer in this context.

There were significant differences between the measured lung function and the predicted values according to Zapletal et al. The lung function did not only depend on the child's height, but also in a non-linear way on the age. The variation coefficient did not depend on age.

To avoid diagnostic errors, the currently often used reference values according to Zapletal et al. should no longer be used. The non-linear dependence on age corresponds to the recently published results by Stanojevic and Quanjer.