Paediatric lung function testing : determinants and reference values

Paediatric lung function tests provide objective measures in diagnosis and follow-up of lung diseases, and give insight in the pathophysiology of lung growth and development. In the first part of the thesis, paediatric lung function tests were used to investigate determinants of lung growth and development. The implementation of smoke free legislation resulted in less pregnant women being exposed to environmental tobacco smoke, and a concomitant rise in birth weight and birth-weight-adjusted neonatal lung function. Prenatal tobacco smoke exposure resulted in reduced neonatal lung function in healthy newborns, but this did not persist into childhood when there was no postnatal smoke exposure. Parental smoking during childhood resulted in diminished airway function in healthy children, with the most marked decrease in peripheral airway function. Furthermore, in healthy newborns parental lung function was found to be a determinant of neonatal lung function. Additionally, children with accelerated weight gain during the first 3 months of life had more wheezing complaints in early childhood and decreased lung function at the age of five. The second part of the thesis focussed on the use of paediatric lung function testing and reference values in clinical practice. New reference values for paediatric lung function tests were generated. They provide a more valid estimation of a patient’s lung function and result in less over- and underdiagnosis of pulmonary diseases. Measurement of interrupter resistance was found not to be an alternative for forced expiratory volume measurements to diagnose bronchial hyperresponsiveness in individual patients. An exhalation time of six seconds during exhaled Nitric Oxide measurements showed good agreement with the standard exhalation time of 10 seconds and was favoured by young children