[Risk factors for airway obstruction in school children with respiratory symptoms assessed in a five year prospective...

The aim of this prospective study was to assess age-related changes of the respiratory status and to evaluate risk factors for persistent airflow obstruction in symptomatic school children. One hundred fifty children aged 7-12 years (mean age 9.5 yr.) were followed-up. In 1994 parents--administered questionnaire, skin prick tests and three dynamic spirometries in 4-6 week intervals were performed. Airways flow limitation was defined as FEV1%, MEF50 or MEF25 below minimal value. In 1999 questionnaires and spirometry were repeated by the same methods. The response rate was 74.7%. Children's respiratory status generally improved. Frequency of respiratory symptoms and obstructive disturbances (37.5% in 1994 versus 22.3% in 1999) decreased. Significant risk factors for airways flow limitation in 1999 were nocturnal dry cough, doctor diagnosed asthma, female gender and parental smoking. Advanced or persisting airway obstruction during several month in 1994 was valuable to predict lung function impairment in 1999. No relation between skin tests results and persistent airway obstruction was observed.