A PROSPECTIVE-STUDY OF PRONENESS TO ACUTE RESPIRATORY ILLNESS IN THE FIRST 2 YEARS OF LIFE

Background. This study sought explanations for the proneness to respir atory events in young Australian children. Methods. Prospective respir atory symptom diaries on 836 children collected data on respiratory sy mptoms and episodes. Questionnaires to mothers and birth and pregnancy records provided 56 known and possible predictors which were tested a gainst two summary respiratory outcomes in each of the first and secon d years of life. Results. The two summary respiratory variables record ed for first and second year of life give four outcome variables. In f itting multivariate regression models to predict outcomes, use of chil d care in early childhood and mothers' experience of respiratory illne ss in the 12 months before birth were significant predictors for all f our outcomes. Number of siblings was a predictor for three of the four outcomes. Sleep difficulty during pregnancy in the mother, and respir atory hospitalization of the infant in the first year, were significan t predictors for both first-year outcomes. Unexpected and unexplained findings emerged tot alcohol intake during pregnancy, passive smoking and breastfeeding in relation to the second year respiratory outcomes. Less than 9% of Variance in outcome scores was explained in any of th e four multiple regression models but this rose to between 24% and 31% when a corresponding scare from the other year was added to the model . Conclusions. Proneness to respiratory illness is an important entity ; its determinants are largely unknown and events in pregnancy or the perinatal period explain only a small proportion of the between-infant variability.