Abstract
Background: Previous studies have investigated factors associated with poor lung function in children. However, these studies use a cross-sectional approach which ignores changes in lung function over time. In this study, we develop multilevel longitudinal models in order to investigate factors affecting developmental change in lung function in early life.
Methods: In a population-based birth cohort 1185 participants were recruited prenatally and followed prospectively (1, 3, 5, 8 and 11 years). At each time point, a validated questionnaire was administered to collect information on asthma-related symptoms, height and weight. We assessed atopy and lung function (Specific Airway Resistance (sRaw), plethysmography) at each follow-up.We use a longitudinal linear mixed models approach to determine predictors of change in sRaw over time.
Results: Univariate longitudinal analyses revealed marked deterioration in sRaw among children who were atopic (mean difference 2.85%, 95% CI 1.05%-9.84%, p=0.003). Children who wheezed also had poorer lung function (mean difference 5.20%, 95% CI 0.87%-2.54%, p<0.001). Boys had poorer lung function compared to girls (mean difference 3.48%, 95% CI 0.87%-6.52%, p=0.03) and also had a higher rate of deterioration of sRaw over time which increased by 0.011 units (p=0.012) per year. In a multivariate longitudinal model, the factors which best predicted diminished lung function were atopy, increased BMI, paternal atopy, gender and current wheeze.
Conclusion: Multilevel longitudinal models allow us to predict factors associated with diminished lung function as well as factors associated with change in lung function over time.
- © 2011 ERS
