Study objectives: We sought to identify early life factors (ie, first 4 years) associated with wheeze, asthma, and bronchial hyperresponsiveness (BHR) at age 10 years, comparing their relative influence for these conditions.
Methods: Children were seen at birth, and at 1, 2, 4, and 10 years of age in a whole-population birth cohort study (1,456 subjects). Information was collected prospectively on genetic and environmental risk factors. Skin-prick testing was performed at 4 years of age. Current wheeze (in the last 12 months) and currently diagnosed asthma (CDA) [ie, current wheeze and ever-diagnosed asthmatic subject] were recorded at 10 years of age when BHR was measured at bronchial challenge. Independent significant risk factors for these outcomes were identified by logistic regression.
Results: Independent significance for current wheeze occurred with maternal asthma (odds ratio [OR], 2.08; 95% confidence interval [CI], 1.27 to 3.41) and paternal asthma (OR, 2.12; 95% CI 1.29 to 3.51), recurrent chest infections at 2 years (OR, 3.98; 95% CI, 2.36 to 6.70), atopy at 4 years of age (OR, 3.69; 95% CI, 2.36 to 5.76), eczema at 4 years of age (OR, 2.15; 95% CI, 1.24 to 3.73), and parental smoking at 4 years of age (OR, 2.18; 95% CI, 1.25 to 3.81). For CDA, significant factors were maternal asthma (OR, 2.26; 95% CI, 1.24 to 3.73), paternal asthma (OR, 2.30; 95% CI, 1.17 to 4.52), and sibling asthma (OR, 2.00; 95% CI, 1.16 to 3.43), recurrent chest infections at 1 year of age (OR, 2.67; 95% CI, 1.12 to 6.40) and 2 years of age (OR, 4.11; 95% CI, 2.06 to 8.18), atopy at 4 years of age (OR, 7.22; 95% CI, 4.13 to 12.62), parental smoking at 1 year of age (OR, 1.99; 95% CI, 1.15 to 3.45), and male gender (OR, 1.72; 95% CI, 1.01 to 2.95). For BHR, atopy at 4 years of age (OR, 5.38; 95% CI, 3.06 to 9.47) and high social class at birth (OR, 2.03; 95% CI, 1.16 to 3.53) proved to be significant.
Conclusions: Asthmatic heredity, predisposition to early life atopy, plus early passive smoke exposure and recurrent chest infections are important influences for the occurrence of wheeze and asthma at 10 years of age. BHR at 10 years of age has a narrower risk profile, suggesting that factors influencing wheezing symptom expression may differ from those predisposing the patient to BHR.