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Parental and neonatal risk factors for atopy, airway hyper-responsiveness, and asthma
M R Sears1, M D Holdaway, E M Flannery
1Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Insights
Male sex, parental asthma history, and maternal smoking are key risk factors for childhood asthma. Winter births increase risks for cat and dust mite allergies, suggesting intervention targets.
Area of Science:
- Pediatric Allergy and Immunology
- Respiratory Medicine
- Epidemiology
Background:
- Childhood asthma, atopy, and wheezing morbidity require identification of modifiable risk factors.
- Previous studies have not definitively established key predictors for these conditions.
Purpose of the Study:
- To examine risk factors for childhood atopy, airway hyperresponsiveness, and asthma in a New Zealand birth cohort.
- To inform rational selection of interventions for reducing asthma-related morbidity.
Main Methods:
- Longitudinal birth cohort study of 1037 children with data collection every 2-3 years.
- Atopy assessed via skin prick tests at age 13; logistic regression used for factor analysis.
- Parental and neonatal factors analyzed against atopy and asthma development.
Main Results:
- Male sex, parental asthma history (especially maternal), and maternal smoking in pregnancy predicted childhood asthma and atopy.
- Winter birth season increased risk for cat and house dust mite sensitization.
- Sibling number, socioeconomic status, and birth weight were not consistent predictors.
Conclusions:
- Identified male sex, parental atopy, and maternal smoking as significant risk factors for pediatric asthma.
- Winter birth season is linked to increased sensitization to common allergens.
- Findings suggest targeted interventions for children with parental atopy.
Background:
Previous studies have not resolved the importance of several potential risk factors for the development of childhood atopy, airway hyperresponsiveness, and wheezing, which would allow the rational selection of interventions to reduce morbidity from asthma. Risk factors for these disorders were examined in a birth cohort of 1037 New Zealand children.
Methods:
Responses to questions on respiratory symptoms and measurements of lung function and airway responsiveness were obtained every two to three years throughout childhood and adolescence, with over 85% cohort retention at age 18 years. Atopy was determined by skin prick tests at age 13 years. Relations between parental and neonatal factors, the development of atopy, and features of asthma were determined by comparison of proportions and logistic regression.
Results:
Male sex was a significant independent predictor for atopy, airway hyper-responsiveness, hay fever, and asthma. A positive family history, especially maternal, of asthma strongly predicted childhood atopy, airway hyperresponsiveness, asthma, and hay fever. Maternal smoking in the last trimester was correlated with the onset of childhood asthma by the age of 1 year. Birth in the winter season increased the risk of sensitisation to cats. Among those with a parental history of asthma or hay fever, birth in autumn and winter also increased the risk of sensitisation to house dust mites. The number of siblings, position in the family, socioeconomic status, and birth weight were not consistently predictive of any characteristic of asthma.
Conclusions:
Male sex, parental atopy, and maternal smoking during pregnancy are risk factors for asthma in young children. Children born in winter exhibit a greater prevalence of sensitisation to cats and house dust mites. These data suggest possible areas for intervention in children at risk because of parental atopy.