Gender-specific differences in the prevention of asthma-like symptoms in high-risk infants

The prevalence of asthma in children has increased in the last decades, and gender-specific differences in asthma development have recently been suggested. The present study investigates whether gender differences are present in a population of young children (0-2 yr) with a high risk for the development of asthma on the basis of the presence of asthma in first-degree relative(s). The study was performed on 222 children (118 boys, 104 girls) with a familial predisposition of asthma, which received standardized recommendations to reduce exposure to allergens (dust mite, pets and food allergens) and to passive smoking. Health outcome (wheezing episodes and shortness of breath) and compliance with allergen-reducing measures were studied by means of multiple regression analyses. Boys suffered more from asthma-like complaints than girls, as diagnosed by the general practitioner (32% vs. 18%, respectively, p = 0.023). Compliance with intervention measures was similar for boys and girls for most allergens, but food allergen reduction was better applied for girls: duration of exclusive breastfeeding was longer in girls (median 9 wk vs. 4 wk, p = 0.009). Further analysis showed that 4 wk of longer breastfeeding reduced the number of wheezing episodes and shortness of breath in boys by 19% and 15%, respectively, but not in girls, suggesting sex as an effect modifier in the relationship between breastfeeding and asthma-like symptoms. The present findings indicate that application and effects of prevention strategies for children with a high risk for developing asthma might be gender-specific and suggest a special importance of breastfeeding boys.