Background: Historically, evidence of male preponderance in the prevalence of childhood asthma has predominated. More recent studies have demonstrated a sex equalisation in its distribution. This study aims to investigate the sex distribution in the prevalence of asthma in Irish schoolchildren.
Methods: Two identical cross-sectional studies of primary school children were carried out in 2002 and 2007. Parents of children (aged 6-8 years) completed identical ISAAC-based questionnaires in 24 Cork schools in 2002 (n=1474), and in 2007(n=1385). A prospective cohort study in 2002 (n=1474, children, aged 6-8) and in 2007 (n=706, children aged 11-13) was simultaneously performed, also using ISAAC-based questionnaires (parentally completed).
Results: Response rates were 75% (average), with an equal male/female mix. The male:female (M:F) ratio of asthma prevalence in 2002 was 1.4:1,( 26.8%:17.4%) male bias was found to be significant (p<0.001). In 2007, the M:F ratio in asthma prevalence was 1.2:1 (57.2%:59.2%), with no significant differences in distribution (p=0.64). In the cohort study, in 2002 (age6-8), the M:F ratio in the prevalence of asthma was 1.4:1 (26.8%:17.4%),male bias was found to be significant (p<0.001). In 2007 (age 11-13), the M:F ratio was 1.2:1 (45.5%:46.6%), analysis rendered no significant differences(p=0.85).
Conclusion: In both young and older Irish schoolchildren the distribution of sex in the prevalence of asthma has moved towards equalisation. This equalisation and subsequent Movement towards female bias in adolescence and adulthood has been shown in several studies. However, the findings of our study suggest an alteration in the sex profile of asthma in young children.