Sex-specific differences in allergic sensitization to house dust mites: a meta-analysis.

BACKGROUND: The prevalence of allergic airway diseases in childhood is higher in boys than in girls but switches toward a female predominance in adolescents and adults. The sex-specific prevalence of allergic sensitization to 1 of the most common allergens worldwide, house dust mite (HDM), has not been examined systematically by age group and species. OBJECTIVE: To systematically review the literature to examine sex-specific differences in the prevalence of allergic sensitization to HDM. METHODS: On the basis of a systematic MEDLINE search for population-based studies published between 1990 and 2007, we conducted meta-analyses of male to female ratios for sensitization to 2 different species of HDMs (Dermatophagoides pteronyssinus and Dermatophagoides farinae) separately for children and adults. RESULTS: We included data from 7,822 children and 18,522 adults from 15 studies. The prevalence of sensitization to D pteronyssinus was significantly higher in boys vs girls (male to female ratio, 1.39; 95% confidence interval [CI], 1.13-1.71) and in men vs women (male to female ratio, 1.40; 95% CI, 1.22-1.61). For sensitization to D farinae, the significant male predominance in adults was even more pronounced (male to female ratio, 1.95; 95% CI, 1.37-2.79), but there were no sex-specific differences in children (male to female ratio, 0.90; 95% CI, 0.56-1.46). CONCLUSIONS: In adults, the male predominance in sensitization to HDM seems to be contrary to the prevalence of allergic airway symptoms, which has a female predominance. The male predominance is even higher in allergic sensitization to D farinae than to D pteronyssinus. Further research is necessary regarding sex-specific differences in allergy and asthma.