Gender differences in respiratory, nasal and skin symptoms: 6-7 versus 13-14-year-old children.

ISAAC questionnaires were completed by the parents of 6432 children, aged 6-7 y and by themselves by 2864 children 13-14-y-old. Prevalence rates of respiratory and nasal symptoms and a diagnosis of asthma and hay fever were higher in 6-7-y-old boys than in girls, while girls aged 13-14 y had higher rates for most symptoms, except asthma. Underdiagnosis of asthma in 13-14-y-old girls cannot be excluded as an explanation, but our data suggest under-reporting of respiratory and nasal symptoms in 13-14-y-old boys.