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Boys 'grow out' of asthma sooner than girls

20-Aug-08

Boys are more likely to grow out of childhood asthma during puberty than girls, according to the results of a US study.

It showed that the airway responsiveness of boys diagnosed with mild to moderate asthma started to drop after age 11, but remained level in girls.

The study included 1,041 children aged 5-12 years with mild to moderate persistent asthma who were followed up for an average of nine years. They underwent yearly methacholine challenges to test for changes in airway responsiveness.

Airway responsiveness improved at the same rate in boys and girls until age 11.

After this it improved in boys but not in girls. At age 16, the average methacholine dose needed to provoke a 20 per cent loss of FEV1 in boys was more than double the dose needed to provoke the same response in girls.

At age 18, 27 per cent of the boys no longer responded to the methacholine challenge, indicating that had grown out of their childhood asthma. This was true in only 14 per cent of the girls.

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Am J Respir Crit Care Med 2008; 178: 325-331