Asthma and sleep apnea are both respiratory diseases and one can worsen the other. Those who suffer from asthma have a higher risk of sleep apnea and sleep apnea can make the asthma more difficult to control.

As girls usually have a more severe asthma than boys, the investigators believe that girls have a higher risk of sleep apnea.

To test if asthmatic girls have more sleep apnea than boys, the investigators are going to ask them questions regarding asthma and sleep symptoms (such as snore) and the investigators are going test the lung function and how many times they stop breathing during the sleep. The sleep test is going to be performed in children's home.

In children, having sleep apnea can make the asthmatic stay in the hospital 30% more when they have an asthma attack. We also are going to look if sleep apnea increases the number of hospitalizations and asthma attacks in the past 12 months.

Obstructive sleep apnea (OSA) and asthma are both inflammatory airway diseases. A systematic review regarding sleep-disordered breathing (SDB) in asthmatic children analyzed 17 studies but only two of them had objective OSA measurement. In total, 45,115 children were included, 53% boys, mean age 8.6 ± 2.5 years. SDB was present in 23.8% of asthmatic children and in 16.7% of non-asthmatic (p < 0.001, OR 1.9, 95%CI 1.7-2.2).

An American study found that OSA in asthmatic children increases hospital length of stay (OR 2.3; 95% CI = 1.8 - 2.9). Brazilian database of the year 2015 showed that, among children 5-19 years, asthma was the 5th cause of hospitalization: a total of 2.4% of the hospitalization in this age group, after birth and its complication (31%), limb fractures (5.7%), pneumonia (3.8%), and appendicitis (3.2%).

The relationship among asthma severity (mild, moderate, and severe) and OSA has been described previously, but not in every study. Poor asthma control has also been linked to a higher OSA risk in adults and children.

OSA and asthma share many risk factors: rhinitis, increased collapsibility of the upper airway, local and systemic inflammation, gastroesophageal reflux, and obesity.

A higher risk of SDB in asthmatic girls has recently been described (OR 2.55 for girls and 0.70 for boys). Among non-asthmatic children OSA is usually equal among boys and girls until adolescence. A possible explanation is asthma severity in children: younger boys are more severe but after puberty, girls are.

Since OSA and asthma are linked diseases and that little is known about them in the pediatric field, specially differences related to sex, the investigators hypothesize that: 1) asthmatic girls have a higher OSA risk; 2) OSA will be higher in asthmatic children compared to the pediatric literature; 3) asthma severity, asthma control, and rhinitis will be related to a higher OSA risk. The investigators also aim to analyze factors associated with a higher risk of hospitalizations and asthma attacks.

Inclusion Criteria:

• Persistent asthma

Exclusion Criteria:

• Craniofacial malformation
• Thoracic malformation
• Genetic syndromes
• Bronchopulmonary dysplasia
• Bronchiolitis obliterans
• Neuromuscular diseases
• Sickle cell anemia
• Cystic fibrosis