Obstructive sleep apnea common in young cystic fibrosis children

Nov 2 2012

By Lucy Piper, Senior medwireNews Reporter

Children with stable cystic fibrosis (CF) have an increased risk for obstructive sleep apnea (OSA), which could cause sleep disruption, researchers report.

They found that 70% of 40 children with CF and mild lung disease in stable condition had mild-to-moderate OSA, defined as more than two apnea-hypopnea episodes per hour.

"In children, OSA has been associated with several neurocognitive and behavioral abnormalities," note Lucia Spicuzza and colleagues from the University of Catania in Italy. "In 5- to 9-year-old children, these include lack of memory, reduced executive functioning, learning disability, language dysfunction, and a lower intelligence quotient."

The findings, published in the Archives of Pediatrics and Adolescent Medicine, also indicate that it may be younger children with CF, between the ages of 6 months and 5 years, who are most affected by OSA.

The 40 children with CF, aged 6 months to 11 years, had mild lung disease with forced expiratory volume in 1 second values of 72% to 98%. They underwent full polysomnography in a sleep laboratory to monitor nocturnal sleep and cardiorespiration.

Compared with 18 healthy age-matched participants also monitored, the children with CF had significantly higher apnea-hypopnea index (AHI) scores, at an average 7.3 versus 0.5.

The healthy and CF participants had similar oxyhemoglobin saturation (SaO₂) when awake, at 98%, but during sleep this fell to 94% in CF patients with OSA, compared with 97% in healthy participants.

The researchers note that the highest AHI values and the lowest mean SaO₂ were seen in CF children aged 5 to 6 years.

The children with CF also showed mild sleep impairments compared with controls. For instance, they had reduced sleep efficiency (80 vs 88%) and rapid eye movement sleep duration (11 vs 13%), and an increased number of arousals per hour (11.0 vs 8.2).

Spicuzza et al speculate that both tonsillar hypertrophy and nasal obstruction may contribute to OSA in CF children. But the high prevalence of OSA in children younger than 6 years also suggests that factors associated with CF, such as increased mucus secretion in the respiratory tract or upper airway inflammation, may also play a role.

"Although further studies are necessary to assess the effect of sleep disorders on clinical outcomes, these data advise an early inclusion of nocturnal cardiorespiratory monitoring in the routine evaluation of these patients," the team concludes.

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