Incidence of Pediatric Sleep Apnea Related to School Attendance

Scottsdale, AZ - May 8, 2001

The primary cause of Obstructive Sleep Apnea Syndrome (OSAS) in children is enlarged tonsils and adenoids, compromising the upper airway and making breathing difficult at night. Researchers have discovered a correlation in the incidence and severity of OSAS and seasonal bacteria, particularly related to winter/school months.

Each year as the school season begins, children are exposed to new viruses and bacteria. As every parent knows this can lead to upper respiratory infections commonly known as "cold and flu." Tonsils, as part of the upper respiratory system, can harbor these viruses and bacteria, creating a possible source of inflammation. When tonsils remain enlarged, the result can be obstruction of the upper airway resulting in OSAS.

In the study, "Seasonal Variation in the Presence and Severity of Pediatric Obstructive Sleep Apnea," authors Gonzalo Verdugo, MD, of the University of Southern California-Los Angeles County Medical Center, and Debra M. Don, MD, Kenneth A. Geller, MD, and Sally Davidson-Ward, MD, all of Children's Hospital of Los Angeles, have postulated that exposure to increased bacteria levels during school months of November through January may escalate the incidence of OSAS in school-aged children. Their findings were presented at the 16th Annual Meeting of the American Society of Pediatric Otolaryngology in Scottsdale, AZ.

Methodology

A total of 550 sleep studies were reviewed retrospectively for the years 1998 and 1999, including 330 males and 220 females with an age range from one to 17.5 years (mean age 5.6 years). All patients were diagnosed with adenotonsillar hypertrophy and referred for a sleep study (both nap and overnight) during which polysomnograms (PSG) were performed. The respiratory disturbance index, RDI, (the number of apneas divided by the number of hours slept) was calculated, as well as blood oxygen saturation and peak end-tidal CO2.

OSAS was defined as non-existent, mild, moderate and severe based on study measurements. Chi-square analysis was performed to evaluate seasonal variation in OSAS presentation and severity.

Results

Studies showing no OSAS numbered 97; mild OSAS was seen in 288; moderate in 146, and severe in 19 cases. The presentation and severity of OSAS was compared to four blocks of three months each. During this comparison, a decrease in the number of non-existent OSAS was seen in the November to January block. There was also an increase in moderate and severe OSAS from November to January as well as a decrease in moderate and severe OSAS from August to October.

Conclusion

This retrospective review of 550 sleep studies sought to detect variations in the presence and severity of OSAS. The decrease in sleep studies with non-existent OSAS during the November to January block and the increase in studies with mild and moderate OSAS during the same time period is consistent with increased exposure to infectious agents during the school year, possibly leading to adenotonsillar hypertrophy, a known cause of OSAS.