- Email: [email protected]
The epidemiology of sleep related breathing disorder in children
INTERNATIONAl JOURNAl. OF
Pediatric
ELSEVIER
International Journal of Pediatric Otorhinolaryngology 32 (Supp1.) (1995) S63-S66
m9.tg
Larjiigology
The epidemiology of sleep related breathing disorder in children E. Hultcrantz*a, B. Lofstrand-Tidestromb , 1. Ahlquist-Rastad
C
aDept. of Otorhinolaryngology, Uppsala University, S-75J 85 Uppsala, Sweden bDept. of Orthodontics, Karolinska Inst., Huddinge, Sweden 'Swedish Medical Products Agency, Uppsala, Sweden
Abstract
An epidemiological study of sleep obstruction and its orthodontic consequences is under way on a cohort (500) of 4-year-old children. The parents are asked about the child's snoring, sleep apnea, sucking habits, infections and 'genetic clues'. Dental casts have been made from the first 100 children and the group of children who snore are being compared to the non-snorers. A sleep study, a lateral cephalogram and dental casts are done on all snorers in the cohort. Preliminary results show that 6.2% snore every night by age 4 and another 18% when infected. More children use pacifiers among the snorers than in the non-snoring group (60% vs. 35%). Tonsillar angina is 3 times more common in the snorer group and twice as many of their parents have been adenoidectomized (A) and/or tonsillectomized (T). The dental casts show a significant difference in width of the maxilla and length of the mandible. The children are treated for their breathing obstruction with A or A + T. Two years later, the same cohort will be examined again. The prevalence of snoring and sleep apnea among 4-year-olds will be known as will whether and how treatment for breathing obstruction influences facial development. Keywords: Epidemiology; Snoring; Sleep disorder; Children; Facial development
1. Introduction
Most published studies concerning obstructive sleep problems in children are reports of extreme cases with complications [8] or a series of children where a good effect of tonsillectomy has been shown [1]. Thus far, there are only two epidemio-
* Corresponding author. 0165-5876/95/$09.50 © 1995 Elsevier Science Ireland Ltd. All rights reserved SSDI 0165-5876(94)01144-Z
S64
E. Hultcrantz et al.; Int. J. Pediatr. Otorhinolaryngol. 32 (Suppl.) (1995) S63-S66
logical studies in which the prevalence of sleep obstruction has been observed. The first one comes from Oxford, UK where the Stradling group [2] has studied 4-5-year-old children taken from the general health care system register. The results showed a surprisingly low prevalence of sleep related breathing disorder only 0.7%. The second epidemiological study was performed in Iceland, in a small suburb to Reykjavik where children between 6 months and 6 years have been studied [4]. Based on a combination of estimations the prevalence of sleep related breathing disorder in this group of children of different age was calculated as 2.5%. The boys had their peak incidence at 2.5 years of age and the girls at age 4. Mouthbreathing is a symptom which is very often combined with snoring and breathing obstruction. There are several studies concerning the effect of mouthbreathing on the development of the growing facial skeleton [7,9] and some reports showing a positive effect on dental aberration and facial growth after tonsillectomy [3,5].
The purpose of the present investigation is to study the prevalence of breathing obstruction in 4-year-old children and to see whether early intervention with regard to the breathing problems will change the number of children who need orthodontic treatment when they grow older. Another possible benefit of early treatment of breathing obstruction-mouth breathing may be prevention of sleep apnea development in adulthood. However, this matter cannot be covered within the present investigation. 2. Materials and methods
In Sweden almost 100% of all children receive a '4-year check-up', in which they are checked for sight, hearing, dental status and general health status. In connection with this general health control an epidemiological study of sleeping obstruction and its consequences is under way on a cohort of 4-year-old children within one dental district (500 children), in a small town (Enkoping) in the middle of Sweden. During the usual dental examination the parents are being interviewed about the child's sleeping habits, snoring, sleep apnea, sucking habits, infections and 'genetic clues' (whether the parents have been operated with tonsillectomy or adenoidectomy and/or have had orthodontic treatment). Orthodontic evaluations were done on each of the first 100 children and comparisons were made between dental casts of the group of children who snore regularly and those who did not snore. In addition, dental casts and lateral cephalograms are to be taken from all the snoring children in the rest of the cohort, which will make the number of casts from snorers and non-snorers about equal. All children whose parents report that they snore every night are examined with a full-night sleep study, in the ward, including thermistors at nose and mouth, electrostatic mattress registering breathing movements, position analysis, oximetry and heart rate (Eden-Trace II). The children are treated differently depending on their breathing obstruction and physical status: if small tonsils and obstructive adenoid, adenoidectomy (A) will be performed first. A + T (tonsillectomy) is performed only if there is reason to believe that the tonsillar hypertrophy is the main cause of obstruction, so A alone would
E. Hultcrantz et al.J Int. J. Pediatr. Otorhinolaryngol. 32 (Suppl.) (1995) S63-S66
865
be insufficient. The goal is to enable the child to breath freely through her/his nose during sleep. A few children have an extremely narrow maxilla, do not snore but are constant mouthbreathers. These children will have a maxillary expansion treatment. Two years after this first part of the study, the same cohort of children will be examined again. All the children of whom dental casts were made will have new ones made. A revised questionnaire will be used. An untreated cohort of 6-year-old children will serve as a control group with inquires and dental check-up. 3. Results Thus far, questionnaires have been completed for 325 out of the 500 children in the study group. Responses show that 6.2% of them snore every night and an additional 18% when infected. Apneas every night were reported by 1.5% and regular mouth breathing by 7.4%. Significantly more children regularly used pacifiers among the snorers than in the non-snoring group (60% vs. 35%). A history of tonsillar angina was significantly more common in the snorer group (P = 0.002), as was a history that the parents had been adenoidectomized and/or tonsillectomized (P = 0.005). The data from analysis of the dental casts of the first 100 children showed a significant difference in width of the maxilla (25.5 mm vs. 28.4 mm at 53-63, P < 0.01) between snoring and not snoring children, and in the length of the mandibular arch (23.7 mm vs. 25.0 mm, P < 0.05). The first 10 sleep studies have shown a good correlation between the parents observations of obstructive breathing-snoring at night and the objective measurements, except in few cases where the parents report that the child has spontaneously improved in the interval between questionnaire completion and sleep observation. 4. Discussion
No widely accepted definition of sleep apnea in children exists. The usual criteria of 4% oxygen desaturation in combination with 10 s long apneas are not applicable in young children. The results from the present study are still preliminary and therefore difficult to discuss. In most cases, our sleep registrations show very little effect on oxygen desaturation even when both thermistor readings and the electrostatic mattress, indicate obstructive breathing and apneas between 3 and 10 s long. Our prevalence of breathing disorder during sleep, based on apneas and hypopneas, rather than desaturations, will probably be closer to the 2.9% which Gislason has presented [4] than to the 0.7% in the Stradling study [2]. Our measuring method is similar to the Icelandic study. The reason for the lower figure in the UK study may be that they use the oximetry reading in combination with video observations. Since they do not replay the whole night's video recording, but only the events at which desaturations are present, they will miss periods when obstructive breathing and apneas have not given significant desaturations. An interesting observation in our study is that the number of girls snoring every night significantly outnumbered the number of boys. This is in accordance with the
S66
E. Hultcrantz et al. / Int. J. Pediatr. Otorhinolaryngol. 32 (Suppl.) (1995) S63-S66
Icelandic study [4] where the peak incidence of snoring for girls was 4 years. We will look further into the question of whether boys and girls grow differently at that age. Our preliminary data show that there are significant differences in the width of the maxilla and the length of the mandible between snorers and non-snorers. The fact that the use of pacifiers is far more frequent in the snoring group may be part of the explanation of these differences [6]. The number of tonsillitis was correlated to snoring as was the parents' tonsillectomy. This can indicate a genetic immunologic difference which also would be interesting to investigate further. Acknowledgements
This study is supported by The Department of Research and Development of the County Council of Uppsala. References [I] Ahlqvist-Rastad, J., Hultcrantz, E. and Svanholm, H. (1988) Children with tonsillar obstruction: indications for and efficacy of tonsillectomy. Acta Pediatr. Scand. 77, 831-835. [2] Ali N.J., Pitson D.J. and Stradling J.R. (1993) Snoring, sleep disturbance and behaviour in 4-5-year-olds. Arch. Dis. Child 68 (3), 360-366. [3] Behlfelt, K. (1990) Enlarged tonsils and the effect of tonsillectomy. Characteristics of dentition and facial skeleton. Posture of the head, hyoid bone and tongue. Mode of breathing, (Thesis), Swed. Dent. J. Supp!. 72. (4) Gislason and Benediktsdottir. Epidemiological Study of Sleep Apnea in Children. Chest (in press). (5) HuItcrantz, E., Larson, M., Hellquist, R., Ahlqvist-Rastad, J., Svanholm, H. and Jakobsson, O.P. (1991) The influence of tonsillar obstruction and tonsillectomy on facial growth and dental arch morphology, Int. J. Pediatr. Otorhinolaryngo!. 22, 125-134. [6J Larsson, E. (1986) The effect of dummy-sucking on the occlusion - a review. Eur. J. Orthod. 8, 127-130. [7J Linder-Aronson, S. (1970) Adenoids, their effect on mode of breathing and nasal airflow and their relationship to characteristics of the facial skeleton and the dentition (Thesis). Acta Otolaryngo!. Supp!. 265. [8] Menasche, V., Farrehi, C. and Miller, M. (1965) Hypoventilation and cor pulmonale due to chronic upper airway obstruction. J. Pediatr. 67, 198-203. [9] Subtelny, J.D. (1980) Oral respiration: facial mal-development and corrective dento-facial orthopedics. Angle Orthod. 50, 147-164.
Pediatric
ELSEVIER
International Journal of Pediatric Otorhinolaryngology 32 (Supp1.) (1995) S63-S66
m9.tg
Larjiigology
The epidemiology of sleep related breathing disorder in children E. Hultcrantz*a, B. Lofstrand-Tidestromb , 1. Ahlquist-Rastad
C
aDept. of Otorhinolaryngology, Uppsala University, S-75J 85 Uppsala, Sweden bDept. of Orthodontics, Karolinska Inst., Huddinge, Sweden 'Swedish Medical Products Agency, Uppsala, Sweden
Abstract
An epidemiological study of sleep obstruction and its orthodontic consequences is under way on a cohort (500) of 4-year-old children. The parents are asked about the child's snoring, sleep apnea, sucking habits, infections and 'genetic clues'. Dental casts have been made from the first 100 children and the group of children who snore are being compared to the non-snorers. A sleep study, a lateral cephalogram and dental casts are done on all snorers in the cohort. Preliminary results show that 6.2% snore every night by age 4 and another 18% when infected. More children use pacifiers among the snorers than in the non-snoring group (60% vs. 35%). Tonsillar angina is 3 times more common in the snorer group and twice as many of their parents have been adenoidectomized (A) and/or tonsillectomized (T). The dental casts show a significant difference in width of the maxilla and length of the mandible. The children are treated for their breathing obstruction with A or A + T. Two years later, the same cohort will be examined again. The prevalence of snoring and sleep apnea among 4-year-olds will be known as will whether and how treatment for breathing obstruction influences facial development. Keywords: Epidemiology; Snoring; Sleep disorder; Children; Facial development
1. Introduction
Most published studies concerning obstructive sleep problems in children are reports of extreme cases with complications [8] or a series of children where a good effect of tonsillectomy has been shown [1]. Thus far, there are only two epidemio-
* Corresponding author. 0165-5876/95/$09.50 © 1995 Elsevier Science Ireland Ltd. All rights reserved SSDI 0165-5876(94)01144-Z
S64
E. Hultcrantz et al.; Int. J. Pediatr. Otorhinolaryngol. 32 (Suppl.) (1995) S63-S66
logical studies in which the prevalence of sleep obstruction has been observed. The first one comes from Oxford, UK where the Stradling group [2] has studied 4-5-year-old children taken from the general health care system register. The results showed a surprisingly low prevalence of sleep related breathing disorder only 0.7%. The second epidemiological study was performed in Iceland, in a small suburb to Reykjavik where children between 6 months and 6 years have been studied [4]. Based on a combination of estimations the prevalence of sleep related breathing disorder in this group of children of different age was calculated as 2.5%. The boys had their peak incidence at 2.5 years of age and the girls at age 4. Mouthbreathing is a symptom which is very often combined with snoring and breathing obstruction. There are several studies concerning the effect of mouthbreathing on the development of the growing facial skeleton [7,9] and some reports showing a positive effect on dental aberration and facial growth after tonsillectomy [3,5].
The purpose of the present investigation is to study the prevalence of breathing obstruction in 4-year-old children and to see whether early intervention with regard to the breathing problems will change the number of children who need orthodontic treatment when they grow older. Another possible benefit of early treatment of breathing obstruction-mouth breathing may be prevention of sleep apnea development in adulthood. However, this matter cannot be covered within the present investigation. 2. Materials and methods
In Sweden almost 100% of all children receive a '4-year check-up', in which they are checked for sight, hearing, dental status and general health status. In connection with this general health control an epidemiological study of sleeping obstruction and its consequences is under way on a cohort of 4-year-old children within one dental district (500 children), in a small town (Enkoping) in the middle of Sweden. During the usual dental examination the parents are being interviewed about the child's sleeping habits, snoring, sleep apnea, sucking habits, infections and 'genetic clues' (whether the parents have been operated with tonsillectomy or adenoidectomy and/or have had orthodontic treatment). Orthodontic evaluations were done on each of the first 100 children and comparisons were made between dental casts of the group of children who snore regularly and those who did not snore. In addition, dental casts and lateral cephalograms are to be taken from all the snoring children in the rest of the cohort, which will make the number of casts from snorers and non-snorers about equal. All children whose parents report that they snore every night are examined with a full-night sleep study, in the ward, including thermistors at nose and mouth, electrostatic mattress registering breathing movements, position analysis, oximetry and heart rate (Eden-Trace II). The children are treated differently depending on their breathing obstruction and physical status: if small tonsils and obstructive adenoid, adenoidectomy (A) will be performed first. A + T (tonsillectomy) is performed only if there is reason to believe that the tonsillar hypertrophy is the main cause of obstruction, so A alone would
E. Hultcrantz et al.J Int. J. Pediatr. Otorhinolaryngol. 32 (Suppl.) (1995) S63-S66
865
be insufficient. The goal is to enable the child to breath freely through her/his nose during sleep. A few children have an extremely narrow maxilla, do not snore but are constant mouthbreathers. These children will have a maxillary expansion treatment. Two years after this first part of the study, the same cohort of children will be examined again. All the children of whom dental casts were made will have new ones made. A revised questionnaire will be used. An untreated cohort of 6-year-old children will serve as a control group with inquires and dental check-up. 3. Results Thus far, questionnaires have been completed for 325 out of the 500 children in the study group. Responses show that 6.2% of them snore every night and an additional 18% when infected. Apneas every night were reported by 1.5% and regular mouth breathing by 7.4%. Significantly more children regularly used pacifiers among the snorers than in the non-snoring group (60% vs. 35%). A history of tonsillar angina was significantly more common in the snorer group (P = 0.002), as was a history that the parents had been adenoidectomized and/or tonsillectomized (P = 0.005). The data from analysis of the dental casts of the first 100 children showed a significant difference in width of the maxilla (25.5 mm vs. 28.4 mm at 53-63, P < 0.01) between snoring and not snoring children, and in the length of the mandibular arch (23.7 mm vs. 25.0 mm, P < 0.05). The first 10 sleep studies have shown a good correlation between the parents observations of obstructive breathing-snoring at night and the objective measurements, except in few cases where the parents report that the child has spontaneously improved in the interval between questionnaire completion and sleep observation. 4. Discussion
No widely accepted definition of sleep apnea in children exists. The usual criteria of 4% oxygen desaturation in combination with 10 s long apneas are not applicable in young children. The results from the present study are still preliminary and therefore difficult to discuss. In most cases, our sleep registrations show very little effect on oxygen desaturation even when both thermistor readings and the electrostatic mattress, indicate obstructive breathing and apneas between 3 and 10 s long. Our prevalence of breathing disorder during sleep, based on apneas and hypopneas, rather than desaturations, will probably be closer to the 2.9% which Gislason has presented [4] than to the 0.7% in the Stradling study [2]. Our measuring method is similar to the Icelandic study. The reason for the lower figure in the UK study may be that they use the oximetry reading in combination with video observations. Since they do not replay the whole night's video recording, but only the events at which desaturations are present, they will miss periods when obstructive breathing and apneas have not given significant desaturations. An interesting observation in our study is that the number of girls snoring every night significantly outnumbered the number of boys. This is in accordance with the
S66
E. Hultcrantz et al. / Int. J. Pediatr. Otorhinolaryngol. 32 (Suppl.) (1995) S63-S66
Icelandic study [4] where the peak incidence of snoring for girls was 4 years. We will look further into the question of whether boys and girls grow differently at that age. Our preliminary data show that there are significant differences in the width of the maxilla and the length of the mandible between snorers and non-snorers. The fact that the use of pacifiers is far more frequent in the snoring group may be part of the explanation of these differences [6]. The number of tonsillitis was correlated to snoring as was the parents' tonsillectomy. This can indicate a genetic immunologic difference which also would be interesting to investigate further. Acknowledgements
This study is supported by The Department of Research and Development of the County Council of Uppsala. References [I] Ahlqvist-Rastad, J., Hultcrantz, E. and Svanholm, H. (1988) Children with tonsillar obstruction: indications for and efficacy of tonsillectomy. Acta Pediatr. Scand. 77, 831-835. [2] Ali N.J., Pitson D.J. and Stradling J.R. (1993) Snoring, sleep disturbance and behaviour in 4-5-year-olds. Arch. Dis. Child 68 (3), 360-366. [3] Behlfelt, K. (1990) Enlarged tonsils and the effect of tonsillectomy. Characteristics of dentition and facial skeleton. Posture of the head, hyoid bone and tongue. Mode of breathing, (Thesis), Swed. Dent. J. Supp!. 72. (4) Gislason and Benediktsdottir. Epidemiological Study of Sleep Apnea in Children. Chest (in press). (5) HuItcrantz, E., Larson, M., Hellquist, R., Ahlqvist-Rastad, J., Svanholm, H. and Jakobsson, O.P. (1991) The influence of tonsillar obstruction and tonsillectomy on facial growth and dental arch morphology, Int. J. Pediatr. Otorhinolaryngo!. 22, 125-134. [6J Larsson, E. (1986) The effect of dummy-sucking on the occlusion - a review. Eur. J. Orthod. 8, 127-130. [7J Linder-Aronson, S. (1970) Adenoids, their effect on mode of breathing and nasal airflow and their relationship to characteristics of the facial skeleton and the dentition (Thesis). Acta Otolaryngo!. Supp!. 265. [8] Menasche, V., Farrehi, C. and Miller, M. (1965) Hypoventilation and cor pulmonale due to chronic upper airway obstruction. J. Pediatr. 67, 198-203. [9] Subtelny, J.D. (1980) Oral respiration: facial mal-development and corrective dento-facial orthopedics. Angle Orthod. 50, 147-164.