Blackwell Publishing AsiaMelbourne, AustraliaSBRSleep and Biological Rhythms1446-9235© 2006 The Author; Journal compilation © 2006 Japanese Society of Sleep ResearchJanuary 2006514049Original ArticleInfant and children sleep surveyY-H Chou
Sleep and Biological Rhythms 2007; 5: 40–49
doi:10.1111/j.1479-8425.2006.00245.x
ORIGINAL ARTICLE
Survey of sleep in infants and young children in northern Taiwan* Yi-Hung CHOU Division of Neonatology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Chang Gung Children’s Hospital, Taipei, Taiwan
Abstract An infant and child sleep survey questionnaire was performed in a well-baby clinic to investigate parent-reported sleep problems in the children. A total of 506 children aged 0–6 years were enrolled and divided into five age groups. The results contain important clinical implications, as follows: (i) frequent night waking is observed in 37.5% of the children; (ii) more than 70% of the children take 30 min or longer to fall asleep; (iii) illness interferes with sleep at night in 35.0% of the children; (iv) caregivers’ perceptions of sleep problems is very common (64.2%); (v) the children sleep for a total of between 11.5 and 15.4 h; (vi) they go to sleep between the hours of 21.00 and 22.00 hours; (vii) they wake between 07.00 and 09.00 hours and (viii) the frequency of sleep problems is related to their age, and problems are more prevalent in the going to bed schedule, night waking, and daytime sleepiness. We conclude that sleep problems of infants and young children are very common in northern Taiwan, and the data analysis of sleep problems may provide valuable information to medical personnel and parents in the clinical evaluation and management of sleep problems.
Key words: infants and children, sleep, survey.
INTRODUCTION Sleep plays a major role in children’s well-being, and it is strongly influenced by the child’s health status, psychological stress and family issues as well as by multiple aspects of the environment and culture.1,2
Correspondence: Assistant Professor Yi-Hung Chou, Division of Neonatology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Chang Gung Children’s Hospital, Taipei, Taiwan. Email:
[email protected] *Presented at the World Federation of Sleep Research and Sleep Medicine Societies 2nd Interim Congress, New Delhi, India, 22–26 September 2005. Accepted for publication 8 May 2006.
40
Research has shown that sleep problems in infants and young children are prevalent. Cross-cultural studies show that between 15 and 35% of all children aged 6 months to 6 years are reported by their parents to have some kind of sleep problem.3–6 In Australia, 36– 46% of parents report a problem with their infant’s sleep in the second 6 months of life. Despite the prevalence of infant sleep problems and their associated morbidities,7–12 few studies have examined the natural history of early infant sleep problems.12–14 Numerous studies have shown that clinical sleep disorders are associated with significant morbidity, functional impairment, a decreased quality of life and substantial direct and indirect economic costs.3,6,15 Despite this empirical evidence, medical professionals often pay inadequate attention to sleep disorders and their serious health consequences.5,16 This discrepancy
© 2007 The Author Journal compilation © 2007 Japanese Society of Sleep Research
Infant and children sleep survey
may be related, in part, to the fact that sleep science and sleep disorders have traditionally received little attention in medical school curriculae.13,14 Since there are no known parent-reporting sleeping problems in young children aged 0–6 years in northern Taiwan, we used a specially designed sleep questionnaire to explore sleeprelated problems in infants and children. The aim of this survey is to understand the current sleep problems of infant and young children: (i) to study the occurrence of sleep problems; (ii) to analyze the characteristics of sleep problems; (iii) to explore the possible causes of sleep problems; (iv) to calculate the pattern of sleep problems related to age; and (v) to analyze the relationship between common sleep problems and predicting factors.
Instrument (ICSSQ)
This study comprised a survey of parents who attended the well-baby clinic of the Chang-Gung Children’s Hospital. A total of 506 mothers were requested to fill in a well-designed infant and children sleep survey questionnaire (ICSSQ), which contained basic information about the participants who were enrolled, a sleep log and 53 items of sleep questions in five categories. The study period was between January 2004 and July 2005. The ages of children enrolled ranged between 0 and 6 years.
The ICSSQ is a sleep survey designed to evaluate sleep problems and related conditions in infants and children. The instrument comprises three parts: (i) basic information, such as their age and gender, whether they were full-term or preterm at delivery, how they were fed, and their parents’ perception of their sleep problems; (ii) a sleep log; and (iii) a 53 item questionnaire assessing domains of bedtime behavior, sleep behavior, waking at night, time of waking in the morning and daytime sleepiness. The reporting measure is rated on a 3-point scale ranging from “rarely” to “usually.” This measure also includes an open question that asks parents to record their child’s usual amount of sleep per day, including both sleeping during the night and daytime naps. The parents of all the children who were enrolling in the study were invited to complete a detailed questionnaire about their child’s sleeping habits. In addition to their demographic information and the child’s relevant medical history, questions were included on whether the child had difficulty getting to sleep, experienced restless sleep, enuresis, apnea, cyanosis during sleep, and snoring and, if the child snored, the severity of the snoring. The responses were graded as “rarely” (0 to once a week), “sometimes” (2–4 times a week), and “usually” (5–7 times a week). Structurally, the ICSSQ was modified from the children’s sleep habits questionnaire by Owens, which has been validated elsewhere and is widely used in the related literature.17,18
Procedures
Data analyses
The selection of sleep problems was based on related pediatric sleep articles as well as on the feedback of parents in the well-baby clinic. The instrument was then piloted on a small group of parents attending the clinic and, based on the feedback to the pilot test, minor modifications were made in the questionnaire’s content, wording and format to enhance its clarity. The relative numbers of questions in each category were chosen to reflect the relative prevalence of various sleep disorders in children, as well as to elicit parents’ levels of knowledge about less common sleep problems. All the questions were open, so as to denote a number or the frequency of a specific sleep problem. The respondents were asked to select the items that most often occurred in their daily life. The children studied in the well-baby clinic were categorized into five age groups; 0– 6 months, 7–12 months, 13–24 months, 25–36 months and 4–6 years.
The parameters used in the ICSSQ, including the case characteristics, environmental and feeding problems, medical illness and items of sleep problems were analyzed. The percentages of the ages of the infants and children, their gender distribution, their gestational age at birth, how they were fed, who their caregiver was, and the perception of the parents of the severity of their child’s sleep problems were calculated. In addition, the frequency of their waking at night, whether they usually needed more than 30 min to fall asleep, whether they usually required parental presence before falling asleep, the reversal of day and night rhythms, whether illness interfered with their sleep at night, environmental and feeding problems and whether they had a sleep routine were measured. In addition, the distribution of total sleep hours among different age groups, the length of night time sleep among the different age groups and the time at which the different age groups woke up in the
METHODS Subjects
© 2007 The Author Journal compilation © 2007 Japanese Society of Sleep Research
41
Y-H Chou
cases studied revealed that 53.8% of the infants were male and 46.2% were female. An analysis of the age of the infants and children showed that they were aged between 0–6 months in 136 cases (26.9%), between 7– 12 months in 134 cases (26.5%), between 13–24 months in 158 cases (31.2%), between 25–36 months in 30 cases (5.9%) and between 4–6 years in 48 cases (9.5%). The data on their gestational age at birth showed that full-term babies accounted for 90.1% of the children (456 cases), the remainder (9.9%) being preterm infants. Their feeding mode included breastfeeding in 66 cases (13.0%), formula feeding in 372 cases (73.5%) and mixed feeding in 36 cases (7.1%). The analysis showed that the caregiver was the mother in 189 cases (37.4%), a babysitter in 145 cases (28.7%), grandparents in 110 cases (21.7%), the father in 26 cases (5.1%) and a day-care center in 36 cases (7.1%).
morning were analyzed. According to the frequency of important problems (i.e., answers chosen as “usually”), five major categories in the different age groups are also further evaluated. During the analysis, we first looked at the correlation among the basic information and the questionnaire; later significant factors were chosen to perform a logistic regression to investigate the most relevant factors of the sleep survey. Statistically, the factors selected were modified into a binary mode (1 for “usually” and “sometimes” and 0 for rarely). Finally, we explored the possible sleep problems associated with the 12 major selected questions in the regression model. Descriptive statistics and a frequency analysis were performed to evaluate the distribution of sleep patterns in the five age groups. A correlation analysis with 2-tailed and a binary logistic regression were performed to investigate the association among the various factors. All the data were analyzed with SPSS for Windows, Version 13.0.
Analysis of sleep patterns RESULTS
The typical sleep patterns were selectively depicted in four age groups, including 1 month of age, 6 months of age, 18 months of age and four years of age. The different log patterns clearly showed the evolving change of sleep patterns with age. It was evident that the daytime sleep became shorter with increasing age and the nighttime sleep became longer and more constant with age (Table 1). Regarding the total hours of sleep, the results (Table 2) show a gradual decrease among the five age groups. The 0–6 month-old infants have the longest hours of sleep of 15.4 (SD = 3.2), and children aged
Sample characteristics A total of 506 cases completed the survey during the study period. The age distribution of the mothers was between 21 and 30 years in 292 cases (57.7%), between 31 and 40 years in 181 cases (36.8%), and over 41 years in 33 cases (6.5%). Most mothers were employed (72%) and were in a marriage relationship (98%).The mean age of the children was 18.9 months (standard deviation, 14.2; range, 1–72). The gender distribution of the
Table 1 Typical sleep logs in different age groups of children, by time of day, from 00.00 to 24.00 hours
One month old 0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Six months old 0
1
2
3
Eighteen months old 0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Four years old 0
42
1
2
3
© 2007 The Author Journal compilation © 2007 Japanese Society of Sleep Research
Infant and children sleep survey
Table 2 Distribution of total hours asleep by the five age groups Age groups 0–6 months Sleep hours 8–10 h 11–13 h 14–15 h 16–18 h 19–21 h Total n †
7–12 months
3.2† 16.3‡ 8.2‡ 30.6‡ 24.5‡ 20.4‡ –
15.4 16 8 30 24 20 98
13–24 months
2.3† 17.6‡ 18.7‡ 39.6‡ 24.2‡ 0‡ –
13.4 16 17 36 22 0 91
12.5 32 30 42 14 0 118
25–36 months
2.1† 27.1‡ 25.4‡ 35.6‡ 11.9‡ 0‡ –
11.9 10 10 8 2 0 30
4–6 years
2.7† 33.3‡ 33.3‡ 26.7‡ 6.7‡ 0‡ –
11.5 16 22 14 0 0 52
2.1† 30.8‡ 42.3‡ 26.9‡ 0‡ 0‡ –
SD, ‡percentage.
Table 3 Distribution of bedtime by the five age groups Age groups 0–6 months SD Bedtime at night <17.00 17.00–18.00 18.00–19.00 19.00–20.00 20.00–21.00 21.00–22.00 22.00–23.00 23.00–24.00 Total n† †
21.7 2 6 4 12 20 36 28 14 122
7–12 months
%
SD †
1.6 1.6 4.9 3.3 9.8 16.4 29.5 22.9 11.5 –
21.8 0 0 0 18 24 48 36 2 128
% †
1.0 0 0 0 14.1 18.8 37.5 28.1 1.6 –
13–24 months
25–36 months
SD
SD
22 0 0 2 10 34 54 40 10 150
% †
1.0 0 0 1.3 6.7 22.7 36 26.7 6.7 –
22.8 0 0 0 0 0 12 6 8 26
% †
0.9 0 0 0 0 0 46.1 23.1 10.8 –
4–6 years SD
%
21.9 0 0 0 0 14 24 4 4 46
0.9† 0 0 0 0 30.4 52.2 8.7 8.7
SD.
4–6 years need the shortest sleep of 11.5 (2.1) hours. Although many children sleep within the average range, some of them were either short of sleep or slept excessively, for example, 20.4% of the infants who were 0– 6 months of age slept for 19–21 h while 16.3% had only 8–10 h of sleep. We analyzed the time the children went to sleep at night (Table 3) and the time they woke up (Table 4) to illustrate the difference in the five age groups. We noticed that 34.4%, 29.7%, 33.4%, 33.9% and 17.4% of the children aged 0–6, 7–12, 13–24, 25–36 and 37– 72 months, respectively, go to sleep late (after 22.00 hours); and 24%, 16.1%, 61.4%, 69.1%, and 27.8% of the children in the five age groups, respectively, wake up after 08.00 hours. In addition, there are early birds in the five age groups 0–6, 7–12, 13–24, 25–36 and 37– 72 months (35.1%, 30.7%, 17.1%, 0%, and 0%, respectively), who wake up before 06.00 hours.
© 2007 The Author Journal compilation © 2007 Japanese Society of Sleep Research
Occurrence of common sleep problems No problems were reported by mothers in 184 cases (36.4%). A mild degree of sleep problems in 236 (46.6%), a moderate degree in 58 (11.5%) and a severe degree of problems was noted in 28 cases (5.5%). Firstly, the most common sleep problems of the infants and children were determined by their high occurrence (defined as more than twice per week). “Usually needs more than 30 min to fall asleep” was reported in 401 cases (79.2%); “usually requires parental presence to get to sleep at night” in 278 cases (54.9%); “struggles at bedtime” in 282 cases (55.7%); “restless and moves a lot” in 332 cases (65.6%); “irritable crying in sleep” in 216 cases (42.7%); “snores loudly when sleeping” in 118 cases (23.3%); “wakes screaming and sweating” in 144 cases (28.5%); “wakes more than once” in 192 cases (37.9%); “finds it hard to get out of bed” in 60
43
Y-H Chou
Table 4 Distribution of waking times by the five age groups Age groups 0–6 months SD Mean and SD <05.00 05.00–06.00 06.00–07.00 07.00–08.00 08.00–09.00 09.00–10.00 10.00–11.00 11.00–12.00 Total n† †
7.3 14 24 34 24 14 8 4 0 108
7–12 months
%
SD †
1.5 12.9 22.2 31.5 9.8 12.9 7.4 3.7 0 –
7.2 10 28 42 24 14 4 0 2 124
13–24 months
%
SD †
1.3 8.1 22.6 33.9 19.4 11.3 3.2 0 1.6 –
8.0 0 24 34 32 22 24 4 0 140
25–36 months
%
SD †
1.5 0 17.1 24.3 22.9 15.7 17.1 28.6 0 –
9.2 0 0 0 8 10 4 4 0 26
% †
1.1 0 0 0 30.7 38.5 15.3 15.3 0 –
4–6 years SD
%
8.3 0 0 10 16 4 4 2 0 36
1.2† 0 0 27.8 44.4 11.1 11.1 5.6 0
SD.
Table 5 Frequency of occurrence (percentage of each age group) of common sleep problems in relation to age Age groups
Q6. Q13. Q21. Q25. Q27. Q32. Q35. Q44. Q47.
Takes >30 min to fall asleep Struggles at bedtime Restless and moves a lot Irritable crying in sleep Snores loudly in sleep Wakes screaming/sweating Wakes more than once Finds getting out of bed hard Seems tired in the daytime
0–6 months
7–12 months
13–24 months
25–36 months
4–6 years
73.9 65.2 46.4 43.5 23.2 27.5 52.2 5.8 18.8
81.8 65.1 72.7 50.0 21.2 28.8 40.9 1.5 15.1
79.7 48.1 70.9 43.0 19.0 27.8 27.8 13.9 22.8
86.7 46.7 73.3 33.3 20.0 40.0 20.0 26.7 13.3
83.3 29.2 58.3 20.8 41.7 20.8 8.3 37.5 4.2
cases (11.9%); and “seems tired in during the daytime” in 96 cases (19.0%). An illness that interfered with their sleep at night was reported in 177 cases (35.0%), including rhinorrhea (37), nasal obstruction (48), eczema (23), fever (18) and cough (51). Regarding the higher occurrence of common sleep problems in relation to age, the above nine problems were evaluated to delineate their pattern of distribution (Table 5). From the analysis, several items, including “takes more than 30 min to fall asleep”, “struggles at bedtime”, “wakes more than once” were the first three common problems encountered. Most of the sleep problems had a trend to decrease as the child got older, especially for question 13, struggles at bedtime; question 25, irritable crying in sleep; question 35, wakes more than once. However, some problems occurred more fre-
44
quently with increasing age, especially for question 44, “finds it hard to get out of bed”.
Associated factors related with sleep Environmental conditions related to sleep were recorded. These included sleeping in the same bed as parents, sleeping late, sleeping too much during the day, excessive sweating at night, reduced activity during the day, a noisy environment and too much light at night. In addition, feeding problems were also recorded, including needing a pacifier, needing to be bottle-fed at night, frequent feeding and infantile colic. Parents noted that related illnesses, which include rhinitis, eczema, fever and coughing interrupted the children’s sleep at night.
© 2007 The Author Journal compilation © 2007 Japanese Society of Sleep Research
Infant and children sleep survey
in the basic information; the time when the child goes to sleep at night and the number of hours asleep; two items in (i) takes more than 30 min to fall asleep, struggles at bedtime; four items in (ii) restless and moves a lot, irritable crying when asleep, snores loudly when asleep, wakes screaming and sweating, one item in (iii) wakes more than once in the night, one items in (iv) finds it hard to get out of bed, and one item in (v) seems tired during the day. After regression analysis, several parameters were found to be statistically significant. In the linear regression, four factors were related to the time when the child goes to sleep at night; and another four factors were related to hours spent sleeping (Table 7). The results of binary logistic regression showed that three factors were related to “takes more 30 min to fall asleep”; three factors were related to “struggles at bedtime”; one factor was related to “restless and moves a lot”; four factors were related to “irritable crying when asleep”; one factor was related to “snores loudly when asleep”; two factors were related to “wakes screaming and sweating”; four factors were related to “wakes more than once”; five factors were related to “finds it hard to get out of bed”; and two factors were related to “seems tired during the day” (Table 8). A total of 33 sleep items of the questionnaire can be used to predict the 11 selected important sleep problems.
Further, a subset of 123 cases in the study of environmental and feeding factors related to sleep were analyzed. This revealed that environmental factors were reported in 29 of 123 cases (23.6%), including sleeping with parents in 11, excessive sweating at night in 11, a noisy environment in 5 and light at night in 8. As far as feeding was concerned, there were problems in 53 of the 123 cases (43.1%). Of these, 24 children needed to have a pacifier at night, 19 needed to be bottle fed at night; 11 needed frequent feeding. In addition six suffered from infantile colic. A bedtime routine had already been set up in 15 out of 79 cases (19%), while this had never been established in 40 cases and was being tried out in 24.
Five categories of sleep problems There were five major categories of sleep problems in the questionnaire. These were: (i) bedtime schedule (e.g. takes a long time to fall asleep at night), (ii) sleep behavior (e.g. sleeps too little), (iii) night wakening (e.g. wakes once or more in the night), (iv) morning wakening (e.g. wakes too early or too late); and (v) daytime sleepiness (e.g. looks tired in the daytime). Some important sleep problems were selected to calculate the frequency of occurrence, including five questions on the bedtime schedule, 17 on sleep behavior, four on night waking, six on morning waking and two on daytime sleepiness. In Table 6, the distribution of problems marked as “frequent” in the five categories shows the different manifestation of these traits. It appears that (i), (iii) and (v) are most commonly observed in this group.
DISCUSSION The article is the first report to survey sleep problems in a cohort of infants and young children in northern Taiwan. The main findings from the survey include the facts that: (i) on average, Taiwanese children sleep later than their counterparts in the USA; (ii) 37.5% woke frequently during the night; (iii) more than 70% took 30 min or more to fall asleep; (iv) 35.0% suffered from an illness that interfered with their sleep (v) parents’
Regression analysis of sleep problems The predicting factors of the 11 selected important sleep problems were investigated. These included two items
Table 6 Relative frequency (percentages) of problems (i.e. answering “usually” to the questions) in five categories in each age group Age group Category of sleep problem I. II. III. IV. V.
Bedtime schedule (5 items) Sleep behavior (17 items) Night waking (4 items) Morning waking (6 items) Daytime sleepiness (2 items)
0–6 months (n = 136)
7–12 months (n = 134)
13–24 months (n = 158)
25–36 months (n = 30)
4–6 years (n = 48)
22.9 5.7 20.9 8.8 30.1
31.6 8.1 31.6 7.5 42.6
32.8 7.6 24.3 8.8 30.6
38.7 9.0 26.7 18.9 43.3
43.3 6.1 19.8 13.4 37.5
© 2007 The Author Journal compilation © 2007 Japanese Society of Sleep Research
45
Y-H Chou
Table 7 Linear regression analysis of selected parameters in sleep survey 95% CI for Beta Parameters Time to sleep at night
Sleep hours
Predicting factor
t
P values
Lower
Upper
Afraid to sleep alone Wakes and falls asleep by himself Time to wake up in the morning Wakes early in the morning Age Night bedtime Needs parents in room to go to sleep Duration of waking in the night
−3.078 −2.202 4.309 2.348 −2.605 −2.173 1.983 3.222
0.002 0.029 0.000 0.020 0.010 0.032 0.049 0.002
−0.447 −0.401 0.139 0.047 −0.091 −0.810 0.001 0.186
−0.098 −0.022 0.375 0.538 −0.012 −0.038 0.976 0.777
CI, confidence interval.
Table 8 Binary logistic regression analysis of selected parameters in sleep survey
Parameters Takes 30 min to fall asleep
Struggles at bedtime
Restless and moves a lot Irritable crying in sleep
Snores loudly in sleep Wakes screaming, sweating Wakes more than once
Finds it hard to get out of bed
Seems tired in the daytime
Predicting factor
P values
Odds ratio (OR)
Lower
Upper
Goes to bed as usual Falls asleep in another’s bed Sleep too little Needs to hold special objects Sleeps too little Sleep problems when traveling Cries irritably in sleep Sex Feeding mode Needs parent in room to fall asleep Sleeps too little Snorts and gasps Cries irritably in sleep Snores loudly Age Wakes once Wakes and falls asleep after comfort by parents Wakes up in a negative mood Afraid to sleep in the dark Needs an alarm clock to wake up Wakes up in negative mood Takes a long time to be alert Wakes early in the morning Sleeps in a rocking bed Parents’ sleep affected by the child
0.05 0.011 0.01 0.004 0.040 0.014 0.000 0.007 0.051 0.020 0.005 0.000 0.000 0.016 0.000 0.007 0.001 0.015 0.027 0.009 0.009 0.048 0.018 0.032 0.021
3.044 0.621 2.106 1.797 0.575 0.476 3.872 0.454 1.875 0.692 0.559 0.247 3.899 2.524 0.891 0.416 0.323 0.268 0.428 0.210 0.282 0.399 6.898 0.468 0.510
1.002 0.431 1.347 1.209 0.339 0.264 2.08 0.256 0.996 0.507 0.371 0.135 1.842 1.189 0.835 0.220 0.163 0.093 0.202 0.065 0.109 0.160 1.393 0.234 0.288
9.253 0.891 3.291 2.669 0.975 0.859 7.114 0.807 3.528 0.944 0.842 0.450 8.253 5.359 0.950 0.789 0.639 0.773 0.909 0.680 0.731 0.994 34.158 0.938 0.902
perception of their children having sleep problems is common (64.2%), and the proportion of these problems which are moderate to severe in character is 17%. It was found that the different ages groups varied with respect to (i) their total hours of sleep, including excessive or
46
95.0% CI for OR
inadequate sleep; (ii) the time at which they go to sleep at night; and (iii) the time at which they wake in the morning. The frequency of sleep problems (in the “usually” category) was also related to the children’s age. This was more prevalent in their bedtime schedule, waking at
© 2007 The Author Journal compilation © 2007 Japanese Society of Sleep Research
Infant and children sleep survey
night and sleepiness during the day. Lastly, the regression analysis of important sleep parameters may help in the better understanding of sleep problems. Many sleep problems that occur before the age of 6 months are likely to be transient in nature; others represent a mismatch between the infant’s behavior and parental expectations. It is estimated that about 25–50% of 6–12 month-olds and 30% of 1-year-olds have problematic night awakings, and about 50% have difficulties in sleep onset or settling at 12 months.19 This occurrence is compatible with our study. Of the children enrolled, 37.9% were reported to have woken more than once, including 52.2% of those aged <6 months, 40.9% of those aged 6–12 months, 27.8% of those aged 13–24 months, 20% of those aged 25–36 months and 8.3% for those aged 4–6 years. Numerous epidemiologic studies of sleep disorders from a variety of populations have documented high levels of sleep disturbances in children. These include difficulty in settling and frequent night waking in up to 40% of infants,20–22 bedtime resistance, delayed sleep onset, and disruptive night waking in 25 to 50% of preschoolers,23–27 a 27% prevalence of marked bedtime resistance28 and a 37% prevalence of parent-reported problematic sleep behavior in school-aged children,29 and significant daytime drowsiness in 10 to 40% of high school students.30 The 53 items of five categories in the questionnaire have different impacts on sleep, which were commonly discussed as influencing factors of sleep problems in many literatures. In the 2004 sleep in America poll, parents/caregivers reported that the usual time when their child had gone to sleep at night in the past two weeks was between about 20.45 and 21.15 hours. Children who are two months old or younger go to bed, on average, at 21.51 hours, whereas children between 6 months old and 7 years old tend to go to bed, on average, around 21.00 hours or earlier. Children between the ages of 18 and 23 months tend to go to bed the earliest, on average at 20.25 hours.31 Our study showed that on average Taiwanese children go to bed later than their US counterparts. More than half the parents/caregivers of school-aged children and preschoolers report that it takes their child 15 min or more to fall asleep at night (54% for each group) compared to toddlers (46%) and infants (43%).31 Although this is not significant statistically, it seems that more time is needed to fall asleep with increasing age in our study, and more than 70% of Taiwanese children needed more than 30 min to fall asleep. The regression analysis showed that taking more than 30 min to fall
© 2007 The Author Journal compilation © 2007 Japanese Society of Sleep Research
asleep is positively associated with falling asleep in someone else’s bed and sleeping too little. Parents/caregivers say their child tends to wake up in the morning, on average, between 07.00 and 09.00 hours, although older children tend to wake later than younger children, unlike children in the USA (who usually wake between 06.52 and 07.35 hours).32,33 Despite this, some children wake up earlier or later than most. The analysis of the number of hours children sleep in a 24-h period shows that infants tend to get more sleep (15.4 h) in a 24-h period than older children. The average total sleep hours of children in a 24-h period decreases as children get older. We also noticed that although many children sleep within the average range, there are some in both extremes. In the literature,34,35 a sizable proportion of children across all five age groups wake and need help or attention during a typical night. In our study, three in 10 of all parents/caregivers surveyed said their child wakes once (23%) or more than twice (7%) per night needing help or attention, and infants are more likely than the children in the three older age groups to wake at night (71% at least once, vs 14–46%). Our study also found that a range of 20.8–36.4% of children wake and need parental help, which showed that infants need more help when waking at night than the older age group. Anders et al. reported that about one in 10 parents/ caregivers of toddlers and preschoolers thinks their child has a sleep problem, and parents/caregivers of children who sleep the least are twice as likely to say they think their child has a sleep problem.32,36 In our group, 46.6% children were reported to have mild degree of sleep problems, 11.5% to a moderate degree and 5.5% to a severe degree. For a significant proportion (19%) of children, daytime sleepiness is severe enough to interfere with their daily activities. Almost one in 10 experiences daytime sleepiness every day or almost every day. Children who rarely or never have daytime sleepiness tend to get more sleep at night on average (6.9 h), while those who experience daytime sleepiness at least a few days every week tend to get less sleep (6.4 h).31,37 In our results, the range of occurrence of “seems tired in the daytime”, a major item of category (v) (daytime sleepiness), is 4.2–18.8% across five age groups, and it also is positively associated with sleep in a rocking bed, and parents’ sleep being affected by the child. The prevalence of obstructive sleep apnea in toddlers and preschoolers is conservatively estimated to be 1– 3%, and primary snoring occurs in 20% of children.38–40 In the self-reported questionnaire, although this has not
47
Y-H Chou
been clinically evaluated, from 19.0% in the 13–24month-old group to 41.7% in the 4–6-year-old group are reported to snore loudly at night in the five age groups. According to the American Academy of Pediatrics guidelines, all children should be screened for snoring, thus the snoring children in this study should receive further investigation for the benefit of their health. The study may provide useful information for the health professionals who counsel parents about the likely outcomes for their child with sleep problems,41 and it may be helpful in recognizing the sleep patterns and possible problems in different age groups of Taiwanese children. The results support the notion that a regional survey of sleep behavior and possible problems may give important information for further research, and the implications for clinical practice should be utilized and shared by the pediatricians, educators and the community to promote better sleep behavior in early childhood.
REFERENCES 1 Mindell JA, Owens JA, Carskadon MA. Developmental features of sleep. Child Adolesc. Psychiatr. Clin. N. Am. 1999; 8: 695–725. 2 Armstrong KL, Quin RA, Dadds MR. The sleep patterns of normal children. Med. J. Aust. 1994; 1: 202–6. 3 Blum NJ, Carey WB. Sleep problems among infants and young children. Pediatr. Rev. 1996; 17: 87–92. 4 Kerr S, Jowett S. Sleep problems in pre-school children: a review of the literature. Child Care Health Dev. 1994; 20: 379–91. 5 Lozoff B, Wolf AW, Davis NS. Sleep problems seen in pediatric practice. Pediatrics 1985; 75: 477–83. 6 Lam P, Hiscock H, Wake M. Outcome of infant sleeps problem: a longitudinal study of sleep, behavior, and maternal well-being. Pediatrics 2003; 111: e203–7. 7 Hiscock H, Wake M. Infant sleep problems and postnatal depression: a community based study. Pediatrics 2001; 107: 1317–22. 8 Armstrong KL, Van Haeringen AR, Dadds MR, Cash R. Sleep deprivation or postnatal depression in later infancy: separating the chicken from the egg. J. Paediatr. Child Health 1998; 34: 260–2. 9 Lavigne JV, Arend R, Rosenbaum D et al. Sleep and behavior problems among preschoolers. J. Dev. Behav. Pediatr. 1999; 20: 164–9. 10 Owens-Stively J, Frank N. Child temperament, parenting discipline style, and daytime behavior in childhood sleep disorders. J. Dev. Behav. Pediatr. 1997; 18: 314–21.
48
11 Kataria S, Swanson MS, Trevathan GE. Persistence of sleep disturbances in preschool children. J. Pediatr. 1987; 110: 642–6. 12 Zuckerman B, Stevenson J, Bailey V. Sleep problems in early childhood: continuities, predictive factors and behavioral correlates. Pediatrics 1987; 80: 664–71. 13 Jenkins S, Owen C, Bax M, Hart H. Continuities of common behavioural problems in pre-school children. J. Child Psychol. Psychiatry 1980; 25: 75–89. 14 Thunström M. A 2.5-year follow-up of infants treated for severe sleep problems. Ambul. Child Health 2000; 6: 225–35. 15 Adair R, Bauchner H. Sleep problems in childhood. Curr. Probl. Pediatr. 1993; 23: 147–70. 16 Owens JA. The practice of pediatric sleep medicine: results of a community survey. Pediatrics 2001; 108: e51. 17 Rosen R, Zozula R. Development of a brief, selfadministered instrument for assessing sleep knowledge in medical education: the ASKME survey. Sleep 2001; 24: 227–33. 18 Gozal D. Sleep-disordered breathing and school performance in children. Pediatrics 1998; 102: 616–20. 19 Mindell JA, Owens JA. Sleep in infancy, childhood, and adolescence. In: Mindell JA, Owens JA, eds. A Clinical Guide to Pediatric Sleep. Lippincott Williams & Wilkins: Philadelphia, PA, 2003; 22–33. 20 Boyce P, Stubbs J, Todd A. The Edinburgh postnatal depression scale: validation for an Australian sample. Aust. N. Z. J. Psychiatry 1993; 27: 472–6. 21 Murray L, Carothers AD. The validation of the Edinburgh postnatal depression scale on a community sample. Br. J. Psychiatry 1990; 157: 288–90. 22 Smith J, Prior M. Temperament and stress resilience in school-age children: a within-families study. J. Am. Acad. Child Adolesc. Psychiatry 1995; 34: 168–79. 23 Liu X, Liu L, Owens JA, Kaplan DL. Sleep patterns and sleep problems among schoolchildren in the United States and China. Pediatrics 2005; 115: 241–9. 24 Achenbach TM, Ruffle TM. The child behavior checklist and related forms for assessing behavioural/emotional problems and competencies. Pediatr. Rev. 2000; 21: 265–71. 25 Wake M, Hesketh K, Lucas J. Teething and tooth eruption in infants: a cohort study. Pediatrics 2000; 106: 1374–9. 26 Sharpley CF, Rogers JH. Preliminary validation of the abbreviated Spanier dyadic adjustment scale: some psychometric data regarding a screening test of marital adjustment. Educ. Psychol. Meas. 1984; 44: 1045–9. 27 Miller IW, Epstein NB, Bishop DS, Keitner GI. The McMaster family assessment device: reliability and validity. J. Marital Fam. Ther. 1985; 11: 345–56. 28 Sawyer MG, Sarris A. Family assessment device: reports from mothers, fathers, and adolescents in community
© 2007 The Author Journal compilation © 2007 Japanese Society of Sleep Research
Infant and children sleep survey
29
30 31 32
33
34
35
and clinic families. J. Marital Fam. Ther. 1988; 14: 287– 96. Astbury J, Brown S, Lumley J, Small R. Birth events, birth experiences and social differences in postnatal depression. Aust. J. Public Health 1994; 18: 176–84. Lozoff B, Zuckerman B. Sleep problems in children. Pediatr. Rev. 1998; 10: 17–24. National Sleep Foundation. The 2004 sleep in America poll. National Sleep Foundation: Washington, DC. 2004. Anders TF, Sadeh A, Appareddy V. Normal sleep in neonates and children. In: Farber R, Kryger M, eds. Principles and Practices of Sleep Medicine in the Child. W.B. Saunders: Philadelphia, 1995; 7–18. Chervin R, Archbold K, Panahi P, Pituch K. Sleep problems seldom addressed at two general pediatric clinics. Pediatrics 2001; 107: 1375–80. Goodlin-Jones B, Burnham M, Gaylor E, Ander T. Night waking, sleep-wake organization, and self-soothing in the first year of life. Dev. Behav. Pediatr. 2001; 22: 226– 33. Mindell JA. Empirically supported treatments in pediatric psychology: bedtime refusal and night wakings in young children. J. Pediatr. Pshchol. 1999; 24: 465–81.
© 2007 The Author Journal compilation © 2007 Japanese Society of Sleep Research
36 Anders TF, Sadeh A, Appareddy V. Normal sleep in neonates and Children. In: Farber R, Kryger M, eds. Principles and Practices of Sleep Medicine in the Child. W.B. Saunders: Philadelphia, 1995; 79–89. 37 Dahl RE, Ryan ND, Matty MK et al. The regulation of sleep and arousal: development and pshchopathology. Dev. Psychopathol. 1996; 8: 3–27. 38 American Academy of Pediatrics. Clinical practice guideline: diagnosis and management of childhood obstructive sleep apnea syndrome. Pediatrics 2002; 109: 704–12. 39 Gozal D, Pope D. Snoring during early childhood and academic performance at ages 13–14 years. Pediatrics 2001; 107: 1394–9. 40 Gottlieb DJ, Vezina RM, Chase C et al. Symptoms of sleep-disordered breathing in 5-year-old children are associated with sleepiness and problem behaviors. Pediatrics 2003; 112: 870–7. 41 Olson AL, Kelleher KJ, Kemper KJ, Zuckerman BS, Hammond CS, Dietrich AJ. Primary care pediatricians’ roles and perceived responsibilities in the identification and management of depression in children and adolescents. Ambul. Pediatr. 2001; 1: 91–8.
49
