Sleep Problems in Healthy Preadolescents

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Sleep

Problems

in Healthy

Preadolescents

Andr#{233}

Kahn, MD, PhD, Carine

Van de Merckt,

MD,

Elisabeth

Rebuffat,

MD, Marie Jos#{233}

Mozin,

BD, Martine

Sottiaux,

BP,

Denise

Blum, MD, PhD, and Philippe

Hennart,

MD, PhD

From the Pediatric Sleep and Development Unit, University Children’s Hospital, and the Departments of Epidemiology and Social Medicine, Free University of Brussels, Belgium

ABSTRACT. Few data currently exist concerning the

sleep problems of preadolescents. A parent report

ques-tionnaire concerning sleep habits and problems was

de-veloped. The questionnaires were completed by the

par-ents of 1000 unscreened elementary school children

at-tending the third, fourth, and fifth grades. The schools

were randomly selected from an urban area. Of the 1000

questionnaires, 972 were completed and could be used for

statistical analysis. Among the parents, 24% reported sleeping poorly and

12%

regularly relied on sedatives to induce sleep. Sleep difficulties lasting more than 6 months were present in 43% of the children. In 14% (132 of 972), sleep latency was longer than 30 minutes, and more than one complete arousal occurred during the night at least two nights per week. The following variables were seen among the poor sleepers: lower parental educational and professional status, parents who were more likely to

be divorced or separated, and more noise or light in the rooms where they slept. They also presented a higher incidence of somnambulism, somniloquia, and night fears

(nightmares and night terrors) than the children who slept well. Boys who slept poorly were significantly more likely to have insomniac fathers (P < .010). Regular use of sedatives was described in 4% (5 of 132) ofthe children who slept poorly. Among the “poor sleepers,” 21% (33 of

132) had failed 1 or more years at school. School

achieve-ment difficulties were encountered significantly more

often among the poor sleepers than among the children without sleep problems (P = .001). Of the families with children suffering from sleep problems, 28% expressed a desire for counseling. This preliminary study suggests the

need for more systematic attention by the pediatrician to

the possible presence of chronic sleep problems in appar-ently normal preadolescents. Pediatricians could

contrib-ute to the alleviation ofpanental anxiety and help to limit

the use of sleep medications in children. Pediatrics

1989;84:542-546; sleep, insomnia, parasomnias, sleep

problems.

Received for publication Nov 1, 1988; accepted Jan 18, 1989. Reprint requests to (A.K.) Hopital Universitaire des Enfants Reine Fabiola, Av JJ Crocq 15, B-1020 Bruxelles, Belgium. PEDIATRICS (ISSN 0031 4005). Copyright © 1989 by the American Academy of Pediatrics.

Common sleep problems have been extensively studied in infants and in preschool and adolescent chi1dren.’ Rarely has attention been given to sleep difficulties in preadolescents.7’#{176} The apparent lack of work in this area is probably related to a de-creased incidence of reported behavioral difficulties during the “latency” age.” Stimulated by occasional patients’ complaints in this age group seen at our pediatric sleep clinic, we undertook a survey among

the

local urban population. Questionnaires were addressed to parents of children attending elemen-tany

school.

Responses were used to evaluate the sleep habits and potential sleep problems of these preadolescents.

METHODS

Population

From among the 21 public elementary schools in

Brussels,

5 were chosen at random. The schools are

supported by public funds and enroll children from

all

socioeconomic strata.

A

total of 1000 children attending the third, fourth, and fifth grades, aged 8

to 10 years, entered the study. The families studied

were representative of the overall city population

in terms of lingustic and socioeconomic

character-istics.’2

Questionnaire

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me-* Figures represent absolute values. Fathers usually slept 7.3 ± 0.9 hours (mean ± SD) and mothers 7.5 ± 0.8 hours.

ferred to white collar professions. Information was also obtained pertaining to the children’s daytime

behavior, school achievements, eating habits, and

health problems.

Questions aimed specifically at determining

quantity and quality of sleep pertained to the sleep

environment, the duration of night sleep, night

awakening, and usual sleep habits. Nighttime

events were scored only if they had been observed

for at least 6 months. All variables were graded for frequency on a 7-day week scale from never through

7 nights pen week. To avoid bias being introduced

by the use of parental estimates of severity, we

scored only whether or not an event occurred.

Nighttime was considered to last from the child’s

usual bedtime to the time he or she awoke (night

awakening lasting more than 30 minutes was sub-tracted from total sleep time). An event was consid-ered nighttime awakening if,

once awoken,

the child

remained awake for more than 30 minutes and had difficulty in going back to sleep. “Poor sleep” was

defined as a sleep latency greater than 30 minutes,

plus at least one complete awakening per night, at

least two nights per week. If sleepwalking episodes

occurred

at least

once

a month,

this

was considered

somnambulism. If the child was heard at least once

a week, that was considered sleep talking. Enuresis was defined as nighttime bed-wetting occurring at least 12 nights per month. No attempt was made to differentiate between “primary” and “secondary” enuresis. Likewise, because parents were not

ex-pected

to adequately

differentiate

nightmares

from

night terrors, both were pooled as “night fears.” This received a score if it occurred at least twice a month. Somnambulism, sleep talking, enuresis, and

night fears were collectively called

“parasom-nias.” ‘

The

questionnaires

were tested

on a pilot

sample

of

50 elementary school-aged children. The pilot

sample was chosen at random from the 16

elemen-tary schools not selected for the study. The answers

to the preliminary questionnaires were not included in the present report. Because of evident

misunder-standings, some questions were omitted or clarified.

The

questionnaires

were finalized

and then

distrib-TABLE 1. Major Characteristics of Parents*

Characteristics No. No.

(%)of (%)of

Fathers Mothers

Higher education 370 (42) 301 (49)

Professional class 1 and 2 184 (24) 207 (27)

Professionally active 759 (94) 606 (78)

Poor sleep 103 (13) 127 (14)

Use of sedatives 47 (6) 69 (8)

TABLE 2. Major Characterist

the 972 Children Surveyed

ics and Sleep Problems of

Characteristics No. (%) of

Children

Sex (M/F) 526/446 (54/46)

Children who sleep poorly 132 (14)

Children with parasomnias 283 (29)

Enuresis 21 (2)

Somnambulism 48 (5)

Somniloquy 72 (7)

Night fears 142 (15)

Sleep difficulties 415 (43)

No sleep difficulties 557 (57)

* Figures represent absolute values. Children were 9.1 ±

0.9 years of age (mean ± SD).

uted to the 1000 children surveyed. Joint letters from the director of the school and the investigators requesting the cooperation of the parents were dis-tnibuted with the questionnaires. The forms were

distributed and collected by the teachers. Collected

data

were

analyzed

with

the

use

of analysis

of

variance

and covaniance,

and the x2 test.

The

level

of significance was P <

.05.

RESULTS

Of the 1000 questionnaires distributed, 5 were not returned and 23 were not suitable for analysis,

leaving

a total

of 972 sets

of analyzable

data.

The

major characteristics of the population are shown in Tables 1 and 2. Among parents, 24% reported sleeping poorly and/on having difficulties initiating or maintaining sleep. Of these, 71% (12% of the parents studied) regularly relied on sedatives to

induce

sleep.

The sleep difficulties of the children are shown

in

Table

2. Sleep difficulties were present in 43%

of the children. Poor sleep was reported for 14% of

the children and had been observed since infancy

in each of these children. Parasomnias were present

in 29% of the children, with enuresis (2%),

som-nambulism (5%), sleep talking (7%), and night fears

(15%),

in ascending order of frequency. Of the 132

children who slept poorly, episodes of sleep talking

were also seen in 49 (37%), night fears in 45 (34%),

somnambulism in 15 (11%), and enuresis in 4 (3%).

Clinical

allergies

or asthma

were

reported

in

127

(13%) children. Ofthe 972 children, 117 (12%) were

unable

to satisfy

academic

requirements

and

had

already failed 1 or more years of school. We

com-pared

the

characteristics

of the

132 children who

slept poorly with those of the 557 children with no

sleep complaints. There were no differences with regard to sex or age between the two groups. The

total

length

of sleep

reported

for the children

who

slept poorly tended to be shorter than that of the

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hours vs 10.7 ± 0.5 hours [means ± SD] for the two groups, respectively; P > .05). This tendency was present on both school days and on holidays and

weekends. No significant difference was seen

be-tween the two groups with regard to bedtime. The children who slept poorly tended to share their room with a sibling on parent (53/132, 40%) more frequently than the children with no sleep

com-plaints (198/596, 33%). The difference was not

significant.

The significant variables differentiating the two

groups of children are shown in Table 3. The

par-ents of the children who slept poorly had lower educational and professional status and were more likely to be divorced or separated. Children who slept poorly were less frequently involved in sports activities. No difference in mean body weight was

described between the two groups of children (29.3

± 5.8/kg vs 31.4 ± 6.3 kg [means ± SD] for the

poor sleepers and good sleepers, respectively).

Children who slept poorly tended to sleep in rooms exposed to noise or light. They had signifi-cantly more frequent parasomnias in the form of somnambulism (15/132, 11%), somnioquia (49/ 132, 37%), and night fears (43/132, 33%) than the children described as good sleepers. The incidence of enunesis among the poor sleepers (4/132, 3%) was comparable with that of the good sleepers (21/

557, 4%). More fathers of poor sleepers than of good sleepers were reported to sleep poorly with difficulty in initiating and maintaining sleep. Sub-dividing the children according to gender, the nela-tion between fathers who slept poorly and children who slept poorly was significant for boys only. Among the boys who slept poorly, 5 of 15 fathers (33%) also slept poorly, compared with only 5 of 145 fathers (11%) of the boys who slept well (P <

.10). No significant difference in sleep quality was found for the fathers of girls. No other significant

characteristic was attributable to gender.

More children who slept poorly were treated meg-ularly with sleep-inducing drugs (4%) than children with no sleep complaints. From our data, we could not distinguish between drugs that were prescribed and those that were self-administered. Because sed-ative administration was more frequently found in families expressing a desire for outside help to solve their children’s sleep problems (P = .05), we as-sumed that most of the drugs were self-adminis-tened.

Among the children who slept poorly, 21% had failed 1 on more years at school. Being unable to meet academic requirements, they could not pro-gress to the next grade. These children had been spending as much time on homework, however, as the children with no sleep difficulties (with a mean

duration [±SDJ of 64.0 ± 36.0 and 63.5 ± 36.0

minutes for the poor sleepers and good sleepers, respectively). Of the children with no sieep com-plaints, 11% had failed 1 year at school.

When parents were asked whether they wanted outside help to solve their children’s poor sleeping or parasomnia, 103 of 415 parents (28%) answered positively. At the time of the survey, however, none of the children were receiving medical supervision for the reported sleep difficulties.

DISCUSSION

Some of the shortcomings of our study must be

acknowledged. We cannot exclude the possibility of

parental bias in the reporting of sleep-related com-plants of their preadolescent children.’#{176} Even with this limitation, we found sleep difficulties in 43% of the 972 children surveyed. These sleep-related behavioral problems had already lasted for more than 6 months at the time of the study. This

incidence is close to the 46% of sleep difficulties

reported in Swedish school-aged children,9 and to the 35% of restless sleepers found among American

TABLE 3. Significant Characteristics of Children With “Poor Sleep*

Characteristics No. (%) of No. (%) of P Value

Children With Children Without

Poor Sleep Poor Sleep

(n = 132) (n = 596)

Mother with higher education 37 (36) 264 (52) .010

Father professional class 1 and 2 20 (19) 164 (24) .020

Divorced or separated parents 32 (24) 80 (13) .010

Father with poor sleep 22 (20) 81 (12) .010

Involvement in sport activities 60 (46) 339 (57) .030

Sleep conditions of child

Environment with noise

34

(27) 134 (17) .008

Environment with light 40 (29) 149 (18) .002

Parasomnias 72 (51) 283 (32) .010

Sedatives 5 (4) 1 (0.1) .001

School problems 33 (21) 89 (11) .010

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elementary school children.13

The 29% of parasomnias found in the present

study is comparable to figures reported in the

lit-erature for various forms of sleep behavioral

char-acteristics, such as enuresis, sleep talking or

walk-ing, or night fears.”2’5”4”5 Because of the answers

given by the parents, nightmares could not be

dif-ferentiated from night terrors, but in this age group

most night fears could be expected to reflect

night-mares.2”4”5

Difficulties in initiating and maintaining sleep,

called poor sleep, were reported for 132 of 972

children (14%) in our study. This figure was

ob-tamed despite the conservative criteria chosen to

define poor sleep: sleep latency of more than

30-minute duration followed by at least one complete awakening per night lasting longer than 30 minutes,

with the child unable to resume sleep. The events

had to occur at least 2 nights per week. Both the sleep latency and the number of complete arousals are in excess of values described for preadolescents

in the literature.6’8”0 These children could be

de-scribed as suffering from insomnia,’0 but we pre-ferred to define them as poor sleepers. This termi-nology is more appropriate, because no subjective

complaints were assessed through interviews with

the children.’4 The 14% prevalence of poor sleep is

unexpectedly strong in the preadolescent latency

age.” It is still within the range of persistent

set-tling difficulties and nighttime awakenings

de-scribed for 10% to 20% of children less than 2 years

of age’6 or for 10% to 15% of children 4 years of

age.17 The prevalence of poor sleep in the

preado-lescent is also close to the 11% and 13% prevalence

of fathers and mothers who slept poorly found in our survey. In confirmation of previous studies,2”#{176} poor sleep among preadolescents had been long

lasting; these children had had problems initiating and maintaining sleep since infancy.

We cannot adequately define the causes for poor

sleep within the limits of this study. Poor sleep is

multifactorial in origin.’4 Socioeconomic disadvan-tage, lower educational and professional status, and

disrupted families were all found to be significant

indicators in our survey, as had already been re-ported in other studies.9”5 Environmental noise and

light, found twice as frequently in the nighttime

environment of the children in our study who slept poorly as in that of the children who slept well, have also been described as unfavorably influencing

sleep.18 In our survey, sharing the parents’ bed was

not associated with poor sleep, as had been

sug-gested in other studies.9 Parental psychologic upset

or depression could also influence the child’s sleep rhythms,4 but we have little or no information

regarding family life events’6 and parental

psycho-logic characteristics. Other stress factors such as

school pressure could contribute to the

deteriora-tion of a child’s sleep.’4

Poor sleep could also be related to individual temperament3 on pubertal development,6 or reveal

the subclinical ailments such as persistent

psycho-physiologic insomnia,’4 attention-deficit

disor-ders,’#{176}or depression.’9’2#{176} Other medical conditions

such as allergies or asthma, found in 13% of the

children, have been described as associated with

chronic sleeplessness in infants.’5’2’ We cannot speculate about the possible influence of the less

frequent involvement in sports activities of the

children who slept poorly.’4 The significant

corre-lation found between the poor sleep described by

23% of the fathers of boys who slept poorly may be

attributable to a possible genetic determinant.

Sleep length and sleep quality could have hereditary

characteristics, as seen in adult twin pairs.22 Still, no other factor significantly correlated with gender. This finding was as expected, because previous studies failed to show significant sex-related sleep

behaviors in preadolescent7’5 and adolescent chil-dnen.6

The poor sleep of their children was sufficiently

severe and prolonged to cause 28% of the parents

to answer positively when asked whether they wanted outside help, although, at the time of the

survey, none of the children was under medical

supervision for the reported sleep difficulties. The presence of undiagnosed sleep problems in the

pe-diatric population has already been reported.2’4”5”9

This lack of medical awareness could at least partly

explain why sedatives were given regularly to at

least 4% of the children who slept poorly. A similar

incidence of sedative administration to pneadoles-cent children was occasionally reported in surveys

from France2 or the United States.’#{176} It appears to

be largely related to over the counter sales of

sed-atives such as phenothiazine syrups.23

A poor school performance, leading to poor aca-demic achievement and severe setbacks in school grade progression, was seen in 12% of the children.

This incidence of school problems in preadolescents

is comparable with that reported in similar

Belgian24 and French elementary school

popula-tions.’9 The relationship between school difficulties

and lower family socioeconomic level has also been

previously reported.’9’24 We do not know whether a

relationship exists between sleep quality and school

performance, as mentioned in other studies.’#{176}”3”9

SPECULATION

AND RELEVANCE

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for counseling and guidance for their children’s sleep problems; 4% relied on the regular use of sedatives. These findings are relevant for the cli-nicians. By paying systematic attention to potential sleep difficulties in pneadolescents, pediatricians could play a determinant role in the alleviation of parental anxiety and help limit the use of sleep medications in children.

ACKNOWLEDGMENTS

This work was supported by the Fondation Nationale

de la Recherche Scientifique (grant 34543.83).

We thank Prof H. L. Vis for his encouragement; Prof

A. Sand

and Dr J. Appelboom-Fondu for critical advice;

Dr M. Martha for her contribution at the Inspection

Medicale Scolaine; and M. Dramaix and A. Poquet for their active collaboration.

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1989;84;542

Pediatrics

Sottiaux, Denise Blum and Philippe Hennart

André Kahn, Carine Van de Merckt, Elisabeth Rebuffat, Marie José Mozin, Martine

Sleep Problems in Healthy Preadolescents

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