Vol.5, No.2, 259-266 (2013) Health
http://dx.doi.org/10.4236/health.2013.52035
Health care experiences in infancy and subsequent
frequent illness in 1-year-old children*
Ruth Ertmann#, Volkert Siersma, Susanne Reventlow, Margareta Söderström
Department of General Practice, Research Unit for General Practice in Copenhagen, Copenhagen, Denmark;
#Corresponding Author:
Received 29 November 2012; revised 30 December 2012; accepted 6 January 2013
ABSTRACT
Background: Parents of infants suffering from
frequent episodes of illness demand more ac-
knowledgement from general practice with re-
gard to their observations of these illnesses,
which is evident from their tendency to book
multiple consultations. Aim: To identify factors
relating to illness and health-care experiences in
infancy which predict frequent episodes of ill-
ness in toddlers. Design of study: A retrospec-
tive questionnaire and a prospective diary study
including 183 infants born in February 2001 in a
district of the capit al region of Denma rk. Setting:
Denmark, primary care. Methods: Infants were
recruited from a birth cohort and experiences of
illness from birth until the age of 11 months
were collected using a questionnaire. Thereafter
the infants were followed prospectively from the
age of 11 to 14 months using diary cards. The
diary data consisted of 1) selected symptoms, 2)
doctor-contacts and 3) parent-rated illness se-
verity, information used to form three aspects of
a frequently ill child. The analyses explore as-
sociations from the infant data with the three
indicators of frequent illness. Results: Experi-
ences of restless sleep, earache, otitis media,
penicillin usage and use of medicine associated
with illness in infancy were highly associated
with factors of excess illness during the follow
up period. Disturbed sleep in infancy was the
factor with the highest probability of frequent
illness as a toddler—an unexpected finding.
Experiences of acute otitis media (earache, fre-
quent visits to the doctor and antibiotic treat-
ment) were strongly related to freque nt illn esses.
Asthma or giving the child medicine correlated
with a higher parent-rated frequency of illness
later on. Conclusions: Sleep problems in infancy
can predict frequent illness episodes later on. In
clinical practice the GP may benefit from talking
about sleep in the c onsul tations in order to learn
something more. The three different indicators
of frequent illness applied to different aspects of
being a frequently ill child.
Keywords: Infants; Toddlers; Parents; GP;
Symptoms; Sleep; Recurrent Illness; Illness
1. INTRODUCTION
Some toddlers suffer significantly more episodes of
illness than others, which affect the use of health ser-
vices and the family’s daily well-being and routine. Stud-
ies of toddlers’ frequent diseases have primarily focused
on genetic, birth and socio-economic factors. Disturbed
sleep, ear symptoms/diseases and use of medicine seem
to be predictors of frequent episodes of illness.
Parents of infants suffering frequent bouts of illness
report dissatisfaction with the general practitioner (GP),
citing a lack of acknowledgment of their lay observations
and accounts of the infant’s illness, and a lack of expla-
nations as to why their child is frequently ill [1]. Parents
could be worried about the infants’ development and
health when the infants’ are fighting off infections [2].
Both lay-people and health professionals use the ter-
minology “frequently ill”, even if there is no clear de-
scription of what that means [3-5]. Using the number of
physician-attended visits is common but reflects both the
illness behaviour of the parents and the health care sys-
tem of the country. A clinically useful definition of a
frequently ill child could make use of several sources,
such as the number of days with symptoms of illness,
type of specific symptoms or how much medicine is
given to the child. It is possible to ask for this informa-
tion in the medical encounter, but there is no obvious
way for the physician to validate that information. By
using information on aspects of the child’s daily life,
such as parental concerns, use of health care services and
disruptions to the daily routine for the child and the fam-
ily, the focus can be shifted from the infant’s illness to
*Funding: Danish research foundation for general practice.

R. Ertmann et al. / Health 5 (2013) 259-266
260
the effect the illness has on the infant, and on the well-
being of the family and the family’s behaviour regarding
the illness. According to Gannik, disease is something
that occurs physically in the tissues, whereas illness is
experienced. In addition, the illness is changed, deve-
loped, formed and created by the context and the way it
is acted on—described as illness behaviour [6]. Illness
behaviour is understood here as the parents’ action or
reaction to their infant’s symptoms, which is found to
correlate to the behaviour and expectations of the whole
family and its social network when illness emerges in the
family [2,7].
Studying parents’ reaction to their infant’s illness, fe-
ver, earache and vomiting were the symptoms most
likely to cause parents to rate their infants as ill, and ear-
ache was the symptom that most frequently tended to
trigger immediate contact with the doctor [8].
It is possible that the parents’ experiences with their
infant’s illness and their interaction with the health care
system also account for their later decisions regarding
health care for their infant. Research exploring the influ-
ences health-care utility and illness experiences in in-
fancy have on later susceptibility to illness is rare [9-11].
No single factor (except immune defects) is yet known to
predict frequent illness in later life. However, recurrent
otitis media is predicted by the debut of a single otitis
media before the age of six months [12]. Other determi-
nants for frequent respiratory symptoms are attending to
child day care, passive smoking or having siblings age 1
- 3 years [12,13]. The frequent prescription of antibiotics
is an indicator of future frequent illness, but may well be
the consequence of a high concern about infectious ill-
ness that leads to frequent doctor contacts [14]. Is it pos-
sible to identify other predictors or illness patterns among
infants that can predict frequent illness episodes in later
life?
The GPs perspectives: the doctor knows that most
children’s infections decrease with increasing age [5,15].
Being frequently ill may be due to an inherent fragility
combined with the interactions of the environment in
which the infant lives [4,16-18]. Even if the GP could act
as a key person to these children/families by diagnosing
the problem, useful clinical interventions targeting the
etiology and treatment are underdeveloped, at least when
the common infections are involved [7,9]. Understanding
the usefulness of parents’ own experiences of the ill-
nesses and their interpretation is fundamental in the con-
sultation [2,7]. Many of the parents’ were met with sen-
tences such as “it will disappear” or “it is a virus”—but
being prepared for those infants/toddlers with frequent
illness could allow the GP to improve the premise of the
consultation.
The aim of this study was to identify factors in infancy
that could predict frequent illness during a later period of
time.
2. METHODS
2.1. Sample and Recruitment
Letters were sent to parents of a birth cohort of 389
infants born in February 2001 within Frederiksborg
County, Denmark, in accordance with data extracted
from the local National Health Service. The 194 partici-
pating infants were followed from birth until the age of
11 months by a questionnaire and (defined as toddlers)
from the age of 11 to 14 months using a diary (January,
February and March = 90 days). The questionnaire and
the diary were filled in by the parents (Figure 1). In or-
der to remind parents during the prospective part of the
study to fill in the diaries completely, a letter was sent
every 14 days during the three-month follow-up period.
2.2. Data Collection Methods
Based on information in the questionnaire, baseline
data were collected covering the infants’ state of health
(symptoms and diagnosis categories, medication usage,
number of episodes of illness and GP consultations) and
family data (family size, educational level of parents),
which were referred to as “Infant data”.
The diary data consisted of three one-month calen-
dars with 14 days per page. Each day, the parents could
tick whether they considered their infant had experienced
any of the following: 1) selected symptoms: crying more
than usual, cold/runny nose, not eating normally, not
sleeping well, breathing affected, fever, cough, vomiting,
diarrhoea, earache; 2) doctor-contacts: telephoned their
doctor, visited their doctor, had a home visit, visit from
the out-of-hours service, visited a specialist doctor or
went to the hospital; 3) parent-rated illness severity: how
they rated the severity of their infant’s illness: 0 = not ill,
(X) = not really ill but not really well either, X = ill, XX
= very ill, XXX = severely ill. The variable X, XX and
XXX indicated parent-rated illness. The diary data will
be referred to as “toddler data”. Parents reported the “in-
fant data” before they handed in the “toddler data”.
Indicators for being frequently ill from the toddler data
during the prospective follow up months were: 1) Pres-
ence of 4 or more specific symptoms for >10 days, 2) >4
doctor contacts and 3) >10 days on which the parents
considered the infant ill. These thresholds roughly cor-
respond to the 75% percentile of the distribution over the
three-month period recorded.
2.3. Statistical Methods
The overall (unadjusted) associations of information
from the infant data: family demographic and socio-
economic characteristics, occurrence of symptoms and

R. Ertmann et al. / Health 5 (2013) 259-266 261
389infants
birthcohort
195families
didnotparticipate
194families
intendedtoparticipate
187families
participated
7families
droppedout
Dataforanalyse183infants
Interviewof
20parents
177completedata
2diarydataonlyfor
Feb ruaryandMarch
4diarydataonlyfor
JanuaryandFe bruary
4only
questionnairedata
Figure 1. Study population.
disease, doctor visits and medicine use, with the three
indicators of frequent illness in the follow up period were
tested using chi-squared tests (categorical variables) and
t-tests (continuous variables). A p-value of <0.01 was
considered statistically significant. Multivariately adjusted
associations were assessed for each of the three indica-
tors of being frequent ill as the dependent variable, in
three logistic regression models: one included as inde-
pendent variable the indicators of the symptoms in “In-
fant data”, the second included the indicators of disease,
use of health care services and medicine and the third
included parent-rated general health from the “Infant
data” as dependent variables. Additionally, the infant’s
sex, the parents’ age, education and employment (highest
of the two parents), housing (apartment vs house),
whether the infant was in day care or not, whether there
were siblings who were often ill, and how many times
the infant was ill during the infant period were included
as independent variables in all models. Reduced models
were constructed by backwards elimination of the health-
care experience factors (p < 0.05) from the full models
that included the symptom indicators or the disease and
clinical behaviour indicator respectively; the models with
parent-rated general health were not reduced. All calcu-
lations were done in SAS 9.12.
3. RESULTS
3.1. Study Population
Of the 389 families invited to participate, 194 accepted
(Figure 1). Seven families dropped out and ten families
returned incomplete data, leaving a study population of
183 families with 16,284 days of observation.
The degree of agreement between the three working
indicators of being frequent ill as a toddler is illustrated
in Figure 2. Fifty-two toddlers were classified with ex-
cess symptoms, fifty-four with excess doctor-contacts
and fifty toddlers with excess illness. Only about 25% of
the toddlers in each group also featured in the other two
groups.
The (unadjusted) associations of the factors of health
care and illness experience, family demographic and
socio-economic characteristics as infants (retrospective
collected questionnaire data) with the three indicators of
being frequently ill according to prospectively collected
toddler diary data are shown in Table 1. Restless sleep as
an infant is significantly related to all of the three indi-
cators for being frequently ill as a toddler (excess symp-
toms, doctor-contacts and illness episodes). Episodes of
earache, otitis media and penicillin usage in infants were
related to excess doctor-contacts in toddlers (Table 1).
Significant relationships were also found between use of
medicine in infants and excess illness in toddlers. The
same tendencies were found if the infants had siblings
who were often ill, had many doctor visits, used com-
plementary therapies and had good parent-rated health.
Multivariate analyses of the infant data on toddler data
adjusted for family demographics and socio-economic
factors are shown in Table 2. Restless sleep in infants
was significantly related to all indicators for frequently

R. Ertmann et al. / Health 5 (2013) 259-266
262
Tabl e 1. The associations of family demographic and socio-economic characteristics and incidence of symptoms, disease, doctor
visits and medicine use in the first 11 months of life with the three indicators of excess illness in months 11 - 14.
Toddlers data
1) 4 or more symptoms 2) Doctor visits 3) Parent-rated illness
Missing Total ≤10 days >10 days ≤4 times >4 times ≤10 days >10 days
Infants data n = 183 n = 131 n = 52 n = 129 n = 54 n = 133 n = 50
n n (%) n (%) n (%) p2 n (%) n (%) p2 n (%) n (%) p2
Socio-demographics
Sex of the child (boy) 0 102 (55.7) 70 (53.4) 32 (61.5)0.3273 (56.6) 29 (53.7)0.72 75 (56.4) 27 (54.0)0.77
Nuclear family 0 177 (96.7) 126 (96.2) 51 (98.1)0.52123 (95.4)54 (100.0)0.11 129 (97.0) 48 (96.0)0.74
Age parent(s)1 0 0.50 0.64 0.76
≤30 years 42 (23.0) 32 (24.4) 10 (19.2) 32 (24.8) 10 (18.5) 30 (22.6) 12 (24.0)
31 - 39 years 120 (65.6) 86 (65.7) 34 (65.4) 83 (64.3) 37 (68.5) 89 (66.9) 31 (62.0)
≥40 years 21 (11.4) 13 (9.9) 8 (15.4) 14 (10.9) 7 (13.0) 14 (10.5) 7 (14.0)
Education parent(s)1 0 0.55 0.29 0.61
≤12 years 9 (4.9) 7 (5.3) 2 (3.8) 8 (6.2) 1 (1.9) 7 (5.3) 2 (4.0)
13 - 14 years 63 (34.4) 42 (32.1) 21 (40.4) 41 (31.8) 22 (40.7) 43 (32.3) 20 (40.0)
≥15 years 111 (60.7) 82 (62.6) 29 (55.8) 80 (62.0) 31 (57.4) 83 (62.4) 28 (56.0)
Profession parent(s)1 0 0.99 0.90 0.67
Self-employed 51 (27.9) 36 (27.5) 15 (28.9) 38 (29.5) 13 (24.1) 35 (26.3) 16 (32.0)
Employee (high) 29 (15.9) 20 (15.3) 9 (17.3) 20 (15.5) 9 (16.7) 21 (15.8) 8 (16.0)
Employee (middle) 40 (21.9) 29 (22.1) 11 (21.1) 26 (20.2) 14 (25.9) 27 (20.3) 13 (26.0)
Employee (basic) 53 (29.0) 39 (29.8) 14 (26.9) 38 (29.5) 15 (27.8) 42 (31.6) 11 (22.0)
Employee (other) 10 (5.5) 7 (5.3) 3 (5.8) 7 (5.4) 3 (5.6) 8 (6.0) 2 (4.0)
Housing (apartment) 0 25 (13.7) 16 (12.2) 9 (17.3)0.3720 (15.5) 5 (9.3) 0.26 16 (12.0) 9 (18.0)0.29
Health history (in the first 11 months of the infant’s life)
Episodes of illness 2 0.11 0.007 0.13
Never 17 (9.4) 16 (12.4) 1 (1.9) 14 (11.0) 3 (5.6) 15 (11.4) 2 (4.1)
1 - 2 times 81 (44.8) 59 (45.7) 22 (42.3) 65 (51.2) 16 (29.6) 63 (47.7) 18 (36.7)
3 - 4 times 59 (32.6) 38 (29.5) 21 (40.4) 36 (28.4) 23 (42.6) 38 (28.8) 21 (42.9)
>4 times 24 (13.2) 16 (12.4) 8 (15.4) 12 (9.4) 12 (22.2) 16 (12.1) 8 (16.3)
Siblings who are often ill 2 35 (19.3) 19 (14.7) 16 (30.8)0.01322 (17.2) 13 (24.5)0.26 20 (15.3) 15 (30.0)0.023
Daycare outside the home 0 60 (32.8) 42 (32.1) 18 (28.4)0.7439 (30.2) 21 (38.9)0.26 39 (29.3) 21 (42.0)0.10
Symptoms (in the first 11 months of the infant’s l ife)
Fever 0 150 (82.0) 103 (78.6) 47 (90.4)0.062106 (82.2)44 (81.5)0.91 106 (79.7) 44 (88.0)0.19
Cough 0 140 (76.5) 101 (77.1) 39 (75.0)0.7699 (76.7) 41 (75.9)0.91 100 (75.2) 40 (80.0)0.49
Vomiting 0 61 (33.3) 42 (32.1) 19 (36.5)0.5642 (32.6) 19 (35.2)0.73 42 (31.6) 19 (38.0)0.41
Diarrhoea 0 88 (48.1) 60 (45.8) 28 (53.8)0.3364 (49.6) 24 (44.4)0.52 61 (45.9) 27 (54.0)0.33
Rash 0 47 (25.7) 31 (23.7) 16 (30.8)0.3231 (24.0) 16 (29.6)0.43 30 (22.6) 17 (34.0)0.11
Wheezing 0 58 (31.7) 37 (28.2) 21 (40.4) 0.1140 (31.0) 18 (33.3)0.76 38 (28.6) 20 (40.0)0.14
Earache 0 44 (24.0) 27 (20.6) 17 (32.7)0.08521 (16.3) 23 (42.6)<.001 31 (23.3) 13 (26.0)0.70
1if more than one parent, this is the maximum over both parents; 2p-value of a chi-squared test.

R. Ertmann et al. / Health 5 (2013) 259-266 263
Table 2. Multivariate associations of symptoms, disease and clinical behaviour, and parent-rated general health in the first 11 months
of life = infants data with the three measures of excess illness later on = toddlers data.
Toddlers data
1) 4 or more symptoms >10 days 2) Doctor visits >4 times 3) Parent-rated illness >10 days
Infants data OR (95% CI) p-value OR (95% CI) p-valueOR (95% CI) p-value
Symptoms
Earache 3.71 (1.48 - 9.31) 0.0052
A cold/a running nose 0.20 (0.05 - 0.90) 0.0353
Restless sleep 3.99 (1.56 - 10.16) 0.0038 2.63 (1.06 - 6.54) 0.0370 2.97 (1.20 - 7.34) 0.0188
Allergic reaction 3.94 (1.03 - 15.13) 0.0456
Disease and clinical behaviour
Bronchitis 6.85 (1.64 - 28.55) 0.0082
Nature medicine 3.49 (1.01 - 12.06) 0.0484
Penicillin 2.68 (1.21 - 5.93) 0.0148
Note: for each of the measures of excess illness at one year three logistic regression models were investigated, one including the indicators for the symptoms,
one including the indicators for disease and clinical behaviour (indicators for Cold and Fever cramps were not included in the models as only very few children
presented with Fever cramps and very few did not present with Cold) and one including parent-rated general health. Each model additionally included the
child’s sex, the parent’s age, education and employment (highest of the two parents), housing (apartment vs house), whether the child goes to daycare, whether
there are siblings and siblings that are often ill, and how many times the child was ill in the first 11 months. A reduced model was constructed by backwards
elimination from the full model of the symptom indicators or the disease and clinical behaviour indicators respectively until all are significant at a 5% level; the
model with parent-rated general health was not reduced. Only the symptoms and disease/clinical behaviours that were in one of the reduced models are reported
in the table; parent-rated health was not significant in any of the models and is therefore not listed in the table.
8
19
17 8
9
14
27
4or moresymptoms
Parent ‐rated illness
Doctor visits
Figure 2. Venn diagram for the three indicators of frequent
illness. N: 183, Toddlers with 4 or more symptoms: 52, Parent-
rated illness: 50, Doctor visits: 77 and Toddlers without sym-
ptoms or illness or doctorcontacts: 4.
ill toddlers (Table 2). Penicillin usage and earache in
infants increased the odds ratio of excess doctor-contacts
in toddlers. On the other hand, it was found that having a
cold in infancy was related to a lower risk of doctor con-
tacts for toddlers. Bronchitis in infancy was associated
with excess illness in toddlers. Allergic reactions and the
use of complementary medicine were also associated
with a higher risk of excess symptoms in toddlers (Table
2).
4. DISCUSSION
The main findings were that some specific factors as-
sociated with illness in infancy were highly associated
with factors of excess illness for another time period
ahead. Frequent episodes of illness in infancy were more
often followed by frequent episodes of illness as toddler,
regardless of the type of measurement. The strongest as-
sociation was between disturbed sleep and frequent ill-
ness later on. While common colds in infancy reduced
the risk of excessive illness in toddlers, allergy, earache
and antibiotic usage were correlated with frequent ill-
nesses in toddlers.
4.1. Illness Assessments
In our study the parents assessed the infants’ symp-
toms. It is well known that the assessment of symptoms
and illness, as well as the amount of doctor contacts, are
highly individual and are influenced by the parents’ ex-
perience and illness behavior [7]. People interpret symp-
toms and create meaning on the basis of their social and
cultural background and experiences [2]. In this process
manifold perspectives on illness can arise. Our results
and the three indicators of frequent illness support Gan-
nik’s situational disease model, in which the parents’
behaviour concerning their infants’ illness is understood,
shaped and handled in the context of the family [6].
4.2. Frequently Ill
We use the term “excess illness” for the toddlers
crossing the 75% percentile for the three indicators. Only
25% of the toddlers featured in the other groups, al-
though we had expected a stronger match. One explana-
tion could be that the impact of the illness and lay peo-

R. Ertmann et al. / Health 5 (2013) 259-266
264
ple’s understanding of the illness differ from the doc-
tors’ perception of these—as described by Kleinman and
illustrated below [11].
We found that bronchitis, but not otitis media, was
significant for the indicator excess illness. This may
show that some diseases are experienced as worse than
others, not from a biomedical point of view but in terms
of how the daily lives of the infant and family are af-
fected [19]. According to Gannik, the parents’ experience
of the illness also depends on whether the infant’s signs
or symptoms can be contained within the situation [6].
An Infant with otitis media often cries and may be diffi-
cult to comfort, but the episodes are of short duration, in
contrast to bronchitis, in which symptoms linger, are
recurrent, unpredictable and need medication [15].
Our finding that penicillin treatment increased the
likelihood of excess doctor-contact was expected, as
doctor contacts are linked with the experience of illness,
parents’ socio-economic status, health and the use of
health care [8,18]. Earache is a strong trigger for excess
doctor-contact [20,21] as parents expect a possible di-
agnosis of otitis to be treated by antibiotics. Furthermore,
seeing a doctor is linked with an increased risk of anti-
biotic prescription [22]. The opposite could also be the
case as early antibiotic treatment alters the ecological
balance of the microbiological flora in the intestine
which makes the child more susceptible to infections as
the microbes in the intestine affect the immune system,
the so-called microbiome [23]. Reverse contact patterns
were found for “having a cold”. A cold is, according to
parents, just part of daily life [19,21].
4.3. Disturbed Sleep
This study found that disturbed sleep can be added to
the list of predictors of frequent illness. Research inves-
tigating this topic is rare. A sick infant with disturbed
sleep can have a severe impact on a family’s everyday
life [19]. Our findings of disturbed sleep in infants and
excess illness in toddlers could be explained physiologi-
cally. Disturbed sleep interferes with systems within the
body e.g. the psycho-neuro-immunological system [24]
and the circadian rhythm [25]. The neuroendocrine sys-
tem produces hormones such as corticotrophin, mela-
tonin, growth hormone and cortisol, which are sensitive
to sleep and regulate cytokine production (il-1 and TNF),
leukocyte activities, proliferation and apoptosis. The hor-
mones have specific effects on sleep (increased/de-
creased sleep influence the sleep architecture1) and
changes in sleep patterns influence the release of these
hormones [25-29]. Infections stimulate the inflammatory
cytokines, which change sleep patterns, and a febrile host
response leads to elevated cortisol [24].
In human experiments with induced influenza virus
and rhinovirus, sleep was significantly disrupted [29].
Illness is a stressful event for the infant, illustrated by the
infant’s disturbed sleep architecture and higher cortisol
levels [25]. This is especially interesting with regard to
infants as it is still a matter of discussion at what age
infants establish the cortisol circadian rhythm [26,28].
Infants with colic symptoms display disturbed sleep ar-
chitecture and sleep less, and this might be associated
with a disruption or delay in the establishment of a cir-
cadian sleep-wake rhythm [30]. One might think that
recurrent illnesses in infants affect the infant’s sleep ar-
chitecture. We think there could be a connection between
a delay in establishing the personal sleep-wake circadian
rhythm owing to (or following) recurrent episodes of
illness around the time when the circadian rhythms are
being stabilized in the infant.
New research found that there probably is an associa-
tion between stress in childhood and the onset of immune
mediated disease [31-33] and maybe the link is that bad
sleep is a stress situation to the infant which can cause
risk of infections. A study supports this view, children
age 7 - 10 with bad sleep (sleep bruxism) were also more
likely to have chronic illness, allergic rhinitis, asthma or
upper respiratory tract infections [34].
4.4. Strengths and Limitations of the Study
The prospective data collection, which used diary
cards, gives a comprehensive picture of the toddler’s
illnesses as experienced every day during a longer period.
Symptoms experienced during the first 11 months (col-
lected by a questionnaire) may on the other hand be un-
derreported, according to recall bias. Some symptoms,
such as earache, may be difficult to interpret in infants.
Neither information from the questionnaire nor the dia-
ries was compared with medical journal data.
The population was mainly from the middle class,
which corresponds to the residents of Frederiksborg
County. Of the invited parents only 47% agreed to par-
ticipate, while another 20% of the responders declined to
participate owing to lack of time or to the fact that they
were already participating in an investigation [9]. How-
ever, among those participating, there was a high re-
sponse rate to both the questionnaire and the diaries—
and this boosted a high validity to the data. The upkeep
of a three-month diary is demanding and may have influ-
enced the selection of parents. Parents from a lower so-
cial class may have had a higher use of the health care
system, but results according to consultations pattern
based on social class are conflicting [9].
1Sleep architecture: is characterized by an optimal length of each sleep
stage. The sleep stages: non-rapid-eye-movements sleep (4 stages) and
non-rapid-eye-movements sleep (1 stage) are characterized by the fre-
quency and amplitudes of EEG patterns and length of each sleep stage.

R. Ertmann et al. / Health 5 (2013) 259-266 265
4.5. Implications for Clinical Practice
Disturbed sleep during an infant’s first year may be
more important than previously understood and the GP
should ask about it, especially if the infant presents with
recurrent episodes of illness. During prophylactic child
health care the GP has a good opportunity to discuss
sleep and its influence on the child’s health. Whether
advice to the parents regarding sleep could help the in-
fant to escape frequent episodes of illness later is some-
thing that remains to be proven. We call for further re-
search concerning the association between child/parents’
sleep patterns and infections diseases and other health
effects as toddlers.
5. ETHICAL APPROVAL
The Danish Local Ethics Committee of Frederiksborg
County. Journal number 2001-1-62G.
6. ACKNOWLEDGEMENTS
We would like to acknowledge the support of the parents who took
part in this study.
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