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P L B J Lucassen a Institute for Research in Extramural Medicine,
Free University, Amsterdam, Netherlands, b Organisation for Research and Policy Advice,
Grave, Netherlands, c Scientific Committee of
the Dutch College of General Practitioners, Utrecht,
Netherlands, d Department of General Practice, University of
Leiden, Leiden, Netherlands
Correspondence to: Dr
Assendelft p.assendelft.EMGO{at}med.vu.nl
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Abstract |
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Objective: To evaluate the effectiveness of diets,
drug treatment, and behavioural interventions on infantile colic in
trials with crying or the presence of colic as the primary outcome
measure.
Data sources: Controlled clinical trials identified
by a highly sensitive search strategy in Medline (1966-96), Embase (1986-95), and the Cochrane Controlled Trials Register, in combination with reference checking for further relevant publications. Keywords were crying and colic.
Study selection: Two independent assessors selected
controlled trials with interventions lasting at least 3 days that included infants younger than 6 months who cried excessively.
Data synthesis: Methodological quality was assessed
by two assessors independently with a quality assessment scale (range
0-5). Effect sizes were calculated as percentage success. Effect sizes
of trials using identical interventions were pooled using a random
effects model.
Results: 27 controlled trials were identified.
Elimination of cows' milk protein was effective when substituted by hypoallergenic formula milks (effect size 0.22 (95% confidence interval 0.09 to 0.34)). The effectiveness of substitution by soy
formula milks was unclear when only trials of good methodological quality were considered. The benefit of eliminating cows' milk protein
was not restricted to highly selected populations. Dicyclomine was
effective (effect size 0.46 ( 0.33 to 0.60)), but serious side effects
have been reported. The advice to reduce stimulation was beneficial
(effect size 0.48 (0.23 to 0.74)), whereas the advice to increase
carrying and holding seemed not to reduce crying. No benefit was shown
for simethicone. Uncertainty remained about the effectiveness of low
lactose formula milks.
Conclusions: Infantile colic should preferably be
treated by advising carers to reduce stimulation and with a one week trial of a hypoallergenic formula milk.
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Key messages
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Introduction |
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Infantile colic
excessive crying in healthy, thriving infants
is
a common problem during the first months of childhood. Crying typically
occurs in the evenings, episodes starting in the first weeks of life
and ending at the age of 4-5 months.1 In studies this
crying is arbitrarily defined as lasting at least 3 hours a day, on at
least 3 days a week, for at least 3 weeks.2 However, the
validity of this criterion is disputed.3 Moreover, whether the symptoms described by Illingworth
high pitched, inconsolable crying accompanied by flushing of the face, drawing up of the legs,
passing of gas, and difficulties in passing stools
are unimportant additional features or an integral part of a syndrome is not
clear.4
Despite over 40 years of research, the aetiology of infantile colic remains unclear. Four main causes emerge from the literature. Firstly, infantile colic may be a problem with the gut in which excessive crying is the main symptom.5 According to this view, excessive crying is the result of painful gut contractions caused by allergy to cows' milk, lactose intolerance, or excess gas. Secondly, it may be a behavioural problem resulting from a less than optimal parent-infant interaction, with a difficult temperament of the infant as a possible explanation for inadequate parental reactions.6 Thirdly, the excessive crying in a child with infantile colic could be regarded as merely the extreme end of normal crying.4 Fourthly, infantile colic is just a collection of aetiologically different entities that are not easy to discern clinically.7
Because of the many possible causes, many interventions have been studied. The gut hypothesis has led to interventions such as substituting cows' milk with soy milk or protein hydrolysate (hypoallergenic), low lactose, or fibre enriched formula milk; using herbal tea; and using drugs to reduce painful gut contractions (dicyclomine) or the formation of intraluminal gas (simethicone). The behavioural hypothesis has led to interventions such as modifying parents' responsiveness, using motion and sound to calm the baby, and reducing stimuli.
Despite the favourable clinical course of infantile colic
most infants
are free of symptoms by the age of 4-5 months
many parents seek
medical help. Moreover, although serious somatic problems are
absent in most cases, doctors and nurses believe that that they have to
do something because of the trouble parents are experiencing. However,
so far, it is not clear which of the treatments is the most effective.
Neither is it clear whether some infants will benefit more than others
from a specific intervention.
We therefore conducted a systematic review of all experimental studies to evaluate the effectiveness of diets, drug treatment, behavioural interventions, and other treatments for infantile colic.
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Methods |
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Study selection
A highly sensitive search in Medline (1966-96),8 an
analogue search in Embase (1986-95), and a search in the Cochrane
Controlled Trials Register9 were performed. Search
headings were "colic" and "crying." In addition, "crying"
and "colic" were separately used as free textwords with an age
restriction (<2 years). This search strategy was supplemented with
checking the references for missing publications. We selected
identified publications on the treatment of infantile colic that used
reduction in crying or colic as the main outcome measure. We did not
include abstracts or letters. To cover the entire clinical range of
infantile colic, we decided to include trials that did not use a time
criterion as well. We excluded trials whose authors said that they had
studied infants with a normal crying pattern and whose mothers had not complained of the crying. Other reasons for exclusion were that the
interventions lasted less than 3 days, a concurrent control group was
lacking, and the infants were older than 6 months. AKN and PL
independently applied the exclusion criteria and reached a consensus in
cases of disagreement.
Methodological quality
We evaluated the methodological quality of all included trials
with the quality assessment scale developed by Jadad et
al.10 Each trial was scored on adequacy of randomisation,
double blinding, and completeness of follow up. We calculated the
percentages of the maximum score on each item to estimate the mean
quality of all trials. The total quality score of each trial is given
in round numbers from 0 to 5. Trials scoring 0 or 1 were at the outset considered to be of too low quality to be included in the evidence. WvG
and PL scored all trials independently but they were not blind about
information on authors and journals because PL was well acquainted with
the material. Consensus was reached in cases of disagreement. The
degree of agreement before the consensus meeting was expressed as
percentage agreement and as kappa.
11 12
Presentation of data
Data are presented on age (mean, range), male to female ratio, age
at onset of infantile colic, baseline crying (number of hours daily),
percentage of infants who were being breast fed, percentage of infants
who were the firstborn, numbers of infants completing the trial, drop
out rates, effect sizes, quality scores, and family history of atopy.
Statistics
The main outcome measurement in all trials was the duration of
crying or the presence of colic, measured on dichotomous, ordinal, or
continuous scales. We calculated effect sizes with 95% confidence intervals as percentage success, using specific modifications for
crossover studies and for different levels of measurement (details
available on web at www.bmj. com). We estimated outcome from figures
for studies that gave results only in figures but not in numbers.
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Results |
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Selected trials
The Medline search yielded 187 publications, the Embase search
312, and the search in the Cochrane database 220. Searching this output
resulted in 34 trials. Reference checking yielded another 16 trials, two abstracts, and one letter. Thus 50 complete publications
were located, of which 23 were excluded, mainly because a control group
was lacking and crying was labelled normal. Six of the excluded trials
studied a dietary intervention, six a behavioural intervention, five
drug treatment, three motion and sound, two chiropractic, and one the
use of a dummy (details available on the web at www.bmj.com). Before
the consensus discussions on exclusion criteria, there was disagreement
on 10 out of 200 items (50 publications, four items per publication;
agreement 95%). Consensus was reached in all cases.
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Methodological quality
The quality score according to the scale of Jadad et
al10 ranged from 0 to 5 (median 3). The percentage of the
maximum score of all trials on the item "adequacy of randomisation"
was 61%, on "double blinding" 31%, and on "follow up" 31%.
Nine trials scored 0 or 1, indicating insufficient
quality.
15 21 24 30 32 33 37 38 40
Interrater
agreement on the scale was good (agreement 86%, kappa 0.71). Most
disagreement was caused by slight differences in interpretation and was
resolved easily. Finally, consensus was reached in all cases. Quality
score and effect measure were not correlated (r=
0.02, P=0.92), indicating that there was no relation between the quality of the study and the magnitude of the effects.
Results from diet trials
Interventions in trials using soy, hypoallergenic, or low lactose
formula milks lasted 6-8 days; follow up in parallel trials was 6-8 days and in crossover trials 12-16 days. Drop out rates were not
reported in three trials; four trials reported drop out rates of
20-47%. Concomitant interventions were not mentioned.
0.40 (
0.83 to
0.03)).19
The trials, including those of soy formula milk, reported no adverse
events. One trial reported no influence of maternal atopy on outcome of
treatment14; the other publications did not report whether
infants with atopic features reacted better than those without atopy to
the elimination of cows' milk protein.
There was no evidence of effect on excessive crying of lowering the
lactose content of the formula milk. Adding fibre to the formula was
not effective either. Herbal tea containing chamomile, vervain,
liquorice, fennel, and balm mint seemed to be effective in treating
excessive crying (table).
Trials of drug treatment
Drug treatment was given for 1 week in all but one trial. Drop out
rates were not reported in three trials; five trials reported drop
out rates of between 10% and 20%. No concomitant interventions were
mentioned.
Trials of behavioural interventions
Trials of behavioural interventions had durations of follow up
ranging from 2 weeks to 3 months. Drop out rates varied from 0 to 16%.
Neither concomitant treatments nor side effects were reported.
an empathic interview whose content was not
clear.35 Specific management techniques (early response to
the crying, gentle soothing motion, avoidance of overstimulation, use
of a dummy, prophylactic holding and carrying, use of an infant
carrier, and maintenance of day-night orientation) in combination with general information and reassurance proved to be worse than the control
treatment (general information and reassurance). A combination of
general information and reassurance with vibration in a device simulating riding in a car together with sound elicited no better result than control treatment alone.36
Trials comparing two active treatments
Taubman found that increasing parental responsiveness was better
than eliminating cows' milk protein and substituting it with hypoallergenic formula milk.39 The studies by Westphal and
Medin38 and Oggero et al40 are of low quality
and therefore not included in the evidence.
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Discussion |
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We conclude that the elimination of cows' milk protein, certain behavioural interventions, and dicyclomine are effective treatments for infantile colic. The clinical importance of the effect sizes in the figure is shown by the congruence of an effect size of 0.18 with a number needed to treat of 6.18 There is no evidence that low lactose formula milks, fibre enriched formula milks, simethicone, and increased carrying and holding are effective. The power of the studies of low lactose milks is too low to make definitive conclusions. The effectiveness of herbal tea is not definitely established because only one trial was performed. Because trials on the use of motion and sound and chiropractic were uncontrolled, no judgments can be made about these treatments.
Eliminating cows' milk protein
Elimination of cows' milk protein is effective not only in highly
selected subgroups of infants but also in primary care settings. This
finding contradicts former reviews.
7 42
One trial was not
considered in these reviews16 and one trial was published after them.18 Elimination of cows' milk protein raises
the question of which substitute to use
a soy or a protein hydrolysate
formula milk. If a hydrolysate is chosen should it be a whey or a
casein hydrolysate?
Dicyclomine and side effects
Dicyclomine is effective in treating infantile colic, but 5% of
the treated infants had side effects. The manufacturer reports breathing difficulties, seizures, syncope, asphyxia, muscular hypotonia, and coma as side effects.47 In addition, apnoea
of short duration was reported in two infants.47 Although
these side effects are probably rare, there seems to be sufficient
reason not to use these substances to treat infantile colic, a
condition with a favourable clinical course and without serious somatic consequences.
Behavioural interventions
The results of the three trials of behavioural interventions that
were of sufficient quality were not comparable at first sight. However,
sensitive differential responding by parents48 may be the
corresponding feature in at least two of the three trials. Both
standard treatment in the study by Barr et al and advice about reducing
stimulation in that of McKenzie contain items fitting with sensitive
differential responding. Unfortunately, the fit was far from perfect as
all treatments contain items that could also lead to overstimulation.
The results of the trial of Parkin et al are not in accord with this
concept.36 A possible explanation is that their specific
management techniques led to overstimulation and thus did not diminish
crying. In short, stimulating responsiveness in the parent-child
interaction may be beneficial in treating infantile colic.
Methodological concerns
At first sight the selected trials show considerable clinical
heterogeneity in design, outcome measure, type of intervention, effect
size, and quality. Therefore, we decided at the outset to pool only the
trials with the same intervention and to use a random effects model,
which gives a more conservative estimate of the effect sizes. The risk
of not selecting trials properly for this review is low because we used
a highly sensitive search strategy in combination with extensive
reference checking. As there was no significant correlation between
sample size and effect size (r=
0.34, P=0.08), we
could not show publication bias.53 However, a funnel
plot54 was not possible without larger trials. Moreover,
removing one trial of low quality21 changed
r to
0.52 (P=0.01). In general, trial quality was
low, mainly because of the low scores for double blinding and
completeness of follow up. Obviously, in trials of a behavioural
intervention double blinding is not possible.
Recommendations for practice and future research
Healthcare workers in primary care faced with parents complaining
about their excessively crying infants should check some common
explanations first. Can hunger or cold explain the crying? Is feeding
technique adequate? Is there any somatic problem causing pain or
itch?42 Having excluded these common explanations of crying, a detailed history should be taken about the timing and the
amount of crying, measures parents have already tried, ideas and fears
of the parents, the care taking routines, and the ways parents handle
the child when crying. The amount of crying is important because the
results of this review apply only to infants crying more than 3 hours a
day.
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Acknowledgments |
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We thank H Rothuis-ter Haar and Anja van Guluck for their help in the hospital library and in performing the computerised search; Rosemarie Tomes for linguistic revision of the manuscript; and Iris Pasternack for a translation.
Contributors: PLBJL had the original idea for the study, designed the protocol, searched the literature, participated in the analysis, and wrote the article. WJJA participated in the data analysis, gave advice on methodological issues, helped in searching the literature, and was actively involved in writing the article. JWG performed the statistical analyses. JTMvanE participated in designing the protocol, raising financial support, and judging the final version of the article. WJvanG participated in designing the protocol and assessing the quality of trials. AKN participated in designing the protocol and assessed the inclusion and exclusion criteria of the trials. PLBJL and WJJA are the guarantors of this review.
Conflict of interest: None.
Funding: The part of the project dealing with the treatment of infantile colic with hypoallergenic formula milk was funded by the Praeventie Fonds (grant No 002824560).
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References |
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primary excessive crying as an infant-environment interaction.
Pediatr Clin North Am
1984;
31:
993-1005[Medline].(Accepted 2 February 1998)
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