J Manipulative Physiol Ther 1999 (Oct); 22(8): 517–522
Jesper M.M. Wiberg, DC, Jan Nordsteen, DC, Niels Nilsson, DC, MD, Phd
Center for Biomechanics,
Odense University, Denmark
OBJECTIVE: To determine whether there is a short–term effect of spinal manipulation in the treatment of infantile colic.
DESIGN: A randomized controlled trial.
SETTING: A private chiropractic practice and the National Health Service's health visitor nurses in the suburb Ballerup (Copenhagen, Denmark).
SUBJECTS: Infants seen by the health visitor nurses, who fulfilled the diagnostic criteria for infantile colic.
INTERVENTION: One group received spinal manipulation for 2 weeks, the other was treated with the drug dimethicone for 2 weeks.
OUTCOME MEASURE: Changes in daily hours of crying as registered in a colic diary.
RESULTS: By trial days 4 to 7, hours of crying were reduced by 1 hour in the dimethicone group compared with 2.4 hours in the manipulation group (P = .04). On days 8 through 11, crying was reduced by 1 hour for the dimethicone group, whereas crying in the manipulation group was reduced by 2.7 hours (P = .004). From trial day 5 onward the manipulation group did significantly better that the dimethicone group.
CONCLUSION: Spinal manipulation is effective in relieving infantile colic.
From the Full-Text Article:
When we compare our results with those of the only other prospective trial on spinal manipulation in the treatment of infantile colic,  we see that the results are virtually identical for our manipulation group. In the previous trial, mean daily hours with colic were reduced by 66% on day 12 of the trial, and in our trial we saw a reduction of 67% on day 12 in the manipulation group, whereas our dimethicone group only had a reduction in daily hours with colic of 38% by day 12. These similarities strengthen the conclusion that a positive effect of spinal manipulation exists in the treatment of infantile colic. These strong similarities perhaps also suggest that we may be dealing with an underlying anatomic/physiologic disease mechanism rather than a psychosocial one, but that remains to be clarified.
Initially we planned to have a baseline observation period of 7 days, but soon after the start of the project we had to revise this to 4 days because the families demand for fast action was too strong. If we had upheld the 7-day baseline observation period, it would have been difficult to recruit a sufficient number of participants because parents would have sought help elsewhere. The problem is understandable in retrospect because families of infants with colic are under a tremendous psychologic strain, as anyone with infantile colic experience will appreciate. We do not think that reducing the length of the baseline observation period has any effect on the validity of the results because this was the same for both treatment groups.
We would also have liked a longer follow-up period, but once again families with small infants are busy families (colic or not). It was our impression, that it would not have been possible to keep those participants who still had colic in the trial much longer, whereas those who were helped by the treatment would want to get on with normalizing their family lives. The result of a longer follow-up period would thus have been an unacceptably high number of dropouts. Furthermore, in the previous trial on spinal manipulation in the treatment of infantile colic, they had a follow-up at 4 weeks but found that the reduction in crying was clearly within the first 14 days, and no significant change occurred in the last 2 weeks of follow-up. 
The pretrial characteristics of the 2 treatment groups show only 1 significant difference. The age of the infant when colic started was 2.2 weeks in the dimethicone group compared with 1.2 week in the manipulation group (P = .02), and this could potentially be a problem. If infantile colic tends to disappear spontaneously after a given number of weeks, the difference could have meant that infants in the manipulation group might be more likely to experience spontaneous alleviation of symptoms than those in the dimethicone group, and this could be the reason for the observed effect. But because the age of the infant on entry into the trial also has the same 1-week difference in age and because both groups on entry had infantile colic for 3.7 weeks, this could not have been the reason for the observed difference.
If, on the other hand, infantile colic tends to stop spontaneously at a given age, then the 1-week age difference would instead have favored a higher rate of spontaneous disappearance in the dimethicone group, and this was not evident. So even if the difference in age on debut of symptoms was statistically significant, it did not affect the validity of our results.
There were 9 dropouts in the dimethicone group and none in the manipulation group. This could be interpreted as a sign of parents' bias against dimethicone, but inspection of the data in the last infantile colic profile completed before dropout show clearly that for all where information is available, the dropout was due to a genuine worsening of symptoms and not parents' bias. By excluding data from the dropouts, we are excluding more severe cases from the dimethicone group, and this has the effect of making that group appear better that it actually was. Thus we are introducing a serious bias against showing an effect of spinal manipulation, and despite this the manipulation group did significantly better.
Spinal manipulation is normally used in the treatment of musculoskeletal disorders, and the results of this trial leave open 2 possible interpretations. Either spinal manipulation is effective in the treatment of the visceral disorder infantile colic or infantile colic is, in fact, a musculoskeletal disorder, and not, as normally assumed, visceral. This study does not address this issue.
Spinal manipulation has a positive short-term effect on infantile colic.