"Babies in Britain, Canada and Italy cry more than elsewhere," The Guardian reports. But the review the newspaper is reporting on only found reliable data from a handful of nations so the accuracy of the claim is unclear.
Researchers looked at previously gathered data on colic patterns. Colic is a common, yet poorly understood condition associated with excessive, frequent crying in babies who appears to be otherwise healthy. The condition is not serious but can be distressing for parents.
Researchers found that colic was most common in the first six weeks of life, and became less common over the next six weeks. It was most common in the UK, Canada and Italy, with Denmark, Germany and Japan having the lowest rates.
Both the researchers and the media speculate why this is the case. The researchers discuss the fact that Danish parents tend to be in closer physical contact with their baby on a daily basis than UK parents. While The Guardian discusses the fact that breastfeeding rates are far higher in Denmark compared to the UK. Both claims are unproven – and the review actually found some data to suggest bottle-fed babies were less likely to cry.
If your baby has colic, it is important to remember that it is not your fault and your baby will get better eventually. There is no single proven method to treat colic, but you could try holding your baby during a crying episode, burping your baby after feeds, gently rocking your baby over your shoulder or bathing your baby in a warm bath. Read more advice about colic.
Where did the story come from?
The study was carried out by researchers from the University of Warwick and Kingston University in the UK. The study was published in the peer-reviewed The Journal of Pediatrics.
One of the authors is supported by a PhD scholarship from the Republic of Turkey Ministry of Education, but they report no other sources of funding. The authors declare no conflict of interest.
While the UK media's reporting of the study was generally accurate, the majority of the headlines, such as the Metro's "British newborn babies cry more than in any other country on the planet," provided a distorted view of the research. It suggests researchers gathered data from around the world. In fact, they only found reliable data from nine countries; all of which were developed nations.
What kind of research was this?
This was a systematic review and meta-analysis aiming to find out the mean length of fussing and crying and the prevalence of colic in infants from various countries in the first three months of their life.
While this type of review and meta-analysis is good for showing an overall picture of research in a certain area – in this case, prevalence of colic and crying in babies – it is only as good as the studies it includes.
What did the research involve?
The authors searched literature databases to identify observational studies (published up to December 2015) that included general population samples of infants aged one to 13 weeks, and measured fussing or crying in 24 hour behaviour diaries and reported average cry duration.
Researchers assessed the studies for quality, looking at specific features such as whether the sample size was adequate, and whether the study accounted for other factors like socioeconomic and household circumstances. In particular they also looked to see whether studies assessed colic according to the modified Wessel criteria. This is a well-validated definition, also known as the "rule of threes", where colic is defined as the baby fussing/crying for more than three hours a day, on at least three days in any one week.
The authors identified 28 relevant diary studies including a total of 8,690 babies from the UK, Canada, the US, Italy, the Netherlands, Germany, Australia, Denmark and Japan.
They grouped the studies according to the age babies were assessed: 1-2 weeks, 3-4 weeks, 5-6 weeks, 8-9 weeks and 10-12 weeks. They looked to see if cry duration changed over the first 12 weeks of life, varied according to country, and varied by feeding type or study quality.
What were the basic results?
The average time fussing or crying across studies was:
- 117 minutes (standard deviation [SD] 67) at 1-2 weeks of age
- 118 minutes (SD 69) at 3-4 weeks of age
- 133 minutes (SD 70) at 5-6 weeks of age
- 68 minutes (SD 46) by 10-12 weeks of age
Crying and fussing durations were higher than average in Canada (150 minutes at 3-4 weeks) and The Netherlands (150 minutes at 5-6 weeks) and lower than average in Germany (69 minutes at 1-2 weeks), Japan (107 minutes at 5-6 weeks) and in Denmark at all ages other than 8-9 weeks.
The prevalence of colic in the first six weeks ranged from 17% to 25% and decreased to 11% by 8-9 weeks and to 0.6% by 10-12 weeks.
Prevalence of colic was high in the UK (28% at 1-2 weeks), in Canada (34% at 3-4 weeks) and in Italy (21% at 8-9 weeks), compared with Denmark (6% at 3-4 weeks) and Germany (7% at 3 to 4 weeks) and Japan (2% at 5 to 6 weeks).
The researchers found some evidence that bottle-fed and mixed feeding babies had lower colic prevalence than breastfed babies at 5-6 weeks. Studies that did not report on feeding type had higher prevalence of crying at the 10-12 mark than studies that did; which further complicates the picture.
How did the researchers interpret the results?
The researchers concluded that they "found no evidence for a 'universal' increase of fuss/cry duration over the first 6 weeks of life culminating in a 'crying peak' at 5-6 weeks of age as proposed previously".
However, they did find that fuss/cry durations were high across the first six weeks of life, followed by a "universal" reduction in fuss/cry duration between six and 12 weeks of age.
They further add that "colic or excessive fuss/cry may be more accurately identified by defining fuss/cry above the 90th percentile in the chart provided based on the review."
This study suggests the prevalence of colic is highest in the first six weeks of a child's life and then decreases over the next six weeks. Colic seems to be less common in babies in Denmark, Germany and Japan and more common in babies from Canada, the UK and Italy.
This study is valuable in demonstrating the pattern of fussing and crying over the first 12 weeks of a baby's life and how this varies across countries, but there are limitations to the research:
- There was a varied number of studies from the different countries. For example, there were seven studies from the UK, but only one study from Canada, Germany and Japan. Similarly the included studies varied in the age groups assessed. For example, the UK studies reported colic prevalence data at both 1-2 weeks and 5-6 weeks of age, whereas the Canadian study only looked at 3-4 weeks. Overall this variability in the quantity of data available from the different countries may weaken the strength of the findings.
- Also, relatively few countries were represented by this review, including no studies from developing countries for comparison. Therefore it cannot be said if the pattern of crying will be consistent across all countries globally.
- Mothers might interpret fussing/crying differently in different cultures so some might have reported fussing/crying more readily than others. Colic may have been more stringently defined in some studies than others. There may also be differences in how accurately the diaries were kept between studies. All of these things may lead to under- or over-reporting of colic which might affect accuracy of the findings.
- Studies also varied regarding the different factors taken into account – like household factors, number of children in the house, and method of feeding.
All of these factors could have an influence on colic, and as the studies weren't consistent in their quality and measurements, care should be taken before concluding too firmly from these results.
Colic remains a poorly understood condition and there is no proven method to treat or prevent it.
Caring for a baby with colic can be very difficult for parents, particularly first-time parents. Support groups, such as Cry-sis, offer help and advice if you need it. You can contact the Cry-sis helpline for advice on 0845 122 8669 (9am-10pm, seven days a week).