Most people would not expect to read a sentence that says, “There was an epidemic of celiac disease in Sweden.” Nevertheless, there was an epidemic of celiac disease in Sweden between 1984 and 1996. Many more young children than expected developed celiac disease at that time. Around 3% of the children born during those years developed celiac disease before the age of two years.
While the number of people with CD is slowly rising, the rate among most European countries and North America seems to be around 1%, as it is now in Sweden.
Articles about epidemics tend to be about infectious diseases like influenza or measles. Celiac disease is not contagious. However, according to the Merriam-Webster MedlinePlus dictionary, a service of the U.S. National Library of Medicine (National Institutes of Health), epidemic means, “affecting or tending to affect an atypically large number of individuals within a population, community, or region at the same time.”
Accordingly, the increase in cases of CD in Sweden between 1984 and 1996 constituted an epidemic. It was recognized during the time period, and the Swedish Pediatric Association started a surveillance system to register patients diagnosed with celiac disease so that the epidemic could be followed and studied.
The study of the epidemic shows that there are things that can affect whether or not susceptible people develop CD. Something happened that increased the rate of CD dramatically in Sweden, and approximately 12 years later, something else led to a decrease in CD to normal levels. The epidemic provided an opportunity to discover some of the things that might trigger the disease in a way that could be modified.
Sweden is remarkable because most children get regular medical care, and there are consistent recommendations for the care of all children. More than 99% of infants go to well-baby clinics. Parents almost always follow the advice given by their pediatricians in regards to feeding.
In fact, there was a change in the recommended feeding practices for infants that occurred before the epidemic. Parents were told to introduce gluten-containing foods at 6 months, not 4 months, which was the previous recommendation.
Many mothers stopped breastfeeding when their babies were between 4 and 6 months old, so that gluten was added to the diet of many children who were no longer being breastfed.
At more or less the same time, the cereal industry in Sweden started adding more gluten to children’s cereals, which in Sweden can be porridges or milk and cereal drinks.
The group of children who were born during this period had many times the usual amount of celiac disease. When diagnosed, Swedish children were then and are now entered into the National Swedish Childhood Celiac Disease Register. Besides diagnosed cases, children were screened for CD as the increase in cases was noted.
A group of children born between 1992 and 1993 in southern Sweden was screened, and another one third of new cases were discovered.
Researchers looked at representatives of the group of children when they were in the sixth grade. Most were 12 years old in 2005, therefore born in 1993. There were a few children in the study who were born before or after 1993 but were in sixth grade. Approximately 7500 children were screened at five different medical centers. Parents of children in the sixth grade were all sent letters inviting them to participate.
All the children were screened for celiac disease using standard antibody and immunoglobulin tests. There were cut-off values for all the tests, with positive results leading to small intestinal biopsies. 192 children had blood test results showing possible celiac disease, and they 180 underwent small intestinal biopsy. 145 of the 180 had biopsies consistent with celiac disease.
Of the 7500 children, 67 already had been diagnosed with celiac disease, and this was also confirmed. Adding the new and the already-diagnosed cases yielded a ratio of 29/1000 cases, which is called prevalence. The prevalence in girls was 34/1000, and in boys, 24/1000. There were slightly different rates at the different locations, which showed more cases in the south of Sweden.
The number of cases, 29/1000, just about 3% among this group of 12 year olds is higher than any other rate reported in Europe or the United States. A previous study had yielded the results of 5.3 per 1000. The results from this study showed more than 5 times as many cases of CD. The researchers also commented on the regional differences, with more cases in the south, as well as the sex difference, with significantly more girls affected than boys.
As noted above, this group of children had been given gluten-containing foods at an older age – 6 months old as opposed to 4 months old. They were more likely to not be breastfed at that time, and were given cereal products with higher gluten levels.
By the middle of the 1990’s, as the numbers of children with celiac disease increased, feeding patterns for infants were suggested to return to what had been recommended in the past, introducing small amounts of gluten-containing food to breastfeeding infants between the ages of four and six months old. The number of symptomatic cases of CD has decreased. When populations are screened, less asymptomatic patients are found.
It is believed that the children born during the epidemic years have an increased lifetime risk of celiac disease, and that changing feeding patterns has already started to decrease the risk. In addition to helping to making sure children at risk are diagnosed and treated, the epidemic in Sweden gives evidence that infant feeding practice can actually change the numbers of people who develop celiac disease. All of this is under continued study and recommendations are being given for infants in Europe and the United States.
There is a chance that in at least some cases, these children would have developed celiac disease anyway, and the change in feeding practices brought it on earlier. Continued monitoring in Sweden will continue to give researchers more information.
This accidental epidemic may actually have given information to researchers that will help lead to ways to decrease celiac disease.