In the mid-1980s, Sweden experienced a dramatic increase in the prevalence rates of celiac disease in children under two years old. Then, after 1996, the prevalence rate dropped. Led by Anna Myléus, researchers from the University of Umeå in Sweden began to examine the rise and fall of the statistics.

In the early ‘80s, Swedish nutritionists advised new parents to keep their babies gluten-free until they were six months old, contrary to prior advice to give infants small amounts of gluten-containing foods when they were four months old. While this advice was given in the hopes of preventing celiac disease, the opposite actually occurred; celiac disease rates quadrupled in children under the age of two.

From these statistics, researchers deduced that celiac and the infant diet are correlated.

While some might assume the increase was due to more diagnosis at a younger age, the researchers say no. They conducted a few follow-up studies, including a screening of more than 13,000 12-year-olds who were born during the epidemic. The study showed a significantly higher prevalence in the children born during the epidemic, meaning that the total prevalence was higher during that time period, not that the diagnosis rate was higher.

Interestingly, the change in infant diet advice is just one factor contributing to the epidemic. During the epidemic, baby food manufacturers also increased the flour used in their powdered porridge, therefore increasing the amount of gluten consumed by infants. Researchers have observed that babies who were weaned from breastfeeding at the same time gluten was introduced to their diets had a higher risk of developing celiac. The average length of time infants were breastfed increased from 1984 to 1996. Researchers speculate that this could perhaps explain the decrease in the number of children who later came to be diagnosed with celiac disease that were born near the end of the epidemic.

Potential causes outside of dietary factors include an unknown environmental factor, infections, and genetics. It’s estimated that 25% of the Swedish population carries the celiac genes, HLA-DQ2 and HLA-DQ8. Despite this high number of gene carriers, a relatively small number of people in comparison develop celiac, meaning an environmental trigger is most likely a contributing factor. Other reports have showed that children with celiac were more likely to have had several infections before they were six months old.

Based on the findings, the researchers have advised the Swedish population to once again to “carefully introduce their babies to a little gluten from the age of four months, preferably while it is also breastfeeding.”

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