More children are getting diseases such as coeliac disease, type 1 diabetes and inflammatory bowel disease (IBD) than before, research shows. IBD is a term for conditions like ulcerative colitis and Crohn's disease. These are all autoimmune diseases, which are the most common chronic diseases in children.
"These diseases are characterized by the immune system attacking the body's own cells. They can be diseases of most organs such as the hormonal system, joints, intestines or nervous system," Ketil Størdal says. He is a professor at the Division of Paediatric and Adolescent Medicine at the University of Oslo, and a pediatrician and group leader at Oslo University Hospital.
Together with colleagues, he has recently conducted a large study that investigates how many children in Norway have one or more autoimmune diseases.
"We are trying to understand why more children are getting these diseases now than before," Størdal says.
The study is published in The Lancet Child & Adolescent Health.
Coeliac disease is the most common autoimmune disease in children
The researchers studied six autoimmune diseases: coeliac disease, type 1 diabetes, inflammatory bowel disease (IBD), autoimmune thyroiditis, juvenile arthritis, and autoimmune liver disease.
They used data from nearly one million children born in Norway between 2004 and 2019, and linked four different health registries.
Their findings showed that 2.6 percent of the children developed at least one autoimmune disease during childhood, before they turned 18.
"Coeliac disease is the disease most children get, followed by type 1 diabetes and autoimmune thyroiditis," Størdal says.
"Both diabetes and inflammatory diseases of the bowel, such as coeliac disease and IBD, have increased quite significantly in the past few decades. Yet we don't know why this has happened," the professor continues. He, himself, treats children with these diseases in his job as a pediatrician.
A child with diabetes can also get coeliac disease or juvenile arthritis
The study also found that it is quite common for children who get one of these diseases to also get one or more other autoimmune diseases.
"These diseases are so closely related that the same children often get more of them during their childhood," Størdal says. "We looked at those who had turned 18. Of those with an autoimmune disease, about 8 percent had at least one additional autoimmune disease."
He believes these findings are important in how we detect and treat these conditions. However, not all six diseases were related.
"IBD was not related to type 1 diabetes nor to autoimmune metabolic disease," the researcher points out.
The further north in the country, the more children get autoimmune diseases
The researchers also studied where in Norway the children who had autoimmune diseases lived. They found that there were large geographical differences.
"Children in Northern Norway have a higher risk of getting three of these diseases than children living in Central Norway. The risk is lowest for children living the furthest south," Størdal says.
"We are looking for an explanation as to why this is so."
Genetics, the environment in which the children grow up, and antibiotics
In the search of an explanation, Størdal and colleagues have studied what might contribute to an increased risk of getting an autoimmune disease. They will also conduct further research on this.
"We have data on genetics from the Norwegian Mother, Father and Child Study that we can use to map whether there are regional differences in genetic vulnerability. It is conceivable, although we do not think it explains everything," he explains.
Furthermore, the researchers are looking at the physical environment in which the children grow up, so-called environmental factors.
"We are studying diet. We are also looking at whether being close to nature or in more grey surroundings such as in cities and towns has something to do with it. In addition, we look at the use of antibiotics. We know that there is a lot of variation in this depending on where you live," says Størdal.
Norway is a long country area-wise, and the regional differences are a clue to finding biological explanations.
"Vitamin D is an example of something that can vary with residence. But we have already studied this and do not think that it explains the differences," the professor states.
A good thing that parents know that these diseases are related
Giving general advice to parents is difficult, according to Størdal.
"But it is clear that knowing that these diseases are to some extent related can be beneficial," he points out. "I also think that it is important to trust that the doctors who take care of your child's illness know that you may have multiple autoimmune diseases. Then they can adapt the treatment and follow-up accordingly."
Healthcare personnel should have a low threshold in considering other diseases
It is important that doctors and other healthcare personnel know about the connection. They should adapt diagnosis, follow-up and treatment.
"We must pay close attention. Tests should be carried out if there is reason to suspect, for example, that a child with juvenile arthritis has a disease in the intestine or liver. We should have a low threshold for checking," Størdal says.
In addition, it is important that the course of treatment is adapted to the patient.
"I think that it is important that patients who have multiple illnesses, receive a coherent follow-up. That we as providers of care coordinate and, as far as possible, provide a comprehensive treatment plan," the professor concludes.
