A Swedish study on children showed that people with gluten intolerance were mainly girls born during the summer.
A Swedish study published in the journal Archives of Disease in Childhoodmade the surprising observation that children with celiac disease (gluten intolerance) are mostly girls born in southern Sweden during the hot season.
In this large study, the authors extracted data from two million children born in Sweden between 1991 and 2009, they followed the children up to the age of 15. Of these, 6,569 (nearly 0.4%) were diagnosed with celiac disease.
Different criteria influence the development of the disease
According to the study, several criteria are to be taken into account regarding the development of the disease. First of all, the season of birth of the child is to be considered. Thus, winter (December-February) would protect against the disease, while spring (March-May), summer (June-August) and autumn (September-November) would increase the risk by 10%. Specifically, children under two years of age are most at risk if born in the spring, while affected children after this age are usually born in the fall.
Then, the region where the child was born and grew up influences the development of the disease. People born in the South are more at risk than others. Finally, the sex of the child appears to be decisive, since the disease mainly affects girls. The researchers make several hypotheses.
Winter viruses and vitamin D
It is possible that children born in spring or summer are more affected because they are exposed to gluten first in autumn and winter, when seasonal viruses and viral infections are higher and alter the intestinal flora, making it more vulnerable at this time.
Researchers suggest another explanation: vitamin D deficiency during pregnancy. Mothers who gave birth in the spring indeed had lower vitamin D levels because they were less exposed to light and sun during pregnancy.
In Europe, one in a hundred people can develop celiac disease. In France, 0.7 to 2% of the population is affected according to the Health Insurance.