Caesarean delivery, preterm birth and risk of food allergy - new article in Journal of Allergy and Clinical Immunology
In a paper published today in the Journal of Allergy and Clinical Immunology, researchers from Örebro University and Karolinska Institutet observe a link between perinatal factors and the risk of food allergy in children. The researchers linked the Medical Birth Register and the Patient Register for all children born in Sweden 2001-12 (n=1.09 million children). This is the first large-scale study on early environmental factors and risk of food allergy.
-Food allergy is becoming more common in Sweden, and this is likely due to environmental risk factors, says Professor Jonas F Ludvigsson, senior author of the study and professor at the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet.
-However, little is known about environmental influence except that food allergy is more common in children with concurrent atopic disease and in those with a family history of allergy. Naturally, the child must also be exposed to the food in question. Meanwhile, perinatal risk factors, especially cesarean section, have been linked to a number of other immune-mediated conditions, but have not yet been examined in relation to food allergy except in small studies with inconsistent results.
During follow-up (up until 13 years of age), more than 26,000 children developed food allergy. Food allergy was more common in children born through cesarean section (+21%) and among children being large for gestational age, and having a low Apgar score (signalling asphyxia). Interestingly enough, food allergy was less common in children born <32 weeks of gestation (i.e. very preterm birth).
-Several earlier studies have shown that cesarean delivery seems to delay and alter the development of the offspring immune system. We believe this could explain the subsequently increased risk of food allergy, says professor Ludvigsson.
-What is particularly interesting is however the negative association with very preterm birth. Very preterm children are followed extensively by paediatricians and in these children a food allergy ought to be detected if present. Despite this, the children are at a lower risk. We hypothesise that the lower risk may be due to different food introduction in very preterm born, or possibly to other factors linked to preterm birth or intensive hospital care in the first weeks of life.
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Link to the publication:
Niki Mitselou, Jenny Hallberg, Olof Stephansson, Catarina Almqvist, Erik Melén and Jonas F Ludvigsson. Caesarean delivery, preterm birth and risk of food allergy – Nationwide Swedish cohort study of over 1 million children. Journal of Allergy and Clinical Immunology., 2018 (ePub Sept 10).