Published Online; July 17, 2015
Atopic dermatitis (AD) is the most common inflammatory disease of childhood, causing much distress and reducing the quality of life for sufferers and their parents. It affects around 1 in 5 children in the developed world and an increasing number of children in cities in developing countries. While genetic factors are important, the precise cause of AD is unknown and there are no proven strategies to avoid the condition. Research on early life events such as mode of delivery and the home environment, including rural versus urban living, childcare, infections, antibiotic use, pet ownership, and pollution have shown inconsistent associations with AD. Nutrition studies in mothers and babies have focused on maternal avoidance of certain foods during pregnancy and lactation and have examined breastfeeding, infant formula, introduction of solid foods, and nutrient intakes that might influence the immune system, such as vitamin D, fatty acids, antioxidants and folic acid. To date, the results are inconsistent. While there is a link between obesity and AD, there are no data in infants and young children that examine the role of body fatness specifically in AD incidence or severity.
O’Donovan et al recently published a study in The Journal of Allergy and Clinical Immunology (JACI) that describes an integrated analysis of many environmental components in relation to AD risk and severity in the first year of life. The research was conducted in a large, atopic-disease-specific birth cohort, in Cork, Ireland. In a sample of 1,537 infants, who were followed prospectively from 15 weeks gestation in the Scope Ireland Pregnancy cohort study through to 12 months in the Cork Baseline birth cohort study, 20.5% of infants were diagnosed with AD in the first year of life and 7.5% of infants had AD at both 6 and 12 months of age. The main risk factors for AD that persisted throughout the first year were maternal history of allergic disease (self-reported) and infant fat mass.
This study shows for the first time that infants in the top 20% for fat mass at birth have a 3-fold higher risk of AD than infants who have lower body fat. Variables that have been proposed to increase risk for atopic disease, including maternal socio-demographic factors, smoking, maternal obesity, mode of delivery, domestic pets, early infant feeding, age of complementary feeding, and vitamin D status during pregnancy and in new-borns did not affect infant risk of persistent AD.
This novel finding that infant body fatness increases the risk of AD in the first year, particularly among infants of parents with self-reported allergic disease, may aid in the early identification of those at high risk of AD.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.