The infant intestine and atopy

For some years it has been known that children raised in farming communities are less likely to develop atopy, in spite of increased exposure to animal allergens, and this is one of the tenets of the ‘hygiene hypothesis’: that exposure to micro-organisms early in life protects against allergic conditions. The PASTURE study was set up to look at this: it is a prospective birth cohort study involving children born in rural areas of five European countries, with comparisons made between those living on livestock farms and others. A spin-off from this correlated evidence of intestinal inflammation at age 2 months with later development of atopic dermatitis and/or asthma at age 6 years (Orivuori L et al. Clinical and Experimental Allergy 2015:45;928–39). Almost 760 infants had stool samples analysed for fecal calprotectin, and a subset of 120 for bacterial colonisation, using rRNA sequencing. Calprotectin is a sensitive marker for intestinal inflammation, often used to diagnose inflammatory bowel disease.

Those with the highest calprotectin levels (>90^th centile) were twice as likely to develop atopic dermatitis (adjusted OR 2.02; 95% CI 1.1–3.8) and asthma (aOR 2.41; 1.3–4.6). Those with E. coli in …