Childhood developmental environment affects adult intestinal inflammation levels: preliminary evidence from older adults in the United States

The Old Friends Hypothesis suggests limited exposure to symbionts during development leads to immune system dysregulation (e.g. allergies, autoimmunity) and inflammatory conditions (e.g. inflammatory bowel disease), with likely sex-specific variation based on exposure risk and sex hormones. Limited research documents how variation in childhood exposures affect older adult health. We tested relationships between current intestinal inflammation and childhood environment in 84 older adults (51-88 years) living in Colorado, USA. Faecal calprotectin (FC), a biomarker of intestinal inflammation, was measured from stool samples. Structured interviews assessed farm animal exposure during childhood and childhood environments (urban, suburban, rural) at different age periods (0 to 5, 5 to 10, 10 to 20 years). Farm animal exposure was not significantly associated with FC. Females who grew up in suburban environments, especially between the ages of 5 and 10, had higher FC than females from urban or rural environments (