Life-course hygiene exposures and disorders of gut-brain interaction: a multinational cross-sectional study

Despite growing interest in its role in immune-mediated diseases, the relevance of the hygiene hypothesis to disorders of gut-brain interaction (DGBI) remains unclear. We aimed to examine the associations between childhood and adulthood hygiene-related exposures and DGBI prevalence, and to assess whether these associations persist after adjustment for sociodemographic and national development indicators. This cross-sectional study included 54,127 adults from 26 countries. DGBI were defined using Rome IV criteria. Childhood (≤ 7 years) and adulthood hygiene-related exposures included farm residence and access to running water, electricity, and rural residence. Country-level development was assessed using the Human Development Index (HDI). After adjustment for sociodemographic factors and psychological distress, several individual exposures showed independent associations with DGBI. Childhood farm exposure was independently associated with higher odds of DGBI (OR=1.11, 95% CI 1.03-1.19), irritable bowel syndrome (OR=1.21, 95% CI 1.03-1.42), and functional dyspepsia (OR=1.22, 95% CI 1.08-1.38). In contrast, rural residence (OR=0.88, 95% CI 0.82-0.95) and absence of running water (OR=0.83, 95% CI 0.77-0.90) or electricity (OR=0.86, 95% CI 0.77-0.97) in adulthood were associated with lower odds of DGBI. These associations remained statistically significant after additional adjustment for HDI. Several individual hygiene-related environmental exposures were associated with DGBI, suggesting that environmental conditions may be associated with global variation in DGBI burden.