A multifaceted ecological approach to explore links between environmental factors and the epidemiology of disorders of gut-brain interaction.

Background: Disorders of gut-brain interaction (DGBI) are characterized by debilitating symptoms not explained by structural or biochemical abnormalities. While functional conditions present with complex, likely heterogeneous pathophysiology, we aimed to investigate if proxy measures of sociocultural and environmental factors are associated with the prevalence of various DGBI in populations across the world.

Methods: We performed an ecological study utilizing peer-reviewed published datasets reporting for 26 countries prevalence rates of DGBI (Rome Foundation Global Epidemiology Study, RFGES), with six independent variables: Helicobacter pylori prevalence and household size as proxy measures for orofecal infections, gross domestic product per capita (GDP), and median age as a proxy measures for socioeconomic development, density of fast food outlets (FFO) per 100,000 population as proxy measure for processed food exposure, and suicide mortality rate per 100,000 people, and world happiness scores were used as a proxy for psychological stress. The data were retrieved from publicly accessible datasets (United Nations, CIA World Factbook, World Bank, World Happiness Report, commercial/financial reports of a global FFO chain). We used linear regression to assess variables in univariate and multivariate analysis and report standardized β coefficients with 95% confidence intervals (CI).

Key results: The regression model revealed that the overall prevalence of DGBI was inversely associated with both GDP per capita (β = -0.57, 95% CI: -0.92, -0.22, p = 0.002) and happiness scores (β = -0.433 95% CI: 0.821, -0.065, p = 0.023), while being positively associated with H. pylori prevalence (β = 0.40, 95% CI: 0.008, 0.81, p = 0.046). The prevalence of functional constipation (FC) was also inversely associated with GDP per capita (β = -0.50, 95% CI: -0.86, -0.13, p = 0.01) and happiness scores (β = -0.497, 95% CI: -0.863, -0.132, p = 0.01), while being positively associated with H. pylori prevalence (β = 0.53, 95% CI: 0.16, 0.91, p = 0.007). The Multivariate model analysis revealed that combining the factors of H. pylori prevalence, suicide rate, household size and happiness scores showed statistically significant association with FC (p = 0.039). Household size (β = -0.43, 95% CI: -0.82, 0.038, p = 0.033) and suicide rates (β = 0.55, 95% CI: 0.19, 0.90, p = 0.004) were statistically significantly associated with functional diarrhea. Irritable bowel syndrome (IBS) was associated with GDP per capita (β = -0.40, 95% CI: -0.79, -0.014, p = 0.043) and happiness scores (β = -0.390, 95% CI: -0.778, -0.003, p = 0.049).

Conclusions & inferences: Utilizing publicly available data, the prevalence of DGBI across diverse countries is linked to various socio-cultural and environmental factors. Collectively, the data suggests that the prevalence of DGBI is increased in less prosperous regions of the world.