Impact of social isolation and loneliness on the risk of functional bowel disorders: findings from a large-scale cohort study.

BACKGROUND: Social isolation and loneliness are recognised as important risk factors for various health outcomes. However, their impact on functional bowel disorders (FBDs) remains underexplored. AIMS: To explore the associations of social isolation and loneliness with the risk of FBDs in a large prospective cohort. METHOD: We included 396 009 participants from UK Biobank who were free of cancer and FBDs at baseline. Social isolation and loneliness were assessed using validated self-reported questionnaires. Incident FBDs were ascertained during follow-up. Cox proportional hazards models were used to estimate hazard ratios and 95% CIs. Mediation, subgroup and sensitivity analyses were conducted. RESULTS: Over a mean follow-up of 15.2 years, 31 877 incident FBDs cases were recorded. Compared with the least isolated, the most isolated had a higher risk of FBDs (hazard ratio 1.15, 95% CI 1.11-1.20). Loneliness was also associated with higher risk (hazard ratio 1.28, 95% CI 1.21-1.35). The highest risk was observed among participants who were most isolated and lonely (hazard ratio 1.46, 95% CI 1.33-1.60). Depression, anxiety and low physical activity partially mediated the associations between social isolation/loneliness and FBDs. The association between social isolation and FBDs risk appeared stronger among male, overweight and unemployed individuals, whereas middle-aged adults were more susceptible to loneliness-related risk. CONCLUSIONS: Social isolation and loneliness were associated with a higher risk of FBDs, particularly when co-occurring. These findings underscore the potential relevance of social disconnection to FBDs and suggest that it may represent a target for future preventive strategies.