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

Abstract

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.