Impact of Social Isolation on Inflammatory Bowel Disease Risk and the Mitigating Effect of a Healthy Lifestyle.

Background: We aimed to evaluate the association of social isolation with incident inflammatory bowel disease (IBD) risk, as well as to investigate whether and to what degree a healthy lifestyle attenuates IBD risk linked to social isolation.

Methods: This UK Biobank cohort study included 429,843 participants without a prior diagnosis of IBD. Social isolation was assessed by three dimensions: the frequency of contact with family or friends, the frequency of engagement in leisure or social activities, and the number of family members. A healthy lifestyle considered included five factors: never smoking, a healthy diet, regular physical activity, an adequate body mass index, and sleep duration. We used multivariable Cox proportional hazards regression models to test the association. Stratified and joint analyses were used to further examine the role of a healthy lifestyle.

Results: During a median follow-up period of 13.3 years, 2762 IBD cases were identified, including 956 Crohn's disease (CD) and 1806 ulcerative colitis (UC) cases. Social isolation (most isolated vs least isolated) was associated with an increased risk of IBD (hazard ratio (HR) = 1.28, 95%CI 1.13-1.45), UC (HR = 1.23, 95%CI 1.05-1.43), and CD (HR = 1.34, 95%CI 1.08-1.66). Among the most isolated participants, adhering to a favorable lifestyle decreased the risk of IBD (HR = 0.53, 95%CI 0.36-0.78) and CD (HR = 0.31, 95%CI 0.14-0.69), but not UC.

Conclusions: Social isolation is associated with a higher risk of IBD and its subtypes. However, adhering to a healthy lifestyle substantially attenuates IBD and CD risks linked to social isolation.