A meta-analysis including 7 studies (5 retrospective and 2 prospective–5 with IBD patients and 2 with CD patients only) comparing obese and non-obese patients, showed no differences in the risk of perianal disease (RR = 0.97, p = 0.81) and use of anti-TNF (RR= 0.89, p = 0.26) or immunomodulators (RR = 0.96, p = 0.43); moreover, obese patients have a lower risk of hospitalization (RR 0.84, p = 0.003) and surgery (RR 0.82, p = 0.003). Here, TNF is linked to inflammatory bowel disease.