Interaction of obesity and inflammatory bowel disease

Table 1 Clinical impact of obesity on inflammatory bowel disease

Medical therapy	Surgical therapy	Natural history and disease complications
Decreased clinical response to azathioprine[77]	Earlier time to 1st surgery[15]	Conflicting data:
Lower 6-thioguanine levels on treatment with azathioprine[78]	Higher rate of perioperative complications[112,114,119-121]	Higher prevalence of perianal disease[22]
Decrease likelihood of response to adalimumab[83]	Increased need for conversion from laparoscopic to open surgery[113,118]	Lower prevalence of penetrating disease[24]
Shorter time to loss of response to infliximab[92]		Increased hospitalization[22]
		Decreased IBD-related quality of life[23]
		Decreased healthcare utilization[14]

IBD: Inflammatory bowel disease.

Table 2 Immunologic effect of adipokines

Adipokine	Levels in obesity	Immunologic effects	Overall effect
Adiponectin	Decreased	Decreases TNF-α, IFNγ, IL-6	Anti-inflammatory
		Inhibits VCAM-1, ICAM-1 expression
		Increases IL-10, IL-1RA
		Promotes proliferation of Tregs
		Antagonizes NF-κB pathway
Leptin	Increased	Increased activation and proliferation of monocytes and macrophages	Pro-inflammatory
		Increased IL-6, TNF-α, IL-12
		Activates NK cells
		Activates NF-κB pathway
		Promotes Th1-differentiation
		Inhibits proliferation of
		Tregs
Resistin	Increased	Increases IL-6, IL-12, TNF-α	Pro-inflammatory

TNF-α: Tumor necrosis factor-α; NF-κB: Nuclear factor-κB; IFNγ: Interferon γ.