Risk factors of non-alcoholic fatty liver disease in patients with inflammatory bowel disease

Abstract Background Metabolic risk factors are associated with non-alcoholic fatty liver disease (NAFLD), but they are less frequent in inflammatory bowel disease (IBD). Aim This study evaluates the frequency of NAFLD and its risk factors among IBD patients including anti-TNF-α therapy. Methods IBD patients who underwent abdominal imaging from January, 2009 to December, 2010 were analyzed in this nested, case-controlled study. IBD patients with NAFLD by imaging were compared with those who had no evidence of NAFLD (control). Results Among 928 IBD patients, 76 (8.2%) had evidence of NAFLD by imaging, and were compared to 141 patients without NAFLD evaluated (study: control ratio = ~ 1:2). NAFLD patients were older (46.0 ± 13.3 vs. 42.0 ± 14.1 years; p = 0.018) and had a later onset of IBD compared to the control group (37.2 ± 15.3 vs. 28.7 ± 23.8 years; p = 0.002). Metabolic syndrome was present in 29.0% of NAFLD patients, with a median Adult Treatment Panel risk factor of 2 [Interquartile range 1,3]. Patients not receiving anti-TNF-α therapy had a higher occurrence of NAFLD (p = 0.048). In multivariate analysis, hypertension (OR = 3.5), obesity (OR = 2.1), small bowel surgeries (OR = 3.7), and use of steroids at the time of imaging (OR = 3.7) were independent factors associated with NAFLD. Conclusion NAFLD occurred in 8.2% of the IBD population. NAFLD patients were older and had a later onset of IBD disease. IBD patients develop NAFLD with fewer metabolic risk factors than non-IBD NAFLD patients. It is also less common among patients who received anti-TNF-α therapy.