Epidemiology and Risk Factors of Nonalcoholic Fatty Liver Disease among Patients with Inflammatory Bowel Disease

Background: Nonalcoholic fatty liver disease (NAFLD) has been increasingly identified in patients with inflammatory bowel disease (IBD). We aimed to determine risk factors of NAFLD in patients with IBD. Methods: We examined 3 groups of patients: IBD + NAFLD, IBD only, and NAFLD only. Data on demographics, body mass index, duration of IBD, type of medication use, laboratory data, and metabolic risk factors were collected. Results: A total of 168 patients between the ages 19 and 82 were evaluated, 56 patients in each group. Patients with IBD + NAFLD were significantly older than IBD only patients 45.0 (±14.1) versus 35.0 (±13), P = 0.007, and their mean body mass index was higher 30.4 (±10.2) versus 25.6 (±6.4); P = 0.002. IBD + NAFLD patients in comparison with IBD only patients had significantly longer duration of IBD (20 [±12.2] versus 10 [±7.7], P = 0.004), had an increased risk of diabetes (16% versus 2%, P = 0.01), and obesity (40% versus 20%, P = 0.02). There were no differences in the mean age or the mean body mass index (32.6 versus 30.4, P = 0.07) between patients with IBD + NAFLD and NAFLD only. More patients were obese in the NAFLD only group compared with the IBD + NAFLD group (59% versus 40%, P = 0.03), had hypertension (55% versus 33%, P = 0.02), hyperlipidemia (53% versus 17.5%, P = 0.0001), and diabetes (40% versus 16%, P = 0.0001). Conclusions: IBD patients with NAFLD had longer disease duration of IBD and developed NAFLD with fewer metabolic risk factors than patients with NAFLD only. These findings suggest that there may be other factors that contribute to the development of NAFLD in the IBD population.