Effect of body mass index on nonalcoholic fatty liver disease in patients undergoing minimally invasive bariatric surgery.

The risk factors for nonalcoholic fatty liver disease in patients undergoing bariatric surgery are under study. We wanted to determine the correlation between nonalcoholic fatty liver disease and patient factors such as obesity and liver function tests. A retrospective analysis was performed on 177 nonalcoholic morbidly obese patients who underwent laparoscopic Roux-en-Y gastric bypass with liver biopsy, to identify risk factors for nonalcoholic fatty liver disease. The histologic grade of liver disease was compared with preoperative body mass index, age, and liver function tests. Simple steatosis and steatohepatitis were present in 90% and 42% of patients, respectively. Elevated transaminase levels were an independent risk for liver disease. Body mass index and liver disease were not correlated with univariate analysis. Regression analysis performed on age, body mass index, and liver disease demonstrated that the risk for liver disease increased with body mass index in the younger (<35 years old) age group and decreased with body mass index in the older (>45 years old) age group. There was a high incidence of steatosis and steatohepatitis in these nonalcoholic bariatric patients, and elevated transaminase level was indicative of disease. Body mass index was a positive risk factor for liver disease in younger patients but a negative risk factor in the older patients.