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Trial Lecture – time and place
See Trial Lecture.
Adjudication committee
- First opponent: Professor Henning Grønbæk, Aarhus University, Denmark
- Second opponent: Associate Professor Jorunn Sandvik, Norwegian University of Science and Technology, Trondheim
- Third member and chair of the evaluation committee: Professor Stine Marie Ulven, University of Oslo
Chair of the Defence
Professor II Tore Julsrud Berg, University of Oslo
Principal Supervisor
Jens Kristoffer Hertel, Vestfold Hospital Trust
Summary
Obesity is associated with increased risk of metabolic comorbidities including type 2 diabetes mellitus (T2DM), cardiovascular disease (CVD) and non-alcoholic fatty liver disease (NAFLD). Bariatric surgery may lead to substantial weight reduction and remission of metabolic comorbidities.
This thesis has three main objectives. First, to assess the prevalence of hepatic steatosis and fibrosis and their association with insulin sensitivity in treatment seeking patients with severe obesity and T2DM included in the randomized controlled Oseberg study (baseline data). Second, to compare the 1- year effects of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), on hepatic steatosis and fibrosis, as assessed with magnetic resonance imaging (MRI) and the enhanced liver fibrosis (ELF) test (Oseberg). Third, to explore possible associations between liver and heart disease in patients with severe obesity by using aggregated data from a previously published study; “Prevention of Coronary Heart Disease in Morbidly Obese Patients”
Three of four patients with obesity and T2DM had hepatic steatosis as measured with MRI, while 6% had severe fibrosis measured with the ELF test. We observed negative associations between measures of insulin sensitivity and liver fat fraction. Patients with shorter duration of T2DM had lower insulin sensitivity, higher degree of steatosis, but lower levels of liver fibrosis.
RYGB and SG were both highly effective in reducing hepatic steatosis, with an almost complete clearance of liver fat 1 year after surgery. However, the results for liver fibrosis were less conclusive. Although the degree of fibrosis was stable in most patients in the 2 groups over the 1-year follow-up period, it increased in 18% of the patients. In the study population of patients with severe obesity and at least one obesity-related comorbidity, liver fibrosis as measured with the ELF test did not independently predict myocardial injury and fibrosis; however, a possible link between liver fibrosis and myocardial injury and fibrosis may be explained by shared risk factors of CVD.
The results of this thesis provides more knowledge about the relationship between hepatic steatosis and fibrosis and insulin sensitivity in patients with severe obesity and T2DM, and further reveals that bariatric surgery is highly effective for inducing remission of NAFLD. The latter might contribute to balance advantages and disadvantages in the shared decision-making process regarding choice of obesity treatment and managing or controlling associated comorbid conditions.
Additional information
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