Introduction: Historically, type 2 diabetes (T2DM) has been regarded as a progressive and degenerative disease and only minority of patients can have disease remission with conventional treatment. It was noticed that gastrointestinal surgery could induce complete remission of T2DM in most of morbidly obese patients. Compared to the West, the development of bariatric and metabolic surgery is slow in Hong Kong. It is unknown whether the knowledge and attitudes of medical doctors and patients towards surgical treatment for T2DM have impacts on the development in this field. The novel procedure sleeve gastrectomy (SG) had been shown to be effective in inducing T2DM remission in obese human. Duodenal jejunal bypass (DJB) and ileal transposition (IT) were reported to be effective for ameliorating T2DM in non-obese diabetic animal model. The anti-diabetic potency of DJB and IT is unknown in comparing to SG particularly in non-obese subjects. Currently, SG is the main procedure for morbidly obese patients with or without T2DM in the authors’ institution. Aims: The aims of the present thesis were to investigate the knowledge and attitudes of medical doctors and patients toward using surgery as a treatment for T2DM, to compare the anti-diabetic effect of SG, DJB and IT in non-obese T2DM animal model, and lastly, to review of outcomes of morbidly obese patients who underwent SG in authors’ institution. Methods: Survey was conducted using questionnaire for interview of both doctors and patients to investigate their knowledge and attitudes toward surgical treatment of T2DM. The anti-diabetic effects of novel surgical procedures SG, DJB and IT were compared using non-obese T2DM animal model (Goto Kakizaki rats). The outcomes were evaluation by measuring fasting glucose and glycosylated haemoglobin (HbA1c) levels. Other parameters including alteration in gut hormones and lipid profile were also analyzed. The outcomes of morbidly obese patients who underwent laparoscopic SG in last 5 years in the authors’ institution were retrospectively reviewed. Results: The knowledge of bariatric and metabolic surgery was inadequate both in medical doctors and patients. The attitude and pattern of referral from medical doctors depends on the amount of knowledge. Patients’ attitudes were positive and they accept surgery as a treatment option for T2DM as long as they were provided with adequate information. This implies that tremendous educational works are required both for medical doctors and patients for the development of bariatric and metabolic surgery in Hong Kong. All 3 procedures (SG, DJB and IT) significantly improved glucose homeostasis and the effect was more potent and durable in DJB and IT than SG. The improved glucose homeostasis in IT was resulted from increased GLP-1 and PYY secretion (hindgut theory). In DJB, GIP, GLP-1 and PYY were raised and the anti-diabetic effect could be explained both by the foregut and hindgut theories. SG reduced the diet triglyceride absorption. DJB reduced cholesterol absorption whereas IT reduced cholesterol but increase triglyceride absorption. The outcomes of SG for T2DM for morbidly obese patients were promising. More than 90% patients had T2DM ameliorated and 70% had complete remission. SG can effectively control the body weight of morbidly obese patients. Conclusion: Education, both to doctors and patients, was crucial to overcome the potential obstacles for the development of this newly specialty. The anti-diabetic effects of DJB and IT were more potent than SG in non-obese diabetic animal model. The lipid absorption varied in different surgical procedures. Application of these procedures in non-obese T2DM patients warrants individual consideration and further investigation. SG in the authors’ institution was effective to induce T2DM remission in morbidly obese patients. / published_or_final_version / Surgery / Doctoral / Doctor of Philosophy