Type 2 diabetes mellitus (T2DM) resolution in morbidly obese patients following bariatric surgery suggests the efficacy of metabolic surgery in non-morbidly obese patients (body mass index [BMI]<35 kg/m2). Many researches have shown available evidence about the efficacy and safety of metabolic surgery for resolution of T2DM in the non-morbidly obese. One of the most effective metabolic surgeries is laparoscopic Roux-en-Y gastric bypass (LRYGB). The investigators intend to run a 3 year prospective multicenter study to evaluate the remission efficacy of laparoscopic Roux-en-Y gastric bypass in Type 2 Diabetes mellitus with low BMI (BMI:25-35) in Asia area.

The study is designed including 9 bariatric centers across Asia region( China, Korea, Phillipine, Singapore and Taiwan). Totally 500 patients with confirmed diagnosis of T2DM and BMI between 25-35 kg/m2 will be enrolled from January 2011 to December 2013. Preoperative surgical parameters, blood, biochemistry data, gastrointestinal hormones, upper gastrointestinal studies, abdominal ultrasound, peri-operative & postoperative complications will all be recorded and analyzed. Patient inclusion criteria: 1.) T2DM diagnosed over 1 year; 2.) age ranged 30-60 years; 3.) BMI 25-35 kg/m2; 4.) Patient consent and will to receive long-term follow up and periodic check up. Exclusion criteria: 1.) T1DM; 2.) Substance abuse; 3.) Planned pregnancy within 2 year after surgery; 3.) Uncontrolled psychiatric disease; 4.) Lost follow up. Institutions inclusion criteria: Professional experience over 30 LRYGB performed. Trial termination criteria: Surgical mortality over 0.5% in the first year, and Diabetes remission rate failure over 20% in one year.

All data will be collected yearly in one center. The analysis of parameter, statistics and brief results will be informed to enrolled institutions periodically.

Inclusion Criteria:

1. T2DM diagnosed over 1 year;
2. Age ranged 30-60 years;
3. BMI 25-35 kg/m2;
4. Patient consent and will to receive long-term follow up and periodic check up.

Exclusion Criteria:

1. T1DM;
2. Substance abuse;
3. Planned pregnancy within 2 year after surgery;
4. Uncontrolled psychiatric disease;
5. Lost follow up.

Institutions inclusion criteria: Professional experience over 30 LRYGB performed.

Trial termination criteria: Surgical mortality over 0.5% in the first year, and Diabetes remission rate failure over 20% in one year.

500 type 2 diabetes mellitus patients with BMI between 25-35 kg/m2