Obesity is now becoming a worldwide serious problem. Obesity is associated with a spectrum of severe diseases, including diabetes, cardiovascular diseases, and cancers. Lipocalin 2 (LCN2), also known as neutrophil gelatinase associated lipocalin (NGAL), is a member of the lipocalin family. Due to its upregulated expression in infection, LCN2 is originally considered to be a key regulator of immune response. Subsequent investigations revealed that LCN2 is expressed in many tissues and is related to a variety of diseases, including obesity. LCN2 was reported to be increased in obesity individuals. Thus, the investigators decide to investigate the relationship between LCN2 and obesity.

Inclusion Criteria:

1) age ranged from 16-65 years old, 2) BMI over 37.5kg/m2, or BMI over 32.5kg/m2 with diabetes which meets the recommended cut off bariatric surgery of the Guidelines for surgical treatment of obesity accompanied with or without type 2 diabetes in China.

Exclusion Criteria:

1) secondary cause of obesity such as hypothalamic obesity, Cushing syndrome, and hypophysis dysfunction, etc.,2)pregnancy or location, 3) contraindications for laparoscopic surgery, such as gastrointestinal diseases of intra-abdominal infection, adhesion, etc., 4) severe heart, liver and kidney dysfunction, 5) organic and systemic diseases intolerant of surgery.

500 Patients from Shanghai Tenth People's Hospital were enrolled in this study.