The purpose of the Swedish Obese Subjects (SOS) study is to examine the long-term effects of bariatric surgery on overall mortality and obesity-related co-morbidities.

The Swedish Obese Subjects (SOS) study is a prospective non-randomized controlled intervention study designed to examine the long-term effects of bariatric surgery compared to usual care in obese subjects.

Inclusion Criteria:

• Age 37-60 years and BMI ≥34 kg/m2 in men and ≥38 kg/m2 in women.

Exclusion Criteria:

• Exclusion criteria of both groups were: earlier operation for gastric or duodenal ulcer; earlier bariatric surgery
• Gastric ulcer during the past 6 months; ongoing malignancy
• Active malignancy during the past 5 years
• Myocardial infarction during the past 6 months
• Bulimic eating pattern; drug or alcohol (>0·75 L 40% liquor per week or corresponding amount of ethanol) abuse
• Psychiatric or cooperative problems contraindicating bariatric surgery
• Other contraindicating conditions (such as continuous glucocorticoid or anti-inflammatory treatment).