12915
RESEARCH DESIGN AND METHODS The SOS study involved 2 , 010 obese patients who underwent bariatric surgery ( 68 % vertical - banded gastroplasty , 19 % banding , and 13 % gastric bypass ) and 2 , 037 contemporaneously matched obese controls receiving usual care .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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