Variable

Gallstone

No gallstone

P-value

No. (%)

19 (19%)

81 (81%)

-

Mean age in years

38.7

37.2

0.635

Gender Female male

15 4

68 13

0.979

Mean preoperative BMI in kg/m²

51.9

51.4

0.996

Mean percent of EWL in the first year

62.6

55.4

0.042^*

Type of operation RYGPB VBG SG

10 4

5

32 20 29

0.393