Risk of gallstone formation after jejunoileal bypass increases more with a 1:3 than with a 3:1 jejunoileal ratio.

The rate of gallstone formation after jejunoileal bypass and the influence on the rate of the jejunoileal ratio of the functioning segment were assessed in 265 obese patients without stones in the gallbladder. After on the average 20.1 months of observation 231 patients were adequately examined for gallstones, which had developed in 2 (4%) out of 46 unoperated patients, in 9 (9%) out of 100 with a 3:1 jejunoileal ratio, and in 17 (20%) out of 85 with a 1:3 jejunoileal ratio of the functioning segment of the bypass. This result suggests that the association of ileal dysfunction and gallstone formation depends on the length of the functioning jejunum, which, according to previous studies, may reduce bile lithogenicity by stimulating bile salt synthesis.