[Determination of colonic transit time in healthy subjects in Mexico City. Prospective study]

Colonic transit time (CTT) is determined by multiple factors; currently, normal values for the Mexican population are not available. In order to get an estimate one must look at the values reported in the international literature, but cultural, ethnical, nutritional and economic differences may lead to different values.

To determine the normal values of colonic transit time in healthy people in Mexico City by the use of radiopaque markers.

Prospective, longitudinal and observational study, which included healthy patients ranging from 18 to 60 years old; excluding pregnant women. The whole group of patients was given before breakfast a gelatin capsule which had 20 radiopaque markers inside -the markers were each 2mm long, and were made by the researcher-. After that, they were taken a simple abdominal X-ray film every 24 hours until they totally eliminated the markers. Their eating and defecation habits were evaluated and also the total amount of liquid they consumed. Inferential statistics were used; data was validated with both parametric and non-parametric tests, considering a significance of p < 0.05.

A hundred patients were included in the sample in which 48% were female and 52% male, they were divided in three groups: group A (31%)from 18 to 25 years, group B (37%)from 26 to 40 and group C (32%)from 41 to 60 years; there were no important differences in their water consumption, which was in average of 1.87 lts. in 24 hours; also, there were no considerable differences regarding to their meat, vegetables and fruits' consumption, which was in average of 4.4 times a week; the whole group eliminated the markers according to X-rays which was in 54% after 72 hrs, 45% after 48 hrs and 1% after 24 hrs. We can observe an increase of the CTT related to age: in group C 94% eliminated the markers after 72 hrs and there was no significant difference (statistically) with regards to the other groups. A tendency of an increase of CTT with regards to age was observed: in group A, 80% eliminated the markers after 48 hrs, in group B 49% eliminated them after 48 hrs and 51% after 72 hrs and, in group C, 94% eliminated them after 72 hrs without any statistically significant differences among the study groups.

The CTT in healthy patients is in a 100% of the cases studied lower or equal to 72 hrs with a tendency to increase in relation to age.