Background and aim: Colon transit study with radio-opaque markers is helpful in the evaluation of chronic constipation. Normal reference values, based on radio-opaque markers, have not been reported from Chinese adults in Hong Kong.
Methods: Fifty-one healthy Chinese (27 men, age 42 +/- 12 years) were enrolled through a newspaper advertisement. They were requested to fill in detailed dietary records and a gastrointestinal symptom questionnaire. Each subject swallowed, under supervision, a total of three Sitzmarks capsules, one capsule at the same time on each of day 1, 2 and 3. Abdominal films were taken on days 4 and 7, also at the same time of the day. Total and segmental transit times were calculated using Metcalf's method.
Results: The upper limit of normal total colonic transit time (CTT) was 62 h, while right, left and rectosigmoid CTT were 16 h, 31 h and 32 h, respectively. Women of age 18-35 years had a longer rectosigmoid and total CTT compared with their male counterparts (mean total CTT: 39 h vs 18 h, P = 0.05). The CTT appeared to be unaffected by the usual dietary components.
Conclusion: A single normal reference value for CTT appeared to be applicable to Chinese adults in Hong Kong, irrespective of age, sex and dietary content. However, young Chinese women (age 18-35 years) appeared to have longer total and rectosigmoid CTT.