To evaluate the prevalence of orthostatic intolerance and joint hypermobility in schoolchildren with and without functional gastrointestinal disorders (FGIDs) and to assess autonomic nervous system dysfunction in children with FGIDs and joint hypermobility.

Schoolchildren (10-18 years) attending public schools from 3 Colombian cities (Cali, Palmira, and Bucaramanga) completed validated questionnaires for FGIDs and underwent testing for hypermobility and autonomic nervous system dysfunction. Heart rate and blood pressure were assessed in recumbency and upright position at regular intervals. The differences in characteristics between schoolchildren with and without FGIDs were compared with a t-test for continuous variables and with a Fisher exact test (2 × 2 contingency tables) for categorical variables.

In total, 155 children with FGIDs were matched with 151 healthy controls. Children with FGIDs had historically significant greater frequency of 10 of 12 symptoms of orthostatic intolerance, no significant difference in any symptoms of orthostatic intolerance during recumbency, significantly greater frequency in 6 of 12 symptoms of orthostatic intolerance during orthostasis, trend toward statistical significance for orthostatic intolerance (P = .0509), and no significant difference in prevalence of orthostatic hypotension (OH) and postural orthostatic tachycardia syndrome (POTS). There was no significant difference in prevalence of orthostatic intolerance, OH, and POTS between those with joint hypermobility and those without.

Children with FGIDs have a greater prevalence of symptoms of orthostatic intolerance but were not more likely to have OH and POTS as compared with children without FGIDs. Children with joint hypermobility did not have a greater prevalence of orthostatic intolerance, OH, and POTS.