A prospective study of unexplained visible abdominal bloating.

AIMS: To investigate the relationship between irritable bowel syndrome, constipation, obesity and abdominal muscle strength in patients whose primary complaint is visible abdominal bloating.
METHODS: Over two years 46 patients with the primary problem of nonorganic, visible abdominal bloating were seen. The details of their bloating as well as other symptoms were recorded. Body mass index and abdominal muscle strength were measured. Sixty-two sex matched patients with a primary complaint other than bloating served as controls. Twenty-four patients recorded changes in their weight and girth during episodes of bloating; 24 age and sex matched volunteers served as controls.
RESULTS: The patients with bloating did not differ from the other patients with regard to age, sex, body mass index, or the prevalence of constipation or the irritable bowel syndrome. They were more likely to have recently gained weight (p < 0.003) and to have weak abdominal muscles (p < 0.012). During episodes of bloating the increases in girth but not weight were greater than the daily fluctuations seen in the normal volunteers (p < 0.01).
CONCLUSION: Patients whose primary complaint is visible abdominal bloating have greater increases in girth but not weight during bloating episodes than the normal daily fluctuations seen in healthy controls. They have weak abdominal muscles and frequently have recently gained weight. They are not more likely to have constipation, irritable bowel syndrome or obesity than patients whose primary complaint is something other than bloating.