Internet survey on the actual situation of constipation in the Japanese population under 70 years old: focus on functional constipation and constipation-predominant irritable bowel syndrome.

Background In Japan, the prevalence of constipation-predominant irritable bowel syndrome (IBS-C) and functional constipation (FC) diagnosed by the Rome III criteria is unclear, as are the demographic profile, quality of life (QOL), and habits of persons with IBS-C or FC.