Impact of symptoms by gender and age in Japanese subjects with irritable bowel syndrome with constipation (IBS-C): a large population-based internet survey.

Background: Irritable bowel syndrome with constipation (IBS-C) is a representative psychosomatic disorder. Several pathophysiological factors have been linked to IBS symptoms such as the modulation of gastrointestinal motility, visceral hypersensitivity, dysregulation of the gut-brain axis, genetic and environmental factors, sequelae of infection, and psychosocial disorders. It is likely that biopsychosocial aspects of IBS-C underlie its gender and age effects. However, the influence of each symptom of IBS-C by gender and age is not well understood. We hypothesized that the expression rate of each IBS-C symptom in females and in subjects aged 20-49 years was higher than that of subjects who were male and aged 50-79 years.

Methods: We conducted an internet survey of 30,000 adults from the general Japanese population. IBS-C subjects were asked to answer a questionnaire on the degree of anxiety, thoughts about bowel habits, and their dominant gastrointestinal symptoms together with exacerbation factors. The correlation between gender and age and IBS-C symptoms was analyzed.

Results: When analyzed by gender, the expression rate of abdominal discomfort, abdominal distention, and abdominal fullness was significantly higher in female than male IBS-C subjects (66.5% vs. 58.7%, p  < 0.05; 54.7% vs. 43.6%, p  < 0.01; 18.9% vs. 9.6%, p  < 0.01, respectively). When analyzed by age, the expression rate of abdominal distention and abdominal pain was significantly higher among IBS-C subjects aged 20-49 years than those aged 50-79 years (55.7% vs. 46.8%, p  < 0.05; 36.6% vs. 20.6%, p  < 0.001, respectively). In contrast, there was no gender or age differences with regard to the most common and bothersome symptom (abdominal bloating) among IBS-C subjects.

Conclusions: The expression rate of some IBS-C symptoms was higher among females and those aged 20-49 years than males and those aged 50-79 years, respectively. It is important to understand the impact of symptoms by gender and age to evaluate the pathology of IBS-C from a biopsychosocial perspective.

Trial registration: Although this survey was an anonymous internet survey, we obtained informed consent for the study as an online response. The disclosure of this study was approved by the Ethics Committee of Tohoku University Graduate School of Medicine (approval number: 2015-1-405).