Prevalence and correlates of irritable bowel symptoms in a New Zealand birth cohort

Aim: To determine the prevalence and correlates of bowel symptoms and the irritable bowel syndrome (IBS) in a birth cohort of young New Zealanders. Methods: Participants in the Dunedin Multidisciplinary Health and Development Study at age 26 completed a validated Bowel Disease Questionnaire expressing their experience of clearly defined symptoms over the previous 12 months. Results: 980 participants (499 male, 481 female, comprising 96% of the birth cohort) completed the questionnaire. Sixty four per cent had at least one of the measured symptoms; abdominal pain was reported in 46.5%, chronic constipation in 9.1%, and chronic diarrhoea in 17.1%. A diagnosis of IBS could be made by using two or more of Manning's diagnostic criteria in 18.8%, three or more criteria in 10.3%, and more than three in 3.3%. Symptoms were more than twice as frequent and severe in females than males. Conclusions: Bowel-related abdominal symptoms, including those required for a diagnosis of IBS, are very common in 26-year-old New Zealanders; the prevalence of these symptoms is very similar to that recorded previously in Europe and the USA.