Scand J Gastroenterol. 2022 Feb 4;1-7. doi: 10.1080/00365521.2022.2028005.Online ahead of print.

Simen Grøneng Johansen ¹, Eivind Ness-Jensen ^2 3 4

Author information

• ¹Faculty of Medicine and Health Sciences, NTNU, Norwegian University of Science and Technology, Trondheim, Norway.
• ²HUNT Research Centre, Department of Public Health and Nursing, NTNU, Norwegian University of Science and Technology, Levanger, Norway.
• ³Medical Department, Levanger Hospital, Nord-Trøndelag Hospital Trust, Levanger, Norway.
• ⁴Department of Molecular Medicine and Surgery, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden.

Abstract

Objective: To study the changes in prevalence of irritable bowel syndrome (IBS), the distribution between the sexes and age groups, and risk factors for the disease and its subtypes.

Material and methods: Every inhabitant of Nord-Trøndelag county, Norway, over 20 years of age was invited to participate in the Trøndelag Health Study (HUNT). In HUNT3 (2006-2008) and HUNT4 (2017-2019), IBS was assessed by a questionnaire. The standardized prevalence was calculated, and risk factors were assessed by multivariable logistic regression, reporting odds ratios (OR) and 95% confidence intervals (CI).

Results: In HUNT3 and HUNT4, 41,198 and 42,669 individuals were included, respectively. The prevalence of IBS was 7.5% in HUNT3 and 9.5% in HUNT4. Both surveys showed higher prevalence among women and among young adults. In HUNT4, the most prevalent subtype was mixed IBS (46.1%). Women had increased risk of IBS compared to men (OR 1.82, 95% CI 1.69-1.96). Age ≥40 years decreased the risk of IBS compared to age <40 years (OR 0.82, 95% CI 0.75-0.90). Being unmarried increased the risk for IBS compared to being married (OR 1.21, 95% CI 1.11-1.32). Both previous (OR 1.28, 95% CI 1.20-1.38) and current (OR 1.35, 95% CI 1.20-1.51) smokers had increased risk of IBS compared to never smokers.

Conclusions: IBS is a prevalent disease, and the prevalence has increased between 2006-2008 and 2017-2019. Risk of IBS was increased among women, young adults, smokers and unmarried participants.