Marked regional variations in the prevalence of inflammatory bowel disease in a limited geographical region are not associated with compounds in the drinking water

• Published in: Scandinavian Journal of Gastroenterology
• Main Authors: Segerman, Fredrik, Clarkson, Spencer, Sjöberg, Klas
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor & Francis 2019
• Subjects: Gastroenterology and Hepatology; Public Health; Global Health; Social Medicine and Epidemiology; Crohn’s disease; drinking water; epidemiology; prevalence; ulcerative colitis; Faroe Islands
• Online Access: https://lup.lub.lu.se/record/266b8326-e39d-434a-bde8-f39746a822fe; https://doi.org/10.1080/00365521.2019.1674374

Objective: The incidence of autoimmune diseases, especially inflammatory bowel disease (IBD), has increased substantially. Globally, there are vast differences varying from 0.2/105 in some Asian countries to over 80/105 in the Faroe Islands. Environmental factors have been suggested as triggers. The aim was to investigate the incidence and prevalence of IBD in the 33 municipalities in the county Scania in Southern Sweden, an area comprising 100 × 100 km with 1,274,069 inhabitants. Furthermore, we wanted to explore whether compounds in the drinking water could contribute to IBD; one report from Norway has suggested that iron in drinking water could contribute to UC. Methods: Patients with CD and UC were identified through the ICD-10 diagnosis database during the period 2000–2013. Water analyses for pH, alkaline, nitrate, sulphate, iron, magnesium and calcium were based on established methods and compared with the prevalence of IBD using Student’s t-test. Results: A total number of 8925 patients were identified. The incidence for CD and UC were high (mean 16.4/105, range 13.6–17.9 and 25.3/105, range 21.3–28.0, respectively). The prevalence varied substantially (p <.0001 for both; CD mean 0.30%, range 0.15–0.42 and UC mean 0.42%, range 0.32–0.56). No correlation between IBD and the chemical compounds in the drinking water could be shown. Conclusions: The incidence rates of both CD and UC were high. The prevalence varied from 200% to 300% between the municipalities, despite the limited geographical area indicating that local conditions are of importance. However, chemical compounds in the water were not associated with this variation.