Johanna K Larsson [1], Spencer Clarkson [2], Klas Sjöberg [1].

Affiliates

[1] Department of Clinical Sciences, Department of Gastroenterology and Nutrition, Lund University, Skåne University Hospital, Malmö, Sweden; [2] Digitalisation IT and MT, Medicon Village, Lund

Abstract

Background
The incidence rates of immune driven gastrointestinal diseases have increased the last decades. In both IBD and MC regional variations have been detected in Sweden and Denmark, respectively. The aim of the present study was to determine the incidence of lymphocytic (LC) and collagenous colitis (CC) in Skåne, Sweden, during the period 2010-20.

Methods
The MC diagnosis was retrieved from the biopsy registries at the Departments of Pathology in the county. Established diagnostic criteria (increased lymphocyte count, inflammation in lamina propria and in CC a collagen band) were used for diagnosis. Differences over time was compared with Kruskall Wallis H test.

Results
The incidence for CC was stable with a total age standardized rate (ASR) per 100 000 of 6.34, (range 4.6-8.1). In LC the ASR was 7.90 (range 1.7-15.2) but increased markedly 2015-20 reaching 15.2 in 2019. The north-west parts of Skåne had the highest incidence. In Figure 3 those with a significant increase 2016-20 compared with 2010-15 are marked with *.

Conclusions
The incidence of LC differed substantially from that of CC in a way that indicates that it most probably must be two different entities. In LC, in view of the marked and rapid increase, causative agents (water contamination, infectious agents etc.) could be contemplated, and further studies are indicated.