Decreasing incidence of celiac disease in Southern Sweden.

Background: The incidence of celiac disease (CD) has increased rapidly in the late 20^th and early 21^st centuries, but there are recent reports of rates levelling off in countries with a high prevalence. The aim of this study was to investigate current trends in CD in southern Sweden.

Patients and methods: Children and adults diagnosed with CD by biopsy or serology in the region of Skåne, southern Sweden, from 2010-2022 were included. The home address was identified through registers to analyze temporal and geographical trends.

Results: A total of 3218 CD-patients were identified (52.2% children), the vast majority detected in clinical care but a few children by screening studies. The age-standardized incidence rate was 18.6 cases/10⁵. The incidence decreased at a rate of -0.75 cases/10⁵ (95% CI -1.14 to -0.35, p 0.002). The incidence among girls under 18 years almost halved throughout the study period, decreasing by -2.94 cases/10⁵ (95% CI -4.59 to -1.29, p 0.002), while there only were small changes among men. The most common age of onset was 3-9 years. CD incidence varied by place of living and was more common in small towns than urban or rural areas.

Conclusions: The incidence of CD in southern Sweden is decreasing, primarily in children and women who traditionally have had the highest risk of CD. CD was diagnosed most frequently in children 3-9 years old. There were regional variations in incidence. CD was most common in small towns, pointing to the importance of environmental factors in CD etiology.