Trends in the Observed Versus Expected Incidence of Eating Disorders Before, During, and After the COVID−19 Pandemic: A National Patient Registry Study

Abstract

Objective: This study investigated post-pandemic trends in the incidence of eating disorders (EDs) by comparing the annual observed incidence from January 1st, 2020, to December 31st, 2023, to the expected incidence based on pre-pandemic trends (2010–2019). Method: Primary and auxiliary ICD-10 diagnoses of new-onset ED cases were retrieved from the Norwegian Patient Registry which is a national register covering all specialized healthcare services in Norway. Incidence rates (IRs) per 100,000 were stratified by age, sex, and diagnosis: anorexia nervosa (AN; F50.0 + 50.1), bulimia nervosa (BN; F50.2 + 50.3), and other EDs (F50.4–50.9). To assess the impact of the COVID-19 pandemic, linear regression models were used to estimate the annual excess incidence of EDs between 2020 and 2023. Results: IRs for EDs peaked in 2021, with the overall rate for females being 45.5% higher than expected in 2021 before declining to an excess of 19.4% in 2023. The highest IRs were observed in females aged 15–19, followed by females aged 10–14 and 20–24 years. In 2021, the IR for females aged 15–19 was 64.7% higher than expected before declining sharply to 10.9% in 2023, whereas IRs for ages 10–14 and 20–24 remained approximately 30% higher than expected. Increases were particularly pronounced for AN, while the incidence of BN remained comparatively low, tracking with observed pre-pandemic declines. Conclusions: New-onset ED cases peaked in 2021, then declined in 2022 and 2023, despite remaining higher than expected based on 10 years of pre-pandemic data. Future research should continue to monitor trends in incidence, and community-based studies are necessary for replication.