Design and characteristics of the national Danish injury cohort (NDIC)

The National Danish Injury Cohort (NDIC) is a nationwide, register-based cohort established to examine the incidence of total and specific injuries in Denmark and to provide insights into causes and consequences. Comprehensive individual-level information for this cohort is stored in the NDIC dataset, serving as a foundation for analyses of injury determinants and supporting the planning and evaluation of preventive measures aimed at reducing injury-related harm. Individuals registered in the Danish National Patient Register with an injury from 2010 onwards are included in the dataset. Additionally, it comprises persons in the Cause of Death Register whose deaths was attributed to accidents, violence, or suicide. The cohort is currently updated through 2022 and contains information on more than 7.2 million primary injury contacts and 26 thousand accident-related deaths. Analyses based on NDIC demonstrated substantial demographic and geographical disparities in the incidence rates of injuries. Overall, men exhibited higher rates of both injury incidents and injury‑related mortality compared with women. Marked differences were observed when stratifying by sex and age, as well as by region of residence. NDIC offers a solid data foundation facilitating research into injury trends, causes, and impacts, including disparities across social groups and geographic areas. It presents unique opportunities to explore novel research ideas to boost injury prevention, improve targeting of interventions, and reduce health inequalities. Strengthening this research area will help further reinforce NDIC's role in injury surveillance and evidence‑based policymaking.