Socioeconomic status as determinant for the development of comorbidities in adults with type 1 diabetes: A nationwide register study in Denmark from 1996–2018

Aims: To describe the incidence of type 1 diabetes (T1D), and incidence of comorbidities in addition to T1D, in adults over a 22-year period in Denmark and explore the associations between socioeconomic status (SES) and the development of comorbidities. Methods: We conducted a retrospective cohort study on nationwide registry data to describe incidences of T1D and comorbidities in adults (≥21 years) from 1996 to 2018. People were followed from T1D diagnosis until a first event of interest, death, or end of follow-up, whichever came first. Cox proportional hazards models were used to quantify the associations between SES and development of comorbidities. Results: We included 7877 adults with T1D. Overall, the incidence of T1D decreased (411 in 1996 to 191 in 2018) while it increased for comorbidities in addition to T1D (< 3 to 38 and 10 to 53). Low education and income, compared to higher counterparts, increased the risks of comorbidity by 55 % (HR 1.55, 95 % CI 1.36–1.77) and 82 % (HR 1.82, 95 % CI 1.60–2.06), respectively. Conclusions: Low SES increases the risk of comorbidities in adults with T1D. This indicates that SES is an important factor to consider when aiming to prevent or predict development of comorbidities in adults with T1D.