Diabetic retinopathy in Greenland and Denmark-Can differences in risk factors explain the lower prevalence in Greenland?

PURPOSE: The prevalence of diabetic retinopathy (DR) is low in Greenland. Factors underlying the low prevalence may potentially protect against the development of DR. Comparing Greenlandic and Danish populations, this register-based study explored differences in risk factors that may explain differences in DR prevalence.

METHODS: Data on DR and risk factors from Greenlandic (n = 1941) and Danish (n = 110343) patients with diabetes were collected from 2019 to 2023 through the Greenlandic electronic medical health records system Cosmic, the Danish Adult Diabetes Registry and the Danish Registry of Diabetic Retinopathy, respectively. Logistic regression models were used to estimate odds and odds ratio (OR) of selected risk factors by cohort (Greenlandic or Danish). Furthermore, the ethnic difference in age and diabetes duration at DR screening was modelled using natural splines.

RESULTS: The prevalence of DR was 10.2% in the Greenlandic cohort and 20.9% in the Danish cohort. In multivariate analysis, longer DM duration and higher HbA1c were the most important risk factors of prevalent DR in both cohorts. DM duration longer than 15 years was associated with higher OR in the Danish cohort than in the Greenlandic. In the Danish cohort, overweight and obesity were associated with higher OR of DR (OR = 1.20, 95% CI = 1.02; 1.41 and OR = 1.24, 95% CI = 1.04; 1.48, respectively) while lower ORs were observed for overweight (OR 0.57 95% CI = 0.28; 1.15) or obesity (OR 0.56, 95% CI = 0.30; 1.07) in the Greenlandic cohort. High systolic blood pressure was also associated with prevalent DR in the Danish cohort.

CONCLUSION: Long DM duration was a more prominent risk factor for prevalent DR in the Danish population than in the Greenlandic population. Future studies may address the potentially lower sensitivity to DM duration in the Greenlandic population.