BACKGROUND/OBJECTIVE: Previous studies have found that ethnicity influences glycemic control. We hypothesized that differences between Nordic and non-Nordic patients are less pronounced for children with type 1 diabetes in high incidence countries in Northern Europe.

RESEARCH DESIGN AND METHODS: We investigated patients aged 0-15 yr in national pediatric registers in Denmark (D), Iceland (I), Norway (N), and Sweden (S) (2006-2009). Ethnic origin was defined by maternal country of birth as being Nordic or non-Nordic (other countries).

RESULTS: The cohort (n = 11,908, 53.0% boys, onset age 7.7 (3.9) yr, diabetes duration 6.1 (3.6) yr, [mean, (SD)]) comprised 921 (7.7%) non-Nordic patients. The frequencies of non-Nordic patients according to country of residence were: 5.7% (D), 2.7% (I), 5.5% (N), and 9.4% (S). Sex distribution and BMI z-score did not differ between Nordic and non-Nordic patients, but non-Nordic patients were 0.5 yr younger at onset than Nordic patients (p < 0.0006). Non-Nordic patients had a lower number of daily insulin bolus injections and higher daily insulin doses compared to their Nordic peers. Patients of non-Nordic origin had slightly higher HbA1c levels (0.6-2.9 mmol/mol, p < 0.001) and, with the exception of Norway, were less frequently treated with CSII (p = 0.002) after adjusting for confounders.

CONCLUSIONS: The reported differences in glycemic regulation between Nordic and non-Nordic type 1 diabetes children and adolescents in four Nordic countries are diminutive, but persist after accounting for treatment intensity.