AIM: To examine the association between early onset of type 2 diabetes mellitus (DM) and clinical and behavioural risk factors for later complications of diabetes.

METHODS: We conducted a cross-sectional study of 5115 persons with incident type 2 DM enrolled during 2010-2015 in the Danish Centre for Strategic Research in Type 2 Diabetes-cohort. We compared risk factors at time of diagnosis among those diagnosed at ≤45 years (early onset) with diagnosis age 46 to 55, 56 to 65 (average onset = reference), 66 to 75, and >75 years (late onset). Prevalence ratios (PRs) were computed by using Poisson regression.

RESULTS: Poor glucose control, ie, HbA1c ≥ 75 mmol/mol (≥9.0%) in the early-, average-, and late-onset groups was observed in 12%, 7%, and 1%, respectively (PR 1.70 [95% confidence intervals (CI) 1.27, 2.28] and PR 0.17 [95% CI 0.06, 0.45]). A similar age gradient was observed for severe obesity (body mass index > 40 kg/m2 : 19% vs. 8% vs. 2%; PR 2.41 [95% CI 1.83, 3.18] and 0.21 (95% CI 0.08, 0.57]), dyslipidemia (90% vs. 79% vs. 68%; PR 1.14 [95% CI 1.10, 1.19] and 0.86 [95% CI 0.79, 0.93]), and low-grade inflammation (C-reactive protein > 3.0 mg/L: 53% vs. 38% vs. 26%; PR 1.41 [95% CI 1.12, 1.78] and 0.68 [95% CI 0.42, 1.11]). Daily smoking was more frequent and meeting physical activity recommendations less likely in persons with early-onset type 2 DM.

CONCLUSIONS: We found a clear age gradient, with increasing prevalence of clinical and behavioural risk factors the younger the onset age of type 2 DM. Younger persons with early-onset type 2 DM need clinical awareness and support.