The effect of parental type 2 diabetes on the offspring with type 1 diabetes.

Objective: To study the association between a parental history of type 2 diabetes and the metabolic profile, as well as presence of the metabolic syndrome and diabetic complications in patients with type 1 diabetes. Research design and methods: Cross-sectional study design in 1,860 patients with type 1 diabetes from the Finnish Diabetic Nephropathy Study; 620 with and 1,240 age-matched without a parental history of type 2 diabetes. Information on parental history was received from the type 1 diabetic offspring by a standardized questionnaire. Results: Patients with type 1 diabetes and a positive parental history of type 2 diabetes had a higher prevalence of the metabolic syndrome (44 vs. 38%, P = 0.013), and a metabolic profile related to insulin resistance (higher BMI, larger waist circumference, higher triglycerides, HbA(1c), and insulin dose/kg), and also had a later onset of type 1 diabetes (17.2 +/- 9.2 vs. 16.1 +/- 8.9 years, P = 0.008), which was also confirmed in the publicly available Diabetes Control and Complications Trial dataset. In contrast, no association was observed with blood pressure, diabetic complications, or HLA genotype distribution. Parental history of type 2 diabetes was independently associated with age at onset of type 1 diabetes odds ratio 1.02 (1.01-1.03), BMI 1.07 (1.02-1.12), triglycerides 1.18 (1.03-1.35), and insulin dose/kg 1.63 (1.04-2.54). Conclusions: Parental history of type 2 diabetes is associated with a later onset of type 1 diabetes, the metabolic syndrome, and a metabolic profile related to insulin resistance.