Background: We assessed the effect of parental and sibling age at diabetes diagnosis on index individuals’ risk of developing diabetes.

Methods: We carried out a register-based closed cohort analysis of 869,489 initially diabetes-free index individuals living in Denmark between 1995 and 2012. We assessed the effect of parents’ and full siblings’ age at diabetes diagnosis on the incidence of diabetes in the index individual, beyond the general effect of a positive family history. We calculated incidence rate ratios (IRR) in sex-stratified Poisson regression models.

Results: A total of 58,339 index individuals developed diabetes during 14 million person-years of follow-up. Diabetes risk was highest when parents had a diabetes diagnosis at a younger age. Men and women with a mother diagnosed with diabetes at age 50 had an IRR of 3.62 (95% CI: 2.86 to 4.57) and 5.03 (95% CI: 3.90 to 6.49) respectively compared to people of the same age and sex without a mother with diabetes. At a maternal diagnosis age of 70, the IRRs were 1.56 (95% CI: 1.46 to 1.57) and 1.67 (95% CI: 1.53 to 1.82) for men and women respectively.

Conclusions: Diabetes early detection strategies might consider that younger parental age at diabetes diagnosis may reflect more severe forms of diabetes, conferring a higher risk of developing the disease.


J. Silverman Retana: Other Relationship; Self; Danish Diabetes Academy, Steno Diabetes Center Aarhus. A. Hulman: None. J. NIelsen: None. B. Carstensen: Consultant; Self; Leo Pharma. Speaker's Bureau; Self; Novo Nordisk A/S. Stock/Shareholder; Self; Novo Nordisk Inc. R.K. Simmons: None. L. Bjerg: None. L. Johnston: None. D.R. Witte: None.


Danish Diabetes Academy (to J.O.S.R.); Novo Nordisk Foundation; Steno Diabetes Center Aarhus

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