Risk of diabetes among related and unrelated family members. (February 2020)

• Record Type: Journal Article
• Authors: Aasbjerg, Kristian; Nørgaard, Caroline Holm; Vestergaard, Nanna; Søgaard, Peter; Køber, Lars; Weeke, Peter; Gislason, Gunnar; Torp-Pedersen, Christian
• Is Part Of: Diabetes research and clinical practice. Volume 160(2020)
• Publication Date: 2020-02
• Subjects: Diabetes -- Heredity -- Epidemiology -- Genetic factors -- Environmental factors; Diabetes -- Periodicals; Diabetes Mellitus -- Periodicals; 616.462
• DOI: 10.1016/j.diabres.2019.107997
• Languages: English
• ISSNs: 0168-8227

Abstract

Abstract: Aims: The aim was to explore familial aggregation of diabetes in genetically related and unrelated individuals. Methods: We included citizens from Danish nationwide registries between 1995 and 2018 and calculated rate ratios (RR) of diabetes based on family relation using Poisson regression. Results: Of 7.3 million individuals eligible for inclusion, we identified 343, 237 (4.7%) with diabetes. The RR of diabetes was 2.02 (95% CI: 1.99–2.05; p < 0.0001) if any relative had diabetes, 1.79 (95% CI: 1.76–1.83) if a father had diabetes, and 2.06 (95% CI: 2.02–2.10) if a mother had diabetes. If both parents had diabetes, the RR was 3.40 (95% CI: 3.24–3.56). Among full siblings, the RR for developing diabetes was 2.77 (95% CI: 2.71–2.84) and 5.76 (95% CI: 5.00–6.63) for twins. For second-degree relatives, half siblings with a common mother had a RR of 2.35 (95% CI: 2.15–2.56), and with a common father 1.99 (95% CI: 1.81–2.17). Furthermore, the RR was 1.60 (95% CI: 1.56–1.64) if a wife had diabetes, and 1.41 (95% CI: 1.38–1.44) if a husband had diabetes. A subgroup analysis of individuals receiving insulin only treatment (N = 23, 054) demonstrated a similar risk pattern, although with slightly higher risk estimates. Conclusions/interpretation: Family aggregation of diabetes is associated with genetic disposition with maternal status being the predominant factor. Furthermore, we observed increased risk of diabetes in second-degree relatives, and between unrelated spouses, indicating that environmental factors influence diabetes risk substantially.