Do Familial Factors Impact Type 2 Diabetes Risk?

A cohort study assessed whether type 2 diabetes risk and the age of onset were influenced by the age of diagnosis of family members with the disease.

Data were examined on residents of Denmark between 1995 and 2012 aged 30 years or older who did not have a diabetes diagnosis at the start of the study and who had available data on their parents. People turning 30 years old during the study period with parental information available were added to the study cohort from that date. Factors were compared between patients who did and did not develop type 2 diabetes over the course of the study. The researchers used multivariable Poisson regression models adjusted for current age and educational attainment to calculate type 2 diabetes incidence rate ratios (IRRs).

Final analysis included 2,000,552 people who were followed for a median 14 years (24,034,059 person-years). Over the study period, 76,633 new type 2 diabetes cases were identified. Those with family members who were diagnosed with diabetes at an early age were more likely to develop type 2 diabetes compared with age- and sex-matched individuals without a parent or full sibling with the disease. Individuals who had a parental diagnosis of diabetes at age 50 years had an IRR of 3.9 compared with 1.4 among individuals with a parental diagnosis at age 80 years. Those who had a full sibling diagnosed with diabetes at age 30 years had an IRR of 3.3 compared with 2.0 for those with a sibling diagnosed at age 60 years.

The researchers summarized, “People with a family member diagnosed with diabetes at an earlier age are more likely to develop diabetes and also to develop it at an earlier age than those with a family member diagnosed in later life. This finding highlights the importance of expanding our understanding of the interplay between genetic diabetes determinants and the social, behavioral, and environmental diabetes determinants that track in families across generations.”