Increased risk of Type 2 diabetes in Elderly Twins

Abstract

Objective: Genetic susceptibility, low birth weight (LBW) and ageing are key etiological factors in the development of type 2 diabetes (T2D). LBW is common among twins. It is unknown whether twin status per se is associated with risk of T2D, and valid concordance rates of T2D in twins on a life-time perspective are lacking.

Research design and methods: Clinical study of a population-based cohort of same-sex elderly monozygotic (MZ) and dizygotic (DZ) twins (n=297) and singleton controls (C) (n=71) including measures of anthropometry and glucose tolerance. In addition, T2D incidence cases in twins (n=626) and singletons (n=553) were identified through the National Diabetes Register.

Results: Twins were more abdominal obese, insulin resistant and glucose intolerant as evidenced by a higher HbA1c (%) (mean (SD)) (MZ: 6.0 (1.0), DZ: 5.8 (0.7), C: 5.6 (0.3), p=0.004) and 120-min post OGTT plasma glucose levels (mmol/l) (MZ: 8.6 (4.6), DZ: 8.4 (3.9), C: 6.8 (2.4), p=0.003) compared to singletons. Importantly, twins had a higher prevalence of T2D (MZ: 17.5% (95% CI; 14.4-20.6), DZ: 15.7% (13.1-18.3), C: 5.6% (3.0-8.2), p=0.03) together with a 60% higher incidence rate of T2D compared to singletons. Cumulative concordance rates of T2D to the age of 84 years were similar among elderly MZ (0.76 (0.68-0.84)) and DZ (0.71 (0.63-0.78)) twins.

Conclusion: Twin status per se is associated with abdominal obesity, insulin resistance and increased prevalence of T2D in elderly twins. The data supports a quantitatively significant impact of the fetal environment as opposed to genetics on risk of T2D.